I just got my last hardware parts today (belts and drivers) and couldn’t wait and just had to finish the build to the state i could at least let it run allthough i will probably regret that tomorrow (it is 5 am now … ).
Sourcing of some of the parts was a little hard in germany and i still haven’t decided on a router yet, though i want to start out with a dremel and upgrade at a later point, once i am confident enough and satisfied with my abilities to not destroy anything.
It isn’t the prettiest crown i have seen in the forums, and I just realised that I put the gantry on in an awkward orientation, but nevertheless I am happy like a 5-year-old. Most of the defects can be attributed to the paper sliding though i think.
Still have a lot of cleaning up to do in the range of getting a proper table, housing and holder for the power supply and rambo setup and add some cable sleeves. But that will be done in the next days.
PS: I am sorry if my grammar or spelling isn’t on point, but i hope it wasn’t too bad
After doing some more tests and suspecting after some time that it might be a squaring issue, i am now baffled.
I plotted a square and crown (stopped the machine after seeing it wasn’t better then the old ones) right after without shutting off the steppers and would appreciate any help or advice what could cause the weird crowns ( circle especially ) to come out like that.
I hope it’s ok for me to highjack my “first move” thread a little. If not, I can of course make a seperat thread in the troubleshoot area.
PS: The “circled” red parts in the picture are the ones i am talking about.
Someone else will come along who has much more experience with a wider array of issues, but, I did observe one thing that is similar to a problem that I was having. If you look at the cross part of the crown and a couple other places, it’s clear that one of your axis are getting ahead of the other… this was a loose stepper gear for me. If you look at the image, there are green line showing where this is happening. It ends up looking like a squaring problem. A good way to prove that it’s not is to run that crown file with a depth so that the pen goes two or more times around the same tool path. My guess, from my experience, is that it will get further and further away from the original path with each pass.
First, post a pic of the machine, please. Ryan will spot any goofiness.
Second, how is the pen mounted? Is it pushing far enough into the paper to wiggle laterally?
Third, some slack or slop in the axes. The loose drive gear is a good one, or the tension sint right on the belts, or something. Posting a pic of the zip ties will help a little. You should be able to push the parts with a little force to see where it’s slipping (unless it’s the drive gears as John mentioned). You could see the belt moving or the ziptie stretching.
Another good test would be a square clockwise and then counterclockwise.
First tape the paper down 100%, lets see the machine to make sure it is good, but it could also be a loose zip tie or simply mounting the peen sticking out too far. The drawings look good but you might be getting a little too worried over a really quick and dirty test. I just watched a YouTube video where he had forgotten to tighten the lower ziptie on the pen mount. From the camera angle you could see the pen moving.
Yeah the build seems legit. The XYZ bolts are a bit sketchy but it it works and doesn’t wiggle, but those are a bit loose for my comfort. You might want to grab near the pen and give it a wiggle and see how it feels. Actually the the rest of the build looks to be spot on with my instructions, nice!
Yeah, I had some problems finding the right length of bolts in the local hardware stores near where I live so i improvised a little. I might change those in the future. I’m gonna try tightening them more and see if that makes a difference.
I am currently reprinting the pen-holder due to the fact that I printed it in ABS and it might have a little too much give.
I will report back with new results, but thank you so much for the speedy replies
The pen holder should be fine as long as you don’t put a ton of pressure on it, about 1-2mm is all it takes. I see some killing it with like 10mm that will make a sloppy drawing.
The bolts seem loose because the washer on one side are super loose, fine if you add a few more maybe.
I have the suspicion that either my belt tension is too low or my zip ties have too much give. I watched them closely as it is plotting and it seems like they give quite a way (1-2mm) on a direction change. Could that be the issue i see happening?
Tightening didnt do anything but I got curious about the pulleys again as I tentioned the belts. I originaly ordered 5 16teeth pulleys but apparently got delivered 4 16T and 1 20T .
Switched the wrong one out and now its working great !
Now that I’m thinking about it. That alone would just make the end with the 20T skewed wider. I don’t think that was the only problem. Specifically, in the first pic, the cross at the top is straight, but each side is offset. Maybe it was binding. I think it should look like a perspective drawing, with everything closer to the 20T just bigger. Interesting. Anyway, I’m glad it’s fixed.
I can only guess, that the fact of 2 different pullies on one axis produced this effect.
Or I fixed something by mistake without paying attention …
Either way, working like a charm now and I am currently starting to get a grip on Estlcam and am reading lots and lots about the basics of cutting/milling.
Since the only possible spindle is a Dremel 3000 i have laying around, I probably have to experiment a lot to see if I can get any results that I’ll like
No freaking way, that is a bummer, I have no idea how you caught that I would have chased that for a long time I am sure.
Dude, if I would have spotted that I would have felt like a super hero, “Detail Man”. I went back and looked, Jan please tell me it was on the one motor we couldn’t see in the pics closest to the wall?
I did the first little tries with my dremel and already experienced, that I still have a lot to learn but am very happy that I went with the MPCNC. Such a fun and most importantly well documented and easy to follow project.
Thank you so much for providing the support and up-to-date info !
Thanks but I really feel like I do such a poor job at this. Once I get something working my brain moves straight to the next project. Hopefully I can get better at it but I am glad it was enough to get you going.
The cuts look pretty good, using a more proper endmill will really help clean that up I think that is pretty good for a dremel bit, you seem to have done the gcode well.
A couple things changed. I went for a 500w spindle from my trusted china ebay seller and installed that. After getting my hands dirty with that one, i decided to put the whole thing into a little DIY enclosure.
On the To-Do list are still a couple things:
-Getting a better feeling for work-piece securing ( I think most of my vibration problems come from that, and it isnt that easy with thin/bendy plywood)
-Dust collection
-Building a box for the electronics, which atm, are just sitting on top of the enclosure
-Finding a safe way to run the wires into the enclosure ( I am thinking of cutting out slots and filling them with the cable+some insulation ( probably heatpipe insulation) to make it airtight and dust-proof again
Some pictures in the post of my progress and a little video of cutting out a small piece.
