Problem 1: My tool chatters during the cut.
Explanation: Vibration causes the cutter to not cut smoothly. This vibration is due to the natural frequency of the tool/spindle.
- The feed and speed, and/or step-down and step-over need to be adjusted. See the feeds and speeds tutorial for more information.
- Turn the spindle speed up.
- Adjust the feedrate, usually moving slower will be smoother, but this is not always the case.
- Increase the step-down, taking a deeper cut into the material.
- Increase or decrease the step-over, the width of the cut. Typically the ideal step-over is about 60% of tool diameter.
Problem 2: Spindle sounds like it is slowing down during the cut.
Explanation: The spindle power is insufficient for the amount of material being removed.
- Decrease the feed rate in 5% steps until the spindle stops bogging down
- Decrease the step-down and step over in your toolpaths.
- Switch to a tool with more cutting flutes.
Problem 3: The Pocket NC is not cutting in the location that I expected.
Explanation: The stock may not be located in the same position relative to the origin point that it was in the CAM software used to create the toolpaths.
- Make sure that the origin for your toolpaths is the B table offset/machine origin point of the Pocket NC. This is a point in space about 0.839 inches above the center of B table.
- Check if the coordinate system of your machining setup in CAM is set up so that the positive Z axis points at the spindle of the Pocket NC, the positive X axis points at the A table, and the positive Y axis points straight up from the B table.
- Check if the toolpath origin is also the B table offset/machine origin point and that the toolpath coordinate system is appropriate. Remember that the Z axis is always the Pocket NC spindle.
- Make sure that your stock is located in the same place on your machine as it was relative to the origin point in your CAM program.
Problem 4: The drive/lead screws squeak.
Explanation: The end of the lead screw is touching the frame of the machine when it turns.
- Make sure that the screw and the hole are free of debris.
- If the noise it minor is is best to let it wear into position. The noise should decrease with time.
- To re-grease:
- Use a very small amount of general purpose synthetic grease to lubricate the tip of the screw.
- Do not grease the whole screw.
- Do not put grease where it will contact the anti-backlash nuts.
- Grease will collect debris and may cause increased wear on your machine.