Editing CNC Router (section)

==The Chip Load Equation==

Chip Load is a critical parameter for the CNC mill. It determines the size of the chips produced by the end mill. Ideally the chips should not be a fine dust or coarse chunks but somewhere in between. You can use the equation below to determine your spindle speed and feed rate.

''ChipLoad'' * ''CutterDiameter'' * ''NumberOfFlutes'' * ''SpindleSpeed'' = ''FeedRate''

For .25" end mills and up chip load of .01 is a good upper limit. For plywood chip load should be between .005 and .01 inches per tooth. A chip load of .01 can be aggressive depending on the material so you may want to play around with a lower chip load if you want to have a cleaner cut. You can reference this ShopBot guide for a list of good speeds and feeds. [http://s3.amazonaws.com/fablab-uc/handbooks/files/000/000/012/original/Feeds_and_Speeds_Chart.pdf?1457118600] Make sure you have your units set correctly. Chip Load should be in inches per tooth, Spindle Speed should be RPM, and feed rate should be in inches per minute. Too high of an RPM and you risk starting a fire, and too low of an RPM may produce a poor cut. 10,000 RPM is slow and 18,000 is pretty fast. I chose 12,000 RPM as a good in between. Too fast of a feed rate can also produce a poor cut, but more critically it can damage the spindle. 120 inches per minute is 2 inches per second which is a pretty good clip for plywood. You shouldn't feed faster than this and you should err on the side of a lower feed rate (assuming it doesn't start producing smoke) to preserve the spindle. The node had to replace a spindle that was damaged to excessive axial load and it was expensive. Please treat the tools kindly.

 <nowiki>!!!SAFETY NOTE!!!
   You can cause a fire running at excessive spindle speeds, or having too slow of a feed rate and letting the end mill dwell in one area for too long.</nowiki>
All of these numbers are based on a step-down of the radius and step-over of the diameter of the end mill. [https://makezine.com/2014/03/21/cnc-routing-basics-toolpaths-and-feeds-n-speeds/]