[WSS]

I am putting together a bunch of cut charts for the HP PM1250. It will include mild steel, stainless steel, aluminum and the fine cut chart. These charts will not include part numbers for consumables (maybe later on a separate sheet). I am looking for info such as cut height and any other proven ideas to put in the empty sections at the top and bottom (text).

It would be nice to hear input from users here on the Zone. I will try to get these up in a week or so, provided the info is clear. I will put it in a zip file and post them here in this thread for those who need or want them. I will include both a regular facing and "mirror image" files for paper or transparency printing. They will be under letter size to fit most printers.

Jim Colt, please chime in if this is a good idea or you have some input. I won't ask if your ideas are proven (lol).

WSS

Edit: Added CNC Zone logo to chart.

[Mongkol]

WSS,
It's interesting. Do you have pdf file?

Mongkol

[WSS]

Mongkol,
A pdf is no problem. That is the kind of input I am looking for. I had not thought to save it as a pdf. I will post it next week as a pdf as well.
Thanks! WSS

[WSS]

Any other ideas? How about pierce height and delays? Should I go by the manual? I would like to get this finished this week some time.

WSS

[Mongkol]

WSS,
I agree to add pierce height,pierce delay,cut height,air pressure for the kind of material.
Other?

Mongkol

[WSS]

Monkol,
OK, I will add the pierce heights according to the HP manual. I'll get them put together this weekend and PM a pdf to you. It should be about six pages. I will remove the color from the background to work better as a pdf, unless you have a preferred color? I generally use blue for LP oxy torches and red for acetylene torches. I am not sure if plasma has a reference color?

[jimcolt]

Its a good idea....however you can download these charts from the Hypertherm website right out of the operators manual for each system...they are in .pdf format.

I would suggest leaving part numbers on the consumables. It is very hard to tell the difference between say a 40, 60 or 80 amp shielded nozzle if you don't have a part number for reference.

Jim

[ajclay]

It would ge nice to see what Hypertherm recomends for the pierce heights. My manual doesn't even mention pierce heights.... Why did Hypertherm leave out such important info? I just learned that pierce height should be 1.6 to 2 times the cut height; But, I haven't seen it in a chart yet. Thanks, Aj

[WSS]

AJ,
Can you put together some info regarding the pierce heights? I just realized it is not there! I see the cut height but not the pierce heights. And if possible some info on delays? I can modify if needed but it would be good to nail it on the head the first try. I would need it for aluminum and SS as well if possible. I also have a fine cut chart to put together as well. So I may be further off than I think.

THANKS for any input!!

[WSS]

here is a chart i will use when our table is up and running. I will have to experiment with heights and modify the chart when I am sure of the specs.

WSS

[jimcolt]

I'm wondering what Hypertherm system you have? My manuals for both the Powermax45 and the Powermax1000 list pierce heights. Perhaps you have an older manual from before they were on the list.....let me know and I will check it out.

The rule of thumb for pierce height: 1.5 to 2 times the recomended cut height.

Jim Colt

[ajclay]

I've just downloaded the other "powermax 1000, 1250, 1650" manuals and basicly they are all the same. They leave out the pierce information.

The Powermax 45 seams to be an updated manual with pierce info in it. It also goes a step farther and explains how to optimize cut quality and explains torch height and taper. This was nice of the Hypertherm guys.

Hypertherm recommends a pierce height 2.5 times higher than the cutting height on the Powermax45 reguardless of amp and thickness of metal.


I wish Jim would put his 2 cents in and give us the rule of thumb on pierce heights for the 1250and 1650 machines.

Aj

[jimcolt]

AJ.....I stand corrected. The pierce height info is not in the older system manuals...only in the Powermax45 cut charts. I guess 31+ years of Plasma cutting makes me blind to some of the missing information as it is igrained into my memory...or whats left of it!

1.5 to 2 times the cut height is a good rule of thumb for pierce height. Typically....on materials 1/8" and thinner you can pierce at the same height as the cut height as the pierce happens so quickly that material blowback is not an issue.

Jim

[ajclay]

I'm trying optiimize. I've never seen another plasma system work, only mine. (except for movies) So all these details are a big deal. I'm trying to do it correctly - going by Hypertherms info. It's just hard to get the info needed sometimes when it's not in the manual.

The torch being square to the material is what I worked on yesterday. A guy can't assume it's square to the plate. All the business about torch height will be missleading if the torch isn't right. I made a tool to replace the nozzle that would hang down about 4 inches. This makes for an accurate place to square up at.

My taper on 1/2 material isn't the same on all sides of the piece. hypertherm1650, 60amps. Also the torch got caught on a piece of slag from the pierce being to close to the cut line.... It's just a lot going on...

Now that I have the squarness put to bed, I can work on getting the torch height correct by looking at the taper and cut quality.

The job is in the details.....

[jimcolt]

You are on the right track.....I see so many plasma operators that just complain about cut quality.....yet don't stop to think about everything that causes angularity/dross/roughness. Forget the rocket sciece and work on making the torch perpendicular to the plate, ensure that the motion is smooth and accurate, pierce and cut at the recomended cut every time (one pierce too close will ruin a nozzle).....and the system will do a good job for you.

There are some other tricks in regards to designing lead ins and lead outs...as well as with freezing the height control and lowering the speed in corners and on small holes that definitely help with cut quality as well.

Attached is a photo of 1/4" steel standing on one edge....this is a raw cut with no chipping or grinding....and holes down to 3/16" that have a little taper but are very round top and bottom....cut with a Hypertherm Powermax45 on a PlasmaCam machine.
Jim

[ajclay]

Jim, that's some good looking work! That gives me something to work toward...

Right now I'm woking on trying to get the taper out. That's easy to talk about but seems to be kind of hard becasue of all the variables. TH, Torch squareness, Nozzle condition, cutting speed.

The cut below has about .020 taper on two sides of the square part. the other two are almost straight. Out of the several I cut, changing different things this was about the best for now. If 5 degrees is about normal... on a 1/2 plate that's about .043. So I guess I'm doing fair...

The the aluminum tool is what I made to replace the torch nozzle to give a good place to put a square next to. It's easy to see a few thousands with a machinest square next to it.. The plate condition is another factor that will only let me get things fairly close. The .5 plate I've been cutting on isn't new/clean/flat. That's another factor in the mix.

I took an old nozzle, built it up a little and made a pointer that takes two seconds to put on the end of torch to help lines things up. That's a must have!.

Any comments on the cut quality of the plate? Thanks, Aj

http://www.awningandsheetmetalbr.com....5%20plate.jpg

http://www.awningandsheetmetalbr.com...ing%20tool.jpg

http://www.awningandsheetmetalbr.com...gin%20tool.jpg

[WSS]

OK, I will use the suggested rule of thumb of 1.5 to 2 times the cut height and add that info in. I will work up a draft and post it this weekend. Have a look and see if anything needs tweaking.

Aj, that line up tool looks like it would work good. I have yet to get ours up and running. I am sure I will find a need for it the first time I run off the plate! I have two laser locators (one for oxy the other for plas), but I think they will work with thin material only, They would be a melty mess after a sheet of 1".

[ajclay]

My little experance tells me to error on the high side for the pierce. The thin gauge material like 16g and less isn't a big deal, 1.5 or a lettle less will work just fine. As material gets thicker I would start going up in pierce height.

With .5 material, twice the cutting height isn't to high. I was higher than that for a little while just after I crashed the torch. Now I'm back down to twice the height. The slag splatter on top of plate seems to be a little thinner or flatter. As I went higher than 2x the cutting height on the pierce the globs of slag got higher.

So I guess it's one of those seat of the pants rules...

Aj

[WSS]

Aj, can you ramp pierce? that would put the top side dross behind the nozzle (I think).

Sorry for the delay in getting these put together. SOON!!!!

WSS

[ajclay]

WSS, you know, I've noticed that the dross is behind the torch when it moves forward during periceing, but never put the two and two together till now.... THANKS! I'm going to work on that.

I have indirect control of the THC. I'll have to adjust the gain to move the torch a little slower, and get the dwell time just right to make a "ramp pierce" on the thincker stuff.

I've been turning the THC off and making a longer lead in during piercing of thicker material to prevent torch tip from touching material and from impact on lead out...

Nothing like OJT....... on the job training....

Aj