Initial Cut Settings

[TrinityFabworks]

I just finished making the swap from a hand torch on my miller spectrum 625 x-treme to the xt-40m (machine torch). Unfortunately miller does not have nearly the support that hypertherm has. My machine torch is shielded, and my cut settings are now all completely different than with the hand torch. My prior settings were all based off of a LOT of trial and error with a 2 inch square with a hole in it. I was just wondering if anyone had any initial test cut suggestions so that I can get my machine dialed in on my different materials as quickly and as affordable as possible? I have no idea where to even begin. With my settings exactly the same, the shielded machine torch does not cut all the way through the same material that it would with the hand torch.

[Ironken]

Take my words with a grain of salt......do you have torch height control? Here's what I do to come up with cut settings of my own.

I disable the THC and do a series of straight line cuts for each material and thickness. The first cut, I start with the cut height at .060 (Hypertherm) and a very low feed rate and increase by 10% with each cut. I note the feed, voltage (if you have THC), amps, dross and quality of cut. I choose the best cut and the noted parameters......these will be my new setings. The suck part is that you need to do this for each material and thickness. Kinda tedious. The good part is that the straight line cuts don't waste an aweful lot of material like cutting squares.

[TrinityFabworks]

Thanks for taking the time to respond! This is actually what I spent the day doing today. I had to get rid of the shield, because it wouldn't cut anything! When I went unshielded I got decent results! One thing I was wondering is when cutting 1/4", the cut quality is great! The edges are square and smooth, but my parts are hard to remove because of how much dross build up is on the back. It is dirty material (scrap 1/4 inch from the junkyard with a thin layer of dirt on the back from being on the ground in the junkyard.) Would the dirt on the back be causing the immense amount of dross that I am getting? The dross comes off easily with just a set of needle nose, but it is sticking to the bottom on both sides of the cut making it difficult to remove.

[TrinityFabworks]

Here is a test with 16g. The picture that has no penetration is with the shield, and the other is unshielded. Any idea why I can't get a single decent cut with shielded consumables?

[WyoGreen]

My guess is the shield is affecting your initial torch touch off to the metal surface and results in you cutting too high.

Steve

[Mr. Fixit]

Thanks for taking the time to respond! This is actually what I spent the day doing today. I had to get rid of the shield, because it wouldn't cut anything! When I went unshielded I got decent results! One thing I was wondering is when cutting 1/4", the cut quality is great! The edges are square and smooth, but my parts are hard to remove because of how much dross build up is on the back. It is dirty material (scrap 1/4 inch from the junkyard with a thin layer of dirt on the back from being on the ground in the junkyard.) Would the dirt on the back be causing the immense amount of dross that I am getting? The dross comes off easily with just a set of needle nose, but it is sticking to the bottom on both sides of the cut making it difficult to remove.

As I have learned, dross build up on the back is typically from to slow of a feed rate. Did you try to increase the travel speed? If not, I would try that.

[TrinityFabworks]

I'll give it a shot. Thanks! I notice that it can be wavy when it changes directions. On a straight path, the cut quality is great! When it changes directions though, it can get inconsistent. I did this with my THC off to make sure that that wasn't the problem, and I got wavy cuts.

[mdwalker]

Assuming the plasma machine is operating properly and the cnc table is operating properly I would make sure you have clean dry air at the proper pressure measured at the back of the machine. Have you measured your cut height during the middle of a straight line cut? I would measure actual cut height and see what you get. My guess is most of the problem will be related to speed, cut height, and clean dry air. All of this should be measured with clean new consumables installed.