Compression Molding

Primary silicone route with 20+ presses, 200–400T capacity, and parts up to 800×1200mm

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Process Overview

Silicone Compression Molding

Compression molding places a pre-weighed silicone charge into an open cavity. Heat and tonnage close the mold, the compound cures in place, and the part is then demolded and deflashed.

At SIKING, it is the standard route for HTV silicone parts that need dependable press capacity, large-format tooling support, and DFM review tied to the final geometry.

  • Primary material: HTV solid silicone
  • Hardness range: 0–90 Shore A
  • Approved suppliers: Dow, Wacker ELASTOSIL, Shin-Etsu
  • Large-format press: 400-ton, up to 800×1200mm
20+
Compression presses
200–400T
Tonnage range
800×1200mm
Max part size
Production line of blue molding presses on factory floor
Equipment Specifications

Compression Molding Specs

ParameterSpecification
Press Tonnage Range200 – 400 ton
Number of Presses20+
Large-Format Press400 ton — up to 800mm × 1200mm parts
Primary MaterialHTV Solid Silicone
Hardness Range0–90 Shore A
Material SuppliersDow, Wacker ELASTOSIL, Shin-Etsu
MOQ Guidance1,000 units for tooled parts
Tolerance PlanningConfirmed at DFM review against geometry and critical dimensions
Buyer Implications

Compression stays strongest where scale and geometry are steady

This route carries the broadest in-house silicone press footprint, so it works when part size, tooling economy, and dependable press capacity matter more than finer-route complexity.

Critical tolerance planning still happens during DFM review, which keeps geometry-sensitive promises tied to the actual part instead of a generic standard line.

Large parts without outside sourcing

The 400-ton press keeps larger silicone parts inside one manufacturing system instead of handing oversized work to a second supplier.

Wide material window

The published 0-90 Shore A range and approved supplier set give engineering room to tune feel, sealing, and durability before tooling is released.

DFM-led tolerance planning

Compression capability depends on geometry, wall section, and critical dimensions, so tolerance planning is locked at DFM review rather than assumed from a generic standard.

Process Flow

Compression Molding — Step by Step

1

Material Preparation

Compound is selected, weighed, and logged for traceability.

2

Mold Loading

The heated mold is loaded, and inserts are positioned where required.

3

Press & Cure

The press closes under defined tonnage and cure conditions matched to the compound and geometry.

4

Deflash

Flash is removed with the method suited to the part geometry and cosmetic requirement.

5

Inspection & Pack

Parts are checked to drawing and control plan, then packed under the same batch record.

Best Suited For

  • Large gaskets and seals requiring a single-piece form
  • Thicker-section silicone parts
  • Medium-to-high hardness components
  • Programmes where tooling economy matters
  • Parts where standard parting lines and deflash are acceptable

Not Suited For

  • Features better suited to LSR precision
  • Very thin-wall structures
  • Very high-volume production where cycle time dominates
  • Parts where flash cannot be tolerated
  • Complex insert-led geometries better suited to transfer molding
Common Questions

Compression Molding — FAQ

How large a part can SIKING compression mold in-house?
+
SIKING's published range is 200–400T, with a 400-ton press supporting parts up to 800×1200mm.
When is compression molding usually the right process choice?
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It is usually the first option for larger silicone parts, thicker sections, and programmes where tooling economy matters. Final selection is confirmed at DFM review against geometry, cosmetic demands, and production volume.
How should I approach tolerance planning for compression-molded silicone?
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Mark function-critical dimensions on the drawing and confirm the tolerance plan during DFM review. Geometry, wall section, and compound shrink all affect the result.

Request a Compression Molding Review

Send drawings for DFM review, process selection, and quotation tied to geometry, material, and volume.