Help With Hypertherm PMX 1000

[vishnu]

Hi,
I am totally new to Plasma cutting, I have just setup my CNC plasma table & Hypertherm 1000 cutter with machine torch. I just want to know what kerf width to set in Sheet cam for The following

1. 60A Nozzle
2. 40A Nozzle
3. Fine Cut Consumables

At present i have only 60A nozzles with me, can i run the same nozzle at 40A for thinner materials ie from 3mm to 6 mm.

Guess i can get some answers today so i can try them up tomorrow. Also what IPM should i set for the rapids and Velocity / acceleration too.

Vishnu

[jimcolt]

Kerf width....Powermax1000

Kerf width will vary with any of the following parameters:

- Amperage, consumable size, consumable wear
- Torch to work distance
- Air Pressure, flow rate
- Cut speed (faster = narrower kerf, slower = wider kerf
- Material thickness

For these reasons...it is best to determine the kerf width for what you may e cutting. The Powermax1000 has a very good operators manual.....so follow the specifications in the "machine torch" cutting chart....even if you are using a hand torch. Use the consumables listed, the pierce height, cut height, pierce delay time and the speeds in the optimum travel speed column. Once these are all set up, then do a staight line cut, measure the kerf width (it will be a bit wider at the top than the bottom....but you should measure the width about 1/2 way down.)...use this as your kerf setting.

You do not say what machine/software you are using. On some you enter the full kerf width, others you enter 1/2 of the kerf width.

Another suggestion....for best cut quality always cut with the lowest power setting consumables for the material thickness you are cutting. These will provide the squarest edge and the narrowest kerf.

The Kerf width that I use for my Powermax 45 is .038" for most materials when operating near the optimum speed listing at the book spec for cut height. On my PlasmaCam software....you enter 1/2 of the actual kerf width. My parts are typically within .003" to .005" of tolerance.

I would make a wild guess that the kerf width for your 1000 with 40 amp consumables would be about .040", with 60 Amp consumables about .055".

Jim Colt Hypertherm

[Edwardo]

Using fine cut with my 1250, i set my kerf in sheetcam at .05, when i measure the finished parts afterwards they are bang on.

[vishnu]

Thanks for the info, i am ordering a set of 40A nozzles & Fine cut consumables, will try them and post details.

[Rbeckett]

Vishnu,
If you will follow Jim's directions and also look into the manual, you will find the kerf will be quite small and the edge quality to be excelent. The Heat Affected Zone (HAZ) on the edge will be quite small (even on fairly thick materials) and require less preperation for further welding/machining tasks. Depending on the use of the material you cut, edge prep is a very important "next" step not to be overlooked. If the edges are to be welded, the material should be prepared properly to remove any precipitates/slag to prevent weld contamination and failure. The Plasma process lends itself to this very well since it cuts at such a high temp and speed that the HAZ remains quite small and precipitates/dross on the edges have little time to form. Hope this helps.
Bob

[vishnu]

I did some cuts today on 3mm mild steel at 150 IPM on 40A, but i found some slug at the bottom of the circle & not on the side. The picture clearly shows the slug. Please suggest me ways to eliminate them. I am using a new set of consumable also.

[jimcolt]

It looks like a small amount of dross (dross is resolidified material that sticks to the bottom of the plate) only in the holes. If that is the case it means your machine is slower in cut speed on the holes....which is normal, and will cause dross.

Jim

[vishnu]

I would like to know the calculation for the minimum hole diameter that is possible with a clean cut with the PMX 1000 plasma machine. The manual in the machine says i can cut upto 10 mm in mild Steel, But can i go upto 15 mm for smaller runs , can i overdo any implications. And should i set my pierce height higher when i cut Thicker Sheets.