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In this article, we will explore the intricacies of milling plexiglass, one of the most commonly processed materials on CNC milling machines. Plexiglass is widely used in the production of exhibition and retail equipment, advertising structures, office nameplates, and various other applications. Its versatility and affordability make it a popular choice across multiple industries.
Why plexiglass?
Despite its widespread use, there is a continuous demand for efficient plexiglass processing. This is primarily due to the material’s unique combination of transparency, durability, and cost-effectiveness. However, working with plexiglass requires specific techniques to achieve clean cuts and avoid defects.
Cutting plexiglass
To ensure precise milling, we recommend using spiral or double-helical cutters. When finishing, the depth of cut should be limited to 1–2 mm, while roughing should not exceed 4 mm. Plexiglass is a brittle and sensitive material—cutting too deep may lead to splitting or material fusion due to excessive heat.
Optimal feed rate
Through practical experimentation, we have determined that the optimal feed rate for milling plexiglass ranges from 2000 to 2500 mm/min. Exceeding this speed increases the risk of breaking the cutter, while a lower speed causes the material in the cutting area to overheat, darken, and melt.
Parallel flow milling
When milling plexiglass, we recommend using parallel flow milling, where the cutter’s rotation direction is parallel to the spindle movement. Unlike other materials, this approach yields a significantly better surface finish. Through trial and optimisation, we have found that the ideal spindle speed is between 16,000 and 18,000 RPM.
Blowing system for cooling
To enhance cutting quality and prevent overheating, a blowing system is often used. This helps cool the cutting area, preventing material fusion and improving overall milling efficiency.
Ensuring a clean edge
For optimal results, the milled edge should be straight, free of chips, and smooth without any melting. If residue remains on the cutting tool, it indicates either a dull cutter or an incorrect cutting mode. Additionally, do not use cutters that have previously been used for hardwood, carbon materials, or non-ferrous metals, as they may compromise the quality of the cut.
Conclusion
Milling plexiglass requires careful selection of cutting tools, feed rates, and spindle speeds to achieve high-quality results. By following best practices—such as using spiral cutters, maintaining moderate feed rates, and employing a blowing system—you can prevent common issues like melting and chipping. With the right approach, CNC milling machines can efficiently process plexiglass, producing clean and precise components for a wide range of applications.
