Common Rubber Extrusion Defects
Like all manufacturing processes, rubber extrusion is vulnerable to certain defects, such as surface imperfections, dimensional inaccuracies, and curing problems. Extrusion defects can lead to a wide range of performance issues and considerable problems for the end user.
Understanding what causes extrusion defects is the first step for rubber manufacturers seeking to develop the proper care and quality assurance practices for prevention.
Surface Imperfections
Pits, bumps, scratches, and other surface imperfections on extruded parts can cause performance problems such as leakage and insufficient sealing. These polymer extrusion defects may be caused by poor die design, inadequate cooling, material contamination, or something as simple as a poorly cleaned die.
Dimensional Inaccuracies
Precision and tight tolerances are very important for many applications. Variations in raw materials and issues with die design can result in parts that don’t meet the required dimensions and cannot be delivered. Any time spent correcting the issue and completing a corrective production run extends the rubber manufacturer’s delivery timeline, which can lead to production delays, stress, and frustration for the customer.
Poor Wall Uniformity
Improper operation of the rubber extruder can result in poor wall uniformity, namely, thin or weak spots. This can lead to issues with structural integrity and performance, as well as poor fit within an assembly. Performance and fit issues can lead to serious problems in high-pressure applications and extreme service environments.
Incomplete Curing
An extruded rubber part that has been insufficiently cured may be soft, sticky, or tacky. This can be the result of problems during the extrusion or curing process. Incomplete curing often leads to poor performance and durability.
Poor Performance Characteristics
While there are many rubber extrusion issues that can lead to a reduction in performance characteristics, a common cause is overheating during the extrusion process. Overheating during the extrusion process can damage the molecular structure of the material, which can lead to production issues as well as problems with the final product. Overheating during the extrusion process can be caused by excessive heat during processing, insufficient cooling, or long exposure to heat, which can occur if the material sits in the rubber extruder for too long.
Ways to Prevent Rubber Extrusion Defects
Thankfully, there are many effective strategies for preventing rubber extrusion defects, some of which are surprisingly simple. Adhering to a consistent maintenance schedule, ensuring proper operation of equipment, and following through on quality assurance practices makes a significant difference for rubber parts manufacturers and their customers.
Die Maintenance
The extrusion die should be cleaned on a regular basis and examined for defects or damage. Regular polishing keeps surfaces smooth and cuts down on scratches or other issues.
Temperature Control
Temperature fluctuations during extrusion can lead to inconsistencies in product dimensions and surface quality. Tight temperature control practices are key to preventing these fluctuations and overheating during the extrusion process. This may require both manual monitoring and regular maintenance of mechanical temperature controls.
Material Prep
Proper material preparation can make a meaningful difference in extrusion results. However, the material preparation process for extrusion can be quite involved, depending on the material and the requirements of the final product. Some important steps include testing for contamination and adding process aids, such as slide agents and lubricants, to the compound to achieve the desired outcome. Some rubber manufacturers test every incoming batch of material, even from trusted suppliers, to ensure consistent quality and no contamination.
Quality Assurance
One of the most important methods for preventing rubber extrusion defects is consistent quality assurance. Because rubber extrusion defects can occur at many stages of the extrusion process, quality checks should occur on a regular basis, to ensure that any possible issues are detected early and can be addressed in a timely manner.
Experience Excellence with UP&R
Preventing rubber extrusion defects requires robust and consistent quality assurance, from the early stages of material preparation to the curing process and beyond. Universal Polymer & Rubber (UP&R) has spent years honing our quality assurance practices to ensure consistent delivery of top-quality extruded products, earning the trust of customers all across northeast Ohio and beyond.
Our robust quality assurance system includes IATF 16949 and ISO 9001:2015 certifications, both of which require rigorous auditing and review. We also follow a strict internal protocol, from pre-manufacturing spec checks and material tests to visual inspections and sample checks of completed product runs. Our stringent adherence to these practices allows us to fulfill our promise to provide first-rate, timely service and quality—every time.
Whether you’re starting a new product or seeking help troubleshooting a recurring issue, UP&R can help. To learn more about our quality practices or discuss a project, contact us.
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