So, we are setting up our machines to run wood parts. The issue we are having is that eventhough during set up I am inputting wood height at the measured size (for instance… say .375 measured with digital calipers), and I am inputing the finished height desired at .270, we will sometimes get runs (rough 3d) where the 102# will run into the wasteboard, and we get a final part size of .245-.250+/-
We are scratching our heads to figure out what is happening. This is expensive material and we need to get this issue solve so we are not creating scrap.
Either the Nomad 3 is not consistent in measuring tool height for Z, or… is it possible the bit itself is “moving”… pulling outwards… during a run, and throwing the Z off?
Hello… Sadly I can’t due to proprietary issues. However, We measure with expensive Mitutoyo Calipers that are zeroed out. The wood are cut and decked hard slabs, so very flat. Measuring the bit before and after sounds like a good step.
Have you run into issues with these collets allowing a bit to “pull down” while its working thru material? I have seen something similar in aluminum milling.
Zman tight is different than Ed tight. That is the problem moving parts encounter when we use them. I do grunt tight. But we have to remember that threads wear out on the collet and the spindle. Unfortunately it is part of life. Luckily I have not worn the threads on the spindle beyond use.
I am surprised that Carbide Motion does not measure the cutter at the end of the cycle. It could provide useful warning about tool slippage or breakage.
I have ran two programs, and with careful measuring and extra tightening of the collet, and the problem has disappeared. Parts are coming off the machine within .002 of input height, so I am sure this bit slippage is the issue. Knowing this, the fix I guess is to torque the nut tighter. The small wrench limits torque, but I am getting good results with it still.
Well not always. You could get longer wrenches but then you could over torque the spindle and cause bigger issues. Every operator has different hand strength and have their own feeling for when things are tight enough. Now that you have felt what is required just duplicate that. It would easy if you had a torque wrench and a specification to what torque to set at but those specifications do not exist. From now on it is just rinse and repeat.
Upside the machine is very affordable and can be very tight in finished tolerances. Down side, there is no way to know that the bit was “tight enough” until you’ve ruined an expensive piece of material. Hopefully this solution will work moving forward. This spindle seems tough enough to take being tightened enough to withstand the bit slipping. In this case more is better… as otherwise the machine would be useless.