Cut Quality

[miketodesca]

Hi,

I have been having cut quality problems for a long time. I am running some parts that are 5/8 HR plate. I was having trouble with excessive dross,bad cuts,poor consumable life and was having trouble removing the cut pieces from the sheet. I was noticing that the torch was plunging after the initial pierce and almost dragging for about 3/4 of an inch before raising up. it also was moving up and down frequently. I turned off the THC and the machine has been running great since.
I am getting parts that are to size, clean edges manageable,minimum dross and the parts have all been easy to remove after being cut. I have cut 150 pcs. 5/8 X 5-11/16 square parts and am still using the same consumables.
All of that being said, I would like to get some advice on how to correct the problem with the THC. I am running a bladerunner dragoncut control.

I am also wondering how much plasmaquench should be in the water table. It seems that if it is too close to the plate it makes a mess, and I am not sure if the torch will get damaged.

any suggestions or advice will be appreciated.

[I Lean]

It sounds like you might just need to increase your THC Delay time in Mach.

[WyoGreen]

The torch height control works by monitoring the cut voltage and comparing it to the voltage you set in the g-code. If the actual voltage is less than the set voltage, then the torch is raised to bring the voltage up. If the actual voltage is more, then the torch is lowered to reduce the voltage. So it sounds like your torch is either too high, or too low, which means you probably need to change your set voltage. You can start the cut on a part with the THC on, then stop the machine in mid-cut and measure the height of the torch. If it's higher than the cut height should be, then lower the set voltage. If it's lower, then raise the set voltage. Make sure the torch return clamp is on the material being cut, and on a clean spot, so you get good voltage readings. Watch the voltage readings as you cut, and see what voltage you are running at. I don't know if you are using Sheetcam, but if you are, you can use cut rules to turn off the THC from before the pierce extending to after the torch has descended to cut height and moved a bit. This eliminates the voltage spike you get when you first start a cut.

I run my water table level 1/4" to 3/4" below the material being cut. A few things I do to control the mess: Make a torch shield out of a toilet plunger or a rubber sink stopper to stop the water from splashing on the gantry and Z axis. Cut in the middle of the table if possible. And park the torch either in the middle of the table or over metal after the cut is finished. With the amount of air coming out of the torch, I don't think water splash will get close to the torch. At least I haven't had any problem with that (so far anyway LOL).

Hopefully this will help some, Steve

[ben de lappe]

Outstanding explanation of the issues sir, could not be more on target. Excellent presentation, lot's of experience behind those thoughts.