CNC drag knife machines use a knife to cut soft materials like foam and rubber that CNC routers struggle to cut. CNC drag knives are similar to CNC routers, but they have a sharp knife cutter instead of a spindle.
Types of CNC knife cutters vary depending on the type of knife they use.
CNC drag knives are the simplest, putting the blade in the material and dragging it until the cut is finished.
Another type of CNC knife cutter is the tangential knife. Tangential knives can pull the blade out, spin it 90°, and put it back in for cutting. Certain materials like rubber will bend when a drag knife moves to the side at higher speeds, but a tangential knife can always redirect the blade.
Finally, oscillating tangential knives have a motor that moves the knife up and down, while another motor can rotate the blade like a tangential knife. This type of CNC knife cutter can cut even small contours (cutting small contours on soft materials like foam and rubber is difficult since they bend).
