Cutting expanded metal / Hypertherm

[magma-joe]

This question is for Jim Colt or others who might have experience at cutting expanded metal.

I have a customer who manufactures a product that has circular 2' diameter expanded metal cut outs. I would like to get his business and cut them with my CNC air plasma. He is using 11 gage (twisted style) expanded metal.

My Hypertherm has a switch for cutting expanded metal but I have never tried it. What thicknesses can be cut? How about the maximum hole size in the expanded metal? Can the Twisted variety of expanded metal be cut as well? Should you run with the torch height control on or off? If the THC is on, how would you determine correct arc volts?

Thanks for any help!

Magma-joe

[jimcolt]

When you switch to the expanded metal mode on a Hypertherm system....the system senses the loss of current flow through the metal and switches back to pilot arc current at high speed to maintain the arc. As soon as the torch approaches the metal again, the current rapidly ramps up again.

It takes a bit of experimentation to make this work...to get the speed right so that the arc cuts all the way through the material when it has to restart. I have had good luck cutting perforated steel up to about 5/16" thick with my Powermax45. (perforated steel has a lot of holes punched in it....the arc often has to cut accross the holes). Expanded metal is generally quite a bit thinner gauge and seems to work pretty well. For hand cutting...simply drag the torch and hold the trigger. For mechanized cutting shut off the height control....or the torch would be diving on all of the holes!

Make sure for normal cutting that your plasma is in the cutting mode. Normal cutting with the switch in the expanded metal position will cause shorter nozzle life, and may also affect cut quality.

Jim Colt Hypertherm

My Hypertherm has a switch for cutting expanded metal but I have never tried it. What thicknesses can be cut? How about the maximum hole size in the expanded metal? THC on or off?

Thanks for any info.

Magma-joe

[magma-joe]

Thanks for the info Jim, I will give it a try.

Magma-joe

[Edwardo]

Hi Magma-Joe

I only used this feature once to cut the sheet of expanded metal i have under my slats in half, unfortunately it was along time ago and i dont remember all the details except switching the 1250 to that feature and turning off the height control then playing with the speed, i used 40 amp fine cut and it took a few tries to get it going but once going it worked ok with only missing a few places in a 8 foot run that it didnt cut all the way through the metal. I would be cautious running with the torch height off though as the expanded metal warps alot but once you know your tool path you may be able to set some weights on the sheet to hold it down or use the cheap plastic electrical ties and cinch the sheet down to the slats...just saying

EDD

[magma-joe]

Thanks for the info Edwardo. Weighting down the expanded metal when cutting is a great idea. Once I get the new Powermax 85 I'm going to give it a whirl.

Magma-joe