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The router is loud. Check
volume before playing.
The bit is 1/2 inch diameter, and the cuts are 1/2 inch deep; the feedrate is 100 inches per minute. Video compression causes the movement to appear uneven; however, the router is moving smoothly and the quality of cut is good. The vibrato-tremelo sound of the bit carving the wood indicates that the speed is approaching its upper limits at this depth and width of cut. Climb cuts and cutting across the grain add extra loads which will cause chatter. The version of the machine used for this video has an aluminum gantry and carriage. It uses racks and pinions on the X axis, and 3/8 inch 5 turn per inch Acme leadscrews with Delrin anti-backlash nuts on the Y and Z axes. These plastic leadnuts can contribute to chatter since they are flexible. The machine is powered by the HobbyCNC 305 oz.in. kit. Xylotex systems performed similarly. The machine used around $700 in materials, not including the HobbyCNC components. ........................
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Climb Cuts A climb cut is made when the cutting edge of the tool is moved in the same direction as the cut is being made. It is the same process as feeding a table saw from the back of the table. The stock is pulled into the blade by the motion of the blade. The stock climbs onto the blade. (Or the blade climbs onto the stock.) With a router, since the stock is fixed and the router is moving, a climb cut happens when the router is moving in the same direction as the bit's cutting edge is moving. This causes the router to pull forward and to then snap back; this is chatter. Any flex or looseness in the system will aggravate this situation. Some CAM software can remove climb cuts by changing the direction of cut in the g-code. With less sophisticated software the problem is reduced by making shallower cuts. |