Step 1: Raw Material Selection
Every quality rubber seal starts with the right material. At Sunwell, we source virgin rubber compounds — EPDM, NBR, silicone, natural rubber, and butyl rubber — from certified suppliers. Each batch is tested for purity, viscosity, and material properties before production. Recycled or reclaimed rubber is never used in our sanitary seals.
Step 2: Compound Mixing
The raw rubber is mixed with curing agents, accelerators, fillers, and other additives in an internal mixer (Banbury mixer). This creates a homogeneous rubber compound with the specified hardness, elasticity, and chemical resistance. The compound is then sheeted out and cooled before molding.
Step 3: Compression & Injection Molding
Compression Molding: Used for larger parts like toilet wax rings and gaskets. Pre-weighed rubber blanks are placed into heated molds and compressed under high pressure. The heat activates the curing agents, cross-linking the rubber molecules into a durable, elastic final product.
Injection Molding: Used for precision parts like valve diaphragms and O-rings. Heated rubber is injected into closed molds at high pressure for tight tolerances and complex shapes.
Step 4: Quality Testing
Every production batch undergoes rigorous testing in our in-house lab. Key tests include:
• Hardness (Shore A) — verifies the rubber is neither too soft nor too hard
• Tensile Strength & Elongation — ensures the seal won’t tear under stress
• Compression Set — measures recovery after prolonged compression
• Dimensional Inspection — verifies exact size and thickness tolerances
Step 5: Finishing, Packaging & Shipping
Finished products are trimmed, inspected, and packaged according to customer specifications — from bulk industrial packaging to retail-ready blister cards. Products are labeled with batch numbers for full traceability. We offer FOB, CIF, and DDP shipping options worldwide.
Why Manufacturing Process Matters
The difference between a seal that lasts 20 years and one that fails in two comes down to three things: material quality, precise molding, and consistent testing. At Sunwell Sanitary, our ISO 9001 certified process ensures every seal meets international standards.
Sunwell Sanitary — your partner for quality rubber seals. Contact us for factory pricing or to discuss your OEM project →