Re: [CAD_CAM_EDM_DRO] What is the practicality of cutting 1' x 3' x 1/8" aluminum on a gantry CNCRouter?
Posted by
Alan Marconett KM6VV
on 2001-11-29 14:48:02 UTC
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:
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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