In this Instructable, I'll be experimenting with an idea I had about making things... Really small things, on my MakerBot 3D printer.  I need small parts for models I make for museums.  The last model I made required 21 guns ranging from .137" to .500" in length.  And it took me forever to make them the "traditional" way.

The process I'll be describing is simple, but hard to believe it really works.  I'm fully aware that incredible claims require incredible proof.  Please watch the video, taken in 1 shot, of the extruder doing what I claim it can do.

This Instructable could be a "Game Changer" for people like myself who sometimes need many copies of small, highly detailed parts.  In my case, to help with those models.  3D printers are great for many things, but some things, not so great.  In the past, the only other way I could make small parts was by hand, with a high-pressure injection molder (which I don't have) or cast them in resin.  

By hand is tedious, my eyesight isn't what it used to be and it takes what little time I have away from other things.

Resin is brittle, costs $150 per gallon, has a shelf life measured in weeks and makes a horrendous mess every time I use it.

Injection molders are inexpensive, clean, easy to use and take up little space.  But, they require metal dies.  Metal dies are made with machinery called "mills".  Mills are horrendously expensive and take up lots of space.  They also produce tons of oily dirt, and require years of training before they can be mastered.



With your printer, the filament that's sitting on your shelf and the demonstration mold I provide, you can make an injection molded "proof of concept" part without adding, modifying or removing a single thing on your printer.  And it will only take about an hour from start to finish.

This is one cool paradigm shift for people who love making things with their 3D printer, but also want small, highly detailed parts or jewelry, far beyond the printer's limited resolution capabilities.

Don't have a 3D printer?  Don't worry, you will.  As of this month, Staples is selling them, and within 2 years, I predict you'll be able to pick one up at WalMart.  3D printing is having the same growth cycle as the microwave oven had (remember when those came out?).  All "WOW factor at first, but in everyone's home within a couple of years.

Enjoy the descriptions and images I have so far.  And while you're waiting for me to post more information, please vote... 

Vote for anyone... But preferably me :)

This is a new idea and new ideas need data.  Negative feedback is actually more valuable than Positive.  And don't worry, I'm very comfortable with criticism.  You won't hurt my feelings and you may have a better idea we all can use.


Step 1: What You'll Need:

Here's what you'll need:

1.   A  3D printer.  Now, if you don't have a printer, but have an extruder and heater from an old printer or from a printer you're making, you may be able to construct a "free standing" version of an injection molding machine that may actually work better than the method I'm describing here.

2.   A mold.  Printing the supplied mold will allow you to produce a true injection molded part, but it will still have all the external characteristics of a 3D printed part.  As I've said, you can make a mold from just about any standard mold-making material, but I don't yet know what materials work best for this process.  I've been experimenting with polymer clay, a hard, inexpensive, heat resistant and easy to use material that can be picked up at WalMart.  Silicone RTV rubber is a material I've had success with and recently, I've tried a product called "Sugru" which works better than polymer clay, but not as well as RTV.  I've added instructions on how to make a mold out of Sugru in the next step, along with the instructions for using the downloadable printed mold.  If you just want to get on with it and print the mold I'm supplying, You can download it at the bottom of this page.

If you have mold making experience, you may want to use RTV, or do as I did, use an old mold to prove to yourself this process works.

The pressures involved aren't large, so metal dies aren't necessary.  However, if you do experiment with metal dies, I'd be very interested in hearing how it works out.  I have no way of making metal dies myself.  

If you use my printed mold, you'll also need higher and lower melting temperature filaments.  I used ABS for the mold and PLA for the part.  If you use a more heat resistant mold material, theoretically, you may be able to print in ABS, PLA, Nylon or any other material that fits through your machine (chocolate bars, anyone?).  One person even suggested hot glue.  None of these other materials have been tried.  I've only used ABS for the mold and PLA for the injection medium.  So far, other than the lack of color, I'm quite happy with it.

3.   A watch.  You'll need to time your injections.  Too short and the mold won't fill completely.  Too long and you'll have to trim too much flash from around the parting line. The time it takes to fill a small mold is measured in seconds.  Once you work out the best time for each shape, your parts should be good every time.

4.  Time: The "proof of concept" demonstration in this Instructable will take about an hour of your time.  Most of this time will be taken up by printing the mold.  For best results, the mold needs to be warm, so plan to be there when the print finishes and you can make the injection then.

READY?  Let's begin:
<p>funny that he says 2 years later one in every home, davinci have made a very home friendly and low cost printer.</p><p>i just got one, dont worry once i have mastered it i plan on getting a more open source one so i can actually have freedom with it.</p><p>good article. some thing i may consdier trying in the near future.</p>
<p>Is this amazing idea still being developed? I can imagine this being quite the boon to all those designs needing high resolution and duplicate parts. is there any way that anyone has thought of for making a mold that is a bit more rigid and handles higher temperatures? I can imagine doing this with polycarbinate. </p>
<p>You wouldn't really need to program, just write g-code. It could say something like:</p><p>G1 X0 Y0 Z0 E0</p><p>G1 X0 Y0 Z10 E0 (assuming the mold opening is 10mm high.)</p><p>G1 X10 Y10 Z10 E5 (assuming the mould opening is 10mm in on both the x and y axis and that the mould needs 5mm of filament to fill.)</p><p>I don't know if that is valid g-code but that is what i can remember from a few quick glances. You would then home it, break open the mould, take the part out, put the top half back on and start it all over again. The bottom half would have to be secured down though.</p>
Very neat :) I'll certainly have to try this out when I finish building my reprap!
Thank you. Can you try using just the extruder connected to its nozzle to move the plastic through? It should work... Also, maybe you could design your reprap's plate to accept a specially built mold container and program your machine to auto-locate the mold's opening. I'm not a programmer so that's beyond me. As you can see in the video, aligning the head with the opening in the die can be awkward.
<p>I might be able to figure out programming for that if I really wanted to, but I'm going to try this just using clamps to hold the mold down and using repetier to manually position the nozzle.</p>
you are most welcome.. <br>sorry, i can't accept them, i have to earn them.please save them for someone who deserves them.. <br>I hope the same, 3D printers should become open and affordable for common people to use. <br>well, me too enjoyed your ideas alot.
You did earn them... For the reasons i stated in my PM. With your forgiveness, I'll restate one thing publicly because I think it's important. (I have to paraphrase and go into more depth here to make it understandable). <br> <br>Ideas need to be critiqued. Every person's ideas are every bit as important and valid as anyone else's. Everyone, even &quot;Experts&quot; know a lot. But there's a much larger expanse surrounding our personal areas of expertise that may or may not have an impact other people's ideas. Everyone... And I mean EVERYONE has knowledge of things others don't know about. And that knowledge may impact or improve other people's ideas. <br> <br>I have no idea if what I just wrote makes any sense, but what it means is, &quot;Everyone's input, whether you believe it or not, is as important as anyone else's.&quot;
Nice stuff! Casting 3D prints is definitely the way to go if you want something useable.
Hi Tomdf: Thank you for your comment. For the first 2 months I owned my printer, most of the things that were printed on it were for the printer. Now, a good portion of the items on my car that aren't structural or require engineered plastics are printed, including the parts like badges that cost a gazillion dollars. Being able to hold the detail on the smaller things, just widens the door for 3D printers as they are today. I've just re-invented the Instructable, added another video and as soon as my favorite UPS guy drops off my RTV, I'll be adding a plethora of new things. Keep coming back and continue the conversation :)
whoa that`s a large pen!
LOL.. i LIKE that!
This is awesome
Thanks. If you have a 3D printer, please try it.
its nice work there bro.. <br>i didn't get all technical aspect of it, but, as a whole, you seem to make progress towards less expensive and efficient way of 3D printing, this will help the next step of evolution for 3D printers. <br>hope you do best here on too.. <br>and i think this thing worth comments...no need of anything in return.
Thank you, thank you, thank you chiragkhatri999. <br> <br>I'm good to my word and I'll PM you 6 months worth of Pro... You can use them or pass them on. Thanks again for breaking the ice. <br> <br>As all technologies develop, the ways to use them increase along with them. AutoDesk gets kudos for their 123D work and Instructables. Open source is like steroids for inventiveness. because every mind on the planet has the opportunity to pitch in. <br> <br>3D printing will be in everyone's home within a few years and is no more complicated than the inkjet printer sitting on your desk. As a matter of fact, it's the exact same technology, and everyone knows how an inkjet works. <br> <br>Thanks again, I enjoyed your comment and wishes.

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Bio: Retired inventor, reverted back to my 10 year-old self. A shop full of tools, a boat, race car, 3D printer and a beautiful wife who ... More »
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