My Rapid Postions are changing

after I start jogging. (Shapeoko3 XL). Just finished another vacuum spoil board, starting in to resurface the top. Chucked a 1/4" endmill to find all my Rapid Positions. Initialize Machine goes to the same spot (Home) every time, so that’s “good”.

Jog to NE, then E, then SE, then N, then S, then NW, then W, then SW. Each stop make a .03" plunge.

Here’s the frustrating part. After an Initialize and end my jogging at the SW corner, jog back to NE and it’s approx 12mm to the right of the plunge I made. Jog to E and approx 12mm to the right, jog to SE and 12mm to the right.

Jog to NW, W and SW and they stay the same. Jog to N and S and they alternate from same first plunge to being 12mm to the right.

Does this sound familiar to anyone?

The internal code is not the problem. The machine moves to where it “thinks” it should be. Likely you have a mechanical problem and you are losing steps. Start with your V-wheels. Then check your belt tightness. Power off your Shapeoko and slowly move the gantry front to back and back to the back. Then left to right and back right to left. The machine should move smoothly. If you move anything too quickly the stepper motors create an EMF back force and it will sound like the belts are slipping. So go slow. If everything moves smoothly adjust your v-wheels. Make sure your belt tension clips are not canted. When you tighten the belt retaining clips they tend to rotate. So if they are crooked slightly loosen the bolt and hold the clip with a pair of pliers and tighten. This keeps the belt clips from rotating from the torque of tightening the bolt. When the machine gets to the front and/or back one of the belt clips could be stopping the machine from going all the way and you will lose steps. Since you said the offset is right/left check the belt on top of the gantry.

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I appreciate your response. After poking around google search I found the assemble manual. It details assemble of the Z carriage and Y’s. I can’t see where the v wheels are adjustable. I looks like they come installed on the Z carriage. I’ll inspect the idler pulleys closely again tomorrow, they appear to have a gunzy build up on them.

I’ve also got an email into Carbide to see if they stock 9mm timing belts.

Ah, I found a video on adjusting the V-wheels…

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Check the stepper motor pulleys too.

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Can you post the link to this video please?

See

Tnx William, you beat me to it.

I’m back to it troubleshooting. Doesn’t make sense that the machine is missing steps because the end of the mystery jog is outboard of the initial position. Beginning to wonder if Rapid Positions are exactly precise repeatable coordinates and the machines working coordinates are what matters.

The rapid positions are very precise. I preface that with this. Every time you initialize the internal coordinates are created and that is used to go to the rapid positions. So the initialization position could be off a few thousands but not 12MM. You are losing steps and that is the only explanation for you losing your position shy of a few thousands from homing. Keep troubleshooting and if necessary contact support@carbide3d.com for help. Of course as always help is also available here.

Check mechanics of v-wheels, stepper pulley, belt tension and any obstruction like your drag chains or router power cord. Keep going you will find the issue. If this was a software issue you would find it all over the forum. There are people that have issues but it is not with the software. It is 99% of the time mechanical and the 1% a mystery. I will take those odds in Las Vegas.

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