Putting Materials to the Test — Rheometers and Vulcanization Data

All OEMs want a high level of confidence that every lot of parts received will perform the same — at the highest level, with the lowest risk, and most efficiency.

Coming up with the right recipe or “rubber formula” is often the critical starting point in providing best in class rubber parts. At Rahco Rubber, we not only customize solutions but individualize them so that every aspect of your part meets exacting specifications, with the expertise necessary to guide you through complex material and custom formulation requirements.

Rahco’s material science experts and engineers will create a robust formulation based on your material specification(s), end item application’s necessities, testing and performance criterion. We aren’t satisfied until our materials are capable of molding zero defects and processing efficiently.

Rahco analyzes compounds to avoid performance issues that could affect part quality, assess the lifespan in the field or shelf life so that we can determine if a material that’s been in storage is still fit for use under service conditions. In addition, we can measure cure rates so that we can establish the optimal processing parameters.

Used in Rahco’s lab, our new Moving Die Rheometer (MDR) is one method utilized to ensure batch-to-batch consistency, so that molded rubber parts have the material and performance properties expected.

The rheometer is used to measure the curing characteristics of rubber compounds. By applying a constant strain at a set frequency to the rubber sample, measurements are taken to measure changes in torque or the resulting force required to deform it, allowing for analysis of the material’s stiffness and vulcanization process under controlled temperature conditions.

The metrics gathered in the test and data analysis generate a “cure curve,” which show how the rubber compound’s stiffness changes over time, allowing for determination of important parameters like scorch time, optimum cure time, and reversion time, as well as the ability to measure dynamic properties like storage modulus and loss modulus.

An MDR can provide the highest levels of precision and repeatability for measuring vulcanization properties of rubber and elastomeric compounds. Tests that can be performed include Isothermal Cure tests, Cure with Simultaneous Sponging / Foaming reaction tests, Advanced Cure Kinetics modeling tests, Tan Delta, and more.

Data is displayed live as the test is performed the recorded metrics are used to assess compounds to ensure they meet quality control specifications. Test results can also be compared to previous test data to ensure uniformity between batches.

Our quality system is aggressively structured to ensure that all required materials, tools and processes are designed to support our goal of superior quality and manufacturing efficiency.

Critical to our success is the ability to create new Custom Formulations in-house. Rahco can custom formulate nearly every natural and synthetic polymer type including Fluoroelastomer (FKM), Vamac (AEM), FDA and medical grade compliant Silicone compounds. For example, we mix natural rubber (NR), EPDM, nitrile rubber (NBR), styrene-butadiene (SBR), polychloroprene or Neoprene (CR), butyl (IIR), and many others.

If you’re developing new products, facing performance challenges with existing ones or concerned about the materials in your current parts and their alignment to specification — Rahco Rubber can help.