Wednesday, September 06, 2006
New Character Enter
Observe the rough-and-ready converted-drilling-press milling machine that didn't exist last week. And I can contribute... um... totally nonstandard imperial-pitch parts that nobody in their right mind would use. Oh, and one-piece acorn nut nozzles turned on a 3" lathe that's older than I am.
I really wish they'd kept the name Polymorph in Canada. One feels like an idiot wandering from craft store to craft store asking for 'friendly plastic'. Anyway. The Teflon, motors, nichrome, pics, and polymorph are in the mail. If I can build the printing head, I will know the rest is possible.
Your drill press milling machine looks great. You're making me jealous!
It seems to me (and I don't think I'm the only one) that if you can build a sturdy enough 3-axis CNC table, you can use it for either milling or for RepRap -- Just change the hardware from a nozzle to a high speed drill. A table capable of milling machine work should work great for a RepRap -- the opposite is not necessarily true (the reduced forces on the work piece in additive manufacturing allow you to use a less sturdy base.)
"slide vise" is the magic word if you want a neat X/Y platform like the one pictured. If you don't know these magic words, you'll find nothing but those hyperexpensive axis systems for industrial manufacturing.
The one I have is incredibly cheap at $55 CAD, therefore is hard to turn and has more backlash than a head-on collision. but I'd imagine the more expensive ones would be far better yet still cheaper than a "real" axis system.
Your idea is intriguing. I'd considered putting the reprap on the lathe, but not the drill press... On one hand, a drill-press-based reprap would have great difficulty building itself. On the other hand, a working reprap would make it much easier to build one that could. And I'm all for sparing myself the headaches of building my own Z-axis system.
I believe I will. Thanks for the suggestion.
If that doesn't work, drop me a line, I've got a bit more than I need.
Regarding 3-axis CNC, this is a snippit from an old email:
I'd been poking around in an industrial supply catalog and noticed this:
the compound milling table, for about US$250 :
with the addition of a pair of stepper motors, it might make a useful
(My mini-mill is basically a compound milling table plus another axis:
This is what I'm using as a RepStrap.
Don't worry about not being a heavy-hitter, I'm a non-hitter and they still talk to me here. ;)
If I can ever build a RepRap, I'll have to call it "Le RepRap, eh". (French-Canadian thing)
It also goes by the name ShapeLock.
Steve: It does, in ridiculously small quantities.
I'm rethinking the axis idea. If I just use milling machine parts I'm back at square one once I've got the head... You can't reprap a milling machine unless you want to cast metal, and I've got nothing to do but wait for the weekend after this one before I can work on the head. As such I've been thinking on axis ideas. The ones I see are nice, but I want something even simpler.
How about hydraulic movement? Two ordinary plastic syringes, full of mineral oil or something, connected with tubing. Drive one end with a worm gear on a stepper motor, the other moves an axis -- heck, IS an axis. Just a little reinforcement and they're sliding structural elements.
* They're cheap, come in a variety of sizes, seal well, and are precisely graduated(in millilitres... can't have everything)
* There's fewer linkage headaches since you can put the input end wherever you please.
* You can match up different size syringes to get "gear ratios".
* The reprap might even be able to build them someday, being they're 100% plastic and all.
This does have it's problems, though.
* It's great at shoving but it can't pull very well. Could be enough force for a deposition head but no milling unless you want to use two syringes for each axis -- one forward, one back.
* Air bubbles. I wonder if Jiffy Lube does flushes for non-cars...
* Tubing flex -- if they're building Godzilla with wire suspension, some flex must be permissible, but how much?
* Short range of movement -- intended as handheld instruments of sharpened pokies, syringes don't generally move more than a few inches.
Taylor, Saskachewan? My grandmother was from Coderre, not far! Well, for Canadians...
I've built a number of little hydaulic/pneumatic pistons using copper plumbing pipes. Very smooooth inside! Easy to solder little fittings to. Also bigger ones with black PVC drain pipes. You can get bi-directional movement by feeding pressure from each end, depending on which way you want to go.
Plaasjaapie, the first tool a person needs is a drill press, the second is a cross slide. :)
I dug out a 12cc ink-refill syringe and noticed something useful. It's marked in milliliters but graduated in millimeters. Put a ruler on it and they line right up, 1cm=2ml. It's hard to give something an inner radius of √(2/pi) by accident, so I hope it's the standard for that size. It'd make calibration a snap.
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