Just ran my first actual cut in MDF, the cut went well. Cut time was 23 min vs 43 min that Chillipeppr estimated which was kinda strange. But the part that’s bothering me is that the circles are not perfect circles. I ran square tests with a pen prior to my first cut and seemed to be making accurate squares within 0.006". But I can clearly see that my circles are not perfect. Anyone have recommendations on how to tune that? I thought once I got my motor travel per resolution tuned I would be good to go.
I literally was doing the same thing tonight. It ended up being a loose belt on my X axis. If you have slack in the belt the backlash will show up more in cutting a circle then a square. Tightened up my belts and things are much closer to perfect circles.
@Jason_D
What a coincidence, come to think of it I do remember putting less tension on my X Axis during the build. I will give that a try thanks Jason. congrats on your first cut too!
Thanks Matt. Hope that solves it for you too. My circles were more like two capital D’s put together back to back. Adjusting my steps on the x axis corrected the overall dimensions but the circle was still skewed. Tightening the belt and putting the steps back to the original setting solved it. Still have to fine tune a bit but familiarising myself with my software and workflow first. I built this mostly for 3d wood carving. I thought there was more freeware out there for 3d milling, but I’m are seeing now that there is not as many options as I thought.
My machine is not a true ox, rather a varient based on open builds 40x40 extrusions. I 3d printed all the plates and a few other parts (almost 30 total) now that the machine is built and running I plan on cutting replacement plates out of aluminum. I plan on doing a write up of the build once it’s finished.
@Matt_Herrera Here is a set of lines and circels I used to tune up my ShapeOko2. https://dl.dropboxusercontent.com/u/50261731/ShapeOko_Calibration_Pattern_01b_cjm2_complete_2.nc
Run with a pen or engraving bit for minimum drag on machine
@Matt_Herrera Also, are you running tinyG fw-440.18? Do you have motors set for “in-cycle”, $_pm=2?
I learned the hard way that setting the motors to “when moving” was not correct - as my Z axis lowered into the material then ploughed down another inch into it - luckily I was hovering over the feedstop and didn’t break the bit.
Pulley set screws have caused this a couple times for me.
@Jace_Richardson @cmcgrath5035 @Jason_D @Kevin_Warner
Hi guys sorry for the delay in response I’m on Hawaii time so when I get off work it’s already pretty late for most of you. I’m going to try to tighten up the belt today and double check pully tightness. I am runny TinyG V8 firmware 17. I also need to double check how straight my X/Y extrusions are, my X extrusion was a little short and when I bolted the gantry plates to it I noticed some strain when rolling back and forth on the Y axis. I really appreciate all the feed back I get on this forum it’s very helpful to ping thoughts off one another.
quick update, my belts were pretty loose so I snugged them up and one of my pulleys was also loose which surprised me because I just tightened it the other day. I think I need a new pully, the set screw keeps coming loose I think because the Allen wrench can’t really tighten down on it. I’ve tried all my Allen wrenches metric and standard and none really fit well. I think the set screw is not sized correctly maybe a bad screw? I had to use needle nose pliers to turn the screw snug. I’ll probably use some lock tight as well to keep it in place. Didn’t have time to run any test but I’ll give it a try tomorrow. Mahalo again for all the tips.
@Matt_Herrera
It does sound like set screw or perhaps pulley issue. Lots of torque on that shaft interface with NEMA23s, need a good tight grab.
Do your stepper shafts have a ‘flat’ for set screw? you might want to file one for improved grab.
Quick update: I tightened up my pulleys and gave some test runs things are looking allot better! Thanks for the support guys!