DIY CNC Router from old printer/scanner parts

[C-Bag]

Thanks for the offer kiwiles, I'll keep it in mind. Don't know how I would get around the floppy disc but at this point I'm hoping to dump the whole idea of trying to use printer parts. I think the super proprietary nature of them makes it tough to hack for a non hacker like myself. That's probably why I've found so few tutorials on how to repurpose them on the net. That really sux on the part of the manufacturers they made them so proprietary but I guess that's the nature of the corporate beast.

[kiwiles]

You didn't say the size you were wanting to pull, though it must be small. Perhaps the best way would be a couple of small air rams one to pull one to clamp. With so many different options in rams these days, it would be a good path to follow - no computer required, simple mechanical automation.
Depending on your cutting arrangement, a rifle cartridge trimmer might be used for clean up and final length trim

les

[C-Bag]

Yup, buried in all that rambling I mentioned it's 1/4"dia 1/8" wall silicon hose. And the pieces need to be 1.25" long.

So the stuff is soft but oddly sticky but not like in a goopy way, but in so soft and clean it clings to stuff. You know how silicon caulk is? So feeding through a tube is not going to work. Like all silicon it's weird to cut. Like it resists being cut fast but cutting slow is no problem if it's done right.



So here is a grouping for y'all of the hose, the little scissors I use that work so well and on of the 7 or 8 air motors I have. I didn't get a pic of the sliding glass door rollers that I think would be the bomb for guiding the hose, next time.

[PJs]

Thanks for the pic C-Bag. The sticky is a bit of a problem and now understand better the parameters. I have that same pair of scissor (nice) but just picked up a pair of similar Fiscars with my SO a few weeks ago for her wool work, but they are titanium...I warned her they might end up being MIA. They leave no thread uncut and square as my head...Super Nice but pricey.

Have you tried pulling a single edge razor blade through the tubing for cutting? The other thing that came to mind for cutting if it is that persnickety is a pair of "Guppy" style tubing cutters. Either scissors or a pull blade could be anchored and connected to solenoids or a pneumatic of some type.

The thing with pneumatic motion is the peripheral costs on a cheap and cheerful budget. I found this 2" linear slide on Ebay for a decent price but you will need pneumatic solenoids, fitting, and such to build up your system. They might be available on Ebay or CL but haven't looked. Don't know if your "Air Motors" would work...have you tried them? Are they linear motion or rotational?

Like your screen door roller idea but think it could only be used for a guide system...not sure the sticky will give you enough traction to drive it. They could be made of Delrin or similar on the lathe and scored to give some traction??

Ultimately IMHO it would be better to buy it on a roll for an automated machine...pricey I know, I looked but may be a bit cheaper/ft in bulk. That package looks to be 25' or 50'?? From your numbers it looks like you go through about 312' for your 3k/per year. If you did 3, 100' rolls say, 1k at a time you could manage the outlay over the year. The other thought is; Can your supplier cut it to length for you and send you bags of cut lengths? A lot of them do that for a price and are likely set up to cut it already...as long as they can maintain the QA for you. Maybe look into it for an ROI comparison to a machine build. The cost of a machine is too difficult to assess at this point especially on a Cheep and Cheerful budget and some good scrounging/re-purposing...but I love the challenge of it!

Thoughts for now...~PJ

[C-Bag]

As usual your observations are spot on Wiz. I looked into having the hose cut and it's almost impossible to nail down because nobody does it with this hose because it's lab grade and triple sanitary packed. Add to that its not offered on a reel and the only place I can get a decent break on the price is through a non medical vendor so it's still most cost effective to cut it by hand by demand. It's not like it's hard or that time consuming. I've made all my other jigs, fixtures and even machinery so every once in a while I contemplate adding an auto hose cutter to the lineup. I think it's more ADD behavior than a brick wall need

I got inspired by looking through this guys blog:Michael McKGyver McKinley / FrontPage

Manufacturing anything is a exercise in rapid response flexibility. Suppliers are constantly being bought out or put out of biz or certain things are discontinued and it always seems to be the very item that seems to fit my application. Without the net and places like this where I'm constantly finding out about stuff that is useful to my processes I'd have to give up and price myself out of exsistance. Like this hose, it's 8x's more expensive than the old hose I used to use. But when I updated my design I use about 1/6the amount of hose I used to use. So I'm actually cutting less hose than I used to. Bottom line is I'm grateful to even be in the position of having the time, $$, and support to contemplate an auto hose cutter.

The air motors are outrageously strong. It's a 3" piston with linear motion, not rotary, with a heavy duty return spring and built in stroke stops. I'd never bumped into these until I found them and two plastic milk crates at a ReStore of all places. They had no idea what they were and it was 8x "motors", a board with three foot pedal air valves and a bunch of custom brass plumbing, quick couplers and switch valves. Said some woman came in and asked if they took donations and dropped the whole thing off. All looked unused and got the whole lot for $100. So all it would take is a simple two way valve because of the return spring to actuate.

I tried my big Olfa rotary cutter on the hose and went through it like a hot knife through butter. That cutter is astoundly sharp. For cutting anything where you want long straight super clean runs they are absolutely to way to go. So that's definitely to way to auto cut the hose. I also scored some used 1" stroke guided air Rams off eBay last year in the deal of the century. They were obviously scavenged off a box making machine as I'd seen them used for holding boxes in place for assembly. Guy was selling them for $46 for 4 of them +$10 shipping! They were US made the list for $260ea.! So I have a couple of spares for the project.

I also started looking over PLC on eBay......of course I have NO idea what I'm looking at or what I need. But you are right, they are cheap! I saw a used small one for $40. You really think they are easier to program than an Arduino?

[kiwiles]

been thinking about your problem. I think perhaps you might be over engineering in your thoughts. Ist off, how much of this stuff do you need to cut, if its an ongoing contract then yes, think a little harder, but start off simple.
example, grab a block of UHMO, bore a hole through it,so that the fit of the tube is firm, but not tight (slides with little effort). It's a naturally slippery product so should slide easily, if not , add a lubricant, something like water could work. next make a simple guillotine on the exit. this could be a knife cutting blade from a stanley, (think thin, less drag) but the blade must run hard against the exit hole of the UHMF. and have plenty of blade exposed on the outside of the cut. By doing this, the tube is supported all way round so there should not be any distortion of the cut, leaving it square. to make it easier to work, screw it down onto some thick ply as a base.
when that is sorted, add a stop of the required length, push through a length and slice. If the length has a hang up, add a small bar above the height of the cut on the outside of the blade, but above the tube. cyno should deal with that, do another cut. the bar added onto the blade should knock it down after the cut, and leave it open for the next length to come through.
so we now have a simple machine to do the job.
From there, break down the requirements to automate it, I would start at the feed side, small actuators are around and cheap, New PhD Pneumatic Linear Actuator MS04 2x2 | eBay
as an example. find one that can be adjusted in length of pull, and another than can be used as a clamp, they don't to be very big obviously, so there you go. mount a half block on the top for the tube to lie in, and another half block on the clamp. You may have to muck around with materials, but not impossible.
tackle the cutting end the same way. Manifolds can be sorted out to make things like this fully auto

start of small, use the kiss method and you will get it.


les