The BluumaxCNC Router

[paulrussell]

What started me down this odyssey of woodworking was the purchase of the BluumaxCNC Gantry Router ( http://www.bluumaxcnc.com )

(Photos in later post below)

If you have looked at CNC routers you know they are not cheap. Well, the Bluumax is an interesting beast. It is a complete CNC router which uses a Dremel as the cutter. $400 gets you almost everything you need. The buyer needs to provide their own Dremel and bits, a half sheet of 3/4" MDF for the base and table, a power supply (an old PC supply will work), a 1/4-20 threaded rod to make table standoffs, and a handful of nuts.

The Bluumax is a lightweight machine, suitable for plastics and wood. The working area is 12" x 17" with a z-axis (up/down) travel of 2". The structural components are mostly 1/4" plexiglass. Due to use of plexi as a structural material, the BluumaxCNC is a light-duty machine. Slow and easy is the way with the Bluumax - too high a feed rate and there will be structural flex and loss of accuracy.

However, impressive projects have been made with the Bluumax, and examples can be seen in the Yahoo users group photo gallery.

A word of warning -- although there is a Linux CNC control solution, and though some folks have used Sketchup successfully, the combination of CAD, CAM, and motion control software can easily be twice the cost of the Bluumax.

There is a steep learning curve with all things CNC, and the best (though somewhat overwhelming) resources are the forums at CNCzone.com. There you will find CNC professionals and hobbyists working in wood, metal, and plastic, as well as an active forum of people designing and building their own CNC machines.

The million dollar question is whether, if I had it to do over again, if I would buy the Bluumax again. I don't know! With the knowledge I have gained I find myself in want of a slightly bigger and more rigid machine. The entry-level price in this category is about $1500 - 2000. Had I been faced with that price to begin with, not knowing how interested I might become, I would have never bought my first CNC. But now I'm hooked, and along with my Shopsmith, I feel like I can build ANYTHING out of wood and plastic.

Lastly -- BluumaxCNC is a one-man venture run from a spare bedroom. You will always get an answer to your questions within a day. Shawn, the owner, is probably one of the hardest working people I've ever encountered. He's a bit crusty, but he is honest and will make things right if ever there is a problem.

[boostfan]

Wow, that is very interesting. I don't understand why he doesn't offer more parts direct. I can handle the table, but I think it would be easier to pay a little more and get everything from one place.

[paulrussell]

Wow, that is very interesting. I don't understand why he doesn't offer more parts direct. I can handle the table, but I think it would be easier to pay a little more and get everything from one place.

You bring up a good point. I asked about that. Bluumax (Shawn) wrote that the mdf is more expensive to ship than it costs, and most home supply stores have both mdf & threaded rod.
Dremels - lot of folks have them already. He would need to mark them up & figures you'd be better off getting on on Amazon. Same for mill bits. (i get mine on ebay)
That leaves a power supply - and again they are cheap and plentiful. I'm certain that if you wrote and asked for a complete bundle he would do it for you, or send you links to the exact items you need.
He is of the mindset that this is a project for hobbyists with a bit of know-how. He doesn't want to sell and have someone not be able to get it working. On the other hand he doesn't want to spend his life on customer support. So having the customer need to do a small bit (order & buy the few needed parts) helps thin the ranks of less-technically proficient buyers. I don't know if that was a good business decision.
I do know that Bluumax (Shawn) is dedicated to getting every buyer up and running no matter what it takes.

[paulrussell]

A few things I forgot to mention - the first is the BluumaxCNC is easily modified. I've made improvements to the rigidity of the gantry, and modified my z-axis to support a Bosch Colt router with precision collets.

Once built, the BluumaxCNC is capable of replicating most of its own parts! (Assuming you have the CAD file, which you can either design in your favorite CAD program, or a polite email to Shawn will probably get you what you need.)

Brad: I see you live in Fenton -- I'm in Lansing if you wish to see one in action.

[gregf]

Interesting. I hadn't seen this before.
Thanks for the info.

[paulrussell]

A few pictures -- Here is a mostly stock BluumaxCNC.
Sitting on the worktable are a few parts I made using the Bluumax. The flat plates are for my Z-axis upgrade and the smaller parts are for a cable-carrier chain.

[attach]8951[/attach]

And from the front --
The plexi plate running across the back supported by two pieces of aluminum angle were my first mod. It significantly improves the rigidity of the gantry.
I made the dremel holders as my first project. However Bluumax now includes one set of Dremel holders with the kit.
-- It occurs to me that I did not make it clear that the Bluumax comes as a box of parts. You must assemble it yourself. It took me about an hour, not including the MDF purchase, cut, paint, and drill.
[attach]8953[/attach]

Here is the current configuration.
You can see the grey pieces from the above photos mounted behind the router.
[attach]8952[/attach]

A side view of the updated Z-axis
This mod also had the advantage of bringing the center of gravity back so it is better centered over the long axis (X) support bearings.
[ATTACH]8954[/ATTACH]


Future dreams -- to replace the z-axis upgrade plates with aluminum to reduce flex.
I've also plans to make a major chang to the x (long) axis bearing system. The intent is to remove some of the torsional flex that can occur when using a faster feed rate.

If anyone is interested, I'll post a bit about the software options and what I'm using.

[gregf]

I'd like to hear more about this on a continuing basis.
Now I need an excuse to get one.

[paulrussell]

A quick CNC software primer

To make a part using a CNC router is a multi-step process, typically requiring three pieces of software:

1) Part Design = CAD
2) Creation of cutting instructions i.e. "g-code" = CAM
3) Cutting the part (interpreting "g-code") = Motion control

Each of these steps traditionally takes a separate piece of software, although integrated packages are available for the CAD/CAM process.

A bit of CNC lingo you should know is "2.5D." In the CNC world a 2D part is like a flat metal washer. Either the metal is there, or it is not. 3D is like one face of a coin -- there are curves and contours in the Z (up/down) axis. Lastly comes 2.5D. 2.5D allows multiple depths, but no curves in the z-axis.

An example of a 2.5d object would be the iron table on my SS bandsaw. The center hole, blade change slot, and outside edge is cut to the full depth of the material (as in 2d). The miter bar slots are cut to a second, lesser depth. And finally, the lip around the saw opening is cut to a third depth.

Another way of looking at 2.5D is that the z-axis can be set to any depth, but it never moves at the same time as the x and y axes.*

I know I've gone on a bit about the techie stuff, but a basic understanding is really important before looking at the software options.

Note that CNC does not end with 3D. There are "4th axis tables" which allow the piece to be rotated, either incrementally, or smoothly for a lathe like effect. And it doesn't end there. But 4-axis systems and above are much beyond the budget of the average hobbyist, so I'll only mention them for completeness, and that's the last I'll say on the matter.

*Some software manufacturers have extended 2.5D to include linear (straight line) movement of the z-axis while x/y are in motion. Also, simple rounded edges can be simulated by going around a part cutting slightly deeper with each cycle.

[boostfan]

I have to admit, I find these hobby CNC's very intriguing, I appreciate the intel. I am finding a problem, I use a Mac, and software appears to be an issue.

[paulrussell]

I have to admit, I find these hobby CNC's very intriguing, I appreciate the intel. I am finding a problem, I use a Mac, and software appears to be an issue.

Yes, that can be a problem. There really isn't a lot of hobby-level CAD/CAM software available, and I am not aware of anything for machine control. This is probably due to the fact that because of hardware timing issues, parallel printer ports are used for control.
The good news is that it doesn't take a powerful computer, and you could be in business with a craigslist junker in no time.
CAD can be done in CorelDraw on the Mac, and then the CAM and motion control on the PC.
Since CNC routing is no tidier than the conventional kind, most people use a dedicated computer and not their "good one."