Help me spend my school's money.

[Dave Cav]

Good evening. I don't normally hang around here; I'm usually over at General Woodworking (when I'm not at OWWM).

I'm a high school Manufacturing Technology teacher, and I have a conventional, "old school" manual (wood) machine program. We have table saws, bandsaws, router tables, and so on. I'm an old school guy, too. I have zero CNC experience, although I can hold my own with a manual lathe and mill.

Next door is the CAD classroom. They teach CAD (Rhino, Chief Architect, Solidworks) to CAD 1 and 2 students, and they have a pre-engineering class where they use Rhino/Solidworks and export their work to a 3D powder printer, a laser engraver/cutter and a small CNC mill. The CAD teacher is pretty good with the various programs and machines.


Today I got a call from our Tech Ed director. He came into some money he needs to spend this summer, and the CAD teacher and I decided we need a good 3D router setup. Our idea was to more or less combine my advanced shop class with his pre-engineering class, since they are the same period anyway, and see what we could come up with.

Here's what I think I'm looking for:

First of all, I think my budget will be at least $10K, and maybe up to $20K, but let's assume the lower end for the time being.

Most of the stuff we do will probably be 2D, at least initially (signs and the like) and then we will probably get into some other stuff like clock gears, robot parts and so on.

It needs to be compatible with Rhino and Solidworks. We don't use Autocad.

It needs to be Plug and Play, and hopefully have good tech support.

Most importantly, it needs to be able to survive in a high school environment. A number of years ago the previous shop teacher had some kind of relatively low end 3d router setup and the kids apparentl destroyed it, but to be fair, I believe there was a problem with lack of supervision as well. That won't be a problem this time.

Thanks for your help; any and all input will be appreciated, as I have essentially zero experience in this area.

Dave

[Michael Kowalczyk]

Even though we have 2 Thermwoods, and are pleased with them, I would say for between 10-20K a Shopbot would be the way to go and try to get an ATC. They may have a school program also.

Remember you will also need: tooling, possible vac pump (10 to 20 hp depending on size of table), make sure you have enough CFM with your dust collector or you will need a dedicated one, you might also need a CAM or you might be able to bring your Rhino and SW files into ShopBots control software.

There are many options but I would suggest that you decide what you think you want to do now and get what you can afford so you can grow into it. Better to get it when you purchase than to add on after, if possible.

ShopBot will also work with Thermwood's Ecabinets System. The software is FREE and I believe you should qualify but call them. Who knows, they may even have a tech school program. Many of them will give steep discounts so that their CNC is what the students are trained on. Thermwoods service is top notch.

If you have any questions, let me know.

Hope this helps and ...

[Dave Cav]

Good information, thanks. I was already leaning toward Shopbot as they seem to have very robust educational support.

[james mcgrew]

IMG_7090.jpgIMG_7091.jpgIMG_4178-1.JPG

i helped put cnc in two of our local schools here in SC. camaster provided a two head machine for the richland northeast high school here in columbia, they are in university programs as well, there is a strong owners forum for support.

www.camaster.com

[Dan Hintz]

I'll second "Don't forget tooling"... you can eat up money real fast at $20/bit if students are having a go at it. It doesn't take much for a student to put in a wrong value and snap a bit.

[Doug Griffith]

In this economy, many good used CNC routers are out there. I'd opt for a more durable machine with a welded steel frame, ball screws, and a true spindle (if 3 phase is available). I'd say Thermwood but the interface for anything but the later machines is archaic. Multicam's interface is great and they have models that are built as solid as Thermwoods. In a nutshell, a used industrial machine will hold up to a lot of wear and tear.

It doesn't matter which CAD program is used as long as the CAM software has a post for the machine. If it doesn't, this can be an extra expense if it has to be custom programmed.

Whatever machine you get, be sure to use a thick spoiler board. Something like 1" MDF. That will help keep your machine from eating itself when the z axis is programmed too low.

[Brad Knight]

I have to go with James on this one - welded steel frame - all rack and pinion drives and the same industrial build quality on the CAMaster CNC machines are hard to beat. You have systems from the Stinger I & II to the Cobra's - all with the same welded frames and rack and pinion drives.

I looked long and hard for my CNC and went with CAMaster for 2 huge reasons that beat out everyone else - 1 the welded steel frame and 2 the recoil lathe that Shopbot doesn't have - plus their systems run on WinCNC which - granted I don't have the Shopbot system to compare it to - but it's simple to run and it's pretty rock steady because it doesn't run off of the PC for it's pulse output, meaning that if you decide to do anything else on the control PC, you won't rely on the PC resources. If you open up your design software and recalculate tool paths and suck up a lot of the computer resources - the WinCNC controller will continue to run without a hitch because it's got it's own clock.

That's just my 2 cents...

[Nicholas Bukky]

I too agree with going camaster. My 5x10 ATC with rotary is excellent and the guys and support are excellent as well!!!

Best,
Nic

[Jerome Stanek]

Shopbot is in many schools and they seem to do fine in that environment. there are collages that also have them. Not taking away from Cammaster but the Shopbot support I think is better.

[Jim Underwood]

Whatever machine you get, be sure to use a thick spoiler board. Something like 1" MDF. That will help keep your machine from eating itself when the z axis is programmed too low.

I'd like to pitch in here and say that you may want to do more than this to prevent crashes. I have a section in my post that converts cellar digging -Z values into Z -.003".

Then as a redundancy, I use a utility a friend of mine wrote for checking values on all the G-code output files. With this utility I can check for any disastrous values within multiple text files at once, and it will flag any found.

You can manually check the code with notepad by using the "find" feature, but it only takes one missed instance to ruin your day (and possibly your spindle).

[Richard Coers]

Seems like you are getting plenty of advice, with not much concern about your budget numbers.
Here's some places for your research with a ShopBot.
http://www.shopbottools.com/products.htm
http://www.shopbottools.com/mProduct...htm#edPackages
http://www.shopbottools.com/mSupport/forteachers.htm

[Michael Kowalczyk]

Hey Jim,
Sounds like a neat utility but isn't that what the simulator is for like in ArtcamPro? Although it may not catch a plunge into the spoil board directly I would think that it would still show up as a distorted part on the tool path. I will take a sample file and change a "Z" to go through the material and see what happens.

I can run a DRY RUN on my Thermwood and look at it from top, side and front on the screen and i shows the depth and height of every tool path, so I can see immediately if it was heading for a crash or it would tell me that there is an error on line 1235 so that I could edit it. I believe that most CNC's have a software boundary also that would not allow it to venture out of the default settings. Try putting an X73 or a Y142 on your Komo. It should show an error on the screen like mine does that it exceeded the boundaries if not it still has either limit switches or proximity sensors as a back up.

I still like your utility. You know you can never have enough tools.

[Gary Campbell]

Jim, Michael...
I am sure many of the Gcode operating systems have the ability to "precheck" a cutting file, as does the ShopBot software. If Table limits are set accurately, you will get an error message stating that the (x,y,z) is out of bounds on line #X. This can be enabled as a default so that all files are checked prior to cutting.

[Doug Griffith]

Jim, Michael...
I am sure many of the Gcode operating systems have the ability to "precheck" a cutting file, as does the ShopBot software. If Table limits are set accurately, you will get an error message stating that the (x,y,z) is out of bounds on line #X. This can be enabled as a default so that all files are checked prior to cutting.

The problem is that the software won't automatically know how long the cutter is or how tall the material to be cut is. A wrong z offset value can still bury the cutter.

[Gary Campbell]

Doug...
IF.... the table limits are set properly based on bit/material lengths/heights prior to loading the file, I stand by my statement. You are correct, the software doesnt automatically know anything. That why there is an operator. The only intelligent item in CNC machining.