serrated cuts

[Madammetal]

I'm having hell with the cut being serrated on 16GA. I have a powermax 85 i run fine cut on 45 amps. I have resorted to turning my volt up to 91 and dropping my cut speed to around 90 inches per minute. I was wondering if anyone might have some tips. The funks jig part is with the settings from the book. The next picture is of the setting I have posted. I still think I can get the cuts alot better any help would be greatly appreciate it

[sphurley]

That looks like mechanical issues not a setting issue. With the table powered and the stepper holding, can you move any axis with your hand?
I cut 16ga a lot with a PM65 and finecut consumables and they look laser cut.

[Gamelord]

have to agree, you have somethng that is giving you massive wiggle, either your slats are waving or something is not right on your gantry/side rails. That needs to be cleared up before anything else with the settings.

[exapprentice]

Hi madammetal
I would also check how secure your torch and /or torch mount are. Some of the cut details look like the torch is wobbling during change of direction of your axis

[acourtjester]

Also look for loose setscrews in any of the drive parts. It show a lot of heat marking of the metal and divots in the corners.
With the S and G it looks like the g-code finished and the table had not caught up with it the heat shows the torch sat there for to long.

motion.jpg (39.42 KiB) Viewed 3122 times

[tnbndr]

Definitely looks like a mechanical issue, unless you are drawing those letters with a bunch of tiny arcs and it is cutting what you drew?!!!!
Cut speed for 16 gauge seems way too slow. But as others have said fix the mechanical issues before you deal with cut settings. Are these your first cuts?
Was it cutting fine before?

[Madammetal]

thank you for all of your help. This was some of the first cuts I made on the table. I have spent a lot of time making scrap trying to get it all set up. I'm still not a 100% happy with the cut quality. I will check all the things that have been brought up and see what I can come up with.

Thanks again for all your help

[acourtjester]

Same story attach a ink pen to the torch and only use G-code that moves the X and Y axis this way you will be able to see what it looks like with making scrap. Find and correct the problem, your not the first to have this problem, help can be had here. draw circles and squares and then put the square on a 45 degrees angle and draw it again all sides must be equal.
https://www.youtube.com/watch?v=z56Hjot7dSQ

[tcaudle]

Sometimes the weight and length of a machine torch "flopping " around at higher speeds will cause wiggle. There is no software setting or THC setting that will stop wiggle cuts. Its like your car. If the front ball joints are loose the car will not track smoothly. As the driver you can't fix it. Neither will tuning the motor.

The faster you do the more forces are involved and the Z will "vibrate" and give you the type cuts you see. A light hand on the torch body as it cuts can let you feel any vibration and even if its got head bounce from the DTHC. Set up a cut that has the problem and lossly grip the torch body and close your eyes and FEEL the cut.

[Madammetal]

thank you all for the help. im going to boycott my shop for the day and go back at it tomorrow i will be trying all of the advice that you guys are giving.

[Madammetal]

I could not take sitting in side knowing I might be able to fix my problem. I went ad tried all of your suggestion. I did find that one side of the gantry seemed to have some play in it. it was not a lot I'm trying to figure out to tighten it up. I will call the manufacture on Monday and see if they can lead me In the right direction.

[Nacs Fab]

If there is ANY Play at all, that is definitely a problem and will lead to that type of cut. Here is another thing to consider. My machine is as tight as it can be, but I recently started noticing some unsatisfactory cuts when it would cut a straight line in the X-axis... Found out the Pinon had some slight wear marks on it - basically each tooth had a bur on it. I jogged my X-Axis left to right with my hand on the torch mount and could feel a vibration. This small vibration was enough to cause a serrated cut - not to the degree yours is, but it was enough I want pleased with the cuts. Changed out the pinion, took a little time to do some maintenance on my V-Bearings (mine is a V-Rail system) and while the motor was free, I rolled the truck back and forth after cleaning it and it rolled smoothly. Buttoned it up and cut perfect again.

These machines once operating, do require maintenance so prepare to keep an eye on how your cut quality is and if it ever diminishes outside of being consumable issues, it is likely something that mechanical in nature.

[jimcolt]

Like an other poster said, replace the torch with a spring loaded pen, tape a piece of paper on top of the plate and run the same part at the same speed. Could be mechanical.....could be drive tuning is a bit hot, likely is a little of both.

Jim Colt Hypertherm

[Madammetal]

Thank you for all of your help. I think I am starting to make some head way. i had some track rollers that seemed to be loose. i have fixed that issue. the cut quality it getting better. i did the pen thing and did not see and of the same serrated ares. i have attached photos of where i have got to now

[sphurley]

What brand of table is it, and how is the axis driven (direct, belt reduction, etc.)
You should have cuts that look like a laser cut them.
Both X and Y look like the same issue, so the suggestions of issues with Z and/or the torch mount might be real.

[Madammetal]

its a arclight. i would call it belt. but it has two small belts to gear and to gear rail if that makes since.

[sphurley]

Never mind I see you have an ArcLight table. Any chance you are out of square and it's shuttering/binding as it moves?
What does a straight line (12inches or so) in both X and Y look like?

[Madammetal]

i have not cut just the square lines like that but i have cut alot of long lines and they look about the same

[tcaudle]

Like an other poster said, replace the torch with a spring loaded pen, tape a piece of paper on top of the plate and run the same part at the same speed. Could be mechanical.....could be drive tuning is a bit hot, likely is a little of both.

Jim Colt Hypertherm

What the pen method does not simulate: The weight and leverage of the torch in the Z causing it to wobble or vibrate AND the material oscillating back and forth with the higher speeds and greater forces when the gantry changes direction. I have seen the material move front to back on a table with flexible slats and cause lines to be scalloped (usually in same direction of the gantry travel)

The pen method will point out things like slipping belts/pulleys, bad backlash , or out of calibration motor settings. If it draws the shapes perfect with a pen and you stiil have the problem with the plasma torch then yu need to look closer at the torch holder and the Z.

[Madammetal]

i wish i knew the easy fix for this. the plate and or the slats moving might be something i need dig a bit deeper into it. because it does not do it on 12ga or thicker. i have not cut any 14 ga

[sphurley]

Have you called ArcLight? They make enough tables they should have an answer for you. Like Tom said it looks like something is oscillating.
Also where did you get your volts and speed for 14ga fine cut?

FineCutwithLowSpeed03_12.pdf

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finecut.pdf

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[Madammetal]

i have called them. i have tired everything they have said and some. still not seeming to get any better. i made a straight cut around a foot long with our the torch high control on and took the volts it was cutting at. i then set the volts to that and starter playing with thew speed tell i got to a better cut nut its still not great. at the book setting it is almost at it worst

[sphurley]

Where do you have the ground clamp?

[Madammetal]

the ground clamp is on a tab that is welded to slats in the water tray

[vmax549]

Have you tried cutting with teh THC turn off. Its it the same problem with it off ??

Try Turning teh THC SPEED % down . Cut the value in half to test . IF it is too fast for teh THC it will cause those ocilations in Z.

(;-) TP