So, I want to build or buy a CNC Plasma Table

[bmorefj40]

Just like the title says, I'm getting ready to build or buy a CNC plasma table in the next 6 months. I've been reading on the topic over at weldingweb and cnczone for a few months now and I think I can at least ask some good questions. I've always respected and got some good advice on this forum, so I decided to start a thread here for my benefit and anyone else in the same boat. I'm going to put a laundry list of items for discussion here and hopefully narrow down my choices.

First, I thought I was sold on the idea building my own table, but reading through the hundreds of posts about issues with a diy "kit" table and the related software to hardware integration, I now know that this can eat up countless hours/weeks. I'm confident I can build it, build it well (level and planer), and connect it all together, but the software and g-code thing can be a little intimidating. So, plasmacam enters the equation with their designedge software that does get a lot of praise. Arclight and LDR are also other possible solutions. This is a side business/hobby for me and I don't want to spend 2-3 months just learning how to cut out a circle. I would be using this for custom metal furniture that I build and its been getting enough looks that bringing the plasma in house makes sense. (Can't seem to find anyone in the Bmore area that will cut less than a 100 pieces for me). Most of the time, I need to just make 2-8 pieces of something and it's getting more complex than my hand can do (well). Material thickness is mostly 18 gauge to 3/8's, but could be thicker (1/2") on a very small one-off basis.


Brands
DIY Kit:
Precision plasma
Bulltear (also turnkey)

Turnkey:
Plasmacam
Burntables
LDR
Arclight

Questions about the vendors:
*Length of company history and customer satisfaction- I hear great things about Precision Plasma and CandC, as well as plasmacam, but I hear horror stories as well. Anyone here have relevant experience with some vendors?
*Warranty- What should be expected?
*Replacement components source (proprietary or off the shelf)
*Programs included (cad/cam- sheetcam, mach 3, design edge, etc)
*Plasma compatibility- I have TD Cutmaster 52. I know hypertherm might be a better solution down the road, but this will have to work in the interim.
*Type of x / y rail- V-rail or flat CRS. Rack and Pinion is a must. I don't want chain or balls crews in this application. Dual drive x axis is a must.
*Type of z mech: how many starts do you need? I've seen 2-start all the way up to 5-start. Also, is 1" acme necessary. Some only go up to 3/4". I need capacity for 4 inch tube to be laid on the bed and cut. Wood routing and plate marking are options I would want down the line if things go well.
*Pc requirements- this seems pretty universal and simple. Something that has a parallel port or space for a pci card that has one. Anything else?
*Gantry kits or turnkey- any issues with the kits that I should be aware of?
*Shipping cost and packaging- I'm on the east coast and haven't seen any that I can easily drive to and pick up, so this may become a factor. Wish some of these vendors were closer so I could inspect them in person. Might be able to do that before purchase, but I would have to be pretty close to the final decision.
*Bearing type- does it matter?
*Auto digital torch height control- this is a must, but I've seen touch-n-go, ohmic sensing, and I think one other type. Any advantages of one over the other?
*Wipers on rails- Is this necessary or does mounting location of them make it moot?
*Water table /water bladder- I don't have the ability to vent a table properly, so it would have to be a water table. since this isn't production use, I think a water bladder would be necessary to drain the table and adjust water height easily. Correct me if I'm wrong here.
*Rail replacement options- I heard some of the v-rails can get pricey. What is the life expectancy of these items?
*Sheet loading- I'm a one man operation, so ease of loading is a big consideration. I may need flat or below bed rails so i can easily place and remove sheets.
Servo vs stepper- Seen this debate everywhere. I think servo gets the nod in the industrial world, but steppers should be fine here. Is there anything I'm missing other than the bi-directional closed-loop set up of servos? I plan on mostly cutting from 18 gauge to 3/8's.
*Gear reduction- is this necessary or should I avoid it?
*Max ipm cutting- based on my depth of cuts, what ipm range should I be shooting for?
*Resolution- seems like .01 should be realistic, but correct me if I'm overly optimistic


Sample Est Cost for a Gantry Kit
Precision plasma HD 5x10 Gantry kit 6000
CandC Electronics- bladerunnwr with auto dig torch height 1500
Steel for table and crs for rails 1000
Software 300
Air dryer and pluming 500
TD 52 Mech torch 500
Computer and monitor 500
Misc fasteners and switches 500
Water table bending and slats 500
Air/water bladder plumbing 500
Total cost 11800

If you guys have costs for your set ups, please post them up. I know this was an extremely long winded post, but just looking for advice from guys that have done this or other people in the research phase that may other things for me to ponder. I'll try to do the same estimated cost breakdown for the other options as well, but I think that's enough typing for today.

Appreciate all the help!

 

[PAToyota]

You're missing Torchmate from your list. Definitely take a look at them.

I've got one of their little 4'x2' "Growth Series" tables, but they've been great to deal with. They offer a number of options starting off with the Torchmate 1 which you supply all the steel and fabrication for the table and they supply plans, unpainted steel brackets, timing pulleys and belts, gearing, x-axis hardened needle bearing cam followers, hardware, and then all of the motion equipment and controls. The Torchmate 2 and 3 are available in bolt-together systems or as just a gantry kit and you build the table. Those two are pretty similar with the 3 having upgraded features from the 2. Then the Torchmate X is available either as a full turn-key system or as a gantry and you build the table.

They were acquired by Lincoln Electric a couple years ago, but their facility and team are still together - not like Lincoln assimilated them into the rest of their stuff.

 

[69rambler]

My experience is that everyone and their cousin has a consumer grade plasma system in their garage, nobody wants low def plasma cut parts, high def plasma is troublesome, laser technology is growing by leaps and bounds, plasma technology has dead ended, waterjet is good for everything that laser and plasma cannot do and CNC turret punching is absolute king for parts that are a mix of cutting and forming. Turret punching is also 10 times faster than anything else.

In your position of starting a business selling furniture using plasma cut sheet parts I would recommend using a good local laser cutter and training your attention on your business, not investing in and learning a consumer grade plasma system.

Programming in G-code is similar to speaking a second language. There are two aspects to overcome- Understanding the code (how to tell the machine what to do) and the more important one- Knowing what you want the machine to do. Cutting sheet with plasma is not rocket surgery, but you will have a learning period where you generate an unacceptable scrap rate.

I would vote for a good working relationship with an established sheet cutting business (preferably laser) leaving maximum focus for designing, marketing, sales, etc.

I have never heard a minimum qty # from a laser shop before. They are a time and materials business.

It's very important to take a microscope to the ROI math for your business. The time you waste assembling a plasma system from pieces VS buying one readymade VS farming out all the work and focussing on what's important.

 

[bmorefj40]

PA Toyota-
I didn't forget about Torchmate, but they got excluded after some of my initial research. Can't remember off the top of my head what it was, but I'll look through my notes again and post up what it was to make sure it wasn't unfounded.

69rambler-
You make some good points. I wish laser, water-jet, or even CNC Turret Punching (I didn't even know that existed until you brought it up) was in my ability to build/buy, so I'll have to leave that to the pros. Consumer grade plasma is about where my skill level and pocket book are right now. And I agree that if "good, small quantity, metal cutting outfits" were available to me, then I might head that route. But I haven't found that to be the case. Found a bunch of guys in PA that will do one-offs, but then you're still stuck talking everything over the phone, fax, and email, and would still either have to go pick it up or have it shipped- neither are time or money friendly. I could probably get good accurate results from a third party if I could design it in a CAD program, but then I thought if I was going to take the time and effort to learn that, then why not take the next step an import it into something that can cut it too.
I understand this would be an uphill battle, with a ridiculously steep learning curve, but I'm fortunate enough that this is not my primary business and a slow grow of this one isn't going to wreck me. (Just need to work harder at my day job in the meantime to make up the difference in cash outflow to support it.) But you are right on the ROI topic, I probably need to assign a better value for the less tangible items of building and running a cnc plasma on my own. I'm sure the number won't be low, just low enough that I can live with. I'll take a stab at assigning some figures and see if people agree.

 

[69rambler]

There's a reason why CAD/CAM is here and everyone in manufacturing has to know how to use it.

Don't overlook the importance of the software.

My advise would be

1) learn CAD and the basics of GD&T. If you cannot communicate prints effectively with other shops this will be a huge limiting factor in your business. If you can't make a quality print any real shop will avoid your work and charge you a PITA factor to deal with you. Learn CAD. Shoot over a nice DXF of the part. Have it shipped back to you on your own commercial UPS account.

2) If you do the above and the business grows to where there is a problem with time or quality of supplied cut parts and alternative shops don't exist then it's time to look at bringing the process in house.

3) I'm not joking when I mention it seems everyone has a CNC plasma in their garage. My impression is that these guys are always trying to justify the expense of this machine. They have the plasma table, but no support equipment to use it effectively (Good software, forklift, material storage, etc.). They always want to make parts for everyone else, but they don't know how to quote the work, they don't have materials in inventory, they just don't have the experience a real laser/plasma/WJ shop does to make nice parts in a timely manner.

4) Laser/Plasma cut parts are not expensive. If you feel like they are and you can do it cheaper in house you may be in for a wakeup call when you try it. The biggest reason to use a commercial laser/plasma/WJ shop is so that you get a feel for how they quote the work and you build the cost of those parts into your product. The big shops aren't screwing you over on pricing. They're almost always charging a realistic price for the part they deliver. Too often somebody has a great idea for something the only problem is the only way it will ever sell is if it's retail price was less than it costs to make. I guess I'm saying if you think you can make the same quality parts on a plasma table in house for cheaper you need to look at the real numbers, you need to know what those numbers are (this is a business, if you don't know the numbers whatever you do don't quit your day job) and price your products where the cost of materials and cutting isn't a big factor.

 

[PAToyota]

I'll agree with 69 on learning CAD. At the most simple, how do you think you're going to cut something on a plasma CNC without knowing CAD?

And 69 has a point on drawing it up and having someone else cut it. But I think the issue is whether you're going to cut eleventy thousand of them or just a few? Or just one? If you want to make something and sell it - in other words, make those eleventy thousand of them - then draw it up and send it out to be cut. You're never going to be able to do as good a job or do it cost effectively with one of these little setups.

But I think that Torchmate has it right when they call these "prototyping" machines. You might be able to get in good with someone at the local laser shop and they can nest a few extra parts in on jobs here and there and get you what you want for some one-off stuff. But for the most part they want to talk about hundreds or thousands of an item - or at least a full sheet of material.

 

[bmorefj40]

OK, valid points and I think they deserve some more research on my end. So, I'm going to pull back a bit and attack this a different way.

now, I want to purchase CAD software (most likely TurboCAD- it's about $100) and I can play around with that to see if I can effectively use it. I've used Google sketchup (free version) in the past to try out designs of parts, but nothing overly complicated. I know making a good rendering is already going to be difficult, not to mention exporting to dxf file and then importing to a CAM software where adding cut paths, pierce heights, looping corners, and all the other parameters is going add a lot to the learning curve. But, I think a month of using some CAD software will tell me whether I'm in for a good metal working adventure or a mind numbing headache.

Any other recs on affordable CAD software, preferably something that can play nicely with SheetCAM down the road?

Thanks!