Application of Silicone rubber Parts in Product Structure Design
Characteristic and Application of Silica Gel
Silicone rubber is a kind of rubber, vulcanized silicone rubber has heat resistance, cold resistance, ozone resistance, air aging resistance and good electrical insulation properties.
The disadvantage of silicone rubber is that its tensile strength and elongation at break are small and its compression deformation is large.
It is suitable for manufacturing parts and electrical insulation parts used in high temperature, low temperature, sunshine, atmosphere and ozone environment.
Dimensional Accuracy and Recommended Marking Tolerance
Track material is an elastomer. Compared with plastic material, the direct influence factors of shrinkage rate are more complex. Precision is more difficult than plastic parts. It should be fully considered in concrete design, and there should be no place with high precision.
If the basic size is too large to meet the design requirements of dimensional accuracy, it can be solved by the method of deformation of the base plate of the positioning column. Where the dimensional accuracy is required, there should be room for easy die repair in design.
Etching Texts and Patterns
Trademark patterns and characters can be designed on silica gel substrates, which can be formed at the same time when forming products. There are convex and concave shapes on the products. Considering the convenience of die processing, convex shapes are generally designed.
For the convenience of marking or model replacement, marking parts can be designed as inserts in die design. When the model of product is changed, only the inserts of marking parts in die cavity can be replaced to meet the needs of marking replacement. As a part of this kind of product, it should be allowed to have flying edge remnants at the outline of the insert block in the marking part.
Design of Silicone Gel Keyboard
Typical structure of silicone key:
Substrate thickness can be 0.8-1.2 mm. Excessive thickness of the substrate will increase the shrinkage rate and affect the dimensional accuracy.
For conductive rubber, the stroke is usually 0.8-1.5 mm, and the exhaust chute is designed to prevent the adsorption between the PCB board and the button.
For light touch switches, the stroke depends on the switch's own stroke (and the trip to prevent misoperation), as described later. If the substrate does not fit the PCB board, the air tank can be omitted.
Force-stroke curve
In order to design keys well, it is necessary to have a better understanding of the press-stroke curve.