Serrated Cuts


I am very new to the Arcdroid, I got this file from our sign company and cut it on the Arcdroid. most of the cuts are smooth but across the top especially the top of the letters have a serrated edge. what is causing this?

How thick is the material and what feedrate were you using? Does this appear if you cut a Simple Trace developed rectangle?

Thanks for the reply, I believe it is 14-16 ga. Feed rate: 200 inches. I will try cutting Simple Trace rectangle this evening and let you know.

Also, why is the cut line Right and Left? I would think Inside and Outside. How do you do you decide the inside cut of a circle? Right or Left?

Might try slowing the feed rate some, maybe try 150 in/min. Might be getting oscillations when abruptly changing directions. Is the Droid bolted down?
You decide right or left or center depending on what the end result is desired to be. For a 1” hole, if you go right start it will be oversized by the kerf. If that hole is in a 3” washer and you cut the OD with a left start your 3” OD will be undersized by the kerf.
Lettering I usually use center start. That usually gives good results on the supports for the letter interior bits.

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It is bolted down, I will slow it down this evening.

I still wrap my head around the Right and Left. Should be inside and outside.
I will remember your example for the future.
Right cut = Outside of center cut
Left cut = Inside of center cut
Right?

You got it. If you get a good measurement of the actual kerf of your plasma cut and plug that into your tune settings you’ll be ahead of the game. Doing practice pieces and playing with settings will let you see what the results are. It takes some experience to get it all dialed in. That way your not spoiling big pieces of metal trying to make a large project right off the bat. Jot down settings that work well for given material and thicknesses for future reference.

@Bobert33

If you look at the little graphic on the button L/R will make sense. It is related to the direction of movement.
Inside/Outside only applies if it is a closed shape… what about a straight line?

As for the wiggles. what type of torch are you using? If you have one of those Giant baseball bat type CNC torches and it’s just mounted at the tip, you basically have a flag pole waving about and at 200"/m every time you change direction it’s gonna go twannggg. You can actually improve things a lot by flipping the torch mount over and clamping in the middle of the torch. In fact even with a hand torch you get better results if you clamp as high up on the body of the tip as you can

Cheers
AM

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When I get home this evening I will check this out. Thank you very much!

Bob DeLorme
Deerfoot Mechanical Ltd.
403.291.5633

Attached are pics of my set up,


Here is a simple trace rectangle cut at 150 in/min
Still has a slight wobble.

I found reducing the JERK setting to 1 from default 5 reduces these kind of waves massively .

check out AMP MECHs vid on how to do change settings. JERK is the important one I have found but you can copy his settings in full.

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Thanks, I will try it out.

Bob DeLorme
Deerfoot Mechanical Ltd.
403.291.5633

@Bobert33 I am a little suspect of your plasma torch cable support. I think you can easily improve it and reduce influence on arm movement. Lengthen the support arm, make sure the arm can freely pivot and reduce the cable loop size.
You might try running your test rectangle at different table locations with what you have and see if the cut results differ.
Here are three pics of my set up with the Droids arm at different locations. You can see the cable loop stays consistent and with the support arm able to pivot there is never any lateral influence exerted on the Droid’s arm.



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I like that, thanks. I will make some modifications. I am camping for a week so I will be silent for a while. Thanks everyone for the info and tips.

The Droid is portable!! Take it camping!

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Good idea! But the wife would not be happy :joy:

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She’ll warm up to it after she sees it waving a hotdog or marshmallow over the fire. Just substitute a long fork for the torch!

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