When using my plasma to cut some SS, I am able to cut it nicely, however on the
bottom
of the kerf sits welded balls of the kerf. Am I using to much air pressure ? or
is it
to high current ?
I posted this last night but it didn't show up - I think my ISP is purging or
not providing.
Martin
I agree - I was concerned I had water in the mix (still) - have a mech dryer and
a pressure valve
that extracts water (so it seems prior to dryer) concern was spraying steam and
cooled the SS.
Today I went from 40 to 20 back to 30 amps. At 20 and 25 there were some hit
and misses - not enough
electrons.
I'm going to try a few other exotic experiments when time permits. Lots of work
when you cut out
a long name and there are hundreds of welded balls.
Thanks - I'll keep the group posted.
Martin
You can minimise the amount of melted-and-resolidified crud hanging to
the bottom of a plasma cut of stainless sheet, but you will never (???)
be totally free of it, using a shop plasma cutter using compressed air.
It is time-consuming and fiddly to grind it off while leaving no other
marks on the sheet, for sure - takes longer than the cut itself and
then some.
I have been told that if you are making a lot of things to the same
design, the only (???) way to get your blanks with a clean kerf is to
have them lazer-cut, where they will use pure nitrogen blowing as well.
Advice I got from some of the more experienced folk on the group.
Riuchard S.
Remember the Stainless Steel - and the ragged bumps of metal with oxide coverings
after the plasma cutter cut a line ? - Tried some of the magic stuff :
[ Seems likely nothing will unless a glass tape or the like - plasma does what
it wants! ]
I finally unpacked enough boxes, trunks and cases and found the spray can of
welding
inhibit 'oil'. Man is that stuff thin. I sprayed a wave under the table and
under
the area where I was about to cut - it was there (near by) after the cut of the
plasma -
No - No effect to speak of. I appears to just be vaporized around the area.
It does get hot there - blue steel and all of that for a boundary around the cut.
And in the digging, I came across a sheet of Al. - Man did that cut nice. It
was 1/16
so it wasn't much of a task - but the edges were singed off to a very clean edge.
On the floor was tufts of AlO2 maybe.
Martin
it wants! ]
I wonder what there is about SS and not aluminum that causes this problem?
The alloy? Heat dissipation? Is it that oxides on the aluminum prevent
adhesion of the molten stuff from the cut?
Have you tried backing the SS up with aluminum scrap so that it acts as
a heat sink? Place the SS on some aluminum sheet and then cut through both?
It's an interesting problem. I wish I had a plasma cutter to try some
experiments myself.
it wants! ]
I think the problem is the same as with trying to cut SS with a torch;
the chromium oxide is very, very tough and the melting point is so high
that it just don't melt.
The backing sheet idea may have some merit- I'll try it next time I cut
stainless, unless someone else says it doesn't work.
John
it wants! ]
I think the alloys that make up SS - chrome and the like are the nasty items.
Likely cool faster due to higher temp to melt.. As steel - carbon type that is
doesn't.
Al had a little edge much like a saw would put - if only pushing... - the finger
could
feel it - but it was tiny. When I cleaned up the layer of wood and area of
floor around
the ground protection wood - I found splatters of Al and a lot of heavy oxidized
stuff.
Some larger chunks due to cutouts but one or two big splatters - likely where a
plunge cut
was made and the holding in position was to long for Al - but functional for SS.
I haven't tried to sandwich some, but did a fools stunt today : spotted some
double sided 0.013"
copper clad PCB. - the foolish thing was forgetting the composite contents.
Epoxy is BAD when
burnt. And a wind blew the gas back into the shop against the two fans blowing
it out the door!
Quickly I held breath and turned one fan around and that did the trick.
Now what - a Weather vane Go-NoGo 220 V cut off ? -
Anyway - after washing the stinky corner in water I detected a complete burn
through and trace cut.
Just I'll never do that one again. Guess I'll go the the local roofing house
and see if they
have copper sheeting. I bet not in this part of the woods. Maybe the up-scale
houses use it.
Hum - rolls of to be formed gutter. That might be a source of copper sheet to
make stuff from.
More research...
Martin
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