Sorry you’re 100% correct on this particular one, I actually ran the 6x5.4375 file on a 6x6 piece of material so that’s definitely where that huge deviation is coming from. HOWEVER, I was going to post about this before running that piece as I have been having issues with other pieces aligning between the file and real world. I re ran the file on a 6x6 and this was the result. Still not matching what carbide motion thinks it’s sending out.
Top
The left and right distances should be 0.266 evenly top and bottom should be 0.565
So here’s the two pieces next to each other 1st run with the wrong sized file on the left new one on the right, so you can see it’s closer but it’s still not right.
How did you set your work zero? If you want something centered on your stock, use the center of your stock as your work zero.
Can you measure the width of your cut slot?
Work Zero is referenced off a fence. I regularly recalibrate the 0 to the fence with a bitzero as well as using it to set my Z 0 when I switch material thicknesses. Width of cut varies from 0.250 to 0.256 depending on where in the slot so within tolerances I would expect from machining MDF.
There are many ways to get something centered in your stock, in this case the vectors are aligned to center stock in Carbide Create before the toolpaths are created. I assure you it’s centered in the stock as you can see from the images I’ve attached of both the Carbide Create file as well as the preview out of Carbide Motion. You can check out the file I’ve uploaded to this thread if you don’t believe me
Are you using bitzero v1? if so, I believe tool diameter used to zero will make a difference in x, y. I could be wrong because I do not have a bitzero but using a Triqueta with cncjs, I had to write custom macros to account for tool diameter to zero with bits of different diameter. I do not use a touch probe anymore, favoring Neil’s suggestion of zeroing x,y to stock center.
I believe you that the design is centered in your files, but it is not centered on the stock (the reason we’re here). If you set zero at the stock center, the result will be centered regardless of dimensional accuracy issues due to belt stretch or deflection or calibration settings or effective cutter diameter or errors in your XY zero.
In the c2d file you posted your design is in the center of your stock. I would think that if the hex is dimensionally accurate, the .5" squares are the correct size and in the right position, the machine is in good working order. The only other variable is how and where you set X/Y zero. I’d try diagonal lines corner to corner and a vee bit at the intersection to set X/Y zero.
So you’re suggesting that if I drew a line from each corner of the stock across the face and set the zero at their intersection that the file would somehow behave differently than with the zero set at the bottom left like I have it?
What in the world is the point of having a bit zero and a fence setup if I’m going to have to manually set the zero to the middle of a work piece every time and more to the point since my values all line up on the model and on my real world stock pieces why am I experiencing such errors? I understand you’re saying that doing a center zero is likely going to help with this due to the nature of the zero being in the center keeping things better centered regardless of the stock size but why is this necessary if all the data is correct in my file with the zero set bottom left? Seems like the machine isn’t working like it should be at that point. Also my hexagons are coming out at 4.350 instead of the 4.370 which means the tolerances are 0.020 which is higher than I can work with for woodworking and definitely higher than anyone doing any real machining would need, It’s not like there’s just runout in one direction, the whole hex is smaller than it should be.
Sorry if my tone is coming off as frustrated, I am, and I really appreciate the help. I spent all weekend making test pieces that were all wrong on an expensive piece of equipment I’ve spent years learning that I thought I had a real solid handle on that’s suddenly decided to not cooperate with me.
This wasn’t an issue until the last few months and so I’m just really struggling to understand why it’s suddenly such a big issue.
Cutting aligned to the center of a piece of stock by registering at the lower-left (or any) corner will only work if:
the stock is accurately measured and secured square relative to the motion of the machine
the machine is calibrated so that its motion matches that of the measurement used for the stock
The usual way that I ensure things are square/centered is to use an over-size stock area in Carbide Create and first machine a pocket to put the stock into — then secure the stock centered in that pocket, then cut w/o changing the origin.
Sure, but would this affect the hexagon being smaller than it’s supposed to be by 0.02"? My complaint isn’t that the cut paths aren’t square to the edges of the stock, it’s that their real world values have shifted to not be what Carbide Motion shows me it thinks it’s outputting.
How would one do this calibration? Is this the belt calibration that you linked further up in the thread?
So anchor an oversized piece of waste material to the spoilboard, machine a pocket in said material, then anchor the stock to be milled into that pocket?
Again I really appreciate all the help here y’all invaluable.
You need to calibrate the machine for belt stretch in order for it to move at the specified dimensions.
Then, once machine movement is as expected you will need to adjust for how material reacts to being cut — usually the best way to dial in a cut is to cut slightly oversize, then adjust the file/tool specification and take a finishing pass. Iterate on this until you get the desired level of precision/accuracy.
Out of curiosity what is the appropriate amount of belt tension to have? I’m wondering if after 2 years of operation I might want to tighten these belts a bit?
Check the underside of the belt for a damaged tooth. This can cause a skip as the router is moving to position to cut. If the damaged area of the belt is not in the location of your project you won’t see at the distortion in your project but it will not be in the place you want it to be.
nope, just the first time. With what it looks like you are doing, once you set the x-y zero it will remain the same with each piece of stock you place under it and up to the fence. Might have to check the “z” though…
If the machine is configured correctly ($100 and $101) and if the belts are not stretched and are tight, the hex would be accurate in width.
If the machine was configured correctly prior to belt stretch ($100 and $101) and if the belts are stretched and tight, the hex would be cut too large.
Based on the above; assuming the machine was configured correctly and assuming belts do not shrink, the belts are either stretched or they are not.
Therefore, the belts are either not tight or the machine is not configured correctly because the hex is neither accurate nor too large.
