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mdenton
03-31-2008, 04:24 PM
Ok,

So this is just a bit of fun, but has been in the back of my mind for some time now, and seeing one of Zenta's videos prompted me to give it a go.

http://www.hexapodrobot.com/images/BFHexapodCNC01.jpg

Using B.F.Hexapod with an additional floating pen attachment, and a utility I wrote to convert DXF files into translation commands for my p.Brain controller, I have got the start of a walking CNC router! Why... I don't know.. it just seemed like a good idea at the time!


http://www.youtube.com/watch?v=7hEXwyJ2B78

I still have to add a small routing head and test the cutting capabilities, but you get the idea. Resolution of the work area is pretty low, somewhere between 7 & 8 bit, with about 0.5mm repeatability, so it's never going to make precision parts! Also I have only implemented straight lines within the p.Brain, so the utility converts arcs and circles into segments.

One obvious improvement to resolution & repeatability is to have a work surface (in this case paper) that doesn't move around, in this video the only thing holding the paper in place.. is the hexapod's feet. In order to keep the router out of the way while walking, I plan on attaching a servo to the router head to swing the head from a horizontal to vertical position. Or maybe I will have come to my senses by then!! If I'm really mad I could try some 3D milling.. as technically the hexapod Is a 6 axis CNC machine. :eek:

[email protected]

Eric
03-31-2008, 08:21 PM
Very cool idea! Please let us know how it turns out!!!

Dave
04-02-2008, 11:40 AM
It's a graffiti bot! I'd be careful about putting a router on that thing, though. It'll crawl up on you and route a hole in your liver or something.

jdolecki
04-03-2008, 12:21 PM
Would your Hexapod be able to cary a small rechargable dremel tool?

Then it could make its own replacement parts.

mdenton
04-03-2008, 01:10 PM
Would your Hexapod be able to cary a small rechargable dremel tool?

Then it could make its own replacement parts.

I'm currently making a small router head using an R/C car style motor which will run from 7.2/12V :)

matt.

zwitterion
04-04-2008, 08:06 AM
Holy cow, if you can get this thing to do CNC routing then it might be able to make its own parts. Replace the router with a screwdriver and it's capable of assembling the parts into other robots. Which means you've got a walking CNC machine that can reproduce itself. Speaking of which, have you ever heard of the reprap project? reprap.org

Also, how much Z-displacement can you get with it?

And instead of using a router, why not use a 3d print head(also known as an extruder) and turn it into a 3d printer? You can buy a simple one, capable of extruding epoxy silicone, for about $20. http://www.evilmadscientist.com/article.php/fabricpainter
http://www.instructables.com/id/Build-a-Polar-3-D-Printer-from-Legos/
Or you can take a piece of pipe, put end caps on it, connect an air hose to one end and an nozzle to the other, and connect the air hose to an air pump. If you heat up the pipe, you can extrude plastics.

You might also want to check and see if the pen is held in tight, as this might be causing the inaccuracy.


Might I also remind you that if you make a self-replicating walking robot with a router on it,

JonHylands
04-04-2008, 11:00 AM
and a utility I wrote to convert DXF files into translation commands for my p.Brain controller

Matt,

Any chance of making this public? I would love to know how to convert DXF into g-code...

- Jon

mdenton
04-06-2008, 04:01 PM
Holy cow, if you can get this thing to do CNC routing then it might be able to make its own parts. Replace the router with a screwdriver and it's capable of assembling the parts into other robots. Which means you've got a walking CNC machine that can reproduce itself. Speaking of which, have you ever heard of the reprap project? reprap.org

Also, how much Z-displacement can you get with it?

And instead of using a router, why not use a 3d print head(also known as an extruder) and turn it into a 3d printer? You can buy a simple one, capable of extruding epoxy silicone, for about $20. http://www.evilmadscientist.com/article.php/fabricpainter
http://www.instructables.com/id/Build-a-Polar-3-D-Printer-from-Legos/
Or you can take a piece of pipe, put end caps on it, connect an air hose to one end and an nozzle to the other, and connect the air hose to an air pump. If you heat up the pipe, you can extrude plastics.

You might also want to check and see if the pen is held in tight, as this might be causing the inaccuracy.


Might I also remind you that if you make a self-replicating walking robot with a router on it,

Hi,

The Z travel and working area very much depends on the hexapod and the configuration I use. At the moment, I have about 60mm sq working area, and about 50mm Z travel, although I'm only using about 8mm Z in this first test.

I have been contacted by one of the reprap members, and it looks like a very interesting project, I like the idea of a 3D printing head also!

Seems your message was truncated?

Matt

mdenton
04-06-2008, 04:03 PM
Matt,

Any chance of making this public? I would love to know how to convert DXF into g-code...

- Jon

Hi Jon,

I'm converting basic DXF files, lines, arcs and circles only straight into a format that can be read by my hexapod. I haven't looked at G-Code yet, but it would be better to convert G-Code files.

I will look at posting the DXF code on my site when I get time.

Matt.

metaform3d
04-06-2008, 06:57 PM
That's inspired, Matt. Very cool.

zwitterion
04-07-2008, 09:19 AM
Complete message: Might I also remind you that if you make a self-replicating walking robot with a router on it, you're a hop skip away from world domination.

So does the pen move at uniform velocity? As this is required for both 3d printing and routing.

And why not make the toolhead, ie 3d print head, router, screw driving unit, such that it can be switched out. This would give you a lot more capability.

mdenton
04-09-2008, 03:27 PM
Complete message: Might I also remind you that if you make a self-replicating walking robot with a router on it, you're a hop skip away from world domination.

So does the pen move at uniform velocity? As this is required for both 3d printing and routing.

And why not make the toolhead, ie 3d print head, router, screw driving unit, such that it can be switched out. This would give you a lot more capability.

The pen does not move at uniform velocity, but this shouldn't be a problem for routing.

I have got the system reading G-code now, and I'm nearly finished making the routing head, so its coming together!

mdenton
04-19-2008, 04:28 PM
Update on the router progress.

I have just about finished the router head, it took a bit of fiddling to get rid of the vibrations, but managed to find a small thrust bearing used on RC helicopters that did the trick. I have yet to mount it to the hexapod, plus there are a few tweaks to the spindle height, but it's more or less there.

http://www.hexapodrobot.com/images/CNC%20Router%20Head%201.jpg

The collet I have made currently takes 1/8" bits, but I need to finish the 3mm version as most of my small router bits are 3mm shank. The motor is a 14 turn 380 brush-less motor, which gives about 3600 rpm/volt, so plenty fast enough! It will run from 6 to 10 cells, I think I will add a heat sink, as it tends to get a little warm even under no load. The MUX servo moves the spindle 40/50mm up and down the guide rails to the work surface.

Looking forward to getting on the hexapod and running some g-code through it, but work is slowing me down.

mdenton
06-05-2008, 06:10 AM
CNC hexapod cuts its first material!

Ok, so its only polystyrene, but its a start :)

http://www.hexapodrobot.com/forum/images/myimages/mms_hex_cnc_poly_femur.jpg

A couple of improvements were made to the router since my last post, most significantly I had a colleague make me up an dremel collet adaptor to fit directly onto the motor shaft, much better than my brass grub screw style colet.

For these two videos I'm using a 1/16" two flute slot cutter, the router is running at approx 35,000 Rpm, the additional battery on the to of the hex is a 12V NiMh 4500mah pack just to run the router. DXF files are loaded in to artcam where G-code tool paths are created. Due to the 10mm thickness of the poly and the cutter only being 6mm long, I chose to do two passes on the workpiece, this also shows that although the resolution is low, repeatability is good enough for multiple passes. Material is held down by the weight of the hexapod, which is current;y 4.3Kg with the router and additional battery pack.

CNC Cut Poly Square

http://www.youtube.com/watch?v=9LQrzuG5nFA

CNC Cut Poly Femure - 2 pass cut

http://www.youtube.com/watch?v=EhM2bAqwPmY

You may notice in the picture of the poly femur with the hole left in the poly, the hole has a cleaner cut edge than the cut piece. This is due to the fcat that foam and poly cuts better in a reverse direction, however, I forgot and generated the tool paths for a normal cut direction.
I also tried to cut 2mm ABS, however, this caused too much vibration in the tool, which in turn loosened the colet allowing the tool to slip out and cut too deep into the ABS. A square was cut, but not terribly accurate, some work needed yet!

http://www.hexapodrobot.com/forum/images/myimages/mms_hex_cnc_abs.jpg

JonHylands
06-05-2008, 06:21 AM
Absolutely, freakin' amazing!!!

- Jon

LinuxGuy
06-05-2008, 08:39 AM
I also tried to cut 2mm ABS, however, this caused too much vibration in the tool, which in turn loosened the colet allowing the tool to slip out and cut too deep into the ABS. A square was cut, but not terribly accurate, some work needed yet!
Very cool, Matt! I'd like to see a close up of those feet. I want to add feet to the hybrid Hexapod/Octapod I want to build, and have sensors there for presure and perhaps other stuff if there is enough room. I think having some sort of sensory input for the legs is a good thing.

8-Dale

ooops
06-05-2008, 09:13 AM
Holy cow! Itís handwriting is neater than mine! I am feeling obsolete!
That has truly endless possibilities!!!

mdenton
06-05-2008, 10:12 AM
Very cool, Matt! I'd like to see a close up of those feet. I want to add feet to the hybrid Hexapod/Octapod I want to build, and have sensors there for presure and perhaps other stuff if there is enough room. I think having some sort of sensory input for the legs is a good thing.

8-Dale

I have added details and pictures of the V5 foot design here:

http://www.hexapodrobot.com/forum/viewtopic.php?f=13&t=44

[email protected]

mdenton
06-05-2008, 11:22 AM
Just had a second go at the femur shape, I increased the size by 20% and reverse cut the piece.. much better!

Original and larger New part
http://www.hexapodrobot.com/forum/images/myimages/mms_hex_cnc_poly_parts_1.jpg

Close up of the cut edge.
http://www.hexapodrobot.com/forum/images/myimages/mms_hex_cnc_poly_parts_2.jpg

JonHylands
06-05-2008, 11:44 AM
Matt, you should look into cutting Sintra (http://www.solarbotics.com/construction_materials/)... Its nice stuff, fairly sturdy (compared to styrofoam), and cuts like butter.

- Jon

Adrenalynn
06-05-2008, 11:58 AM
:eek:

That is just creepy on so many levels.

It's beautiful! I love it! That's like magic. Where getting the darned things to walk is a challenge for most, you have them cutting pieces to replicate themselves. [boggle]

mdenton
06-05-2008, 11:59 AM
Matt, you should look into cutting Sintra (http://www.solarbotics.com/construction_materials/)... Its nice stuff, fairly sturdy (compared to styrofoam), and cuts like butter.

- Jon

Hi Jon, thanks for the link, looks perfect for this! I have got some high density foam to try out as well.

Alex
06-05-2008, 02:23 PM
viva la skynet!! (http://forums.trossenrobotics.com/group.php?groupid=2)

Great work Matt:D

darkback2
06-05-2008, 03:09 PM
Alright Matt...Guys like you either make me want to give it all up, or step up my game. This robot is beautiful. between this thing and Pheonix, I don't know what to do with myself.

DB2

mdenton
06-06-2008, 06:48 AM
I had a go at 3D profiling today in high density foam. I have a few issues to sort out, mainly with my control software not having a puase or for that matter a stop button :o .. any who, I fed a 3D stl file into artcam and ran a couple of passes through the hexapod to get this:

http://www.hexapodrobot.com/forum/images/myimages/mms_hex_cnc_hdf_face_1.jpg

I admit its not great, but you can kind of make out the eyes, nose and mouth.. kind of. The large 1/8" scar on the face was caused by operator error!

I will post a video of this process some time after the weekend, and try another test next week.

ooops
06-06-2008, 01:29 PM
Holy cow that is awesome!!!
You have brought the world one step closer to the "Iron man" movie concept of "CNC while your out".
You need to stop long enough to get a patent. But keep sharing with us!!!

Alex
06-06-2008, 02:23 PM
Holy crap that is incredible! Has your hexapod been to Mars (http://www.google.com/search?q=face+on+mars&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a)? Fess up man!

Adrenalynn
06-06-2008, 03:20 PM
Holy cow, you're RIGHT, Alex. As soon as you said "Mars" - I KNEW where I'd see that before.

mdenton
06-09-2008, 02:10 PM
Ok, attempt two at 3D cutting was much better.

I made a few improvements to the software that streams the data to the hexapod.. including a stop button! The cutter was the same, 1/8 ball nose. After a roughing cut, I did a raster pass with 1mm step, and a second raster pass in the opposite direction with 0.8mm step.

http://www.hexapodrobot.com/forum/images/myimages/mms_hex_cnc_hdf_face_3.jpg

I could use a smaller ball nose cutter to get a finer finish, but I think I'm approaching the limitations of the robots resolution.

http://www.hexapodrobot.com/forum/images/myimages/mms_hex_cnc_hdf_face_2.jpg

I will edit the video and upload when I have time.

mdenton
06-11-2008, 06:24 AM
I have just uploaded the 3D face video.


http://www.youtube.com/watch?v=quN37YskoaM

To cut the face I did three passes:

1) roughing cut
2) X raster finish
3) Y raster finish.

The face took just under 30 minutes to produce.