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### Author Topic: Can I "level" my work piece in software?  (Read 4317 times)

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#### bmquist

• 5
##### Can I "level" my work piece in software?
« on: May 11, 2015, 02:32:37 PM »
My "problem" is that I have a 1,5x1,5 meter size plasma table and the edges on the table are standing 1-3 mm higher than the working area so if I am cutting larger plate that stands out of the working are it will be inclined, so the Z height is not the same all over the plate. I know the best method is to have a THC to control the Z axis but I find it too expensive and I think that if I could manually "level" working area in software that would mostly solve the problem I am having. the workpiece can also be tilted because of other reasons than the piece standing out of the table of course....

What I was hoping would be possible was that I could go to each corner of my working envelope, and zero the Z axis in mach 3, and that mach3 would then recognize that the plate is a little bit inclined/tilted, and it would take that into account when cutting and increase/ decrease the Z height depending on where it is positioned at each time on the table... is this possible? I was also thinking if it would be possible to manually adjust the Z height when the program is running ( because sometimes I could simply adjust the Z height using the keyboard and watching the gap between the workpiece and the nozzle. with these possibilities it would solve most of the Z height problem, I already have a floating height Z for zeroing the Z height before each pierce.

f.y.i I have hypertherm powermax 45 plasma cutter

#### SSPW

• 26
##### Re: Can I "level" my work piece in software?
« Reply #1 on: May 11, 2015, 07:56:17 PM »
You can use formulas.
I made a excel worksheet that calculated best fit for n points around table.
http://www.machsupport.com/forum/index.php/topic,29597.msg206297.html#msg206297
The sheet assumes the table is planar but sloped.
You can change the formula and solver setup to solve any shape model.
Sounds like your table might be better with a parabolic (2nd order) model.

#### Dazed+Confused

• 11
##### Re: Can I "level" my work piece in software?
« Reply #2 on: May 12, 2015, 04:33:10 AM »
Check this out...for PCB engraving originally
http://www.autoleveller.co.uk/

#### bmquist

• 5
##### Re: Can I "level" my work piece in software?
« Reply #3 on: May 12, 2015, 07:53:28 AM »
You can use formulas.
I made a excel worksheet that calculated best fit for n points around table.
http://www.machsupport.com/forum/index.php/topic,29597.msg206297.html#msg206297
The sheet assumes the table is planar but sloped.
You can change the formula and solver setup to solve any shape model.
Sounds like your table might be better with a parabolic (2nd order) model.

Thanks SSPW
this is exactly what I was looking for, not sure why you think my table might be better with parabolic model (not that I disagree, I just don't know better ) could you explain in few words why you think that? usually the problem is that the whole sheet is planar but sloped like you describe.

#### BR549

• 6,952
##### Re: Can I "level" my work piece in software?
« Reply #4 on: May 12, 2015, 11:21:28 AM »
Why not just trim the edges of the table so it can sit flat ??

(;-) TP

#### bmquist

• 5
##### Re: Can I "level" my work piece in software?
« Reply #5 on: May 12, 2015, 12:02:09 PM »
Why not just trim the edges of the table so it can sit flat ??

(;-) TP

thanks for the advice, but I want to keep the option to have the workpiece submerged in water (or atleast so the bottom side is sitting in the water) and therefor the edges have to be a little bit higher than the "slats" that the workpiece is sitting on, but there can also be all kinds of other things making the workpice not perfectly level/parallel to X and Y, like dross sitting on the slats, or the slats height is a little bit uneven.... but using Formulas like SSPW pointed out was what I was looking for and solves my problem for now... I am thinking to get a Proma THC for controlling the torch height, Then it does not matter if the workpiece is flat, sloped etc.

#### BR549

• 6,952
##### Re: Can I "level" my work piece in software?
« Reply #6 on: May 12, 2015, 09:32:27 PM »
The problem with linear corrections is  the material will never be lying flat on the table and your torch cutting at the correct height WILL hit the material as it will be bowed being propped up on one side NOT linear .   EVEN with a GOOD thc it is not an ideal situation for Plasma cutting.

Just a thought,  You mileage may vary (;-) TP

#### Banr

• 12
##### Re: Can I "level" my work piece in software?
« Reply #7 on: June 05, 2015, 01:08:10 PM »
strange they don't have a way to do this, its basically standard in the 3d printer world

#### rcaffin

• 1,035
##### Re: Can I "level" my work piece in software?
« Reply #8 on: February 06, 2016, 06:49:27 PM »
Quote
You can change the formula and solver setup to solve any shape model.
Sounds like your table might be better with a parabolic (2nd order) model.
Excel Solver is OK for linear models, but is not so good for 2nd order models. I have just spent a day trying to do this for a simple case of a PCB with a bulge in the middle. You can get this sort of surface when you clamp the 4 corners down. The results were not usable imho. A pity.

Cheers
Roger

#### SSPW

• 26
##### Re: Can I "level" my work piece in software?
« Reply #9 on: February 07, 2016, 08:39:50 AM »
Excel works fine for fitting 2nd order and other models. This tool was never intended to you with pcb milling. It was intended as a quick global slope correction tool. The real pity is your assumption that your setup was 2nd order and you spent time on it. As another poster mentioned, there is a perfectly good tool for pcbs.