How accurate is your machine when making any thing other than strait lines?
Reason im asking is mine is incapable of anything better than .026 way off from inventables claim. Thats 9 sheets of paper on a small 1.5 inch circle, way to much to get by with. Now if that was on say a 16 inch or bigger circle then no big deal.
No matter what i have done the past 4 months can this thing cut even close to claimed spec. NO its not v wheels or belts. I have tired belts from 3 lb at one inch to 6 lbs at one inch, 4 ounce increments and v wheels from loose to tight and everything in between
When you cut the same circle, is it always the same offset?
If so, have you calibrated your machine by adjusting the steps per mm settings?
Im having the same problem. especially with the Z axis. I have tried everything suggested by inventables and the forum community. While I appreciate the help, I haven’t resolved this issue since receiving my machine in July. Very interested in anything you may learn.
no exactly the same but very close. I have calibrated it through grbl but that didnt change the circle problem. at the same time customer serive at inventable told me NOT to change the steps. I so frustrated after 4 months of cutting wood for test im ready for a differen machine.
just to let eveone else know the machine is dead on balls square in every direction. i have checked at least 20 times. What a wast of time and money this has been.
They have their engineering position on the steps/mm setting, but the real world proves one might need different settings. If you check other forums such as Shapeoko, the predecessor to X-Carve, you’ll find discussions about calibrating. The result is always an adjustment to the steps/mm setting for X & Y and possibly even on Z. For instance, my X & Y are set at 40.04 to get proper results.
which spindle are you using?
Mine is accurate within .005", and once I get the Y axis stabilized and put on the 611 I will be able to dial it in a bit more. I had to calibrate the steps/mm, and my X/Y are something like 39.8.
i have the Dewalt 611, steel in the x axis and bracing a long the Y axis. im wondering if there is some kind of racking going on, let be be clear the X is square and true.
I have changed the steps per mm but in tryng all suggestion from customer service and the forum BUT changing the steps did not help the circle issue. It did get anything with strait lines dead on.
Does it return to the same home position, or is home off by .013" or .026"?
Have you tried doing larger circles? It would let you know if the error is linear or fixed.
If you are having a problem microstepping, which could be due to controls or low pots, it could cause your machine to lose a few steps when the steppers initially try to accelerate from 0 (twice per circle). The error would be common on every single round, so it wouldn’t compound to give you a stair-step cut on one of the sides. You’d basically get a circle that is just slightly undersized and perhaps slightly misshapen by a few thousandths at the 3, 6, 9, and 12 o’clock positions.
To test the low pot/microstepping theory, I would suggest you cut a circle and measure in the X and Y directions, exactly parallel with the axes (maybe cut a + in the middle of the circle to help find the exact axis points). Then turn just ONE pot up slightly (30 degrees max) and recut/remeasure. If the measurement in the direction of the pot you tweaked changed, you would know the pots are a little low.
There’s no stair steeping going on. Circles are miss shaped in the 5 and 11 o clock position.
Was it cutting clockwise, or counterclockwise?
I ve done both the results are the same. Im using a new bit as well.i cant understand why its only circles. I thought a while back maybe it was a power issue since three steepers are running constantly at the same time. But i don’t know how to test something like that.
I’m thinking it’s the pots. If you think of the stepper motors as cars, then with the pots too low you’re trying to take an old underpowered Buick from 0-60 in 4 seconds (I can tell you from experience that they don’t accelerate worth a crap). With the pots too high, you’re burning rubber on an overpowered sports car, and are likely to blow the tire and crash.
On a circle, the Y axis isn’t moving at the 6 and 12 o’clock positions. It may even be fighting inertia from the travel to get there. With the pots too low, it could take a fraction of a second longer than normal to cause movement on the Y, which means the X would actually cut too far out from the center of the circle. That could happen in the 11 and 5 o’clock areas if cutting counterclockwise. Same idea for the X axis, just rotate your perspective by 90 degrees.
I’m not sure why it wouldn’t be happening in straight lines, but that would explain a little bulge in the 5/11 or 2/8 areas.
Have you measured the actual size of the bit you are using with a micrometer? I have discovered that the marked size is not always very accurate. If your bit is slightly off from what you think it is, the error will be doubled for most cuts.
+1 for the bit size. Bit size and collet runout can add up. My X-Carve became much more accurate after I replaced the stock collet with a Precise Bits and made sure to measure each bit with calipers and manually enter that measurement in the software. I also had to change the washers in the X axis V wheels to keep the gantry tight to the rails after performing the stiffening mod. There will be tilting movement in the gantry if you dont. #10 by 0.032" fiber washers do the trick. I am referring to the spacers inside the V wheels… you have to take them apart.
Unfortunately, your troubleshooting does not sound correct.
Changing the calibration WILL make the object you are cutting a different size. There is no way it cannot.
If you changed the calibration correctly, the a 1.5" diameter circle will 1.501 or 1.499 depending on what you changed the calibration.
Previously, if you were getting 1.484 and still getting 1.484 then you did not calibrate correctly.
Theses are great suggestions. Ill give them a try today and let you know.
I do have the precision collet in the dewalt if i remember my run out with that was .002. I have measured the bit its .125. So somewhere there’s still .024 to .027.
What size stepper do you guy have 17’s or 23’s? and size of your xcarve 500 or 1000mm?
So today I checked everything i could think of spent 7 hours doing so. when i was all done did a test of a 1.5 inch circle and very little improvement. Set the machine to cut .065 Dp, 30 inches/min both climb cut and conventional with a .125 upcut ( actual .116) Dewalt running one setting 1.5. Only .004 so its still cutting a circle that varies in the circumference of .024 before doing all this it was .026.
Have pics to with some explanation of what i did.. A list of things i checked or did or changed.
- Loosened all 3 belts.
- checked and adjusted the v wheels to thumb tight
- took 8 v wheels apart and measured the distance of the seat .046 the washer is .044 thick. put them back on. ( v wheels are new they are not what came with the x )
- checked all the nuts and bolts, locktighted them.
- checked the Y rails for square and parallel, checked out perfect.
- checked Y rails for square to the wast board dead on except 1 its out by .0015
- checked X rails for square to each other top to bottom, front to back. again dead on except one spot .0015 must be in the manufacturing because it less than .5 inches.
- checked X for square to the wast board right on the money
- installed a bit in the spindle and used a fishing scale and dial gauge to check for flex. At 5 lbs of pull toward the front it flexed .010 and when pulled toward the back it flexed .009 so a total of .019.
- checked the X rails for flex only. used a fishing scale and a dial gauge. the dial gauge was set just under the v on the rail. at 5 lbs of pull towards the front it flexed .045 and flexed when pulled towards the rear .035. so a total of .08
- installed a bit in the spindle and measured the flex of the spindle and gantry in the X axis ( left to right) 5 lbs pull with a fishing gauge and a dial gauge. left .011 and right .015 total movement .026
- set a dial gauge in the spindle to measure the Z axis for square to the wast board. what i came up with it measures 7 inches from the center of the spindle to the center of the dial gauge. The difference in 180 degrees and 14 inches is .005 so at the bit its probable not measurable with what i have.
- tighten the all the belts to 3 lbs 8 ounces.
- checked the grbl calibration had to make very small changes.
- turned up the X, Y pot. after running some turned the X back down.
I think its comming from all the flex in the x axis rails, gantry and Z axis where the v wheels are. Its .019 front to rear and .024 side to side.
What do you think. Did i do everything correct or did i miss something?
I forgot to mention the calibration is within .0005 i run it 10 times just to make sure. For some reason it only moves in inches, the last update to Java did that. I cant get it to mm in the calabration.