# 3D Printing



## strantor (Jan 18, 2014)

Anybody here have a 3D printer?

I got one recently, after deciding that I am capable of building a myoelectric prosthesis for my father (right arm amputee). Pretty awesome technology. So far the structural quality sucks, but given this is a relatively virgin technology, I have much opportunity to think of ways of improving it that might not have already been thought of. That seems to be a regular occurrence for me; figure out a way to do something better, only to find out that someone else already thought of that 50 years ago.

I present you with a picture, lovingly snapped in familiar settings so as not to cause anybody undue discomfort. 





If you're particularly aroused by the idea of making a DIY prosthesis, or by the thought of my potential failure, you can keep up with the progress of my build on my blog. 

freehandblog.wordpress.com


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## Ray C (Jan 19, 2014)

Very cool and I hope you're able to contribute to your Father's needs...

BTW:  3D printing is a hot topic and I'm sure will make great strides.  Here in my area, the John Hopkins Applied Physics Lab is apparently ramping-up to do a lot of 3D research.  

Ray


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## Charley Davidson (Jan 19, 2014)

I am impressed, I have been interested in 3d printing for a while. What printer do you have?  And all the specs on it including price if you don't mind


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## nobog (Jan 19, 2014)

We use 3D printing "at work" extensively and 98% of the parts made are junk - oh, you can look at 'em and imagine what it would look like if it was made from a real plastic or aluminim, but they are not flat, surface finish is horrible, and other than the "that looks cool" factor, the parts have very little real use. I actually have no idea the brand or technology our company uses but lets just say we spare no expense - on anything.

Someday they might be able to make real parts but until the material get better - and cheaper - I will spend my money on a real prototype.

Others will no doubt have a different opinon, just my 2 cents after 28 yrs in R&D in a biomedical environment.

Jim


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## Ray C (Jan 19, 2014)

Charley,

Have a look at this system.  I don't have it nor do I have any affiliation with the company other than I'm a satisfied user of their 3D CAD software.  I do know a small company that uses this system and made some small parts for me at my last job.  http://www.alibre.com/3dprinters/Cube/Compare-cubes.asp  Anyhow, it gives you a good idea of price and capability.


Ray





Charley Davidson said:


> I am impressed, I have been interested in 3d printing for a while. What printer do you have?  And all the specs on it including price if you don't mind


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## strantor (Jan 19, 2014)

Charley Davidson said:


> I am impressed, I have been interested in 3d printing for a while. What printer do you have?  And all the specs on it including price if you don't mind



I'm using a Prusa I3. It's a kit I bought off a college student, making the things and selling them from his apartment here locally (well, 65 miles away). It included all the printed parts, linear bearings, glass, literally everything, which is hard to find; kits on ebay include "everything you need to get started, except X, Y and Z," and they cost more too. He also provided a 65 page instruction book with plenty of pictures, and lots more info on CD. Cost me $500 for the kit, or would have been $800 assembled. Here's his website. Specs; kinda depends what spec you're talking about (ask specific what you consider a spec?), how well you put it together and how well you know what you're doing once you do. It's claimed 200mmX200mmX200mm print volume, but by my eyeball, I'd estimate the actual print area is 200mm(X-axis)X150mm(y-axis)X300mm(z-axis). 

Here's what mine looks like. I painted it black so it looks more legit.




It's doing .2mm layers, which makes for pretty good aesthetic resolution. The physical strength of the parts is leaves much to be desired, as nobog mentioned, but I strongly believe it can be made better. We will see. If not, I'm prepared to ditch the 3D printer and whittle the thing out of a solid piece of wood or plastic. But a lot has to go wrong for me to end up at that point.

Here's a sample; not sure if nobog would say the surface finish looks like crap or not. it's good enough for me, and if I wanted a shiny gloss surface I could do that with <60sec of post processing with acetone vapor
.


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## nobog (Jan 20, 2014)

Surface finish depends on your application of course. What they have done with the 3D printing around here is that they turned it into a subsitute for proper planning - since we are always behind - and things can't happen fast enough - we make up time with overnight part procument. Then we try it, then it breaks, then we make the real thing. 

_editorial _) much the same reason Fedex has an overnight shipping (@ huge costs) because people can't plan.

Since its already in 3D (the CAD model), its just as easy to assemble it and "try it" in the eworld. Lots of people need to visualize the final part and thats OK (maybe expensive) but I grew up and was trained to put things together is 2D, the 3D world is just a bonus.

Jim


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## DAN_IN_MN (Jan 20, 2014)

Lost Wax Casting.

Make your parts out of wax on your 3D printer.  Use them to make plaster molds.  Pour a light but strong AL into the mold.

Great idea you have going here!


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## strantor (Jan 20, 2014)

DAN_IN_MN said:


> Lost Wax Casting.
> 
> Make your parts out of wax on your 3D printer.  Use them to make plaster molds.  Pour a light but strong AL into the mold.
> 
> Great idea you have going here!



Actually, you don't even need to use wax. you can use the 3D printed plastic parts directly. Check this out.


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## DAN_IN_MN (Jan 20, 2014)

strantor said:


> Actually, you don't even need to use wax. you can use the 3D printed plastic parts directly. Check this out.



Interesting.  

I wonder if wax would leave less debris than the plastic he was using?


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## John Hasler (Jan 20, 2014)

DAN_IN_MN said:


> Interesting.
> 
> I wonder if wax would leave less debris than the plastic he was using?



It should.  Also interesting is the idea of a 3D printer head that puts down wax.  Should be easier to build than one that handles plastic and the material is cheap, unlike the usual plastics.


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## strantor (Jan 20, 2014)

John Hasler said:


> It should.  Also interesting is the idea of a 3D printer head that puts down wax.  Should be easier to build than one that handles plastic and the material is cheap, unlike the usual plastics.


I don't know. This and all similar 3d printers uses a rigid plastic filament that is forced into the extruder by a nip roll. Super simple, and only possible with this rigid plastic. I'm imagining a wax filament would behave like spaghetti, which is to say it would not work at all with this type of extruder.

Wax pellets would work with an auger-type extruder, but those are complicated and expensive. Actually I don't know if they even exist on this small scale. I've only seen them in industry, the size of a sedan.


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## DAN_IN_MN (Jan 20, 2014)

http://hackaday.com/2012/01/31/3d-print-in-wax-cast-in-metal/


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## John Hasler (Jan 20, 2014)

strantor said:


> I don't know. This and all similar 3d printers uses a rigid plastic filament that is forced into the extruder by a nip roll. Super simple, and only possible with this rigid plastic. I'm imagining a wax filament would behave like spaghetti, which is to say it would not work at all with this type of extruder.
> 
> Wax pellets would work with an auger-type extruder, but those are complicated and expensive. Actually I don't know if they even exist on this small scale. I've only seen them in industry, the size of a sedan.



I don't have a link handy but I've read of extruders built using lag screws for the helix (used for making filament for 3D printers).  Should work with wax.


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## ome (Mar 3, 2016)

I have been watching cad/cam/ 3d scanners / 3d printers, and in mho , they all are not too good. 
It is not something That I would get into because of lack of :
Ease of use
No backwards engineering of parts
No cheap way of scanning and printing
Cad/cam is boring to learn to use
Cad/Cam is expensive with yearly updates
Just not there yet. 
I tried to go cheap with Bob cad
What a joke. 
So many steps, I could make it faster with my manual mill and lathe
Ome


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