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CNC Plasma Cutting - Part Warpage

M

Mike_will8

New Member
Was working with @Janger over the weekend on the CNC Plasma table, cutting his stock (3/8" I believe it was) into strips.

What we noticed was that, even though we were using CNC to cut straight lines, as the cut proceeded the metal was warping due to the heat to the point that the final cut pieces really were not that straight.

@CalgaryPT , @kylemp what do you two reccomend for combatting part warping, presumably from the heat buildup? (Is this a relatively common issue with thicker stock? I haven't come across the issue with thin stuff.)

Possibly related, when we went to move the parts, some of them had bonded to the supports, like the slag had pinned the parts to the supports. Could this be related?

@Janger , could you snag some pics or measurements of those flat bars to help convey the issue?

JW
 
cutting strips always has this problem, a water table will help, faster travel speed (if possible) helps. Constraining the pieces will also help, it will still not yield you with a 100% straight piece, but it will be better than with no restraint.

The longer and thinner the strip the worse it gets.

The problem with a strip is that there often isnt enough material to restrain the expansion and shrinkage on the cut edge. Something that helps is to tack the pieces back together behind the cut, while cutting. Depending on the length of cut, speed, thickness, these tacks often need to be somewhat substantial, there is often enough force from the expansion/contraction to break the tacks.

Unless you can do it completely under water i don't know that it is possible to 100% avoid this problem, when steel is heated it expands...we all know this, but if heated hot enough (melting, or red hot, like in a plasma or torch operation) it will actually contract smaller that the original size when it cools, this is why torch straightening works.

If its worth it to you the metal cutting circular saws work extremely well for this task, much more pricey due to the blade cost
 
Mike_will8 said:
Was working with @Janger over the weekend on the CNC Plasma table, cutting his stock (3/8" I believe it was) into strips.

What we noticed was that, even though we were using CNC to cut straight lines, as the cut proceeded the metal was warping due to the heat to the point that the final cut pieces really were not that straight.
Click to expand...

Forum members - I have no idea who this "Mike_will8" person is, I was not doing this activity with them or anyone. Caution!
 
I'm going to say your cut speed is too slow, or you have an undersized machine that can't cut at a decent speed, because too slow will heat the plate excessively, and you will have a major gob of slag on the backside.
 
Mike_will8 has been banned.
This is definitely the most sophisticated scammer I've seen.
Not sure of the logic of naming members who could verify legitimacy but at the same time naming members gives almost instant cred.
 
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Janger said:
Forum members - I have no idea who this "Mike_will8" person is, I was not doing this activity with them or anyone. Caution!
Click to expand...

Creepy. He seemed so helpful.

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