KR-113A Constant Deflection Compression Set Test Fixture

Additional information

KR-113A Constant Deflection Compression Set Test Fixture

The determination of vulcanized rubber machine applies a constant strain compression deformation of the test method. This test is compressed to the provisions of vulcanized rubber specimens under a high, after a certain temperature and time, or media infiltration, the determination of the rate of the sample compression set.

 

Product Details:

 

Product Introduction

The KR-113A compression set fixture is standard lab hardware designed to measure permanent compression deformation of vulcanized rubber, silicone, foam and flexible polymer materials, fully compliant with ISO 815-1 and ASTM D395 Method B constant deflection test standards.
The test principle is to clamp standard test specimens between parallel steel plates with fixed limit spacers, then place the whole fixture into a constant temperature aging oven for scheduled high-temperature static compression. After cooling and recovery, measure specimen thickness loss and calculate compression set value to quantify elastic attenuation of elastomers under long-term extrusion. This fixture is widely adopted by auto seal manufacturers, silicone factories, foam material labs and accredited third-party testing laboratories for raw material inspection and new formula comparison.

Core Product Advantages

  1. High-Precision Polished Stainless Steel Structure

    All pressing plates, guide posts, fastening bolts and limit sleeves are made of SUS304 stainless steel with mirror precision grinding. Plate flatness tolerance ≤0.02mm, surface roughness extremely low to guarantee uniform compression on every sample. The stainless construction resists rust and oxidation after long cycles inside high-temperature ovens without contaminating test pieces.

    2.Multiple Limit Spacers for Full Hardness Matching

    Equipped with interchangeable limit sleeves of 7.62mm / 8.89mm / 9.52mm / 10.16mm to realize 20%, 30%, 40% compression ratios matching different rubber hardness grades:

  • Shore A hardness below 50: apply 40% compression
  • Shore A 50~75: adopt 30% compression
  • Shore A above 75: select 20% compressionCovers all mainstream rubber and foam testing requirements.

     

    3.Dual Specimen Size Compatibility

    Supports two standard specimen types specified in global testing standards:

     

    4.Solid vulcanized rubber: Φ28.68 × 12.7mm cylindrical samples

     

    5.Foam elastomer: 50 × 50 × 25mm square blanks

    One fixture completes both rubber and foam compression set tests without extra accessories.

     

    6.Stable Locking Structure Without Thermal Loosening

    Four sets of high-strength thread bolts with lock nuts firmly fix the parallel plates. Even after dozens of hours of high-temperature aging, the clamping distance stays unchanged, eliminating test error caused by loose plates. Simple assembly without special tools for fast specimen replacement.

     

    7.Compact Desktop Size & Lightweight Design

    Overall dimension only 200 × 120 × 100mm with total weight 10kg, easy to carry and place inside standard blast drying ovens. No power or air source required, fully manual operation suitable for all laboratory environments.

Standard Complete Test Workflow

  1. Specimen ConditioningCut raw materials into standard test blanks, store them under 23℃ constant lab environment for at least 3 hours to eliminate internal stress, then measure original thickness H₀ accurately with thickness gauge.
  2. Specimen ClampingSelect matched limit sleeves based on target compression rate, place samples evenly between upper and lower steel plates, tighten all bolts uniformly to lock the fixture tightly.
  3. High-Temperature AgingPut the fully assembled fixture into blast drying oven, set specified test temperature and aging duration (24h / 72h / 168h as standard). Keep oven internal temperature fluctuation within ±1℃ to meet standard requirements.
  4. Cooling & Rebound MeasurementTake the fixture out after aging cycle, release bolts and take out specimens. Place samples on heat-insulating flat board and recover freely for 30 minutes under standard environment, then measure recovered thickness H₂ precisely.
  5. Compression Set CalculationCalculate compression set rate via standard formula:

    K = [(H₀ – H₂) ÷ (H₀ – H₁)] × 100%

    H₁ = Height of limit spacer

    Take arithmetic average of at least 3 parallel samples as final test result; discard data if specimens crack after compression.

    Data deviation rules:

  • If compression set value <10%: allow absolute deviation ±1%
  • If compression set value >10%: allow relative deviation ±10%

Applicable Materials & Industrial Scenarios

Automotive Sealing Industry

NBR, EPDM, FKM, silicone O-rings, door and window gaskets, engine shock pads; test permanent deformation under long-term high-temperature static compression.

Silicone & Foam Manufacturing

Food-grade silicone sheets, medical sealing gaskets, EVA/PU cushion foams, electronic conductive rubber pads; evaluate elastic recovery performance after extrusion.

R&D & Third-Party Testing Labs

New polymer formula screening, incoming raw material quality inspection, finished product durability certification to meet international testing standards.

 

Standard Factory Delivery Package

  1. KR-113A stainless steel compression set fixture main body
  2. Full set of interchangeable height limit sleeves
  3. Matching high-strength fastening bolts & lock nuts
  4. Multilingual operation manual aligned with ISO & ASTM standards
  5. Standard specimen dimension drawing & compression set calculation reference table

Technical parameter:

Model RT-113
Rubber specimen Ф28.68(D)12.7mm
Foam plastic 50*50*25mm
Septum thickness 7.62mm,8.89mm,9.52mm,10.16mm
Dimension 20*12*10cm
Weight 10kg

 

Global Technical & Distributor Support

We provide complete test operation training and compression ratio selection guidance, with long-term supply of spare sleeves and bolts. Custom fixture sizes and special limit thicknesses are available for bulk buyers and regional agents. Exclusive distributor policies include priority production, OEM private branding and full sets of English marketing materials.

English Text for Product Image Markers

Main Banner: KR-113A Constant Deflection Compression Set Fixture

Feature Labels: SUS304 Stainless Steel | 20/30/40% Adjustable Compression | ISO 815 & ASTM D395 Compliant | Dual Rubber & Foam Specimen Compatible

Safety Tip Label: Do Not Drop Fixture; Clean Plates After Each Test

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KR-113A Constant Deflection Compression Set Test Fixture

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