Different layers not lining up when cut

[@metalman23]

So I have a file that has 2 different layers, one for the main cutouts at a faster speed, and one for some holes, at a lower speed, so they're more accurate.

When I run the file on my table, the holes are coming out off center from the other cutouts, on my cad file, the holes are perfectly lined up, I don't see how on earth this could be, or what to do about it.

I guess I could drill the holes out later, but thats not the point of spending a bunch of money on the stupid plasma table

20240221_093330.jpg

[Larry83301]

It might not be the table. Have you verified the positions of the holes in the cut program, if so then try doing the holes FIRST and then tthe part. Just my two cents


Larry

[acourtjester]

Are the 2 layers planned together using SheetCam for 2 separate operation or 2 separate plans. The way I would plan that is a single layer in the DXF file and then in Sheetcam move the holes to a new layer. Cut plan cut holes first with slower speeds and the the other as a second step with the original layer at the fast speed.

[68rscamaro]

What software are you running? If you're using sheetcam you simply put everything on one layer and have it slow down on holes.
Without seeing more it's hard to tell what's going on, Could be an offset issue but who knows. I guarantee that it's user error though and the machine is doing exactly what you're telling it to do!

[@metalman23]

It might not be the table. Have you verified the positions of the holes in the cut program, if so then try doing the holes FIRST and then tthe part. Just my two cents


Larry

In sheetcam the holes look lined up perfectly

[@metalman23]

Are the 2 layers planned together using SheetCam for 2 separate operation or 2 separate plans. The way I would plan that is a single layer in the DXF file and then in Sheetcam move the holes to a new layer. Cut plan cut holes first with slower speeds and the the other as a second step with the original layer at the fast speed.

My cad drawing had 2 separate layers, that I used in sheetcam, I'm not sure how to separate entities in sheet cam into different layers

[@metalman23]

What software are you running? If you're using sheetcam you simply put everything on one layer and have it slow down on holes.
Without seeing more it's hard to tell what's going on, Could be an offset issue but who knows. I guarantee that it's user error though and the machine is doing exactly what you're telling it to do!

I'm using sheetcam, how do i use 2 different cut speeds on the same layer?

[68rscamaro]

What software are you running? If you're using sheetcam you simply put everything on one layer and have it slow down on holes.
Without seeing more it's hard to tell what's going on, Could be an offset issue but who knows. I guarantee that it's user error though and the machine is doing exactly what you're telling it to do!

I'm using sheetcam, how do i use 2 different cut speeds on the same layer?

You can make rule in "path rules" something like on holes smaller than 1.5 in. set feedrate to 50%

[TJS]

Edit contours=>Right click on hole(s) then:
Layer 1 Name it "holes", Inside offset.
New Jet cutting operation in sheet cam slow the holes down to 60% of book speed with all the other correct properties as well. Not sure what you are running.
Edit Contours=> Right click on your outside object
Layer 2 Name it "outside cut" or whatever you want.
New Jet cutting operation for this. "Outside Cut", outside offset. Regular book speed with all the other correct properties.

When you state the holes are coming out off center. Do you mean egg shaped and not round.

Note: when I refer to book speed i am referring to the Hypertherm mechanized cutting charts. Not sure what toolset you have loaded in Sheetcam either.

[Larry83301]

It might not be the table. Have you verified the positions of the holes in the cut program, if so then try doing the holes FIRST and then tthe part. Just my two cents


Larry

In sheetcam the holes look lined up perfectly
[/quote'}

Look at the file that you are sending to the machine and see if the center line of your part and the center of the holees are inline, not in your CAD program but in the actual file that your plasma machine gets.

Larry

[@metalman23]

Edit contours=>Right click on hole(s) then:
Layer 1 Name it "holes", Inside offset.
New Jet cutting operation in sheet cam slow the holes down to 60% of book speed with all the other correct properties as well. Not sure what you are running.
Edit Contours=> Right click on your outside object
Layer 2 Name it "outside cut" or whatever you want.
New Jet cutting operation for this. "Outside Cut", outside offset. Regular book speed with all the other correct properties.

When you state the holes are coming out off center. Do you mean egg shaped and not round.

Note: when I refer to book speed i am referring to the Hypertherm mechanized cutting charts. Not sure what toolset you have loaded in Sheetcam either.

When I say not lining up I mean that the hole layer, is completely misaligned with the other layer even though they line up perfectly in the drawing, so the holes are about a quarter inch off of where they're supposed to be

[acourtjester]

here you go

speed.JPG

[weldguy]

These guys have good advice for getting a better quality hole but I realize it won't solve your issue of the holes being misaligned.

Since you are sure everything looks good in your software one thing you could check is your rapid speed. Many people like to max out the rapid speed, but some tables can't handle it and can lose steps or positioning on acceleration, deceleration, during the rapid, or all of them.

Worth looking into anyway. Let us know.

[@metalman23]

i can try running the program after separating the layers in sheetcam, but i'm running out of 14ga, i need to get one of those pen holders TJS has, and figure out how to use it

[@metalman23]

These guys have good advice for getting a better quality hole but I realize it won't solve your issue of the holes being misaligned.

Since you are sure everything looks good in your software one thing you could check is your rapid speed. Many people like to max out the rapid speed, but some tables can't handle it and can lose steps or positioning on acceleration, deceleration, during the rapid, or all of them.

Worth looking into anyway. Let us know.

I can look into that, everything that messes up on this machine, always messes up on the x axis, so it may be a mechanical problem, i'll have to go over everything and check that i'ts tight

[TJS]

i can try running the program after separating the layers in sheetcam, but i'm running out of 14ga, i need to get one of those pen holders TJS has, and figure out how to use it

@acourtjester is your man for the pen tool. Best material saver.

[adbuch]

Sharpie pen holder for cnc plasma on Ebay as well. I often use one for drawing the part instead of cutting while I am getting it dialed in. A great material saver, and very easy to use.



https://www.ebay.com/itm/115805862457?i ... R5r_-t-6Yw

David

sharpie pen holder for cnc plasma.jpg

[@metalman23]

What software are you running? If you're using sheetcam you simply put everything on one layer and have it slow down on holes.
Without seeing more it's hard to tell what's going on, Could be an offset issue but who knows. I guarantee that it's user error though and the machine is doing exactly what you're telling it to do!

It's not doing what I'm telling it to do, it's doing whatever it damn well pleases and Premier plasma doesn't want to help out at all

[adbuch]

What software are you running? If you're using sheetcam you simply put everything on one layer and have it slow down on holes.
Without seeing more it's hard to tell what's going on, Could be an offset issue but who knows. I guarantee that it's user error though and the machine is doing exactly what you're telling it to do!

It's not doing what I'm telling it to do, it's doing whatever it damn well pleases and Premier plasma doesn't want to help out at all

metalman - we really need more information to try to effectively help you. I took a look at your photo showing the 4 holes being offset from the center of the part.

hole pattern off.jpg

The holes appear to be nice and round, so I doubt there is a problem with slop in your machine's x-axis or y-axis. Assuming that your original dxf file has the hole pattern centered on the inner cutout - I would more suspect that this could be the result of using two separate programs to do the cutting - one for the center part and another for the hole pattern. If the work coordinates of these two separate programs somehow got shifted so that they are no longer coincident, then that is one possible explanation.

As Tom asked a while back: "Are the 2 layers planned together using SheetCam for 2 separate operation or 2 separate plans. The way I would plan that is a single layer in the DXF file and then in Sheetcam move the holes to a new layer. Cut plan cut holes first with slower speeds and the the other as a second step with the original layer at the fast speed. "

If they are 2 separate plans, then that could cause this sort of problem with the work coordinates being off between the 2 plans.

David

[adbuch]

So I have a file that has 2 different layers, one for the main cutouts at a faster speed, and one for some holes, at a lower speed, so they're more accurate.

When I run the file on my table, the holes are coming out off center from the other cutouts, on my cad file, the holes are perfectly lined up, I don't see how on earth this could be, or what to do about it.

I guess I could drill the holes out later, but thats not the point of spending a bunch of money on the stupid plasma table
20240221_093330.jpg

Have you tried using a single layer just to see what happens? As has been mentioned previously, I would suggest using a sharpie pen holder and drawing your file (instead of cutting it) so as to not waste any more material. If you decide to try the sharpie method, let us know and we can help you to use the proper settings for your testing. With the sharpie, you could try using your 2 different layers as well as a single layer to see if there are any differences in hole locations between the two methods.

David

[raed]

Double-check everything's tight and the machine's calibrated. You could also try running the holes first, then the cutouts, to see if it makes a difference.

[@metalman23]

So I have a file that has 2 different layers, one for the main cutouts at a faster speed, and one for some holes, at a lower speed, so they're more accurate.

When I run the file on my table, the holes are coming out off center from the other cutouts, on my cad file, the holes are perfectly lined up, I don't see how on earth this could be, or what to do about it.

I guess I could drill the holes out later, but thats not the point of spending a bunch of money on the stupid plasma table
20240221_093330.jpg

Have you tried using a single layer just to see what happens? As has been mentioned previously, I would suggest using a sharpie pen holder and drawing your file (instead of cutting it) so as to not waste any more material. If you decide to try the sharpie method, let us know and we can help you to use the proper settings for your testing. With the sharpie, you could try using your 2 different layers as well as a single layer to see if there are any differences in hole locations between the two methods.

David

I made a sharpie holder yesterday, I'll give it a try, that file is quite large, so I didn't want to run it again on steel.

Here's another Pic of a another part, everything on a single layer, the holes are elongated in the X axis, and you can see the jogs where it's not coming back to the same spot, and the two holes which are perfectly lined up in cad, are not square to each other in the X axis,

20240809_171257_1222.jpg

[adbuch]

Your photo would indicate that perhaps there is some slop or backlash in your x axis. What size are the holes? I don't believe that what you show here would be the cause of your previous small holes in your other part being off by that much when cut. Does your table use stepper motors running open loop, stepper motors with encoders, or servo motors with encoders? If you do have encoders and there is some play in the coupling between the encoder and motor, this could possibly cause something like you show in your above photo.

I doubt that the cut order for your previous part- holes before cutout, or cutout before holes - would make any difference as was suggested above. But for your initial testing with your sharpie, I would recommend sticking with a single layer for your test drawings. I do agree that it would be good to check all of your mechanical interfaces - motor shafts to pulleys, belt condition and tightness, etc. Perhaps show some photos of your table showing the details of the drive systems so we can better understand what you are dealing with. I am not familiar with your particular brand of table.

David

[adbuch]

I took a look at the Premier Plasma site and specifically at the 4x4 specs. It says 4 stepper motors, and for that price I doubt it would have encoders. Perhaps show us some photos of the motor/gear rack interface with the covers off so we can see exactly what you are dealing with.

David

[adbuch]

hole pattern off 1.jpg