Re: [CAD_CAM_EDM_DRO] What is the practicality of cutting 1' x 3' x1/8" aluminum on a gantry CNCRouter?

Alan -

That sounds interesting. I would like to see some pics.

Mike

Alan Marconett KM6VV wrote:

>
> Hi Eric, list,
>
> I have built a robot chassis, possibly similar to what you are
> proposing. Although students at NASA did the rough metal work for me, I
> had designed it so that it could be fabricated by a small sheet metal or
> home shop. The Base is a 1" square aluminum tube, cut and bent into a
> 24" x 20" rectangle. An aluminum plate bolts to the top of that.
> Wheels, batteries, drivers go on this level, about 6" high. 8" "shop
> cart" utility wheels are driven from 23.4:1 Granger gear boxes by a pair
> of "daisy wheel printer" motors. four 12 AH 12V batteries are connected
> in series to power a pair of H-bridge motor drivers. Above this base, on
> 6" pillars, is another 1/8" aluminum plate. In the center of this is a
> 8" dia trunk hole, with a LARGE thin bearing, rotated by a toothed
> pulley.
>
> The "body" of the robot is a 24" high by 24" wide by 20" deep body,
> which truncates up from the 8 sided base to a smaller 8 sided top. The
> top is considerably thinner, so that the front and back of the body
> taper up. There are 1/16" bent plates that serve as the corners and
> create the size transition from top to bottom. There are open
> rectangular areas on each of the four sides, with lips so that the
> openings may be closed off with panels. The corner transitions are
> welded to the top and bottom plates, creating a truncated trapezoid.
> Additionally, there is an 8" trunk hole cut in the bottom plate. Into
> the front of the body, a box deep enough for an old XT mother board is
> set in at an angle.
>
> Probably hard to visualize all of this, but my point is that all you
> need is to get the aluminum plates sheared for you, the corners bent,
> and the frame welded or bolted together. I didn't have any flame
> cutting to do, and probably could have done the cutting with a saber or
> table saw. A few more screws and nuts could have replaced the welding.
> The completed frame and body is quite strong; I was able to sit on it
> and drive it around the garage!
>
> I'll send you some pix if you are interested, and could even post them
> in the files section, if anyone is interested.
>
> HTH
>
> Alan KM6VV
> P.S. This was a project from about 12 or so years ago, no current work
> in progress. "HOBBIT" (Home Orientated Binary BIpedal roboT) doesn't do
> stairs!
>
> glee@... wrote:
> >
> > Background to this question:
> >
> > I desire to (someday) build a robot chassis similar to those found at
> > http://www.irobot.com/rwi/.
> >
> > My thinking would be that I would cut out the parts and then have a local
> > welder heliarc the sides, etc together for a sturdy frame. The rest would
> > be bolted together.
> >
> > The base would be 1/4" aluminum while the sides and rest could be made with
> > 1/8" or thinner if using diamond plate.
> >
> > Assuming that I following my thinking, the next step is to cut these parts
> > out. Since I have the parts to make a CNC Gantry router of size: 36" x 36"
> > I thought that I might use this to do the job. When I purchased my Sherline
> > Lathe and Mill with the CNC Retrofit, I had the Bill Griffin make me a
> > complete cable and 4 stepper set so that I could easily connect it to some
> > future CNC device which I would build.
> >
> > So, the question comes: Just how practical is it to machine aluminum on a
> > small Gantry Router? Most small Gantry routers have no mass and I am
> > concerned that this would make it difficult to cut these parts.
> >
> > Bill and I have been having this discussion and he noted that although many
> > vendors (such as Larkin and others) tout their 24" and 36" gantry routers
> > as capable of cutting aluminum, he has yet to see them actually demonstrate
> > anything other than wood or plastic at the shows.
> >
> > I would like to hear from anyone who is or has machine cut thin aluminum
> > plate of sizes up to 1' x 1' x 1/8" with an occasional piece up to 1/4"
> > thick?
> >
> > Speed is not an issue as this is a hobby. Safety and practicality is. Other
> > options would be to build a cnc plasma table (but that would be a whole new
> > venture) or just find someone with a CNC router or plasma cutter and farm
> > out the cuts.
> >
> > No rush on this, I'm just thinking aloud and would welcome any discussion
> > on this.
> >
> > - Eric
> >
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