Monday, December 21, 2015

3D Printer Filament and the Machine Shop Seed

For the last several days, I have been working on making some products to sell that are 3D printed.  Namely one of those little knives that fits in a sheath and hangs by a lanyard from the neck.

They are popular among Filipinos because they can be worn inside the shirt and accessible even when packed into a crowded jeep as getting to your pockets is quite difficult in the cramped sitting position.

So after a few prototypes using regular ABS plastic, I ran out.  So I called up the local distributor and he had this new stuff in.  It is called ABS+.  Now I heard some hype about it, how it was supposed to be a little stronger and did not warp as readily as regular ABS during printing. 

I personally am not fond of ABS much because it is a serious pain to get dimension tolerances anything near what I need for a lot of projects aside from art stuff that no one cares about.

I just got home, loaded up the machine and printed out a couple neck knives.  I must say, yeah the it really did live up to the hype.  It is not as shiny as regular ABS and printed perfect the second try.  (First try I was a little careless and did not check to see if the adhesive was done properly)

So it looks like this ABS+ stuff is the thing if you want to print some good stuff.

This brings me to my machine shop seed project.

Last items arrived from China, and documentation will commence more than likely after Christmas.

Along the way I was searching for any edge to lower the costs of a printer.  One of my biggest costs is the linear guides. 

Normally I buy from China, and I take a 100% markup once tax and shipping are included cause these things are HEAVY.

So I started researching on how to make my own using stainless steel rod and bushings. 

I can buy half inch stainless rod really cheap and it is a shiny smooth finish.  The sellers let me cherry pick thru the stock to find the straightest stuff.

However there are no linear bearings for english sizes rod.  Not anything affordable anyways.  So i am left with a couple options.

One, I can drill some HDPE, Delrin or Brass and make a bushing. 

Two, I can 3D print one from PLA or that new bushing filament from Igus.  Pla works nice however, no as good as the IGUS stuff, but I deal with cheapskates and they do not want to pay much, so PLA it is.

However this got me to thinking about silicone impregnated bushings.  After researching them, It took me half a day of Google-Fu to find out exactly how lubricant impregnated plastics are made.

The trick is a vacuum chamber.  So I am now thirsting for a foodsaver with the vacuum canister to try this and a liter of silicone lube oil.  Total costs are around $200 for this experiment so it may take me a few weeks to scrounge up the cash. 






2 comments:

Phil said...

More info and pictures of these little neck knives please.
Sounds....... interesting.

John said...

Harbor Freight air powered vacuum pump? http://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html

And a mason jar of suitable size with a lid adapter? (and yes, imploding glass risk, but you knew that!)

That might work for a proof of concept test.