cut quality

[bearwolfe]

I hope this is not a duplicate, I couldn't find my other post.

I am looking at purchasing a plasma cnc machine. I need to do some low number production runs on mostly 3/16" to 1/2" mild steel, stainless steel, and aluminum. Luckily I found a local business with a Torchmate. They agreed to cut a couple test peices that I had drawn in autocad. The cuts were dimensionally incorrect, sloppy and have a VERY bad slag buildup on the back side. The holes were not clean or even perpendicular. I was under the impression that clean, accurate cuts could be made with these units. I have attached some pictures, please review them and let me know if this is typical results. TD 1250 cutter with a 40A tip @ 30 ipm, on 1/4" mild steel.






Thanks,

[massajamesb]

Umm. Wow.
I would have to say that he has some serioius slop in that machine.
The bolt holes have a bit of taper from top to bottom, but that is somewhat normal.
The slag? Not normal at all. That is way too much.
I would look up BlackHollowMfg. He just recently built a TM1 machine.
Here is a link to some of his cuts.
http://www.cnczone.com/forums/showth...427#post273427

[bearwolfe]

Whew! I was hoping that was not normal results. I was really excited about getting this equipment, but I need to make pretty clean cuts in 3/16" to 1/2" plate. I would like to see some cuts in plate this size so I can make an educated decision.

Thanks !!

[Mike@Torchmate]

Those are extremely bad cuts, and would agree that they are not operating their table correctly. The holes where the leadins come into the cut are also just plain bad. Here are some sample cuts that we do here in house.

1/2" Mild steel no cleanup (other then dropping it on the floor)


1/2" mild steel wire wheeled for cleanup (same cut as above just smoother)


3/16" mild steel fresh off the table I cut yesterday (50 amps 50 i/pm TD cutmaster 101)

[bearwolfe]

Those cuts look very good and it appears to be the quality I need. What set-up does it take to get those quality cuts? How hard is it to make the finished product have the correct dimensions as drawn in autocad? The dimensiona on the sample run was terrible, like .2" off.

Thanks,

[Mike@Torchmate]

The 1/2" plate was cut on our TM4 table with a TD 151 @ 80 amps, 22.5 i/pm. However all our machines should produce a cut quality very similar to that.

The 3/16" was TM2 4x4 small shop machine at 55 amps at 50 i/pm.

The dimensioning problem is likely due to them not doing a toolpath, not having the gear ratio set correctly, and the plasma cutter going to hot too slow.

The machine is accurate to within .006 easily repeatable at to under .010"

Was this customer a demo point that one of our sales people told you about? If you could PM me their name I'd like to talk to them about their cut quality.

[massajamesb]

I have posted this one up before, but here is some 3/16" cut at (if I remember right) about 45 IPM at 40 amps.
The second picture is a comparison of a 3/16 part cut with a laser(bottom part), a 3/16 part cut with a 40 amp TD plasma (middle part), and a 1/4 part cut with oxyfuel. All 3 parts were wire wheeled to give cut edge clarity. No real slag to speak of.



EDIT: These were not cut on a Torchmate table, but on a home made machine. A professionally built table might give even better results.

[bearwolfe]

I must admit that I am becoming overwhelmed a bit. I am a small operation and I believe in my mind that I can make money with one of these if the cut quality is sufficiently good and the accuracy of the part can be maintained. It seems that there are a number of members on here making good with their machines and also some that are not. For my small operation the cost of a system is substantial, I just want to make a good choice. I appreciate any and all advice you can give.

TIA

[bearwolfe]

Mike,

What are the hole & slot dimensions of the pictures you posted?

TIA

[xavier2nd]

How do you know the IPM??? my torchmate software uses %

[Mike@Torchmate]

Originally Posted by bearwolfe Mike, What are the hole & slot dimensions of the pictures you posted? TIA

The hole is 1" ID and the slot is .75" x 2" ID.

The Torchmate 2 software has a % override feature that allows you to adjust your Program Feedrate shown in IPM. Whatever the screen displays next to the percentage sign is your Program Feedrate, and Feedrate with override applied, as shown in IPM.

The Program Feedrate is applied when you import a DXF file into the Torchmate 2 software, on the configuration screen. It shows as XY Feedrate in the top right hand corner, the default number is 70 IPM.