1. Recommendations for choosing a material:
Choose materials based on assembly and function of parts. If it is a new material, it must be tested in advance to avoid problems in mass production.
2. Wall thickness:
Wall thickness is most direct cause that directly affects product strength. The wall thickness of conventional thermoplastics should be limited to 4mm.
Stiffening ribs are an integral and functional part of plastic parts.
Reinforcing ribs effectively increase rigidity and strength of a product such as "I" iron without significantly increasing cross-sectional area of the product, but it does not have problem of undercut shape, which is difficult to form like "I" iron, especially suitable for plastic products with pressure, torque and bending.
In addition, reinforcing rib can also act as an internal flow channel, helping to fill cavity, which is very important for facilitating flow of plastic into branched part of component.
4. Die Angle:
There is no specific criterion for value of slope angle, and most of them are determined by depth of product.
The total slope angle is 0.5°~1.0°.
For products with a deep or textured texture, slope angle requirement depends on depth of texture and increases accordingly, typically 2°~3°.
Required slope angles are clearly marked on the general printed form for reference.
5. Pillar (boss):
The thickness of protruding wall of column is used to assemble products, separate objects and support other parts. Hollow spacers can be used to insert inserts, tighten screws, etc.
Try not to use brace on its own, but connect it to an outside wall or use it together with ribs, goal is to increase strength of brace and make rubber flow smoother.
In addition, height of post should generally not exceed two and a half diameters of post, as a post that is too high will trap air when forming plastic part.
6. Boss Holder:
If supports are used in finished product to tighten screws, there must be a positioning support sleeve on top of finished product.
According to general safety standards, head of screw must be stored in an inaccessible place, so height must be at least 2.5mm.
And since there will be a mating of edges of mold after adding support sleeve, you need to add an R1.0 or larger round fillet to each support where cap screw is placed.
For ease of insertion during manufacturing and assembly, no more or less chamfer should be added to bottom of each Insertion Rack Bushing.
Due to location, bottom of support sleeve must have a minimum depth of 1.0mm to store support.
7. Defining an empty position: also known as avoidance position
In product design, it is imperative and very important to give space between parts. With product size, part shape and function, virtual position value also needs to be changed accordingly.
In terms of space, it should be at least 1-2 mm, and positioning surface should be as small or small as possible to facilitate assembly.
8. Round Pin Hex Hole Design (Tight Nail):
In product design, parts may be disassembled due to functional and safety issues, but also due to many factors, disassembled parts may not match appearance after reassembly. So some exact numbered positioning columns are needed to fit shape.
9. Hex nut assembly method:
The method of assembling battery door and case body is to tighten battery door with fixing screw and hexagonal screw cap hidden in case body, and make hexagonal hole sleeve in case body according to size of hexagonal screw cap The sleeve has a free position of 0.15mm on one side, and a hot melting or cold stamping method is used to ensure that wire cover does not fall out. ) can also be added to sleeve to apply glue. How to put on a cap on a sleeve.
The buckle provides a convenient and economical method of product assembly, since combined part of buckle is formed simultaneously with production of finished product, and there is no need to cooperate with other fixing accessories such as screws and mesons. during assembly, buckles on both sides of combination can be fastened with each other.
11. Ultrasonic welding:
Ultrasonic welding technology has very short cycle times, with a standard machine capable of up to thirty operations per minute.
If joint design is perfect and welding parameters are adjusted correctly, clean and stable welding results can be obtained, since welding results are not affected by operator's working conditions.
Ultrasonic welding technology is designed to fuse plastics together, which allows you to create high-strength joints without internal stresses.
No need to pinch
The workpiece is considered finished when it leaves machine, post-weld processing is not required.
12. LCD Assembly:
To ensure normal contact between zebra and PCB, zebra and PCB must have 0.5 mm interference, and holder and zebra must be precisely matched to prevent poor contact between zebra and LCD (Figure 12.0.2) ). Since length tolerance of LCD lens is relatively large, there should be about 0.5 mm free space between bone around LCD lens and LCD lens on one side.
13. Rubber Button:
There must be a gap of at least 1.0 mm between plane of rubber key and printed circuit board.
To prevent jamming, key cover and rubber key must have a gap of 0.15mm on one side.
There must be a difference in level of at least 0.2mm between bottom of reset and plane of housing to prevent unnecessary contact.
If rubber wrench is to be combined with PCB before being assembled to case, a pin must be placed on rubber wrench for assembly.
14. PCB Location:
For ease of assembly, each PCB needs to add two locating pins on finished case body.
In addition, some positioning bones need to be added to top and bottom shells to clamp PCB to prevent PCB from deforming under force.
In addition, there must be a gap of at least 1.0 mm between PCB and case.
The greater distance between dowel pins, better, because in this way position of PCB can be maintained without misalignment.
After setting size and position of PCB, some cosmetic elements need to be added to bottom and front of PCB to indicate empty position of electronic components. And on PCB, add Solid to indicate space that electronic components can be placed in.
After that, mark size of PCB shape, size of recess, and position and size of electronic parts on drawing to facilitate design of electronics.
15. Battery compartment:
There must be adhesive between battery and battery.
If there is a product intended for children under age of 3, a battery-protected sink must be added.
16. Battery Door Design:
Because medium thickness battery door is very thin. Therefore, for reinforcement, it is necessary to add stiffeners.
Especially if battery door is in center of finished product and there are no pits around battery door. A concave finger position must be added to easily open battery door.
17. Speaker Hole:
If finished speaker is not visible, you can make some speaker holes in case instead of speaker to spread sound.
18. H-shaped buckle:
It is used for comparison in production and assembly, and can also be used to apply glue.
20. To wishbone:
Wishbone is mainly used in shell of some larger finished products or some finished products that need to be loaded, plus a wishbone. Sometimes seam of product is replaced with a transverse lever based on requirements of manufacturer.