The KR-108 constant-load compression set fixture is a fully manual stainless steel testing apparatus engineered to evaluate permanent compression deformation and elastic recovery capacity of vulcanized rubber, silicone foam, EVA cushion materials and polymer elastomers. It strictly complies with ISO 815-2, SATRA-PM64 and FIA304 global testing standards.

Its core working principle relies on calibrated heavy-duty springs to deliver fixed static pressure onto standard specimens. The clamped assembly can be placed inside blast drying ovens for scheduled high-temperature aging. After cooling and free rebound, operators read thickness variations via the built-in precision dial gauge to calculate compression set value, which quantifies long-term elastic attenuation of sealing and shock-absorbing rubber materials. This bench fixture is widely deployed in footwear labs, auto seal manufacturers, silicone processing plants and accredited third-party testing centers.

Core Competitive Advantages

1. Calibrated Constant Spring Pressure System
   Built-in heavy compression spring provides stable 500kgf maximum load, maintaining consistent pressure throughout long high-temperature aging cycles without pressure loss or shifting. Unlike weight-loaded fixtures, spring structure saves lab space and avoids counterweight dropping hazards during oven placement.

   2.Full Mirror Polished Stainless Steel Framework

   All parallel platens, guide columns, threaded spindles and top handwheel are precision-machined anti-rust stainless steel. Flatness tolerance of upper/lower platens is controlled below 0.02mm, guarantee uniform contact force across every specimen to eliminate uneven compression test errors. No rust contamination after repeated oven circulation.

   3.Dual Standard Specimen Compatibility

   Supports two universal test formats specified by international standards:

• Solid vulcanized rubber: Φ12.7mm / Φ14.5mm cylindrical samples
• Foam & soft polymer: 25.4×25.4mm square blanks
  One unit completes both rubber and foam compression tests without extra auxiliary jigs.

4. Multi-Station Batch Testing Capacity
   Single fixture holds 3–27 specimens simultaneously to boost lab batch inspection efficiency. Interchangeable limit spacers are provided to realize 20%, 30%, 40% compression ratios matching different rubber Shore A hardness grades:

• Shore A below 50: 40% compression
• Shore A 50~75: 30% compression
• Shore A above 75: 20% compression

  5.Integrated Precision Dial Thickness Indicator

  Equipped 0–50mm analog dial gauge with 0.01mm minimal resolution, mounted directly on the fixture frame. Operators measure specimen rebound thickness without separate thickness gauges, simplifying test workflows and reducing measurement deviation from tool switching.

  6.Compact Portable Vertical Design

  Overall dimension Φ230 × 650mm with only 40kg net weight. Integrated vertical structure fits all standard blast ovens; fully manual design requires no power or air supply, suitable for all factory and laboratory environments. Quick handwheel screw locking enables specimen replacement within minutes.

EVA shoe midsoles, latex cushion sheets, sports protective foams, shoe lining elastic materials; evaluate permanent deformation under long static compression.

NBR, EPDM, FKM, silicone O-rings and door gaskets, engine shock buffer pads; test high-temperature compression aging performance for auto sealing components.

Food-grade silicone sheets, electronic conductive rubber pads, household sealing rings; screen different silicone formula elastic recovery properties.

New polymer formulation comparison, incoming raw material quality inspection, finished product durability certification to meet international testing compliance requirements.