Are Lasers Making Plasma Obsolete

[beefy]

This topic question is more related to general service cutting as opposed to artistic cutting.

Lasers seem to be out in number and the cut quality they give can't be argued with. High accuracy, nice straight / bevel free edge, no nitriding like air plasma gives (possibly important to welders that need a quality joint), less heat affected zone, distortion, etc. I've seen laser cut parts on 10mm steel and it makes my Duramax machine torch seem like a blunt axe by comparison. Oh, can't forget to mention hole quality with laser too.

Talking on welding and fabrication forums, it seems many would prefer their parts cut by laser. Of course there are other factors like cost and lead time, but as far as cost goes are laser cutting services getting cheap enough to "threaten" us plasma guys. Does anyone get a decent amount of work doing basic service cutting with air plasma (not high definition if anyone has one).

[JJsCustomDesigns]

Theres still prep work with Laser cut parts if your welding on an edge or joint. I used to have a ton of parts lasered. Still had to tumble or wire wheel the crap of the cut edges. Didnt weld too swell with TIG if you didnt clean em up

In my area, the guys with the laser cutters are still at least 3x more than what i would charge for custom signs and such. But are alot cheaper for production type parts. I quoted a job a few weeks ago to make some kind of bracket for a motorcycle. Laser beat me by almost 2x cheaper.

As far as plasma and hole quality. Read this thread. http://plasmaspider.com/viewtopic.php?f=4&t=7401 -

[beefy]

Thanks JJ,

that's good to know. I guess many of the laser lads wouldn't want to bother with one off custom designs.

I initially misread what you said about production type parts and thought you meant quantity runs, but what you actually meant is mechanical type parts like you'd draw in a "normal" cad program, e.g. brackets, flanges, baseplates, etc. That is very interesting and gives me some idea where I must focus - arty stuff.

The more I read and learn the more it seems you either have to have your own unique product, or you have to do one off custom designs to succeed in this game.

I seen a video on hole cutting quality and something that was also recommended was to lower the cut height in an attempt to reduce the bevel. Because doing circles has a tendancy to cause more taper and reduce hole diameter at the bottom, then reducing cut height causes more "flare out" at the bottom. They recommended that put together with 60% cut speed and ATHC off.

[bhamer62]

I don't have my own equipment, but work for a guy that has 6 lasers, 5 x 10, with pallet changers. We mostly do production parts of various quantities, but do a little art type stuff. Mostly things that are 50 pcs of this and that. I cut my stuff after hours on my time, they are kind enough to let me play!! I must say that for production runs, lasers are the way to go, BUT, for artistic value, I would much rather cut with a plasma. The cut quality provides that custom made look that you simply will not get with a laser!!!! It is difficult for me to make really nice 1 offs with a hand made look. (dream catchers, outdoor scenes, artsy signs...) There are times I would love to have access to a plasma for my work. It would produce a more handmade look instead of cookie cutter look. At a craft fair, I tend to feel a little out of place up against more rustic art. Just my opinion. However, I love this hobby and will continue to create whatever I can dream up, that is the fun part anyhow

JJ, regarding the TIG welding issues with edge quality. When laser cutting with house air or O2, you will leave a scaling on the cut edges that can be problematic for some welding applications or finish coat adhesion. A way to avoid this is to get your parts "clean cut" which means cutting with nitrogen. It TOTALLY eliminates any edge scaling. We do this on cutting all SS, alum, or parts to be powder coated or painted. Just a FYI

[JJsCustomDesigns]

hmmm... Thats good to know. Good info. Thanks

[beefy]

Thanks for that input bill, you've just given me a selling tool if somebody says that laser gives a better cut LOL

My table actually needs a bit of a rebuild to give it more rigidity. I can get a slightly scalloped edge at the higher speeds used with the thinner metals (artistic cutting thickness). Caused by chain bounce and a gantry which is too high. I want to rebuild with rack & pinion, and a more "squat" rigid gantry. I can always try and say it's the cut style to give a more natural look

One issue with nitrogen cutting on steel is it will cause a bit more nitriding than what air will do (100% vs 80% nitrogen). I think this can cause porosity in welds if it isn't ground off. Don't laugh but I didn't even realise laser uses a gas too.

Keith.

[bhamer62]

yeah, we need gas too! I think the excess nitriding could be due to the different process. We havn't experienced that. We cut a good bit of SS and alum that gets cert welded and have had no issues with nitrogen, yet.... We also cut using co2 alot.