Plasma ShopBot in job shop environment

[desimulacra]

I have been lurking (mainly) on the ShopBot forum for a year or so, thinking about buying a machine for home use (wood). I have decided to buy a ShopBot for my use and will the next time a good used system close to me comes up for sale. Meanwhile at work we are buying machinery and due to my personal interest I suggested maybe using a ShopBot for the shops use.
Before I put my reputation and ShopBot’s up for grab I would like to get a couple of answers (opinions also excepted).
1-

[Brady Watson]

Mark,
I have a ShopBot plasma cutter with Hypertherm 1250. You may want to opt for the 1650 for more capacity, although the thickest I have cut has been 1/2" mild. It does a very nice job with the Hypertherm unit.

It is very easy to run, and included in your purchase is PartWizard which will allow you to seamlessly import DXF, AI and EPS file formats right in. It is more of a CAD/CAM package, so you can also do design work in there as well. It is probably the easiest and most straight-forward software to use of any competitor.

Unlike other plasma machines in this price range, the SB is made of steel...not extruded aluminum. It can stand up to the abuse that a steel shop can dish out. The shopbot easily and seamlessly hooks up to any PC via USB. It's pretty much plug and play. In addition to the machine itself, you will want to think about smoke extraction because as you already know, the plasma generates smoke. I would recommend building a water table (6" deep water pan) below the cutting grid. This will reduce smoke by about 70%.

If you have any other questions, feel free to contact me via e-mail. I am probably one of the only owners of the plasma system that visits this board.

-Brady

[desimulacra]

Ok
ShopBot got back to me and they have quit making the Plasma. I don't think we would be interested in anything but new. This is a disappointment to our shop but I understand it was a marketing decision due to the increased interest in the router and that’s good for me as an individual. I still wonder though if anyone has compared SB plasma to the expensive machines?
Thanks Brady for your timely reply! Hope to talk to you in the future as a ShopBot owner.

[paco]

And a sad thing... maybe not selling enought... I would have look for a SB PRT Alpha for a plasma machine... and maybe water jet too!?

Hey Brady!
Curious to know if you got more than one tip configuration for your torch (for cutting from very thin to thick)?... or do you only set the AMP and voltage/torch height?
What is the kerf width from 1/16"-1/2"?
And have you done some Aluminium cutting with it (air cutting gas)?

[Brady Watson]

Paco,
I only use compressed air...no specialty gases. So far I have cut up to 1/2" mild, 3/8" SS and 3/8" AL. Aluminum cuts fine with plain old compressed air.

Kerf width is typically .08", but that all depends on the part. I just got FineCut consumables for cutting materials under 10 gauge...haven't had the time to set things up with them yet. Too busy making $


-Brady

[jthelen]

Brady,
Can you post some pictures of things you have cut with your plasma? I would like to see the edge quality.
Jim

[paco]

Ooouuuh... Good small kerf! I remember you said you were using only air; that's why I specified... Let me know about your findings on thoses FineCut consumables... but do you cut under 10 gauge now and is it good cut?
I believe that it would still be quite feasible to install a plasma on a PRT Alpha ("router" or PRT) without having it "pre-assembled" by SB; what do you think?

[desimulacra]

Poco,
POCO SAID "I believe that it would still be quite feasible to install a plasma on a PRT Alpha ("router" or PRT) without having it "pre-assembled" by SB; what do you think?"

We might still be interested if the retro fit time could be held to a minimum. But if it is easy why did ShopBot drop the product line? My probably misguided thoughts are either it was too unreliable for time intensive METAL Job Shops (unlikely, but downtime and waste is a no-no thats why we are looking at machines in the 100k range) or it never was “pitched” to said shops. Metal Shops would not normally look at a “woodworking” tool “modified” to cut plasma. ;) , even if they found the website. We are talking different worlds here. Plasma is even more uncommon for a 1-2 person/small shop to have than a router.

[Brady Watson]

Not the best pic in the world..I'll see if I can get a close up at some point.

3/8" Mild (http://www.ibild.com/monzavegaparts.htm)

-Brady

[paco]

Poco!! Why not pogo?!

As to why SB discontinued the plasma; they be better to answer than me! I "b-e-l-i-e-v-e" they were not selling enought...
Moving a torh or moving a router is'nt much different!? Though the torch height need to be adjust according to a voltage reading of the main arc. I "t-h-i-n-k" SB could help you to see how you could retrofit their Alpha to a plasma cutter (combined with the help of the torch system fabricant). I'm sure a PRT could do a VERY good plasma machine mostly because you don't need to have a $$$ machine to cut with plasma and you don't need very stiff and heavy frame work. Cutting within 0.015" is quite satisfying for plasma cutting. As to ANY plasma cutting machine, you need to protect the machine (wires, rollers, motors) from molten metal splater and heat.

[paco]

Nice parts Brady... look clean!

[Brady Watson]

Thanks...You should see how nice the 1/2" parts come out ~ unreal!

-Brady

[daveiannone]

Hi Brady,
I have a couple plasma questions....

What speed do you run for burning 1/16 or 1/8 steel?
I know you have a water pan under your cutting area ,but is your table also vented?

Thanks , Dave I

[Brady Watson]

David,
Hypertherm has a chart of optimum speeds, pierce delays and arc voltage for each material. For instance, 1/8" mild steel runs with a .5 sec pierce delay, 1.7 IPS, 137 arc volts and 40A with 40A consumables. I have run 1/16" gauge material on there once, but the machine had to move faster than the PRT was really capable of. If you wanted to cut 26ga SS with the 40A consumables, then it required the bot to move 9 IPS. That isn't happening on a PRT...and I don't like the idea of that kind of speed for safety issues. Metal likes to warp and move around (mostly upwards) when cut.

Now..Hypertherm has solved the issue with FineCut consumables that give a superior finish in 26-10ga material...AND at more reasonable speeds. Most materials now cut between 1 and 2.5 IPS. This is great news!

I have already done all of the legwork required to use the FineCut consumables on my Bot. I just have to actually implement them. I have been so busy actually making money on the bot, that I havent had time to modify the electronics. The Finecuts arc voltage range is below that of the SB control's lower limit. The range can be extended by replacing a few resistors on the THC board and swaping out the dial scale for the rheostat. I'll post when I get the chance to cut with the FineCuts...Just caught a break today...but I am working on my CNC Bridgeport at the moment ~ converting it to PC control.

The water table is below the plasma grid. Essentially, the grid is attached to the SB frame. Under the frame is the pan...yes it is open. The water table reduces about 60-75% of the smoke associated with plasma cutting. The next thing that I will be doing is hooking up a smoke/dust collector of my design that pulls the smoke through a water barrel to cool and condense it. This should eliminate ALL of the smoke in the shop and save me a ton of money on heat in the winter....although I still recommend lots of ventilation.

-Brady

[Shane Bustle (Unregistered Guest)]

Brady,
How about speeds for 1/8" aluminum?

Thanks,
Shane

[Brady Watson]

You should be able to download the info from the Hypertherm site. There are charts for mild, SS and AL broken down by 40A and 80A consumables. There is a separate chart for the finecut that includes mild and SS...no data for AL available from HT using the FC consumables on the web or otherwise.

3/32, 1/8, 1/4 and 3/8 AL cuts nicely (all I have tested thus far) on the PRT with standard 40 and 80A nozzles.

-Brady

[Brady Watson]

I decided to test some 14ga stainless today on the plasma cutter...after getting bored cutting circles and squares to optimize the settings, I took a shot at something a little more creative:


4589

It's not too bad for stainless, but I still have a little more optimizing to do. It's about 8X18" overall. The swirl pattern was added afterwards with the grinder.

-Brady

[Brady Watson]

4590

As you can tell...snapping a shot of shiny metal is not easy. It doesn't look great in either pic.

-Brady

[paco]

Looks good Brady! Was it "burry"?

[Brady Watson]

Not really...There was some light dross on the top that you could remove with your fingernail, except places where there was a pierce, which was a little harder. The back was suprisingly dross free, with only a few black 'berries' where the tool ramped down in a corner.

-Brady