1. Process Principle
Compression Molding ：rubber compound is placed into a closed metal mold. Under heat and pressure inside the mold, the rubber flows to fill the mold cavity and completes vulcanization to form the finished shape.
Extrusion Process ：Rubber compound is continuously pushed forward by an extruder screw. The rubber passes through a fixed shaping die head under pressure to form continuous long profiles, followed by continuous vulcanization.
2. Product Shape Features
Compression Molding
Discrete, single-piece molded parts: washers, stoppers, bumpers, high-hardness rubber blocks, irregular special-shaped rubber parts
Complex 2D / 3D structures, holes, bosses, concave-convex features are achievable
Fixed length, separate individual products
Limited length, cannot make endless long strips
Extrusion Process
Continuous linear profiles: seal strips, silicone hoses, rectangular tubes, solid strips
Simple constant cross-section only; cross-section remains unchanged along the length
Unlimited continuous length, can be cut into required sizes after production
Hard to form complex local structures, protrusions or embedded features
3. Dimensional Precision
Compression Molding Higher dimensional accuracy for complex shapes; tight tolerance control for key sizes. Flash trimming is usually required after molding.
Extrusion Process Good precision on cross-section dimensions; longitudinal dimensions can be cut freely. Slight deformation may occur before full vulcanization.
4. Production Efficiency
Compression Molding Batch intermittent production; one mold makes several pieces per cycle. Longer single cycle time. More suitable for medium & small batch orders.
Extrusion Process Continuous automatic production, high hourly output. Cost advantage for large-volume long profile products.
5. Material & Cost
Compression Molding Higher mold cost for complex molds. More rubber waste from trimming flash. Flexible for customized irregular parts.
Extrusion Process Lower unit cost in mass production. Less material waste. Only one extrusion die head needed for one cross-section.
6. Typical Representative Products
✅ Compression Molding products Rubber foot stoppers, rubber washers, high hardness rubber blocks, buffer stoppers, special-shaped vibration pads.
✅ Extrusion products Solar panel rubber seal strips, automotive silicone cooling hoses, continuous sealing strips, solid rubber bars.
