It’s been a while since I cut anything on the table, but when I finally got it working yesterday to cut a sign, I was less than thrilled with the results.
Torch is a RazorCut 45, at full power. Steel is 18 ga CR. Brand new consumables. Air is def not dry as I have no dryer, and it is hot and humid in the SE this summer. Here’s the pics:
Most of the letters and pieces fell out, some did not. Slag came off in chunks with wire wheel, but not really easily. Kind of had to lean on it.
I’m gonna load a coupon program and do some measurements, check the springback, and do all the things (as soon as I remember what all needs doing).
The thing that really has me frustrated is the cut charts I see online/have gotten from RW. The speeds seem WAY too fast for what I’m able to do, and I just don’t know why. When I run the machine at the speeds on the charts, I can’t even get the slag off with a wire wheel. It just folds over and burnishes. And there are a crap ton of sparks, esp as the machine travels out along the X axis, with fewer sparks in either direction of the Y, and almost no sparks in the return leg of the X. When I slow it down, by a solid 30-40%, it gets better. I’m not in a production environment, and this is supposed to be fun, so maybe that’s just the answer. I keep trying to force it, and it reminds of the saying about doing the same thing and expecting a different outcome. I remember my first cuts last spring/summer, when I knew aboslutely NOTHING, were better than these. I feel like I’m going around in circles.
It may not be all your issues. Until you get some sort of air drying you will probably never see much better. That’s my opinion.
You can’t find and fix a issue when you have a known one. I started the same way. I made a lot of decent cuts but I started early spring. Once summer cranked up it was over.
Start with a decent desiccant dryer. It will make a difference especially if you only use it on occasion.
This. Get a GOOD large volume desiccant dryer and a motorguard immediately following it (to catch any dust from the silica beads). Save your pennies and then put a refrig dryer and water dump before the desiccant dryer if that isn’t enough.
Low speed dross
If the cutting speed is too slow, the plasma jet begins to look for more material to cut. The
arc column grows in diameter, widening the kerf to a point where the high velocity portion
of the plasma jet no longer ejects the molten material from the cut. As a result, this molten
material begins to accumulate along the bottom edge of the plate in a thick globular form.
This is called low-speed dross. At extremely low speeds the arc extinguishes because
there is not enough metal to sustain a transferred arc. Increasing the amperage or
decreasing the standoff (while keeping material thickness and speed constant) have a
similar effect on the cut as slowing down the cut speed. Both of these changes cause
more energy from the plasma jet to contact a given area of the material in a given period
of time. Excessive amperage or low standoff can also cause low-speed dross. (Some low
speed dross in the corners of a plasma cut is normal since velocity does not remain
constant through a sharp turn).
To eliminate low speed dross:
Increase the cut speed in 5 ipm increments
Increase the standoff in 1/16 increments or 5 volt increments
Decrease the amperage in 10 amp increments
If none of these measures improve the cut, consider a smaller nozzle size
High speed dross
If the cutting speed is too fast, the arc begins to lag back in the kerf leaving a small hard
bead of uncut material or rollover dross along the bottom of the plate. This high-speed
dross is more tenacious and usually requires extensive machining to remove. At
extremely high speeds the arc becomes unstable and begins oscillating up and down in
the kerf causing a rooster tail of sparks and molten material. At these speeds the arc may
fail to penetrate the metal or extinguish.
High standoff or low amperage (for a given material thickness and cutting speed) can
also cause high speed dross since both of these changes cause a reduction in the energy
of the plasma jet.
To eliminate high speed dross:
Check the nozzle first for signs of wear (gouging, oversize or elliptical orifice)
Decrease the cutting speed in 5 ipm increments
Decrease the standoff in 1/16 increments or 5 volts increments
Increase the amperage (but do not exceed 95% of the nozzle orifice rating)
Top spatter dross
Top spatter is an accumulation of re-solidified metal that sprays along the top of the cut
piece. It is usually very easy to remove. A worn nozzle, excessive cutting speed, or a high
standoff is usually the cause. It is caused by the swirling flow of the plasma jet, which at a
certain angle of attack flings molten material out in front of the kerf rather than down
through it.
To eliminate top spatter dross:
Check the nozzle for signs of wear
Decrease the cutting speed in 5 ipm increments
Decrease the standoff in 1/16 increments or 5 volt increments
What I would immediately try:
Make sure to empty the water out of your compressor every 20 minutes of run time for the compressor. Set up an autodrain.
Check consumables. Look for wear of the nozzle.
Check your cut height.
Check for corrosion of the work lead clamp and wires both at the clamp and the cutter (look inside).
Don’t overfil your waterbed. This could be exaggerating your bottomside dross.
Jim has shared a lot of great information as well … Just remember Change one variable at a time so you can see the difference and identify the issue.
My first air drying setup I coiled a air hose up in a bucket of water add ice to chill even farther. Then I used a small cheap desiccant dryer on each end with a screw on filter like a paint filter to catch the dust… It wasn’t the best but it helped me identify what I needed.
