To ensure that our materials meet the requirements and expectations set out by our customers, Redwood Plastics & Rubber conducts a variety of material tests on a per order basis. Our team of experts perform these material tests with precision, care, and accountability. All our testing procedures follow the latest industry procedures and standards to ensure full accuracy and credibility.
Listed below is an overview of the 6 regular material tests that we provide to our customers. For more information about our full range of testing capabilities, please contact our Manufacturing team.
ASTM D624
The ASTM D624 test measures the tear strength of vulcanized rubber and thermoplastic elastomers, which often fail due to tears. ASTM D624 measures both the force required to create a tear through a sheet of rubber, and the overall resistance to tearing. The test is performed by straining the test piece until it is completely ruptured. Once ruptured, the maximum force is recorded by our team.
ASTM D412
The ASTM D412 test measures the tensile properties of vulcanized (thermoset) rubber and thermoplastic elastomers: the elasticity of soft material while under stress, and the soft material’s behavior when it is no longer under stress. The ASTM D412 test measures the elongation that occurs when external force is applied. By stretching the material until failure occurs, we are able to determine its tensile strength: the amount of force needed for a material to permanently deform when stretched.
ASTM D695
The ASTM D695 test is performed to determine the compressive strength of both unreinforced and reinforced plastics: how much stress the material can sustain under crush loading. Together, ASTM D695 and ASTM D638 tell us the core properties of common polymers. ASTM D695 requires a universal single or dual column testing machine. After placing the test material on the lower rigid platen, an upper compression platen is lowered at a constant rate. The material is squeezed until permanent deformation occurs.
ASTM D429
The ASTM D429 test determines the adhesion of rubber to hard materials such as metals. Although this standard contains several test methods, Redwood conducts this test via a 90-degree peel strip test. As an elastomer bonded to a different material can weaken over time, this test is used by our team to measure bond strength and the method in which the bond fails.
The 90-degree peel strip test is performed using a specialized machine that moves the material at a constant rate as the rubber strip is peeled off by an upper grip. The results are obtained by measuring the force needed to separate the rubber from the rigid metal surface.
ASTM D1894
The ASTM D1894 test calculates the friction coefficient: the amount of force needed to slide one object over another. ASTM D1894 calculates the friction coefficient of plastic sheeting as it slides over itself and other substances. The test is performed using a machine that moves at a constant rate. The plastic sheet is secured to a flat surface, while a sled of known weight is wrapped in the same material. The force needed to slide the plastic film over itself and the other object is calculated, allowing us to determine the friction coefficients.
ASTM D638
Similarly to ASTM D412, ASTM D638 is performed to calculate the tensile strength of hard materials. Along with tensile strength, ASTM D638 test allows us to determine other key properties including tensile modulus and elongation. After calculating the thickness of the test sample, the sample is placed between two grips which tighten and secure the sample in place. The sample is then pulled apart at a smooth, constant rate until permanent deformation occurs.
