[Normsthename]

I have just finished converting my homebuilt 3 axis Router machine over to a Plasma.
It has a Hypertherm 1000 plasma with machine torch, and it is using a Campbells THC300 Torch Height Control.
Everything seems to be working as it should
I have been using the 60amp nozzles that came with the Plasma, and I also have some Finecut consumables.
I will mainly be cutting 16swg / 10swg

I am having a major problem getting good cut quality, because I just don't know what to start adjusting!
I am just going around in circles!

I have acheived 'Laser' perfect cuts by hand when I tested the plasma before I attached it to the machine, so I know that the air is clean and the plasma can acheive good cuts!
So what do you test-cut to get the best set-up, and in what order do you adjust the different settings

Amperage
Tip Voltage
Cut Height
Cut Speed
Air Pressure

I have wasted a load of material trying to get a good cut, I did manage to get a good cut once, but in my speed I did'nt write the settings down....

Any help would be much appreciated.

Thanks

Andy

[jimcolt]

Andy,

With the Hypertherm Powermax1000....follow the operators charts in the owners manual. The Hypertherm manual will list for most material types and thicknesses all of the parameters.....including cut speed (for mechanized cutting use the "optimum" speed....not the "maximum")...arc voltage, pierce height, cut height, pierce delay time. Use the consumable part numbers recommended on the cut parameter chart as well as all of the settings....and you will be very close to good cut quality. Assuming you rmachine and height control are providing the correct height and speeds (very critical) and your consumable parts are in good condition and have the correct part numbers for the application....and the plasma system has clean, dry air at the correct inlet pressure....then you will get good results.

To fine tune further...only play with the cut speed (slower will square up the edge....but will produce low speed dross, faster will produce more bevel....but will minmize dross).

If you do not have the operators manual...you can download it from the www.hypertherm.com web site....on the upper right corner of the home page is a tab marked "library"....search through that and you can download any Hypertherm manual in .pdf format.

Jim Colt

[Normsthename]

Thanks Jim
I did start with the Optimum Hypertherm settings, but the cuts were not that good.
My biggest problem is what to adjust, and which way to adjust it!
Some of the parts I cut (10swg) had a terrible bevel (It was nearer 45° )
I think I need a lot more practise.......

Andy

[jimcolt]

Andy,

In order to get a 45 degree angle with your system....you would have to be doing something terribly wrong! The most common issue that could create a bevel like that would be either a damaged nozzle orifice...or the wrong combination of consumables installed in the torch.

1. First inspect all of the consumables....shield, nozzle, retaining cap, swirl ring and electrode. Make sure the part numbers (if they are Hypertherm parts they are laser etched on each part) match up to those recommended in the manual for the material and thickness you are cutting.

2. Assuming the parts are all correct (above)...carefully inspect the nozzle orifice....to do this I use a jewelers eye loupe....the orifice must be perfectly round....with no notches or slots. This round orifice shapes the arc. If is cratered...or has notches....it most likely was damaged by piercing too close...or dragging on the plate.....or it was subjected to more Amperage than it was designed for. (a 40 amp nozzle must never exceed 40 Amps)

3. Inspect the shield just as you would the nozzle.....if the orifice is out of round....or the bleed holes (only on some shields) that surround the orifice are plugged....then expect the arc to get pushed to one side, causing a bad bevel.

If you have questions about inspecting these parts...take digital pictures and post them or email directly...often I can tell whats wrong by looking at these parts.

JimColt

[Normsthename]

Thanks Jim
Perhaps I was exaggerating the 45° Angle, it was more like 30°
I have just cut some 304 Stainless Steel 16swg and the cut was not bad at all!
I think there is still room for improvement, but I can definitely live with the cut quality that I got!
I currently have these parts Laser cut, which costs me £10.58 ($20.81 USD) for a set of parts.
I calculate that with my Plasma I can produce the same set of parts for £3.50 ($6.88 USD)
So you can see that I will be saving a lot of money
Its a pity that I have only just got my Plasma up and running, I have had approx. 2000 sets of these parts made in the last 3 years or so...... I would have saved myself a fortune!
As soon as I get the batteries charged on my Digital Camera, I will post a sample or two of the Cut Quality that I currently have, and see what you think I can do (if any) to improve it.

Thanks

Andy

[Jcar]

Normsthename,

I've found that I need to run around 20-30% slower than Hypertherm's "optimum" feed values in order to get the least amount of slag. These are the numbers that I use:

16ga - Mild Steel
Finecut Nozzle Setup - I prefer the finecut handtorch swirlring (small holes) in my machine torch.
40 amps
70-75 P.S.I.
79v - Arc voltage (THC300 Finecut switch turned on)
.120" - Peirce height
.060" - Initial cut height
120 I.P.M. - Cut Speed


10ga - Mild Steel
40 amp Shielded Nozzle Setup
40 amps
70-75 P.S.I.
146v - Arc voltage (THC300 Finecut switch turned off)
.120" - Pierce height
.060" - Initial cut height
60 I.P.M. - Cut Speed

[Normsthename]

Thanks Jcar
I will give your settings a try
At the moment my Finecut Consumables are not using the correct swirl ring, I don't know what effect the correct swirl ring will have on the cut quality.
Hopefully when I receive the Finecut swirl rings that I ordered, the cut quality will improve even further

Thanks

Andy

[jimcolt]

Andy,

The reason for the (part no) 220327 swirl ring design was for hand cutting....it's flow characteristics allowed the torch to transfer the arc to the workpiece easier and quicker...especially for edge starting. For machine cutting it is recommended that you use the 120925 swirl ring...which is the same swirl ring used for 40 and 60 amp cutting consumables. There should not be a noticable difference in performance in terms of cut quality between the two.

Jim Colt

[Jcar]

Normsthename,

Using the right swirl ring will make a difference. I noticed in your previous post that you were cutting stainless. If you take a look at the Hypertherm manual you'll notice that the cutting height is only .010" with an arc voltage of 64v for 16ga stainless. I usually follow Hypertherm's recomendations other than reducing the feed rate.

[Normsthename]

Using the right swirl ring will make a difference. I noticed in your previous post that you were cutting stainless. If you take a look at the Hypertherm manual you'll notice that the cutting height is only .010" with an arc voltage of 64v for 16ga stainless. I usually follow Hypertherm's recomendations other than reducing the feed rate.

When I cut the Stainless Steel today, I reduced the Feedrate from the stated manual speed of 3810mm down to 2500mm and this produced a pretty good cut
I have built a water table, and I have the water about half an inch below the steel surface.
When it cuts, the air pressure blows the water on the underside and it also comes thru' the cut to cool the metal.
The part I cut was quite a complicated shape, but it was 100% flat with no distortion at all
I was very pleased with the lack of distortion, after hearing that Stainless Steel is very prone to warping!
I will be cutting Stainless Steel 99% of the time

Andy

[Jcar]

I like to cut 2 inch straight lines, in 10 ipm increments. I start at 50% less than the recommended feedrate and go until I get a cut with the cleanest edge and least amount of slag. I then run it at + 5 ipm and -5 ipm to see if it helps even further. That's where I usually stop, even though I've heard that 2 ipm can make a difference.

Even though I know there should be no difference, I swear that I get a better edge with the 220327 swirl ring. Maybe it's just wishful thinking on my part.

[Normsthename]

Thanks for the idea Jcar
I tried a similar thing yesterday when I put 10 slits on a small sheet with 100mm/min increment speed adjustments.
I need to do something similar wih the Stainless I am cutting.
I need to find a speed range where I get a good cut on the slower corners, and then still get a decent cut when the machine is upto speed.

Andy

[RickDLance]

Hey Guys! I'm a newby, but maybe I can help. The 60 amp consumables WILL cut at an angle if you do not run the machine at 60 amps. If you are running a lesser amp setting drop down to the 40 amp consumables.

Also can you post up a picture of the cuts. Too slow or too fast a feed rate can be seen easily by the trailing angle of the cut.

Hope that's understandable.