It is currently Mon Dec 11, 2017 9:39 pm

 

Holes Cutting Off Center

Plasma Cut Quality can often be an issue for many of us. Check here if you have plasma cut quality issues. Ask a question, look for advice, post a helpful tip here.
MPN Signs
Posts: 9
Joined: Sat Oct 28, 2017 4:41 pm

Holes Cutting Off Center

Postby MPN Signs » Sun Nov 12, 2017 1:13 am

Good evening everyone. New to the forum & plasma cutting in general.

I have a 45xp mated to a Wright 5x10 table and could use some help with a cutting issue. I use Adobe Illustrator to create dxf files and the Sheetcam / Mach 3 the table came with. The issue is when cutting holes they're not centered in the piece. I've doubled & tripled checked the original vector file, and everything is centered.

The hole is shifted to the right almost a 1/16". What am I missing or doing wrong?
I'm not sure this would have been noticed on the original products we purchase the table for, but now we have picked up some flange / pipe bracket work and it's becoming an issue.

Any guidance is appreciated.

You do not have access to download this dxf file.
Become a Contributing Member to gain access to the thousands of files shared by our members. Click Here


D.B. FABWORKS
Posts: 1
Joined: Wed Aug 09, 2017 8:53 pm

Re: Holes Cutting Off Center

Postby D.B. FABWORKS » Sun Nov 12, 2017 9:22 am

Is the direction of the offset of the kerf always the same side of the part in relation to the position on the table? Is the topside of the hole centered to the part? Looks like you either have worn consumables or your torch is tilted in one direction and not square to the table. My machine is a LDR Motion 5 x 10 with a Hypertherm 65 Machine torch and have noticed in the past if the torch crashes it can shift the torch in the direction of the movement it was last traveling. I used a small framing square to check that the torch is square to the work piece in all directions. Not sure how to do this with a hand torch setup. After I made the adjustments I cut a square test piece and drew an arrow towards the back of the table so I could reference how it came off the table. This will show you which direction the adjustments need to be made if the issue is in your torch alignment. The bevel of the cut should be equal on all side and "tipped" toward the same surface, usually the top of the material depending on your cut height.
Jim Colt has some great pictures on this forum of what a proper cut should look like and what settings will best achieve those cuts. Im in NC and drove to Potsdam NY to pick up my table from LDR in June of this year. Dan offers a great machine and even better customer service and helped walk me through similar issues like what you are having.
Hope this helps.

User avatar
acourtjester
Elite Contributing Member
Elite Contributing Member
Posts: 2817
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Holes Cutting Off Center

Postby acourtjester » Sun Nov 12, 2017 1:42 pm

Are the outside dimension correct for the part in the same direction. If not you have a steps per problem may just need the steps per calibrations redone.
DIY 4X4 Plasma/Router Table
CandCNC DTHC-IV & Feather Touch
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PM 256 tig

MPN Signs
Posts: 9
Joined: Sat Oct 28, 2017 4:41 pm

Re: Holes Cutting Off Center

Postby MPN Signs » Sun Nov 12, 2017 3:38 pm

The outside is supposed to be 2". When measuring on the front of the piece it measures 1 15/16" and when measured on the reverse side it is 1 31/32"

User avatar
WyoGreen
Elite Contributing Member
Elite Contributing Member
Posts: 600
Joined: Tue Mar 04, 2014 8:36 pm
Location: Cheyenne, Wyoming

Re: Holes Cutting Off Center

Postby WyoGreen » Sun Nov 12, 2017 8:13 pm

Some of your difference front to back is the bevel that a plasma torch makes when cutting. This is due to the taper of the plasma arc itself. If you are cutting slightly too high or too low, that will affect the taper. The torch cuts best on it's right side due to several factors. In other words, when doing an outside cut, the torch should go around the part in a clockwise direction. When doing an inside cut, the torch should be going the opposite direction.
So in your case, there may be several things to check. As acourtjester pointed out, you may need to check your steps per to ensure you are moving the exact distance commanded. Another thing may be the kerf width set in the Sheetcam tool table. If that figure is wider or narrower than the actual kerf width, then that could affect the finished cut size as well (Sheetcam adjusts the cut path based on the kerf width). And of course, the kerf width is also affected by the torch height above the material.

Those are my thoughts on the matter, hope some of it helps you track down your problem. Steve
Precision Plasma gantry
CommandCNC Linux controller w/Feather Touch & PN200 hand controller
HT-45 plasma cutter
Plate Marker
CNC Router table

MPN Signs
Posts: 9
Joined: Sat Oct 28, 2017 4:41 pm

Re: Holes Cutting Off Center

Postby MPN Signs » Sun Nov 12, 2017 11:37 pm

Thanks acourtjester & Wyogreen. I'll be checking the steps and the kerf setting in Sheetcam.


Return to “Plasma Cut Quality Forum”

Who is online

Users browsing this forum: No registered users and 5 guests