One of the challenges in using a plasma cutting machine is to produce high quality small holes. The two measures of hole quality are roundness and cylindricity. If a hole is cylindrical, but not round, it is an indication that one of four key variables is WRONG. The key variables are:

1. Feed rate
2. Height control
3. Lead-in and lead-out configuration
4. Start-up and shut-down synchronization and timing

All four of these variables can be controlled by your nesting software! Nesting software sends instructions to your machine based on the four key variables.

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The closer to 90°, the better the cylindricity. High performance equipment should allow you to achieve less than 2° variation.

Here's how: Automatic nesting software, like SigmaNEST, can analyze the geometry of each part that is nested, and create an NC tool path that optimizes all four plasma cutting variables to ensure that EVERY contour on EVERY part is produced accurately and as precisely as possible. It takes geometric features, like holes and other cut–outs, bevels and external contours into consideration, and adjusts the 4 key variables while it generates the NC tool path.

1. SigmaNEST automatically adjusts the feed rate for each cut in an entire nest, to make sure the machine is going at the optimal speed.
2. SigmaNEST tells a machine when to turn off and turn on height control: AVOID CRASHING YOUR MACHINE!
3. SigmaNEST lead–ins and lead–outs product the best possible roundness.
4. SigmaNEST synchronizes plasma cutting process start–up and shut–down to make sure the cut isn't damaged.

Because the flame shape tapers at the top and at the bottom, cutting height should be controlled so that the flame hits the sheet in the ideal cutting zone.

Image 4 – Start–up and shut down synchronization and timing affect roundness.