It's hard to describe, but yesterday while standing next to the machine manually holding the vacuum hose to clear chip and dust I finally watched the destruction happen. My LEAD is going along nicely then suddenly jams and climbs out of the work piece skipping and destroying. Nothing I could see as warning at all. Several passes were fine but when this does happen it always seems to be while cutting counter clockwise, and on the left side of my bed. Endmill is a down cut Amana Tool Spectra 1/4. It cuts like through this stuff like butter most of the time. Pretty conservative speeds at about 50 in/min and cut depth about 1/16". These have been my go to setting for this type of cutting. Recently this problem has been occurring way too often that I can no longer step away from the machine at all. Any help in diagnosing what's going on would be great.
looks like the tool pressure is overpowering the Y axis when the cut is deep. check motor current and all grub screws. make sure that all chips are sucked out of that slot during the cut. check grounding. vacuums generate static electricity that can interfere with the motor drivers. make sure the workpiece is not lifting during the cut (how are you holding the piece down?)
This sounds like the right track, some of these I didn't think of but may be mitigated by my setup. I use the Dewalt router. I actually took the whole tool mount off the Zaxis between these two cuts because the force tweaked the 4 L brackets out of alignment again. I check these and lock them down with loctite every so often when this happens. I've had too much chip in the cut channel cause this early on when I switched to the downcut end mills. I was actually manually holding the vacuum hose when this happened, there was zero visible chip in the cut path. But yeah I learned this the hard way with MDF a while back. The CNC, and the Vacuum are on separate circuits. I actually run the CNC off an isolated 20 amp in my garage shop, and the vacuum is connected on the other side of the room on a separate 15amp. If I wasn't standing there when it happened with my face practically in it waiting for this to go south I would guess this as well. In this case it was held down with 3M painters tape and CA glue in addition to a couple of clamps. I learned this the hard way a while back too. I usually run the Dewalt speed on 1 sometimes its on 2. The LEADs mounting of the Z axis is really questionable to me. Eccentric spacers don't provide enough tension and there is always a little play in it no matter how much I try and dial it in. It is not fully rigid at all, so I cut pretty slowly. I may have to drop my feed rate even more it looks like.
EMI (caused by static) is the hardest to pin down and not the most likely of causes, but the static builds up in the vacuum hose because of the air rushing through it. Where it is plugged in isn't relevant. Out of curiosity what is your spoil board made of? Did you manage to solve this issue? What limit switches are you using? The blackbox has good filtering built in (limit switch wiring can act as an antenna for EMI) - Xtension Limit Switch Kit add extra protection. Alex.
The issue seems to be the z axis movement or lack of rigidity. I replaced the front most XL gantry plate and Xtreme wheels and that completely removed the movement I had in the z axis. Now I need to rebuild the x gantry slide as there is a lot of movement there. You can see in this video how much movement there is. What I think has been happening is as the cut is deeper the lateral force is increased and the lack of rigidity in mine is the problem. The gantry is rotating and the end mill is engaging the material and then it all goes to hell.
Wow, your top X axis V wheel(s) are no where near engagement. Are the eccentric spacers at maximum adjustment then?
Yup. Checked the stack of spacer and washers and they just don’t engage. I’m going to pull it all apart and figure it out. It’s been like this since the beginning but only been an issue as I’ve gotten into cutting thicker denser stuff.
