CNC Machining for Test Specimen Preparation: More Than Just Cutting Samples

When people think about materials testing, they often focus on the test itself. However, obtaining meaningful and repeatable results starts much earlier. In many cases, the way a test specimen is prepared can have a significant impact on the quality of the data generated.

At Micom Laboratories, our in-house CNC machine plays an important role in preparing specimens and custom components used in a variety of testing programs. Working with non-metallic materials such as plastics, nylon, composites, and wood, the CNC allows our team to produce precise test specimens while maintaining control over the entire testing process.

Precision Specimen Preparation for Mechanical Testing

Many standardized test methods require specimens to be machined to specific dimensions before testing can begin. This is particularly common in mechanical testing, where specimen geometry directly affects the validity and repeatability of results.

Our CNC machining capabilities support a variety of testing programs, including:

• ASTM D638 tensile testing of plastics
• ASTM D790 flexural testing of unreinforced and reinforced plastics
• Environmental aging studies
• Custom mechanical testing programs
• Research and development projects

Because specimen preparation is performed in-house, our team can quickly adapt to project-specific requirements without relying on external machining services.

A Real-World Example: UV Aging Followed by Tensile Testing

One recent project involved evaluating how UV exposure affected the tensile properties of a plastic material.

The testing program required tensile testing before and after accelerated weathering. At first glance, it might seem logical to machine the ASTM D638 dogbone specimens before the UV exposure. However, doing so could introduce edge-related effects that might influence the aging process.

Instead, flat plaques were placed in the UV exposure chamber first. Once the aging period was complete, the plaques were machined using our CNC to produce the required tensile specimens immediately before testing.

This approach allowed the tensile specimens to be cut from the exposed plaques while minimizing concerns related to exposed specimen edges. It also ensured that specimen preparation was aligned with the overall testing strategy rather than treated as an independent step.

Supporting Custom Testing Programs

In-house CNC machining is not limited to preparing standardized test specimens.

In some projects, specially designed molds, fixtures, or test components are required to evaluate a product under unique conditions. For example, Micom has manufactured custom molds used in aerospace sealant testing programs when commercially available solutions were not suitable for the project’s requirements.

Having machining capabilities available on-site allows our team to develop custom testing solutions more efficiently and maintain greater control throughout the testing process.

Why In-House CNC Machining Matters

Bringing specimen preparation and testing together under one roof offers several advantages:

• Greater flexibility in test program design
• Faster turnaround times
• Better control over specimen preparation
• Improved coordination between machining and testing activities
• Ability to support both standard and custom test programs

Whether specimens need to be prepared for ASTM D638 tensile testing, ASTM D790 flexural testing, environmental aging studies, or a custom research project, in-house CNC machining helps ensure that materials are prepared appropriately for the testing objectives.

Partner with Micom Laboratories

From specimen preparation to final test reporting, Micom Laboratories supports a wide range of mechanical, environmental, and customized testing programs. Our in-house CNC machining capabilities provide additional flexibility for projects involving plastics, composites, wood, nylon, sealants, and other non-metallic materials.

Contact our team to discuss your testing requirements and determine whether custom specimen preparation may benefit your project.