PDA

View Full Version : A luddite approach to mechanized cutting



camdigger
12-21-2010, 07:30 PM
This has drawn out way longer than I'd hoped, but it seems to be getting closer...

I wanted an inexpensive low tech plasma cutting guide. I've seen the Torchmate and read the HSM article by Mr Verity. Seems simple enough...

I bought a PWM kit from a kit supplier. I had a cordless drill that the battery had crapped out on. and some miscellaneous bits and pieces.

Pic 1 is a pic of the circuit as it was tested. Ive added a fuse and an enclosure.
http://i766.photobucket.com/albums/xx301/camdigger/DSCN0074.jpg
Picture 2 is the linkage. I'd bought some cheap, nasty unsealed ball bearings from the local discount house. They worked really well on the arm joints.
http://i766.photobucket.com/albums/xx301/camdigger/DSCN0103.jpg
Picture 3 is a close up of the tracer spindle
http://i766.photobucket.com/albums/xx301/camdigger/DSCN0106.jpg
Picture 4 is a close up of the torch holder.
http://i766.photobucket.com/albums/xx301/camdigger/DSCN0107.jpg

camdigger
12-21-2010, 07:32 PM
Picture 5 is a sample cut.
http://i766.photobucket.com/albums/xx301/camdigger/DSCN0108.jpg
Just another view that shows the overall arrangement.
http://i766.photobucket.com/albums/xx301/camdigger/DSCN0105.jpg
Some initial comments..

I need to slow the tracer speed down. The torch speed at the present minimum setting is too fast even for the 10 gage test piece. If I can't reduce the lowest speed on the controller, I have a power window worm gear motor that should do fine.

The welding magnet I used to energize the tracer is a little weak. I've heard that the magnets in magnetic grounds are stronger. That would help.

alanganes
12-21-2010, 07:54 PM
Very cool! Let's call it "Minimalist", that sounds nicer than Luddite.
Nice work, I like the use-what-you-have-on-hand look of it. Are you doing this just as an interesting project, or do you have a bunch of something you need to cut out?

Thanks for posting this. I, for one, love seeing these sort of project posts. Talented bunch around here.

camdigger
12-21-2010, 08:23 PM
Are you doing this just as an interesting project, or do you have a bunch of something you need to cut out?

Thanks for posting this. I, for one, love seeing these sort of project posts. Talented bunch around here.

I don't have a large number of any one thing, but I do have some projects in progress that will really benefit from mechanized cutting.

I dunno 'bout talent. This is a direct offshoot from Verity's HSM article a few years ago. FWIW, it would be simple to adapt to oxyacet use too. In fact, Tom V's machine used an oxy-acet torch, but no magnet on the tracer stylus.

I'm a bit disappointed with the welds. I came by a wirefeed welder and am still getting used to it:o It is a 110v fluxcore only machine. It will weld the tissue paper sq tbg, but will still burn through if care is not exercised.

BTW, you're welcome.

Lew Hartswick
12-21-2010, 10:58 PM
Have you by any chance a not to distant relative by the name of
Rube Goldberg. ? :-)
...lew...

AJA
12-24-2010, 05:37 PM
I don't have a large number of any one thing, but I do have some projects in progress that will really benefit from mechanized cutting.

I dunno 'bout talent. This is a direct offshoot from Verity's HSM article a few years ago. FWIW, it would be simple to adapt to oxyacet use too. In fact, Tom V's machine used an oxy-acet torch, but no magnet on the tracer stylus.

I'm a bit disappointed with the welds. I came by a wirefeed welder and am still getting used to it:o It is a 110v fluxcore only machine. It will weld the tissue paper sq tbg, but will still burn through if care is not exercised.

BTW, you're welcome.


How did Tom V's machine follow the template without a magnet on the tracer stylus?

AJ

Black_Moons
12-24-2010, 06:56 PM
Took me a little while to figure out what it all does.. But after I did, I gotta say, thats awsome.

The magnet setup as is kinda sets up a nice closed loop for the magnet flux. Maybe if you let the bottom magnet get a little closer to the plate, it would incress the strength. Only problem I see is that bottom magnet may attract the tracer to other metal objects.

Maybe spot welding some more nuts onto the bottom of the tracer plate to close the gap and 'tailor' some of the magnetic hold?

Gravy
12-24-2010, 08:37 PM
Allright! Enough is enough!

I'm callin' you out, Mister!

I didn't see more than one or two zip ties, a piece or two of baling wire, and I didn't spot as much as a yard of duct tape...

You call yourself a Luddite? Turn in your authorized Red Green copywrited
suspenders, you fraud!

You are dangerously close to the twin heresies of Fabricator and Prototyper!

(Nice work! And Merry Christmas!):D

v860rich
12-24-2010, 11:33 PM
I built one years ago using a 12 volt w/shield wiper motor and a model train transformer for the speed controler.
I'd get a pic but it would take me a week to unearth it out of a shed!!!

THANX RICH

People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

jugs
12-25-2010, 05:15 AM
Love the torch trigger switch control operator interface in Pic 4 :D

john
:)

John Stevenson
12-25-2010, 05:33 AM
Nice,

I had a 3' square burning O/A table that came from a university, was going to put the Plasma on it but never did and sold it on as taking up too much space

I'm often tempted to bolt a 4' length of box section to the CNC mill table and use the X Y travels to carry the plasma torch over a temporary sub table at the side.

Problem is laser cutting round here is just too accessible to bother about setting up, may be worth doing if I do buy one on those inverter plasma's I'm wondering about as the big Cebora is too much trouble to setup.

Black Forest
12-25-2010, 06:50 AM
What is the point of having the tracer in the first place? I helped a friend build a plasma pantograph. We just clamped the part to the top table and by hand held the stylus and made it follow the template. We wired in a foot pedal to switch on the plasma cutter. With a little practice for consistency moving the stylus it was fast, accurate and simple. I like simple.

John Stevenson
12-25-2010, 07:02 AM
When you are doing a lot of parts the motorised tracer takes the effort out of it to get clean consistent cuts.

Put an over arm above the pattern with a pin that can be placed rougly in the centre of the pattern, just above it.
From this pin a big rubber band [ inner tube ] goes to a bearing on the top of the follower drive.

This will pull the follower onto the pattern and enabled you to use easily cut plywood templates.

camdigger
12-26-2010, 09:18 AM
Thanks for all the comments guys!

Verity held the stylus against the pattern with his hand.

As far as the Red Green/Luddite accusation, I subsituted vinyl electrical tape for haywire and duct tape and an Oring for haywire. It's more discreet.:D

When you are doing a lot of parts the motorised tracer takes the effort out of it to get clean consistent cuts.

Put an over arm above the pattern with a pin that can be placed rougly in the centre of the pattern, just above it.
From this pin a big rubber band [ inner tube ] goes to a bearing on the top of the follower drive.

This will pull the follower onto the pattern and enabled you to use easily cut plywood templates.

As it stands now, I could extend the threaded rod holding the pattern and loop a postie elastic around that and the stylus if I wanted to go that way. I still have reservations re how that would work if the pattern had a surface that was parallel to the elastic band, or had a concave feature like an alternator belt bracket.:confused:

Still, it's been a fun project. Sadly, it may be on the shelf for a while, work seems to be picking up. Hard to get much done in the shop from half way around the world.

They got Heathrow back on track yet?