Machine never cuts the same area twice after homing XXL

[lxkhn (Alex Kahn)]

I’ll run the machine and hog out material very conservatively 2mm passes with a 1in surfacing mill cuts great no chatter very clean cuts, I switch out to a 1/8th in end mill to finish pass the insides of the area I cut and that cutter is off about 6mm in the x and y axis vs where the original cut is right off the bat on every single cut I made 1mm passes this time so it’s not being pushed too hard and skipping on the belts.

I replaced all the belts and all the v-wheels yesterday the machine jogs just fine across the entire area

It’s not consistent ether some times it’s just the x axis that is off some times it’s just the y some times it’s a small amount maybe 3mm some times it’s 8mm

Here are just a few examples.

I’ve checked the CAM, I’ve checked the machine, I’ve replaced all the parts I can replace I don’t get it.

I have everything ferrite beads all everything I could put it on USB, power to the spindle, around the cables for the steppers, everything is grounded spindle, PC, Shapeoko. I’ve checked the grounds and they are all wired correctly.’

It used to work just fine but this has been my life for about 2 months now.

I’m about ready to run into the woods and call it.

[Microwave_Monkey (Scott)]

Maybe check the set screws on the x-axis motor pulley?

[neilferreri (Neil Ferreri Ω)]

If you set zero, home, return to zero… Does it go back to the same spot?

[lxkhn (Alex Kahn)]

set screws are fine just double checked them. I had the machine completely apart last week and reassembled to make sure everything seemed correct I even had the plates off the y gantry.

@neilferreri I’ll see if I can test it a few times

[WillAdams (William Adams (Carbide 3D))]

If you can’t find anything mechanically wrong, it’s feeds and speeds.

I would suspect belt tension though, just be careful not to bend the motor shafts.

[GIban671 (Girard Ibanez)]

Does the gantry track in a straight line … I had 1 v-wheel tight and the gantry pulled to one side on the y axsis.

I only discovered this issues when I laid straight edge and ran the gantry from the front to the back.

[lxkhn (Alex Kahn)]

@neilferreri I set zero drilled a hole homed jogged the machine around for about 3 min and went back to the zero and it hit dead on.

@WillAdams I tightening the belts as much as I could, I could get one finger in between before but now I can’t get any. I’m testing again now my speeds and feeds are fairly conservative and the passes are very light.

@giban671 I tightened all the vwheels before the belts were installed to make sure there was no issues with sticking.

[GIban671 (Girard Ibanez)]

I did the same as you, adjusted all wheels with out the belts. Tested each v-wheel on the eccentric nut by hand, rotating and feeling the friction or force slippage it takes the v-wheel to move before slipping.

Again adjustments were all by feel. I only notice that the Y axis did not track straight was when I paid close attention when I jogged the Y axis front to back and vice versa.

Have tried checking if the gantry runs in a straight line?

[lxkhn (Alex Kahn)]

It does I tightened the belts more and it seemed to help

[GIban671 (Girard Ibanez)]

Shapeoko XXL won't center on stock

After extensive efforts and time; I come to the conclusionn how accurate does the belt tension adjusment need to be? The 125mm known distance using a Chinese HF digi caliper did NOT provide stable results. So I tried another method as seen in the pix. Converted inches to mm, recalibrated, and checked the results along the full travel of the Y axis. Then I randomly pick distances within the Y axis and had good results. What is a good result? Well the naked eye can discern just how far the poi…

[GIban671 (Girard Ibanez)]

Check my post / thread in the above … not sure how to link it using mobil device.

Scroll through the post and I calibrated my Y and X axis using a tape measure and small vbit.