Chattering that appears on the sides of the engraving is generally caused by vibration that is transmitted to the cutter tip. The three possible causes are a bad or worn spindle belt, improper belt tension, or a cutter that is not straight or bad spindle bearings.
Many machines use drive belts that are made by joining two ends of a piece of belting material together with heat or some other means. Some times there will be a bulge or irregularity at the juncture which will bump each time it rides on the spindle pulley. This bumping occurs several thousand times a minute and can result in vibration at the cutter tip. Another very important thing to consider is belt tension. A belt that is too loose will flutter and create vibration.
A cutter that is bent, out of round, or is not straight will also cause vibration that can affect the quality of the cut. There is no way to fix any of these conditions short of replacing the cutter.
Another common cause of chattering is worn spindle bearings. Through normal use, spindle bearings will wear and develop play. When this happens the cutter can flutter and vibrate and the cut will deteriorate. You can try two checks to see if there is a problem with the spindle. Remove the belt and spin the spindle with your fingers. It should turn perfectly smoothly. If you feel any roughness or tight spots, the bearings are probably bad. The other check is to remove the depth nose assembly and with a cutter sticking out the bottom try wiggling it from side to side. If you can see or feel any play at all, there are probably bearing or sleeve problems.
Spindles are extremely precise components that should only be rebuilt or repaired by the manufacturer or a competent repair facility that has experience and expertise with your specific type of spindle. |
