ProE/CREO Bluetooth headset structure design specification

Table of contents

Chapter 1 Summary (1)

Chapter 2 Company Product Introduction (2)

Chapter III Structural Design Standards -Materials Articles (4)

Chapter 4 Structural Design Standards -Design Articles (12)

The design specifications of the upper and lower shells first (12)

Section 2 The design of the keys (73)


The design of the third section (L iGHT P IPE) (112)

Section 4 MIC Sound and RCV Sound Design (114)

Section 5 antenna (125)

Section 6 Battery (126)

Section 7 Model Cut (126)

Section 8 decorative film (131)

Section 9 screw nut (135)

Section 10 shielding cover (138)

Chapter 5 Surface Treatment (138)

Section 1 Surface treatment process introduction (138)

Section 2 (P Ainting) (138)

Section 3 Electroplating, NCVM (VM) (151)


Section 4 printing (153)

Section 5 Lottery (154)

Chapter 6 Ear Hanging Design (154)


1 Definition classification (155)

Chapter 7 Testing Design points related to structure (ESD, salt fog, etc.) (157)

Chapter 1 Summary

First, the purpose

In order to standardize the structure design, there are chapters to follow;


Gradually accumulate experience and lessons encountered in the design and production, and improve the overall structure design level.

2. Scope

This specification is only applicable to the structural design of the Goor Bluetooth headset; it is only for the reference of designers in the CEAP-MD department. Third, confidentiality level

confidential. (For prohibiting leakage, the offenders must be investigated)

Chapter 2 Company Product Introduction

1. Bluetooth technology

Bluetooth headset refers to wireless headphones that use Bluetooth for data transmission, which can be used with other devices with Bluetooth voice functions, such as Bluetooth headsets and computers. Its biggest advantage is “safe and healthy”, because its radiation is small, compared with products such as Bluetooth headsets, the damage to the human body can be ignored.

Under normal circumstances, the frequency of Bluetooth use is: 2402MHz ~ 2483MHz, and the communication distance requirements are within 100m.

My company’s Bluetooth products are mainly Bluetooth headsets. There are the following points to pay attention to:

1. Performance parameters:

See Table 1 for details:

2. Common chips:

There are two cases of commonly used chips (see related specifications of related SPECs and company standard libraries):

1.1 Single -channel headset available solution: CSR: BC03mm/BC03AF/BC04A11 (low -end headset)/BC05mm (high -end ear

(Plash)/BC06AR; Broadcom: BCM2044

1.2 Available solution for stereo earphones: CSR:/BC03mm/BC03AF/BC05mm (high -end headset); Broadcom: BCM2047

3. Common Bluetooth antenna:

Pouring antenna, printed antenna, and Chip antenna (see “Bluetooth Headphones Structure Design Specifications -Antenna Design”)

Table one two, company product introduction

At present, the company’s Bluetooth products mainly include the following 4 categories:

1. GBH series Bluetooth headset

Wear a single Bluetooth headset with a small size and light weight, which is easy to carry. The structure is mainly composed of several parts such as the upper and lower cases, buttons (including multi -function buttons, side keys), light guide hood, MIC rubber sleeve, RCV rubber sleeve, ear hanging (or collar clip), PCB board and battery. The picture below is the appearance map of the GBH100 Bluetooth headset.



2. GCK Bluetooth headset

Due to the design concept of the free division of headphones and speakers, the vehicle Bluetooth headset includes the structure of the headset and

The car kit part, so in addition to the function of GBH headphones, it can also be used in the car to use it. It has the function of free and easy. The picture on the right is the appearance map of the GCK800 car Bluetooth headset.

3. GSH Bluetooth headset

The stereo Bluetooth headset uses dual -channel technology, with two earbuds, and the sound effect is good. The picture below is the appearance of the GSH300 headset.



4. Bluetooth Dongle

4.1 GBDU A data transmission and receiving device with a Bluetooth function. It is installed on the device without Bluetooth function through the USB interface.

Such as a computer, the wireless data transmission is transmitted between the device with Bluetooth Bluetooth headsets and Bluetooth headsets with Bluetooth function. The picture on the right is the appearance of the GBDU60.

4.2 GBDA

Bluetooth audio adapter, installed on devices that do not have A2DP audio output functions, so that it can be transmitted to the stereo effect

Bluetooth audio signal. The figure below is the appearance map of the GBDA60.

GBDA60 Chapter III Structural Design Standards -Materials Articles

1. Selection of parts material

Our company’s current commonly used materials can be divided into: plastic materials, plastic soft glue, silicone, hardware, instant noodles, double -sided glue, sticky glue, waterproof network (dustpage net), etc. The following introduces the materials such as plastic materials, plastic soft gel materials.

1.1 Plastic material


The plastic materials commonly used by Goer are PC, ABS, PC+ABS, PMMA, PP, PP, TPE, TPR, PA6,

PA66+GF10%(or GF15%), SIR, environmentally friendly PVC, etc.

1.1.1 PC (polycarbonate)

It belongs to engineering plastics, has outstanding impact toughness, high heat resistance, cold resistance, bending strength is equivalent to nylon, and has a high extension and elastic modulus. Well, the formation parts can reach a very precise tolerance. The abrasion resistance is comparable to that of nylon and has a certain ability to resist corrosion. However, the injection molding fluidity is poor.

Some graphs of PC materials (such as GE’s PC 141R) have good light transmission and good light transmittance, but they are second only to PMMA. Some parts that require low requirements such as guide light can choose this material.


The shrinkage rate of the PC is 0.5-0.8%, the often takes 0.5%, the density is 1.2 g/cm3, the mold temperature at the time of injection molding is 70-90 ° C, the temperature of the injection molding machine is 260-300 ° C, and the edge value is 0.06mm. Therefore, the depth of the mold exhaust tank is generally 0.03-0.04mm. The drying time before injection is required for a long time, about 3-4h, and the drying temperature is: 80-120 ° C. For all plastic raw materials, the drying time should not be too long, and the temperature should not be too high. Otherwise, the raw materials will be easy to end faster, and it will also affect transparency.

The upper and lower shells of the headset and the parts with buckle are often used as raw materials. The light guide column is also commonly used as raw materials. Material manufacturers are: American GE: PC1414, PC141R, 940A-116, 943A-116, 940A-701 , 943A-701, 923C, 923BK, 141R-111945, 920NC, 920BK, 500R, 3412R, 3413R, 3414R

Taiwan: 110

Japan’s light: IR2200 Mitsubishi: S2000VR, S3000VR Emperor: 1250Y, 1225Y, 2250G, 2250Y, G-3420R, G-3430R, G-3410R Tao: 2010, 201-15, 301V-15

Bayer in Germany: 2805, 2807, 2605, 2405, 2858, 2865, 2857, 6555, 6485.


1.1.2 ABS acryline sunny-butadiene-苯 1 1 1

It belongs to general engineering plastics, with good comprehensive performance, high impact toughness and good mechanical properties, excellent heat -resistant oil resistance and chemical stability, stable size, and plating on the surface (preferably electroplating ABS, such as: Taiwan Chimei ABS ABS 727), easy to injection shaped, cheaper than PC.

The shrinkage rate of ABS is 0.3-0.8%, often takes 0.5%, the density is 1.05g/cm3, the mold temperature at the time of injection molding is 50-80 ° C, the temperature of the injection molding machine is 200-240 ° C, the overflow edge value is 0.04mm, and the edge value is 0.04mm. Therefore, the depth of the mold exhaust tank cannot be greater than 0.04mm, generally 0.03mm. The drying time is required before injection, about 2-3h, and the drying temperature is: 70-80 ° C.

The keys of the headset are often used as ABS as raw materials. Material manufacturers are mainly DuPont and Taiwan Chimei Company.

1.1.3 PC/ABS

PC/ABS resin is a plastic alloy (AlLoy), which has the excellent plastic alloy resin of ABS processability, impact resistance, processability advantages, and PC engineering plastics. This resin is particularly hot stability, size stability, and excellent weather resistance.

And it is second only to ABS, post -processability, and the price world is between ABS and PC.

The shrinkage rate of general-level PC/ABS is 0.5-0.7%, and often takes 0.5%. The density is 1.12g/cm3. The melting temperature of the PC/ABS alloy is about 10 ° C. ° C, the mold exhaust tank is the same as ABS. Before the injection, the drying time is required, about 3-4h, and the drying temperature is: 105-110 ° C.

The upper and lower shells of the headphones that are not too high and PC/ABS with buckle parts are often used as raw materials. Material manufacturers are: US GE: C2950-111, C2950HF-111, C2950-701, C2800-111, C2800 -701, C6200-111, C6200-701, C6600-111, C6600-701, C1200-100, C1200HF-100, C1200-701, C1110-111, C5400-701;

South Korea Samsung: NH-1000T;

Bayer in Germany: T45, T65, T85, FR2000, FR2010, FR3000, FR110, FR3005.

1.1.4 PMMA polymethyl acrylate (also known as acrylic or organic glass)

It belongs to engineering plastics and has excellent light transmission. After 240 hours of light, it can still be passed through 92%of the sunlight. It still has 89%for ten years outdoors and 78.5%of ultraviolet rays. High mechanical strength, a certain amount of cold resistance, corrosion resistance, good insulation performance, stable size, easy to injection molding, the price is cheaper than PC, but the quality is more crispy, easy to melt in organic solvents, the surface hardness is not enough, easy to rub hair, use it, use it, use UVs are usually hardened on the surface.

The shrinkage rate of PMMA is 0.2-0.8%, often taking 0.5%, density of 1.19g/cm3, the temperature of the time mold temperature of the injection molding is 65-80 ° C, the temperature of the injection molding machine is 225-245 ° C, the overflow edge value is 0.03mm, the mold is mold, and the mold is mold. The depth of the exhaust tank is generally 0.02, the drying time before injection is about 2-4h, and the drying temperature is 70-80 ° C.

Material manufacturers are mainly:

Japan Mitsubishi: MF001, VH001 Japan: GF1000, GF1000S, GH1000S Japan Asaka: 560F, 80N Sumitomo: LG2

Taiwan Chimei: CM-211, CM-205, CM-207 Japan Asaka: 560F, 80N Sumitomo: LG2

1.1.5 POM polydehyde (also known as Sai Gang)

The injection performance is good, the strength and stiffness are high, and the abrasion resistance is good. It is suitable for making abrasive and wear -resistant parts, and transmission parts such as gears.

Percent: 1.41-1.43 g/cm3, mold contracting rate: 1.2-3.0%, often taking 2% injection molding time model temperature: 170-200 ° C, the temperature of the injection molding machine tube is: 190-210 ° C, dry conditions: 80 -90 ° C, 3-5 hours. Easy to decompose, the decomposition temperature is 240 degrees. There are irritating and corrosive gases during decomposition. Therefore, mold steel should be made with corrosive materials. The edge value is 0.03mm, and the depth of the mold exhaust groove cannot exceed 0.02mm, and the width is about 3mm.

The main manufacturers are:

Taili Steel: FM090

Japan: Dongli S761

1.1.6 PP polypropylene

The stretch strength and rigidity of PP are better, but the impact intensity is poor, especially at low temperature tolerance. Surface hardness: The surface hardness of PP is low in five types of common plastics, which is better than PE. When the crystals are high, the hardness also increases accordingly, but it is not as good as PVC, PS, ABS, etc. The heat resistance of PP is the best. PP plastic products can work for a long time at 100 ° C. When the powerless effect, PP products will not be deformed when they are heated to 150 ° C.

PP is the smallest density in all synthetic resins, only 0.90 ~ 0.91g/cm3, formed shrinkage rate: 1.0-2.5%, the temperature of the mold at the time of injection molding is: 30-50 ° C, the temperature of the injection molding tube is: 200- 300 ° C. The processing performance is good, and the machining has good liquidity, especially when the melter flow rate is higher, the melt viscosity is smaller, which is suitable for injection molding of large thin -walled products. When the mold temperature is less than 50 degrees, the plastic parts are not smooth, and it is easy to produce poor melting, leaving marks, and prone to warp and deformation above 90 degrees. The edge value is 0.03mm, and the depth of the mold exhaust tank is generally 0.02mm

1.1.7 PA (nylon, polyamide)

1. PA is a polymer compound of many repetitive amide groups on a type of main chain


2. Process characteristics:

(1) Water absorption:

Part of the water absorption

(2) Crystallic: Except for transparent nylon, most of the rest are crystalline hypercuters

(3) Liquidity;

Some PA’s melting point temperature

(4) Thermal stability: PA thermal stability is much worse than PP, PE, etc.

(5) contraction rate: PA contraction rate is large

Some PA varieties for molding contraction rate

2. For molding equipment: Equipment to produce screw heads should be equipped with a stop loop; the head should generally be a self -locking nozzle

3. Products and mold design:


(1) Product thickness: Products are generally not less than 0.8mm, 1-3.2mm is the range commonly used in nylon products

(2) Flower and pouring ports: In addition to a small number of varieties such as PA66, most of the hot runway molds should be available; there should be sufficient cold ingredients; the slope of the mainstream road is 4º-6º; , The cross-section height of the trapezoidal runway is 2/3 of the bottom, 3/4 of the bottom bottom of the bottom; the diameter of the pouring mouth is generally 2/3-3/4 of the product wall thickness, but the minimum must not be less than 0.8mmmmmm

(3) exhaust: The edge value of the PA resin is about 0.03, so the exhaust holes should be controlled below 0.025mm

(4) Mold temperature: The general product wall thickness should be he heating and temperature control. For products with a certain soft and less than 5mm of the wall thickness, generally use cooling water temperature control

The requirements of the heating temperature control device are the highest mold temperature of several PAs below 120 ° C.

4. Raw material preparation:

PA drying craft reference form

5. For molding process:

(1) The temperature of the tube: select the material temperature according to the raw material

(2) Inject pressure: The pressure can be selected at 60-120MPa according to the product conditions.

(3) Injection speed: For nylon, the injection speed is slightly faster, which can prevent problems such as ripples caused by the cooling rate of too fast cooling rate.

6. mold temperature:

The relationship between wall thickness and mold temperature

7. Precautions in molding:

(1) Use of regeneration materials:

(I) The number of regeneration should not be too much, it is best not to exceed three times

(Ii) The amount of usage should be controlled below 25%of the new material;

(2) The use of molding agents: use a small amount of de -molding agent to improve or eliminate the defects such as bubbles sometimes


(3) Safety Instructions: PA resin boot is to turn on the temperature of the nozzle, and then turn on the power supply of the tube.

(4) The post -treatment of the product:

(I) Heat treatment: The product can be treated with infrared rays in the case of anaerobic, but the commonly used method is to put in a certain temperature in the liquid of (mineral oil; glycerin; liquid paraffin, etc.); The thickness of the product at 10-20 ° C at 10-20 ° C is different from the thickness of the product. The thickness is below 3mm for 10-15 minutes, and the thickness of 3-6mm is 15-30 minutes.


(Ii) Wet damp treatment: Wet damp treatment is mainly carried out by products with large environmental humidity. There are two methods: one is the wet water regulation method; the other is the water solution of potassium acetate aquatic solution (potassium acetate and water The ratio of 1.25: 1., boiling point 121 ° C) The former is convenient to operate, as long as the product is placed in an environment with a relative humidity of 65%to make it required to reach the required balanced humidity, but because this method takes a long time, it takes a long time, and it takes a long time, and it takes a long time because of this method. Therefore, the latter is generally used; the temperature of the wet treatment is 80-100 ° C. The processing time mainly depends on the thickness of the product. When the wall thickness is 1.5mm, it is about 2 hours, 3mm is hour, and the 6mm is 16-18 hours.

1.2 Thermoplastic soft glue

1.2.1 TPE thermoplastic elastic body

TPE is a thermoplastic elastic body. It is a material with the excellent performance of thermoplastic plastic and traditional vulcanized rubber. It has good elasticity, shock -resistant non -slip, soft feel, good thermal resistance (100 ° C), often with hard glue materials such as PC, PP, etc. Two -color injection molding together, use for ear hanging.

The TPE density is 0.89 ~ 0.98 g/cm3, the shrinkage rate is 1.2 to 2.0%, the mold temperature of the mold during injection molding is 35-65 ° C, the temperature of the injection molding machine is 160-200 ° C. The components can be baked 50 ° C for about 2 to 4 hours, and the recycling material can be added at any proportion. The edge value MM, the depth of the mold exhaust tank is general

The main manufacturers are:

1.2.2 TPU


TPU (thermoplastic polyurethane elastic body) has the characteristics of excellent tension, high tension, strong toughness and aging resistance, and is a mature environmental protection material. At present, TPUs have been widely used in aspects of medical care and sports. High strength, good toughness, wear resistance, cold resistance (-40 ~ -70 ° C). The long -term use temperature is 80-90 ° C, and it can reach about 120 ° C in a short time. The product can get a better shape, stable size, and small deformation. The disadvantage is that the wet surface friction coefficient is low and easy to slip. Long -term sunlight will change color and dark, and physical properties gradually decrease. Enzyme bacteria also cause degradation of polyurethane. Therefore, agglutants, ultraviolet absorbers, and anti -enzymes used in polyurethane rubber used in industrial production are added. In addition, TPU costs are also high. (TPU/8792 A/Germany Bayer/48500 yuan/ton, TPU/NX-85A/Taiwan Gaoding/35500 yuan/ton)

The USB cover and earbuds of the headset are commonly used. At present, the market is mainly in Germany Bayer, Nuo Yu, and the Santoprene series of AES in the United States.

1.2.3 TPR

T PR integrates the performance and good processability of rubber, and compared with the traditional thermosetable rubber, TPR also has the advantages of recyclable and reuse of processing products. Medical equipment, packaging, household appliances and consumer goods areas and other fields

TPR shrinkage rate is 0.5 to 1.2%(SBS) 1.2 to 2.0%(SEBS), the barrel is 160 to 210 ° C, and the nozzle is 180-230 ° C. The range of the mold temperature should be designed between 30 and 40 ° C. At high temperature, the moisture content of TPR is below 5 %, or even 2 % to 3 %. Therefore, the vacuum drying box is commonly used at 75 ° C to 90 ° C for 2 hours.

The USB cover and earbuds of the headset are commonly used. At present, there is a Santoprene series in the market, with many domestic TPR manufacturers.

1.2.4 PVC

PVC materials have the characteristics of light quality, insulation, insulation, moisture -proof, flame retardant, and simple construction. There are many specifications, colors, and patterns, and are very decorative, and are widely used in production and life. The prominent advantages of general PVC resin plastic products are refractory, abrasion resistance, anti -chemical corrosion, and good hydrophilic leakage. In addition, comprehensive mechanical performance, product transparency, electrical insulation, heat insulation, sound insulation, and shock resistance are also the most superior universal material ratio. The defect is poor in thermal stability and impact resistance. Whether it is hard or soft PVC use, it is easy to produce brittleness. PVC is easily released during the molding process. The contraction rate of PVC is quite low, generally 0.2 ~ 0.6%, melting temperature: 185 ~ 205 ° C, mold temperature: 20 ~ 50 ° C, usually no drying treatment.

Main manufacturers abroad Formosa, SHINTECH, Solvay, Geon, EVE, etc., domestic Shanghai chlor -alkali chemical Co., Ltd., Qilu Petrochemical Company chlor -alkali plant, Tianjin Dagu Chemical Factory, Beijing Chemical Third Factory, etc.

1.3 Silicone

The commonly used silicone materials are SIR, good elasticity, soft feel, seismic anti -slip, and its hardness is 20, 30, 40, 50, 60, 70, 80, 90. The earphone silicone gel is used for Shore20, 30, and the MIC silicone jacket often uses SHORE30. Parts without special requirements such as the block with SHORE60. Can not be injected and molded, you can die for molding.


1.4 Metal material

1.4.1 Stainless steel

The commonly used stainless steel brands are SUS301, 302, 303, 304. Goer Company uses stainless steel as the raw material for springs and metal crusher.

1.4.2 copper


Copper has good conductive performance, often using copper as an antenna raw material.

1.5 instant noodles

1.6 Double -sided glue


1.7 adhesive

1.8 Waterproof network class (Category of Dust Class)

Chapter 4 Structural Design Standards -Design Articles

The design specifications of the upper and lower shells first

1. Introduction to the design content of the shell

The design of plastic shells involves a wide range of faces. In fact, various shapes and structured forms will be encountered. Involved knowledge is: the choice of plastic materials; the knowledge of mold design; the lack of appearance caused by the injection process and injection; The concept of rigidity and intensity in material mechanics; cooperation between shells; connection between shells; structures designed to meet the function of a Bluetooth headset.

For a single shell, the main consideration is mainly considered; the rigidity; the processability of the mold manufacturing; the lack of appearance caused by the injection molding. The intensity refers to the ability of the shell to be undergone in a specific temperature and humidity environment without being destroyed. The rigidity is mainly related to the deformation of the shell. The greater the stiffness in a certain direction, the less likely it is to deform in this direction. The good stiffness design is very important for the Bluetooth headset shell. The design of the rigidity is currently the weaknesses in our design. For the knowledge of mold and injection, please refer to related books. This book mainly explores any parts of the plastic shell from the perspective of design. The problem is related to the overall stiffness of the entire Bluetooth headset. The coordination of plastic shells mainly refers to the design of the bayonet and reverse limits. Connection mainly refers to the connection of hot -melt nuts with screws; self -attack nail connection; ultrasonic welding; hot melting column rivet; double -sided glue adhesion; buckle connection; rivet connection (ear hanging); adhesive connection and sealing (earplugs, RCV lids , Mike). The overall stiffness of Bluetooth headset depends on the stiffness of a single shell, and also depends on the connection stiffness between the shells. This is a very important problem, which is often ignored in fact. If the overall rigidity is good, the appearance of the Bluetooth headset is not easy to deform, the various gaps are easy to ensure, and the electronic devices inside can be effectively protected. The PRT test is easy to pass. At the same time In turn, foam played a role that should have. The performance of the whole confidential seal is also easy to ensure.

2. Function description

The basic function of the plastic shell is: the carrier of the basic use performance of the Bluetooth headset (connecting information, transmission information, operation and other functions) to meet the appearance characteristics of the whole machine (including color, shape, size, etc.), protect electronic components (movement movements (movement movements (movement movements And display, etc.)

And circuit.

Third, the choice of materials


(1) For the housing, the plastic materials generally selected by Housing are PC, PC+ABS. For PC, commonly used: SAMSUNG (PC HF-1023IM) and GE: (PC 1414); for PC+ABS, commonly used: GE (PC+ABS C1200HF), SAMSUNG: (PC+ABS Hi1001BN To. Compared with PC+ABS products, PC products have good mechanical properties such as intensity, stiffness, plasticity, and hardness, but because of the poor liquidity of the PC, injection molding performance is worse than PC+ABS. Some, at the same time, the surface quality of the molding products is relatively poor. However, due to the intensity, more and more PCs are used in actual.

(2) For components that require ultrasonic, because PC+ABS’s ultrasonic welding performance is better than PC, and it is more common. So try to use this material as priority when using.

(3) For cases that need to be plated: Generally, Chimei ABS 727 is used, which belongs to the electroplated ABS


(4) Basic engineering plastic forming characteristics:

(5) Common material characteristics of the shell (Material)

动ABS: high liquidity, cheap, suitable for components that are not too high in intensity (not directly impacted, unbearable components in the structural durability test in the reliability test), such as the support gear inside the Bluetooth headset (Camera Frame,,, Speaker Frame and so on. There is also generally used on parts that need to be plated (such as buttons, side keys, navigation keys, electroplating decorative parts, etc.). At present, Chimei ABS 727 (electroplating), ABS 757 and so on.

SPC+ABS: Good liquidity, good strength, and moderate price. Suitable for most Bluetooth headsets and Bluetooth headphones

As long as the structure design is optimized, the intensity is guaranteed. More commonly used Ge Cycoloy C1200HF, Samsung Hi-1001BN, Mitsubishi IUpilon MB2215R (cold-melting connection resistance has high impact strength, for the main bottom of Sekito, Battery Cover, and flipping surface).

,PC: high strength, high price, poor liquidity. It is suitable for cases with higher intensity requirements (such as two shells that coordinate with the axis in the flip Bluetooth headset, two shells of sliding rails and slider without standard sliding rail modules, etc. Materials must be used). More commonly used Ge Lexan EXL1414 and Samsung HF-1023IM.

,PC+GF, currently the use of PC plus glass fiber on the Bluetooth headset shell has a tendency to increase. This material combines the characteristics of the high -mode strength of the glass fiber and high hardness, and the impact characteristics of the PC, so that so It is used on the occasion where the bending resistance is high, but its fatigue impact strength (such as the flip test) is worse than the PC (because the glass fiber is added). The more commonly used Mitsubishi Mitsubishi GS2010MPM PC+10GF (10%GF). High price.

FPPA+GF, nylon plus glass fiber (PPA+60%long fiber), Ge Verton series PDX-U-03320. The modulus is PC+ABS, but the impact resistance is worse than PC+ABS. This material is very rigid. In some occasions, it can replace metals, sprayed, and the surface is smooth and good. Mostly used for ultra-thin structures, such as the main surface of the LG-KV5900 slider. High price.

TPC+PET, GE’s xylex, transparent, this is a new material for GE. Combining the characteristics of PC anti -impact and PET chemical resistance, used for IMD Lens and shells that require high toughness. This material has a lower processing temperature (HDT HDT

260 ~ 280 ° C) can reduce the impact of the ink Ink in the IMD process. The thermal deformation temperature is 90 ° C, the impact strength is> PC> PMMA, which can be designed to design structural features; liquidity> PC, which can be designed with thin walls; high chemicals. High price.

(6) Pay attention to the following points in the selection of materials:

强 Avoid reducing intensity risks blindly. Whatever components use PC materials or special materials to cause difficulty and increase costs;


全 In the case of not being completely grasped by the intensity, the mold review should be clearly told when the Tooling Review should be told that the mold supplier may use PC +ABS to produce T1 products, but it may not be ruled out that when the strength is not enough sex. In this way, the mold supplier will consider the shrinkage rate and the extraction angle of the special parts in the design of the mold. However, for materials with glass fiber (GF30 %), it is necessary to be designed according to the material in the mold design stage.

由 Usually the shell is composed of the upper and lower shells. The theoretical shape of the upper and lower shells can be overlapped, but in fact, due to the impact of the manufacturing accuracy of the mold, injection molding process parameters, etc. Greater than the bottom shell) or bottom scraping (the bottom shell is greater than the surface of the surface). Acceptable surface scraping <0.15mm, acceptable bottom scraping <0.1mm. When the zero segment cannot be guaranteed, try to make the shell of the product greater than the bottom shell. Generally speaking, because there are more keys on the shell, the molding is large, so the shrinkage rate is large, generally 0.5%. The bottom shell has a small shrinkage, so the shrinkage rate is small, and generally 0.4%is selected, that is, the shrinkage rate of the surface shell is generally 0.1%larger than the bottom shell. When making molds, the rear shell should be a smaller shrinkage rate.

Fourth, the wall thickness and strength design of the shell

The intensity design fingers to meet the ability of various drops, distortions, and sitting pressures without being destroyed. To meet the strength requirements, the design of the thickness of the shell is the key decisive factor. In fact, a variety of shapes of shapes will be encountered, and the thickness will be different. It is difficult to measure with a fixed standard. This section mainly summarizes how the thickness of the shell in various cases is determined from the perspective of experience.

For plastic parts of injection molding, its wall thickness is related to the size, structure, plastic raw material, mold pouring position, injection molding process and other factors. Molding; too thick, causing waste of materials, long molding cycles, easy shrinking, and poor surface quality. The minimum average wall thickness of ABS and PC materials is 0.8mm, and the local minimum wall thickness is 0.4mm. In order to ensure the appearance quality of the Bluetooth headset, the local minimum wall thickness is recommended to be above 0.7mm.

The wall thickness of the headset shell is generally between 1.0-1.2mm and the thinnest is 0.7mm. The thickness of the shell wall of Carkit is a little thicker than the headset shell, between 1.5-2mm.

When designing Bluetooth headsets, in general, when the PC material is used, the front wall thickness selection range of the main shell is 1.0-1.2mm, and the current thickness is 1.0mm. Such as mobile phones.), Specific problems need to be analyzed. In the absence of side decorative strips, the side wall thickness of the main shell is 1.2. In the case of using the side decorative strips, the side wall can be 0.8-1.0mm, and the decorative bar can be 0.7-1.0mm, but at this time the decorative bar should be glued on the side wall of the main shell with a large area of ​​double-sided tape. There is a better strength to get the side wall of the main shell. It can also be used by ultrasonic or hot soup columns, such as GBH909 and other models. If the decorative strip is fixed with hot perm, the side wall thickness of the main shell should be larger. It is recommended to be 1.0-1.2mm. If the decorative bar adopts the active card installation method, the side wall thickness of the main shell should be 1.2mm. Because in this case, the decorative strip has no contribution to the side wall, such as wep350.

In addition, the wall thickness of the face shell is related to the sound quality of the headset. The shell is too thin, it is easy to produce echo, and a little sound quality is better.

Keep as well as as much as possible when designing the wall thickness, avoid sharp changes, uneven wall thickness, and can easily cause defects such as shrinkage, stress, deformation. When encountering mutations in the wall thickness of the product, the design can be improved through the following scheme:

Five, shell rigidity design


The rigidity of the shell includes the bending rigidity and the twisted rigidity, which has little to do with the basic basic of the wall, mainly depends on the shape of the shell. In general, the more three -dimensional design of the shell design, the higher the reinforcement, the higher the rigidity of the entire shell. If you want to increase the stiffness in a certain direction, you must increase the gluten in this direction. Generally, in the X and Y directions of the shell, we need to consider how to arrange the reinforcement. Generally speaking, the flatter the shell, the smaller the size of the height direction, the worse the rigidity (the three backgrounds of the bending modulus and the high direction size are proportional). So regardless of the length and width size, the height of the height determines the stiffness of the shell. Although a certain shell is flat from the appearance of the shell, in order to ensure the stiffness, some high gluten will be made during the design, but it will not be seen from the outside after assembly. See Figure 1, 2 below. The housing with good stiffness is not easy to deform, the rigidity of the whole machine is good after assembly, and the gap in the appearance is easy to guarantee. The stiffness design is very important for the shell.


1 picture

2 This shell is very narrow from the outside, not enough stiffness (color part)

Six, shell coordination design

The shell is contained in more content. Here we mainly discuss the cooperation between large shells. The limited tendons designed with the finger housing in order to maintain a relatively fixed position, touch the zero -based quasi -noodles, stop mouth and skirt edges. At the same time, the cooperation between the shells must have a good sealing performance to achieve the purpose of waterproof moisture and dustproof, while improving the anti -static capacity. In addition, it should be noted that the horn can be opened as little as possible, especially the rear shell with the battery. After removing the battery, you can see the devices on the PCB as little as possible. First, it is ugly. Second, it is not conducive to anti -static and waterproof performance. There are two main forms of large shells in the X and Y directions. Let ’s take two examples below: The first type, buckle and limited tendons are arranged. Benefits: Tightly combined, not loosen, the overall rigidity is good after assembly, saving space. Refer to Figure 3, 4, 5, 6 below.

image 3

Figure 4

Figure 5 Figure 6


The second is the two -layer arranging of the limits. Benefits: Due to the increase in local thickness, the shell strength is stronger. Disadvantages: The thickness of the side wall is increased by a layer of tendons, and the space cannot be adopted under tension. Reference Figure 7, 8, 9.


Figure 7

Figure 8

Figure 9

7. Strengthening muscles (RIB)

Strengthening tendons is a kind of economic and practical enhanced shell strength (Streangth) and Stiffness, which also plays a role in the positioning of components in the assembly; The role of position and orientation. Figure 10 indicates that the rigidity of 2 times should be increased. It only takes 7%of the material to enhance the tendons by design, but it needs to increase the material by 25%through the thick wall thickness

The design of reinforcement involves five aspects: Thickness, Height, Location, Quantity, and Moldability. Rib Thickness is critical, and too thick will cause the surface of the opposite side to shrink and cosmetic.

Figure 10

注意 Pay attention to the following principles to strengthen the design of muscles:

Design a common reference for the thickness of the tendon thickness (strengthening the thickness of the tendon =%of the thickness of the shell wall), and the relationship between several main sizes when the tendon design is enhanced.

Figure 11

Wall thickness <= 1.5mm thin -walled parts allow the thickness of the reinforcement to strengthen the tendons slightly thicker than the above table, but it should be less than 75%of the wall thickness of the shell;

Wall thickness <= 1.0mm thin -walled parts allow the thickness of reinforcement to strengthen the thickness of the tendon as the thickness of the wall.

The highlight should use thin reinforcement;

You can use a few short reinforcement to replace a high enhanced reinforcement. The main size is shown in Figure 12.

More enhanced tendons will enhance the strength of the component and prevent rupture, but it may actually reduce the ability to absorb the impact of the component. According to the principle of removing tendons on the mold, the application of reinforced tendons should be designed in the principle of required reinforcement.

The best direction of reinforcement is consistent with the melt filling direction.

Figure 12

Eight, corner support (gusset)

Usually we also design some corner support to strengthen the thread, the shell bending and other parts. The principle of design corner support is the same as reinforcing tendons, but it should be noted that the square corners are easily supported at the sharp corners. Figure 21 tells us how to design corner support.

Figure 21 Figure 22

Nine, horn (radius)

Too small rounded corners may cause stress concentration. On the contrary, too large rounded corners can cause the surface of the shell to shrink. Figure 22 shows the corresponding relationship between the ratio of the rounded corner and the wall thickness of the shell and the concentration of stress. When the ratio of rounded to the wall thickness is 0.15, the reinforcement effect (for small or moderate impact) and the appearance quality can get a better compromise.

Ten, angle (draw)


Due to the molding characteristics of the plastic shell, we must add the modeling signs to the design of the plastic (this work should be done after all the characteristics are completed), see Figure 23. Pay attention when designing the modeling signs:

To pull out the direction of all the directions parallel to the mold on the mold;

The angle angle of the shell is greater than 2.5 degrees;

Except for the shell surface, the angle of the removal angle of the other characteristics of the shell is based on 1 degree. You can also follow the original original



Take 0.5 degrees to enhance the angle of the reinforcement of the reinforcement of 3mm, take 1 degree of 3mm-5mm, and take 1.5 degrees of the rest;

The angle of the cavity with a high cavity below 3mm is 0.5 degrees, 3mm-5mm takes 1 degree, and the rest is 1.5 degrees;

The surface of the surface to bite the flowers on the surface: 1 degree+H/0.0254 degrees (h = total depth of the bite flower)

Figure 23

11. Undercut (in injection molding, the mold needs to be mandatory)

When designing product design, sometimes it needs to be intended to buckle, as shown in Figure 24. When the material is ABS, PC+ABS or PC, the bottom cut Undercut should not be greater than 2%. [Undercut%= (d-d)/d%]

Figure 24

2. Coordination of upper and lower shells and PCB boards, batteries, USB sockets, MIC silicone sleeves

1. The PCB board is installed on the bottom shell. It is supported and positioned from 3 to 4 pillars or tendons. The pillar distribution should be evenly distributed to prevent turning and transformation during the button. It is best to have pillars support near the top button. The unilateral gap between the pillars and the PCB plate is 0.05mm. There should be 3 to 4 pillars or tendons on the top of the top to the PCB plate. The gap between the PCB board and the side wall of the surface shell is not less than 0.2mm. When designing the shell, consider the maximum size of the PCB board device and leave a certain gap.

2. The battery is generally adhesive to the PCB board with double-sided adhesion, 0.1-0.2mm thickness. It is supported by the tendons of the bottom shell. The thickness of the battery is generally uneven. Consider its maximum thickness.

3. When designing the shell, be sure to leave the placement of the USB socket to ensure that the installation plug of the USB plug is smooth.


4. The assembly method of upper and lower shells

There are 5 common assembly methods for plastic parts: screws, buckle, hot melting, sticky glue, ultrasound welding. Because the screw affects the appearance of the product, and the size of the headset is small, it is rarely connected with screws; the buckle is directly formed on the surface shell, no other parts are required during assembly, and it can be disassembled. It is widely adopted, and 90%of the plastic parts of Gole are used to assemble it with cards; Her Rong is also a commonly used assembly method. The top buttons on the headset are generally assembled on the shell with hot melting methods; adhesive glue It is also a commonly used assembly method. Sometimes, in order to speed up the development progress and reduce the difficulty of making molds, it is often assembled in a sticky manner, but it is not demolished after assembly. Overcoming method; ultrasonic welding is also a commonly used assembly method. Especially when there is no assembly space, ultrasonic welding is used. Ultrasonic is also an irreversible assembly process.

4.1 screw connection

4.1.1 Application of Step

Screw connection is the most reliable connection between the Bluetooth headset shell. Screw columns are usually used to assemble screws (SCREW) or INSERT/NUT. The screw column usually plays a positioning effect on the PCB board. Under normal circumstances, 4-6 screws are recommended.

4.1.2 Types of Nail: Two types of plastic shell screws:

Machine dental screw connection: high connection intensity, high cost, complicated production, nuts needed

Self -attack screw connection: low connection intensity, low cost, simple production, no nuts needed

(1) Due to the precision of Bluetooth headsets, there are many use of machine tooth screws. Most of the nuts of dental screws are hot -melt. As shown in Figure 28, 29 below

Figure 28: Schematic diagram of the screw nut assembly structure (Explode)

Figure 29: Schematic diagram of screw nuts assembly structure

(2) Self -attack screw connection is a very effective and reliable method of fastening shell, but because the split sparning of self -attack nails is often occupied, it often takes up a large height space, but it saves the nut and hot melt. Process, easy to control production, simple and easy to use. Therefore, it is a good design to use self -attack screws in the case of space permit. Self -attack screws usually use the specifications of 1.6, 1.8 or 2.0 in the outer diameter. Considering that too thin screws are easy to slide, it is basically not adopted by 1.4. Generally, it is necessary to ensure that the effective work is not less than 4.

4.1.3 Requirements for Step Design: The screw connection usually requires that it can ensure that the screw connection of more than 10 times of disassembly shells will not be invalid.

Screw test (scream)

Test environment: room temperature (20 ~ 25 ℃)

Test purposes: Repeat the reliability of the screw and shell after the screws

Test equipment: electric screws up

Test inspection items:

1) Screw: Screw head deformation, injury, wire scratch, etc.; Screw column deformation, damage, wire scratch, etc.


2) Screw holes: deformation, damage, cracks, scratches, etc.

3) Shell: deformation, damage, cracks, scratches, etc.


experiment method:

1) Flat the sample on the test table, use the punch torque used during the production assembly, and play 10 times on the same screw at the same position;

2) Every time it is hit, check the screws, screw holes and housing;

3) The speed of the tester is set to “fast” state;

4) Disassembly screws on the measured samples need to be tested;

5) Screw torque is provided by design engineers and production engineers;

Inspection standards:

1) Screw: Screw headless, damage, wire scratch, etc.; Screw column has no deformation, damage, wire drawing, etc.;

2) Screw holes: no deformation, damage, cracks, scratch, etc.;

3) Shell: No deformation, damage, cracks, etc.;

4) After the test is completed, it is necessary to disassemble the machine for inspection. Abnormalities such as cracks and damage inside the shell cannot occur.

Remarks: Test standards are suitable for mechanical screws and self -attack screws

4.1.4 Screw column, screw and nut design guidance:

Under normal circumstances, there are several key sizes in the screw and nut design, and the tolerance and other coordination size can be referred to Figure 30.

Figure 30

Figure size description:

The above size is the minimum size that must be guaranteed by the design. If the space is limited, you can choose a smaller screw.


SCREW NUT is pressed in place, and it can be concave 0.05mm without the surface of the screw column.

Scream Nut tensile:, torque


When choosing screws of different specifications, we must pay attention to the same values ​​of screws and threads.

The thickness of the shell under the screw head is greater than 0.80mm (0.70mm in the figure)

4.1.5 Standardized design of screw nuts: refer to “Bluetooth headset structure design specification — screw nut scream scream”

4.1.6 design considerations of screw column (BOSS): Design of Dental Screw Snails:

Figure 31 is a common M1.6 nut NUT and its materials and specifications. Figure 32 indicates that the nuts in the plastic shell nut in the plastic shell nut:

Figure 32

For hot -melt or ultrasonic nuts, D is the outer diameter of the nut. Determine the inner hole D0 of the nut, the outer diameter D1 and the copper nut and the upper and lower ends of the screw pillar are important. The unsteady in the figure represents the thickness of the shell, l represents the wall thickness of the thread, and H indicates the total height of the thread (from the surface of the shell to the top of the thread). The following is the basic principle of design:

DN: NUT (copper nut) lower end -oriented diameter, corresponding to Figure 31 is φ2.05mm;

D0 = d -(0.20mm ~ 0.25mm); PC takes 0.20mm, PC+ABS takes 0.25mm;

D1 = D+2*(0.6T); of which the value (0.6T) is the minimum wall thickness of the BOSS column wall when the copper nut is hot, generally 0.6T is 0.70 to 0.8mm;

GO = 0.05mm ~ 0.2mm; G1 ≧ 0.5mm; (can be adjusted slightly);

L = 0.6 ~ 0.8T; (this value is generally regarded as space and anti -contraction, but there must be watermarks in the opposite side);

H = 2t ~ 5T; (depending on the structure of the space)

Design experience for NUT hot -melt screw pillars:

The outer diameter of the thread should be more than 1.5 times the outer diameter of the INSERT/NUT. However, we often take small values ​​in the design of the Bluetooth headset. The Insert/NUT diameter of the M1.4×0.3 in Figure 33 is 2.5mm, and the inner diameter of the design of the thread is φ

2.3mm, the outer diameter of the screw is φ

3.70mm. But actual taking φ3.80 or φ3.90mm will be more reliable (unilateral wall thickness 0.70mm).

NUT hot melt must be able to withstand torque and 15kg tension.

Figure 33

PCBA is usually located on the thread. Design the upper surface limit PCBA direction of the RIB on the outside of the thread; the X and Y axis direction of the X and Y axis are used to locate the X and Y axis. As shown in Figure 34:

Figure 34

In Figure 34:


DP = D1 + 2*CPB; DP: PCBA through the aperture of the thread;

If the PCB is located from the direction of the X and Y axis, the CPB is 0.1mm; if the thread is not positioned in the X and Y axis direction, the XC takes 0.15mm;


DR3 = D1+0.5;

CRP = 0.05 ~ 0.1mm;

CRB = 0.05 ~ 0.1mm;

DR1 = ms+0.4mm; MS: indicate the nominal diameter of the screw snail;

DR2 = DS+0.6mm; DS: Indicates the nominal diameter of the screw cap;

Lrf = 0.6mm ~ 1.0mm; LRF: indicate the distance between the thread;


In order to make the upper and lower shell BOSS columns smoothly, it should generally make a 0.3×0.3C chamfer on R/HSG.

Figure 35 shows the size relationship of the sizes of the Narut, screws, screw columns, and rear shell screws of the CT700 project: MD — screw screw diameter; A = md+0.2; B = 2xmd+0.2; C = B+ 0.4; e> = 0.8mm; F ​​size is very key. The distance between the NUT hot melt and the reference surface in the assembly diagram must be clearly marked, and each new sample must be tested. H = Step outer diameter+0.20mm. The distance between the bottom surface of the rear shell to 0.05mm is 0.05mm; the distance between the back of the rear shell snail is 0.05mm and the PCB board is 0.05mm.

Figure 35


In order to be convenient for the hot melt orientation of the copper nut, it is generally made of 0.2×0.2 on the inner hole of the BOSS column, or the countrbore is added to the spattered gel space as the hot melting nut.

BOSS’s internal holes should not be too large, so as to prevent the tightness of copper nuts. Generally, 0 to 0.5 degrees pulling the mold angle;

The outer side of the boss can be taken 1.0 degrees;

The bottom of the boss should have a garden corner R0.2 ~ 0.4 to reduce stress concentration.

4.1.7 Design of Self -attack Screw Snail:

Basic design points for reference, see Figure 36:

Figure 36

D0 = (0.80 ~ 0.85) * D; D: Diameter of Self -attack Screw. Plastic with high hardness and high intensity takes large values, and vice versa. PC material takes 0.85,

ABS takes 0.80. Such as 1.6 diameter 1.6 self -attack nails, ABS materials, D0 = φ1.28mm; D1 = D0+2*(0.4t ~ 0.6T); the value (0.4T ~ 0.6T) is generally 0.7 ~ 0.8mm. There are also experience formulas:


D1 = 2D, for example, for the 1.6 self -attack nail, take D1 = 3.2;

L = 0.6 ~ 0.8T; (this value is generally regarded as space and anti -contraction, but there must be watermarks in the opposite side);

H = 2t ~ 5T, (depending on the structure of the space); generally take H = 3T;

The top angle of the thread is 0.2*0.2c to facilitate the screw entry.

Figure 37 shows the actual project experience of the screw column of the M1.6×0.35 self -attack screw: the outer diameter of the thread should be the outer diameter of the SCREW

1.8 ~

2.0 times, in the design: the outer diameter of the thread = 1.95x screw outer diameter; the inner diameter of the thread (ABS, ABS+PC) = the outer diameter of the screw-0.40mm; 0.35mm (you can design it at 0.30mm first, and the mold is not repaired and the gum is added); the distance between the two -shell screw surface is 0.05mm. Self -attack screw thread hole depth is as greater than as much as possible


Figure 37

The following table lists the torque value to be used when the self -attack screw assembly and test (10 times).

4.1.8 The design requirements of the thread supplement:

The following points need to be paid attention to in the design of the boss:

In order to prevent the appearance of the shell on the back of the thread, the relationship between the wall thickness of the screw column and the wall thickness of the shell should be kept

About 0.75: 1.

If the proportion of the thickness of the screw column wall is more than the proportion of the wall thickness of the shell, the proportion of the recommendation is exceeded, and the design can be considered in its roots

A circle of concave pit (volcanic mouth) to reduce the possibility of shrinking. See Figure 38. When T1 ≥ 0.8T0 and H ≥5 T0, this “volcanic mouth” anti -shrinkage form is very effective. The specific size and detailed shape are generally determined by mold manufacturers based on experience.

Figure 38

Adding a rounded corner to the bottom of the screw pillar can reduce the risk of stress concentration and potential rupture, but the excessive inverted rounded corner can cause shrinkage. For the Bluetooth headset case, the inverted rounded corner of 0.2 to 0.4mm will enhance the strength of the screw column without causing the surface of the back of the screw column to shrink.

Nails should have a certain strength to ensure that they can withstand huge impact in the drop test. As shown in Figure 39, for the relatively high nuts, when H ≥ 5T, usually add 4 triangular RIBs (also known as Gusset) to strengthen the strength of the thread. RIB width w = 0.4t ~ 0.6T (generally 0.7mm can be taken), HC = 0.5mm ~

1.0mm, (generally depends on the spatial structure, it is recommended that RIB does not flatten the surface with the screw).

Figure 39

4.1.9 Nide hot -melt process requirements:

Naruts are usually connected with hot -melt, ultrasonic or inlaid processes. The material of the nut is generally brass, because the brass of the brass

The expansion coefficient is the most similar to plastic.

Hot melting: Good process, need to be hot -melting equipment, recommended.

Ultrasound: poor craftsmanship,


Injection plastic parts: need to be put in inlaid, which may damage the mold

The temperature of the hot-melt processing must be lower than the molten of the mother material 10-20 degrees, usually about 230 ° C, and the stay time is 4-6s.

4.2 Hot Rongzhu

Design skills:

The diameter of the hot column is generally not less than 1mm;

The unilateral gap between the thermal meling column and the hot melody is 0.05mm;

The hot pillar is higher than the hot mellow hole 1.5-2mm;

It is recommended to make hot mellow and sink to install glue to ensure the calm and flat and hot melt strength; as shown in the figure below:

Do not use heat melting columns in the sound cavity to prevent glue loss and affect sound quality.

For small pieces fixing, the hot -melt fixation of solid pillars is advocated, and solid columns and corresponding holes should be made from 1.5 degrees to 2 degrees.

Moom, 0.05mm unilaterally.

When large pieces of fixing or the thickness of the glue shell meat are topped with a high top, it is advocated that the inner diameter is 0.5mm and the hollow column with 1.5mm outer diameter


The bone bone or 0.5mm thickness of 2.5 ~ 3mm is fixed. As shown below:

The sinking holes of the hot melting hole have a cone head and peace head shape.

Customize some other simple shapes.

The hot -melt sinking holes are generally more diameter of 2.2 depth of 0.3 or more, which can be designed by calculating the volume. It is necessary to consider the diameter of the hot melting head. Generally, the diameter is 2mm. The case should be given a position. The hot melting column should not be too close to the edge of the case, which will have a great impact on ESD.

If you want to electroplating decorative parts, try to guide the rounded corner at the root of the hot -melt column to prevent the column from broken.

Yes, when making decorative parts, try to be fixed with hot -melt columns and card hooks. It cannot be fixed with a gel back. It is difficult to pass the high and low temperature test, especially the fixation of IML parts.

The temperature should not be too high when the heat melts, preventing the materials from brushing and aging turning black, generally 20 ° C than the TG temperature bottom of the plastic material.

At the same time, the environmental temperature also has an impact, depending on the specific situation. 4.3 sticky glue

Most of the current high -end headsets adopt this connection method. From the appearance point of view, because the gap is minimized, it gives people a stronger sense of overall. In addition, due to the dotted glue of the weekly circle, ESD has a greater improvement of ESD.

The diameter of the glue column is generally not less than 1mm;

The unilateral gap between the glue column and the glue hole is 0.1mm to facilitate the retaining glue; see the figure below: ·

The glue holes should be poured to the C corner;

The coordination length of the glue column and the rubber hole is not less than 2.5mm;

The sticky glue is not easy to control the upper and lower shell gaps. After assembly, the workpiece fixture is required for at least 5 minutes; the adhesive contact surface should not be polished as much as possible, leaving the virgin;

It is best to be designed as shown in the figure below to prevent glue, or leave 0.5mm depth of 0.5mm gel groove.

4.4 ultrasound

Ultrasonic welding is a fast, clean, and effective assembly process. It is currently used in bonding between thermoplastic plastic products, bonding of plastic products and metal accessories, and bonding between other non -plastic materials. It replaces solvent adhesion and other adhesive technology, which is an advanced assembly technology. Ultrasonic welding not only has the function of connecting assembly, but also has a tide -proof and waterproof sealing effect.

Ultrasonic welding uses low amplitude, high -frequency vibration energy causes the surface and molecular friction to generate heat, and plastic melting and the connected thermoplastic parts are welded together. There are two important points of ultrasonic welding design: the design of the energy band and the design of the gum groove.

Figure 10 shows the size of the typical ultrasonic welding energy band, which is suitable for the case of the shell wall below 1mm. We stipulate that the width of the energy zone is 0.30-0.40mm (ie 0.25W in the figure); the height is also 0.30mm-0.40mm; the angle is determined by width and height.

FIG. 11 shows the design of the Z -shaped energy belt that can prevent glue. This design can help the two parts to locate, tolerate the shear performance of the stretch and resistance during use, and eliminate external overflow. However, the requirements for wall thickness are above 1.2mm, and the width and height of the shoulder part of the shoulder should be based on being able to mold. mm.

Design skills:

Figure 10 Figure 11 In addition, pay attention to the length of the ultrasonic line. When it is too long, there is no place to run when the plastic ultrasound. It is not easy to press it. You need to use a large amplitude. The length of the ultrasonic line is generally 3-4mm. The interval is 1-1.5mm.


When designing ultrasonic welding, pay attention to whether the materials of the two parts can be welded by ultrasound. Figure 12 lists the performance of the commonly used plastic materials. (Red indicates that the intensity is good after ultrasound, orchids indicate that the intensity is acceptable, and white means that it cannot be ultrasound.

Figure 12

Figure 13 sample the size of the ultrasonic structure and the size of the ultrasound site.


Note: In the company, if you install the line board, you can use the ultrasound method; otherwise, you can use ultrasound assembly.

4.5 buckle

Block buckle is a common installation method for plastic parts. This method has been used many years ago. Out of the consideration of easy installation and cost, it has become increasingly important now. The advantage of the buckle is to avoid other connection methods such as thread connection, clamping, and paste. The buckle structure is made of mold, and it is not necessary to connect them. In addition, if the design is properly designed, it can also achieve repeated installation and disassembly without damage parts. The buckle structure can be designed as one -time and multiple times. One -time buckle means that it does not need to be removed after the part is installed. The buckle structure used for multiple times is mostly used in the occasion that needs to be easy to disassemble.

The principle of buckle action is to use the elasticity of the plastic itself and the deformation of the structure to achieve assembly and disassembly, so this type of buckle can be used multiple times. The strength and reliability of the buckle are worse than the screw, so the design of the buckle structure needs to be considered many problems. Designing a buckle structure needs to be considered far more than the design thread connection. The molds required for the buckle structure are also more complicated and expensive. Generally speaking, the cost saved during assembly is more cost than the production process. There are usually three main buckle structures: ring -shaped, cantilever, and reversing. Generally speaking, cantilever beam buckles are often said.

Pocket work principle


The definition of the outer buckle of the shell and the internal buckle of the shell: It specifies that the buckle exceeds the outer shell buckle above the typical line; the shell buckle near the static side side that does not exceed the class line. See Figure 40 and 41.

Figure 40 Figure 41

Seeing the schematic diagram of the buckle cooperation, see the picture


Figure 42

The size that needs to be paid attention to when designing the buckle. When the Bluetooth headset design is designed, 0.5mm is selected.

If the drop test is not available, the public deduction gradually adds glue, and it can also be added to the inverted port (not too close to the bayonet, prevent the box cover when the lid is not the case) to improve the drop test.

The father -in -law buckle should be added with a guided angle for easy card entry.

At present, the buckle that is commonly used by the company (see Figure A) and the buckle shape size (see Figure B)

Figure A


A = 0.1mm;

B = 0.05mm;

C = 0.2-0.3mm;

D = 0.5mm; (The buckle effectively matches the size D at the beginning, otherwise it may be difficult to assemble. If the drop test is considered in the later stage, it is considered to add glue. C is the reserved gel gap. And positioning tendons can also effectively improve the performance of the drop test, but the side distance of the anti -stop buckle cannot be less than 3mm, mainly for the deformation space of the box cover, to prevent interference, and it cannot be too far away. Otherwise, it will lose it. Fit. See Figure C)


E = 0.7mm (when the wall thickness is 1.1mm, the size E size cannot be less than 0.7mm, otherwise the outer surface may shrink. In special circumstances, it is necessary to obtain the mold factory for confirmation))

F = 0.4mm; (also can also be buckled with a tendon, which is convenient for mold molding, and the mold saves oblique top, as shown in Figure D)

G: Under possible conditions, G should be as big as possible, increase cantilever size, increase deformation, and easy to lid.

Figure B



Figure D

The size allocation of the buckle can be referred to Figure 43 and 44.


Figure 43

Figure 44

Different cards can be divided into: live buckle and dead buckle. Among them, the amount of card is less than 0.6mm is called a living buckle. Most Bluetooth headsets are designed on the left and right sides, and the upper or lower sides are designed as a dead card. For design cases of dead buckles, refer to Figures 45 and 46.

Figure 45 Figure 46

Pointing point for buckle design:

The capable of cards cannot be removed when the fall and other external forces are impacted. This depends on the size of the card, and it is generally suitable for taking 0.4 to 0.5 under the case. See Figure 43.

The location layout is reasonable. Usually there are several buckles on the Bluetooth headset. The good location layout can make the entire Bluetooth headset decentralized, and to withstand strong external load capacity. The buckle layout should be considered in combination with the screw position.

Easy to assemble. Generally, the pitching position of the two buckles is made into a diagonal structure.


Easy to disassemble. Generally, it is designed to be designed with a sloping structure on one side buckle. The length of the diagonal angle accounts for about 1/3 to 1/4 of the length of the entire buckle. See Figures 48 and 49.

Figure 48

Figure 49

The buckle must have sufficient strength. Under the impact of external forces and multiple disassembly, it cannot break

In the thickness direction of the Bluetooth headset, the two shells must be tightly stuck, and they must not be loose. Otherwise, the two shells that cooperate with each other will not cooperate with each other, and the US tooling will become larger.

Do not design it as shown in Figure 50. This type of mount is easy to form a melting marks in the middle, resulting in too weak strength and easy to break


But sometimes it is restricted by space. In this foundation, another form of buckle has evolved. As shown in Figure 51, one is added in the middle

Bone or two bones improve the strength of the buckle.

Figure 51

The buckle is achieved by the deformation of the two when the stuck is used. Therefore, there is a need to consider whether there is enough room for deformation when the buckle deformation, and whether there is interference with other components.

Figure 52 is a buckle design in the early days, which is applied more on the flip. The buckle cannot be designed on the edge and moved to the product center. At the same time, in order to avoid local glue thickness, the buckle and its roots have been performed.

Figure 52

Several shapes of buckle

This structure is more ordinary

This kind of parent buckle is improved on the B structure, which can prevent the thickness of the buckle from being too large

Caused shrinkage problem

Improved on the structure B, stole the glue under the mother pass to prevent the shell from shrinking,

At the same time, the intensity is better than C structure

The following two pictures are the buckle forms commonly used in earplugs and earplug lids



The stitching of the buckle should be uniform, and try to put it at the corner of the shell. The figure below is the buckle buckle of the GCK801 face and the GBDA60 face shell.

The theoretical calculation of the buckle

Y =

K is the coefficient, which is related to the material. Capped roots and rounded corners can improve the stress of the buckle

Block and coating binding

Sometimes if the upper and lower shells are simply buckled with a card, or due to the limited space of the space, the position distribution of the buckle is not reasonable, and the upper and lower shells are difficult to pass by the fixed product falling test fixed. To change the relevant size of the buckle, it is also difficult to solve the problem fully, so the following measures are used in actual production in the future: as other technical problems have been resolved, only the left drops cannot be passed, that is, the method of applying glue on the buckle is solved.

The cooperation design of the buckle and limited tendons

The role of limiting tendons: When involving the cooperation design of the two shells, it is required to get stuck two shells on the one hand, and on the other hand, the two shells must have the function of mutual movement to prevent two from two. The shells are murmuring when they are subject to external forces or even cause some squeak noise. At this time, the design of limited tendons is needed to avoid this problem. The outside shell has a dual function of stuck and limit. The typical cases of the buckle and limited tendons are given below:


It can be seen from Figure 54 that the buckle and limited tendons are designed, that is, either on both sides of the shell buckle are the limited tendons of the other party’s shell, or the sides of the limited tendons are the other side of the other party’s shell The buckle and limited tendons. The advantage of this cross -design is that the two shells can be stuck firmly, and they will not be murdered up, down, left and right, and the overall steel properties will be strengthened.

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