Have you tried running the job without cutting anything? If not give that a try… See if the machine returns back to the work zero position.
Also, make double sure that your router AC cord isn’t running near your USB or too close to any other wires for that matter.
Thank you for this, running the this pattern, it seemed to cut flawlessly. I did readjust the Y voltage, prior to the cut, as it seemed to be slugging. Im not sure if that solved the problem at all, as i was then able to cut one our projects perfectly. So it is possible that was my only issue, but, Ive adjusted those before, without any difference in errors. Maybe ive just found that sweet spot. Thank you again.
This is a very great point, and yes we definitely spent a lot of time measuring distances between the board and the rails. Initially that was one of our problems, simply assuming things would be level by default. So for others this is indeed a great tip, thank you.
This is also a great suggestion, one that im going to attempt today. Ive been eye balling UGS, but wasnt really sure of the impact it would have. So thank you for this suggestion, and I will be definitely trying it out.
These are also great suggestions, we have been simply using clamps, or the vacuum board we built, but i think the tape might be the way to go, I will give that a shot today. And i have tried very similar speed settings to what you have listed here, all with no success. I have also used various types of bits, including what you have suggested, all with the same errors. I will be making another post, but currently, after readjusting the Y voltage(again) things now seem to be running fine. Im not 100% confident it will stay that way, but time will tell. So thank you very much for your useful suggestions, all which i will be taking into consideration.
Yes, i adjusted to voltages while the machine was simply running on the X and Y axises. And of course to save material several of my first attempts were without actually cutting anything, in most cases it always returned home. Only once we started to actually cut material did it fail.
Your using lean. Isn’t that extruded plastic from lowes? I haven’t tried that plastic yet but I’ve heard it’s crappie to use anyways I cut mainly cast acrylic you have to play with your speed and feed rate
Im not officially calling this problem solved, as I havent cut enough successful pieces to do so, but after readjusting the voltage on Y, things seem to be running better.
I want to thank all of you for your great suggestions, several tips that i will indeed be implementing. I will return to this post, if i encounter the same problems. Will be cutting a lot today, so if the problem still exists, I will know today.
thank you all again. This is a pretty amazing community.
The voltage seems to be a running “issue.” I don’t see it as a design flaw or anything, but it is something that should be CLEARLY pointed out in the assembly instructions as a needed step. If the last page said “now go turn up your pots” MANY of these thread could be avoided.
I’ve done a bit of 1/4" acrylic and I’m into a fairly complicated build with 1/2" PC. I had to keep upping the pots little by little til it skipped no longer. I was quite surprised how much I had to go up for the problem to disappear. just make sure the mechanical issues are taken care of first. An X mod will help with router deflection. I use F360 and use easel. It works seamlessly every time. It really is slick. 1/2" Abrasion resistant PC settings: 1/8 2F upcut. 90ipm .04DOC. I use ramping so plunge not as important but 40ipm plunge.
I know its been awhile for this post, and my apologies for reviving it so much later. But after calling Inventables about our current issues, it didnt seem to make much sense to create a whole new post.
Hopefully the attached video sheds some light on the issues we are having. And hopefully we can get a resolution to these issues. We have had this machine for a month and a half now, and still can not get it to cut consistently. We recently made the stiffening mod (openbuild) and rebuilt our table, the machine no longer shakes and vibrates, but still loses its path. Ive readjusted the potentiometers after the mod, still the same issues exist. We created a new vacuum table, with a level waste board, measured the rails to make sure they are all parallel and level, changed our bits and speeds, and switched to UGS, still the machine runs off path.
At the time of this post, this video is still uploading.
I recommend cleaning up your wiring. Even if it is not the cause of the issue
See these loose strands of wire? If they touch another terminal or short against the rail it will cause problems. Look for this on all your connections
I tined the ends of the my wires. Coating the wire in a very thin amount of solder so the individual strands as stuck together. This helps a lot to keep things from squishing out when your tighten the screws.
Also what is that exposed wire? Is it a shield? It may be a good idea to wrap that in tape. Again to make sure nothing could momentarily short against it while moving.
It looked like one of the vwheels was not moving on the X gantry at one point, I would double check your wheels make sure they are not too tight or too loose.
The eccentric nuts cam be a real problem. There is a quick mod to use them as spacers, adding lock nuts. You might want to look into that.
You have NEMA 23’s right? Just checking.
The space under the table looks tight. make sure your G-shiled is getting airflow and the fan is working. Although if it was an overheat issue the jumps would be more random. The fact that it always happens on the layer change suggests something mechanical.
When it does a layer change there is usually a rapid move to reposition the bit. It may be slipping / dropping steps then when it try’s to move fast.
As opposed to the load of the second layer cut causing one of the axis to be pulled off course. I have this problem with aluminum, it seems to be a runnout issue. It is made much worse with my collet adaptor.
I guess you could test this by having it carve multiple shapes only 1 layer deep, the measure to see if they are separated the proper amount of space.
It would not tell you why it was happening but would tell you when.
Watching the “slip” it seems to be the Y axis not moving far enough on the second pass.
It is that second pass part that bothers me.
The deeper cut putting a larger load on the system and something is slipping?
If it was a belt you would hear it and things should shake
If it was the motor slipping (low current) you should hear it, it makes a chunk.
If it was an overheat it should stutter or pause.
And it doesn’t do this when air cutting?
Have you tried cutting in a comparable thickness of wood?
I am wondering if it could be a static charge issue?
But again it would be more random if it was. 
i agree cleaning up the wires is definitely a good idea, that exposed wire is actually one of the limit switches, it’s “exposed” but not at risk of touching anything. But I will definitely make the change.
I will double check the vwheels, i know one of them did stop turning during the video. And for the most part, before every cut a run through of the vwheels is done to make sure they are all running, and even then the problem still exists.
Yes nema 23’s.
The gshield and power supply are getting enough airflow, the fan works fine.
Your test suggestion is a good one and one that i will be running this morning, thank you.
I agree it definitely seems like the Y axis is the cause of the problem, it is hard to determine if the same issues exist while “air cutting”, but i have run the machine through its paces without the spindle running, but at high speeds and low, it always seems to run fine during that process.
The crazy thing is that these problems never seem to occur when cutting wood. Ive run several very detailed wood carvings, without a single slip issue. Of course, our primary material is the lexan.
this is definitely something i havent thought about, as far as grounding the hoses. But the vacuum table hose is about 4 feet from the power supply, but very close to the power strip everything is plugged into, Im going to move that and ground the hose to see if it changes anything. And yes during the cut, i have the one vac on the table, and the other sucking chips, between the lexan and the vacs, there very well could be some static discharge issues. Thank you for the suggestion.
