How can you avoid part movement when cutting with a CNC router?

In order to avoid movement, you should follow these steps:

• Replace or skim your sacrificial bed.
• Close any redundant vacuum zones and cover any exposed areas in the required zone. This will concentrate your vacuum directly on the part that requires cutting.
• Ensure the surface of the sacrificial bed is clean and free of debris. Any chips will stop a strong vacuum being made under the material.

There are also several ways to prevent small parts from moving. Here is a selection of methods;

• Ramp into the material. Rather than a making a direct plunge movement, drive into your part as you plunge the tool, leaving a ramp-like start to the cutting process. When the tool is near the end of the cutting process, the tool will meet the surface of the part cut away during the ramping process.
• Use a finishing pass. This process requires you to cut the majority of the material leaving approximately 1/125″ (0.2mm) around the part and 1/50″ (0.5mm) on the base of your chosen material. You complete the process by processing the rest of the material. This process reduces the amount of force being applied to the part.
• Tabbing. These are small uncut sections of the material attaching the part to the waste material. This method is widely supported by most software and is a well-proven method of holding the part in place. However, this requires further work after processing your material.

In addition, selecting both the correct pressure foot and donut will aid your cause.

-Ged Lodge, AXYZ International