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Machining Glass-Filled Plastics

June 24, 2022

Glass and plastic composites are known for their resilient performances, extreme durability, and excellent impact resistance. They are high-strength, chemically resistant, and stable options used to manufacture various structural components, medical devices, and electrical housing parts. However, despite these many advantages, machining glass fiber reinforced polymers is extremely difficult and requires a high level of expertise to produce your desired results.

The Challenges of Machining Glass Fiber-Reinforced Plastics

Compared to machining other plastic materials, glass and plastic composites present unique challenges. While tackling these difficulties is well worth the effort due to the many advantages of fiber-reinforced polymers, it is essential to account for the following considerations while machining these materials.

Managing Stress While Machining Plastic & Glass Composites

CNC milling, CNC turning, or multi-axis CNC machining can create stress or exert pressure on existing internal stress in any plastic, especially glass fiber-reinforced composites. Glass-filled plastics are more prone to stress as glass and plastic melt and cool at different temperatures. Stresses occur unevenly as the two materials cool at varying rates, resulting in objects with more stress on one side than the other. To avoid this and other unwanted outcomes, always consult an experienced machinist before machining any glass or plastic composite.

Abrasive Glass-Filled Polymers Cause Tools to Wear Quickly

Glass-filled plastics require specialty tools for quality machining and accurate production due to their abrasive nature. As a razor-sharp tool edge must be maintained to manufacture precision glass-filled plastic components, typical cutters constructed from high-speed steel (HSS) will not be your best option. Instead, glass-filled polymers require cutters made from extremely hard materials, such as carbide or ceramic, that will retain a sharp edge throughout repeated use.

Glass-Filled Plastics May Delaminate

Running tools too quickly can generate excessive heat, resulting in glass-filled polymers delaminating. Delamination causes the glass and plastic composite to fall apart into layers. If the machinist is not mindful, the material can shred and become unusable. Coolants are critical in avoiding delamination, but they also introduce their own challenges as certain types, such as petroleum-based coolants, can cause cracks to develop over time.

Annealing is an ideal option to avoid delaminating glass-filled plastics. By heating a part to half of the melt temperature and allowing it to cool, the glass and plastic composite relaxes. In addition to managing stress and addressing delamination issues, annealing improves wear resistance, reduces shrinkage and expansion, and adds other benefits to your component.

Maintaining a Safe Work Environment During Machining

Machining plastic and glass composites can create a hazardous work environment. When machined, glass fiber-reinforced plastics release dust containing glass particles, which are dangerous to inhale and can damage sensitive machinery. Dust control equipment and air evacuation capabilities must be strictly monitored and maintained in any facility machining glass-filled plastics. Additionally, all workers should have access to proper personal protective equipment (PPE) and undergo safety training before machining fiber-reinforced polymers.

Partner with an Experienced Machine Shop for All Fiber Reinforced Plastic Machining

The best way to address the challenges inherent in machining glass-filled polymers is to work with a well-established and expert machine shop such as Upland Fab. For over forty years, we have specialized in machining glass-filled plastics, laminate composites, and other polymer materials to produce precision results with high-performance capacities. Our hands-on industry expertise allows us to effectively machine a variety of glass fiber reinforced polymers, such as:

No matter your requirements or planned outcome, Upland Fab will work closely with your team to manage the challenges inherent in machining glass-filled plastic and deliver high-quality parts that meet all specifications while exceeding your expectations.

Contact Upland Fab

Contact us today to learn more about managing the challenges of machining glass-filled plastics. Request a quote to receive specific information regarding your planned machining application. One of our expert representatives will be in touch to provide answers and solutions as soon as possible.
Precision Plastic and Composite CNC Machining

Precision Plastic and Composite
CNC Machining since 1970.

Precision Plastic and Composite CNC Machining
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