What Are The Processes For Customizing Silicone Parts?

What are the processes for customizing silicone parts? In the fields of industrial manufacturing and consumer goods, silicone parts are widely used in medical devices, automotive parts, electronic devices, and other fields due to their high temperature resistance, corrosion resistance, biocompatibility, and other characteristics. However, customizing silicone parts is not a simple order production process, but a systematic engineering involving demand conversion, process design, and quality control. According to industry statistics, about 60% of customization failure cases are due to unclear communication of requirements or improper selection of production processes. From material selection to mold development, from sample validation to mass production, every step directly affects cost, cycle time, and product performance.

1. Requirement analysis and solution design: the cornerstone of successful customization

The customization process begins with a precise understanding of the requirements. Enterprises need to clarify the functional requirements of parts (such as temperature range, hardness, tear strength) and scenario requirements (such as whether they come into contact with food/medical environments). For example, medical grade silicone needs to comply with ISO 10993 biocompatibility standards, while industrial seals need to focus on oil resistance and wear resistance. Manufacturers need to work together with customers to complete 3D drawing review or physical sample analysis, evaluate structural feasibility (such as whether the inverted design requires a parting line) and process adaptability (such as liquid silicone injection molding or solid silicone molding).

At this stage, professional manufacturers such as Dongguan Weishun Silicone will provide material selection suggestions, such as food grade silicone (compliant with FDA standards) or conductive silicone (used for electronic shielding), and recommend process routes based on cost-effectiveness to avoid rework caused by design defects in the later stage.

2. Mold development: the art of balancing precision and efficiency

Mold is the core carrier for molding silicone parts. The development process includes:

Design of parting surface: Determine the parting line position based on the part structure to ensure smooth demolding without damaging the surface of the part. Complex structures (such as porous cavities) require the use of sliders or ejector pins to assist in demolding.

Material selection: The material of the mold directly affects its lifespan and accuracy. Aluminum alloy molds have low cost and fast thermal conductivity, making them suitable for small-scale trial production; Stainless steel molds are wear-resistant and can support mass production for over 100000 times.

Precision machining: Achieving a tolerance of ± 0.05mm through processes such as CNC milling and electrical discharge machining (EDM), and setting exhaust holes to avoid bubble defects. For example, liquid silicone molds require additional design of a cold runner system to control the flowability of the adhesive material.

Taking a certain automotive silicone sealing ring project as an example, aluminum alloy molds were used to achieve 7-day delivery, reducing the cost of a single set of molds by 40%. At the same time, the gate position was optimized through mold flow analysis to reduce the scrap rate.

3. Sample verification: a necessary path from theory to practice

After the completion of the mold, the rationality of the design needs to be verified through T0 trial molding:

Material testing: Use silicone raw materials consistent with mass production (such as Shin Etsu or domestic food grade rubber) to make samples and test parameters such as hardness (Shore A 20-80 degrees) and tensile strength (≥ 8MPa).

Functional verification: Simulate actual usage scenarios. For example, high-temperature resistant silicone needs to be continuously tested in a 200 ℃ oven for 48 hours to ensure no deformation or performance degradation.

Dimensional inspection: By comparing the drawings with a coordinate measuring machine (CMM), the critical dimensional tolerances must be controlled within ± 0.1mm. A certain smart wearable device's silicone button failed to assemble due to a hole diameter deviation of 0.2mm. After 3 rounds of sample adjustment, it met the standard.

The sample confirmation stage usually takes 3-7 days, but it can avoid production risks and prevent losses of tens of thousands of yuan due to design defects.

4. Batch production and process control

After sample verification, enter the mass production stage:

Mixing and pretreatment: Two component liquid silicone gel needs to be mixed in proportion (e.g. A: B=1: 1) Vacuum defoaming eliminates pores and controls the viscosity of the rubber material through a mixing machine.

Molding process control:

Injection molding: suitable for complex structures, injection pressure 80-120MPa, mold temperature 150-180 ℃, vulcanization time 30-90 seconds.

Compression molding: Suitable for thick walled parts, it is formed by pressing with a flat vulcanizing machine, with lower cost but lower efficiency.

Post processing: deburring (burrs must be ≤ 0.1mm), surface spraying (UV coating to improve wear resistance), or secondary vulcanization (to improve physical properties).

A certain medical device silicone catheter project achieved a daily production capacity of 50000 pieces through an automated production line, and reduced the defect rate from 3% to 0.5%.

5. Quality inspection and after-sales service: full cycle service guarantee

After mass production is completed, a three-level quality inspection is required:

First article inspection: Verify the key dimensions and appearance of the first batch of 100 products;

Process sampling: Randomly select 10 pieces per hour for testing tensile/tear strength;

Final inspection: Conduct a full inspection of the cleanliness and integrity of the product before packaging.