I ran my new MPCNC for the first time tonight. I printed the parts, am using 3/4" conduit, bought the parts kit from V1 along with my Rambo and the LCD. The build is 24" x 24" x 4".
When I jog either the x or y axis, the movement isn’t smooth. At some spots across the axis it smoothes out, but it shakes at the gantry and at the stepper motors. I am jogging only using the LCD and the Rambo, no other software, just moving it 10mm at a time, back and forth across the entire 24" x 24" work area.
I have noticed two things, but need the advice of you guys as I believe the shaking is bad enough that the crown exercise would not turn out well.
I cleaned the conduit, but it doesn't seem very smooth. I re-sanded a couple of sections of the rails and it makes a slight difference but not enough, so I'm thinking it's more than this. Should I sand down the conduit more?
When I measure the distance from the y rollers to the corner, the measurement is off by 1/8". When I measure the x axis it is spot on. I took a good deal of time squaring up my rails and squaring the x/y to the gantry, so I'm not sure where this 1/8" is coming from and not sure if it's causing the issue. I'm not sure how to get rid of it either (tension bolts A and B?).... my only thought is my gantry alignment is off. [attachment file=74825]
[attachment file=74824]
I'm very excited about where I am at this point, but don't want to move forward until I know what is going on. Also, my z axis is very smooth.
Any help is greatly appreciated. Thanks in advance.
The rails are square. I checked the distance across the x and y and the distance to both corners.
The belts are not slipping. The tension on both sides of the belts isn’t perfectly balanced, but it’s not far off.
As the unit moved, I felt each bearing and they are all turning. There are a couple in the gantry that I can’t reach, but everything is in contact with the conduit.
FYI, I checked the bearings when the machine was jogged and felt the bearings move. I will check to see if the bearings move without the gantry moving…
At least that tells us that the problem is most likely mechanical. If it was smooth when you moved it by hand and rough when moved by itself that would point to electronics.
It sounds like the tension bolts where a little tight. Check the X rod to make sure it doesn’t have dents, bends, or flat spots from the tight fit. Also make sure Tension “Bolts A” are loose. I mean the bolt not just the nut. Sometimes the bolt threads get caught on the plastic and still hold it tight. (Happened to me.)
The bolts on the bearings in the gantry were too tight and since you can’t get to all of them, it was a total tear down and re-build… but that’s fine, because I’m moving smoothly now!
Wanted to include my crown test here after fixing my issue… Looking good.
[attachment file=75154]
With the crown on the right, I printed it 3 times on top of itself. You can’t see any thickening, blurring, or double lines. I’m happy… any comments from you guys is always helpful.
I cleaned up the wiring yesterday using the tape measure trick… love that for $5.
I’m not happy with the tape measure on the z axis, (especially that it won’t support the DeWalt cord) so I may get my son to print up the y axis caps so I can run some aluminum across and a cable chain.
