Author Topic: Building a Plastic 3D Printed Engine - junk idea or possible?  (Read 5071 times)

Offline raynerd

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Hi guys, most of you know I`ve built a 3D printer recently and I`m getting some real nice prints off it. I`ve been thinking for a while that a printed engine would be amazing, but maybe not possible.

The finish of a 3D printed item is no good, so a wobbler type engine just wouldn`t work because of the required lapped surface. I was thinking however that the rocker type engine would be possible as no lapped surfaces are required and with a bit of sanding, a decent enough fitting piston could be printed to create "enough" of a seal!

Don`t get me wrong, I`m not looking for a perfect running steam engine, just something that does move under pressure.

I`ve attached the original plans for the rocker engine here: http://www.raynerd.co.uk/images/RockingSteamEngine.pdf

...and of course there are loads of build logs of this engine on here and the net.

I`m not great with cab but I am getting better with google sketchup so not only am I hoping people can chip in here, but if anyone thinks this might be an interesting project and is interested in doing some drawing, please get in touch. When doing the drawings, we need to consider how it will be printed, i.e no bridges, steep overhangs etc.

I hope I`m not overlooking something that makes this a total none-goer! I`m sure someone will tell me if I am...

Look forward to some replies!

Chris
Youtube: craynerd
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Offline raynerd

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #1 on: June 30, 2012, 05:34:08 PM »
and before anyone says anything... no, I`m intending to run on compressed air, NOT steam!! That would certainly be a major issue with the idea   :lol:
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Offline John Stevenson

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #2 on: June 30, 2012, 05:46:48 PM »
Have you seen the UP 3D printers ?
video here of it pronting a bearing that works afterwards.

http://www.youtube.com/watch?v=GOEbZ98J1Ks

Is yours of this quality Chris ?
John Stevenson

Offline raynerd

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #3 on: June 30, 2012, 06:43:06 PM »
In theory there is absolutely no reason why mine can not print that bearing - I have looked at the up! printer and it seems to be a limited working space for the money but I dare say it is ultimately more rigid and finely tuned than my reprap prusa. I dare say if I was to build a new 3D printer, which I will when I get more time, I would make something much more stable but my prusa is pretty good and is doing some nice prints.

All that said, in all honesty I don`t think I could print that bearing.... but hell, you know now what I`ll be trying to print tomorrow!! Pictures to follow!

Chris
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Offline John Stevenson

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #4 on: June 30, 2012, 06:50:20 PM »
Chris,
what stops you putting an extruder head on a CNC router or mill ?

BTW did you get my email reply the other day about the bits?
I thinks some have fell thru the cracks, lost one to the laser cutting people
John Stevenson

Offline raynerd

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #5 on: June 30, 2012, 06:59:04 PM »
Hi John, have pm`d you. Didn`t get a reply for the one I sent you a couple of weeks ago and haven`t been having any probs with my email that I know of.

Regarding the cnc machine - speed and acceleration. The bed fair flings itself about on the axis and it would take a long time to print objects. I`m printing at a much higher top speed and acceleration than my little cnc machine could go at.

That all being said, provided you were happy to wait for parts, I see no reason why it wouldn`t work!

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Offline raynerd

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #6 on: June 30, 2012, 07:04:00 PM »
John, pm sent! I lied, I have found the email 20/6/12 !! I must have opened but not read it as it wasn`t flagged as "new". Anyway, replied now.


CHris
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Offline John Stevenson

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #7 on: June 30, 2012, 07:20:29 PM »
Got one of these Roland PNC 3100's kicking about with bad electronics.

http://www.e-engraving.com/machines/roland/Roland_PNC-3100.htm

Thought it might make a good basic machine to start with ?
John Stevenson

Offline raynerd

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #8 on: June 30, 2012, 07:36:25 PM »
Possibly John, but you`d have to sort out the electronics on it as as far as I understand, the motors of all the axis are sync`d with the extrusion rate. The standard electronics for a reprap are an Arduino Mega with a RAMPs driver board attached, running pololu stepper drivers. If you used all that, you`d basically be running it as a reprap and it would all be nicely in sync with the free software needed such as a printrun/pronterface and slic3r. The question is would the pololu and 12v from the ramps board run the larger steppers that I expect are on the Roland. The ramps/arduino are only intended to run small nema17`s on a reprap. That being said, there is a chap on the reprap IRC channel who is running the standard Arduino controller and computer software but with a bigger TB6560 stepper driver, most definately capable of running bigger motors.

It is in an interesting project and I will be having the same issues when I engineer a more stable and rigid 3D printer design for me next build. I will be wanting to run bigger Nema23 motors (because I have some spare and they are a little more powerful for shifting a heavier bed) so will also need to figure out how to use an alternative to the pololu drivers.

Not much help... but I`d be interested to know if you get anywhere. I still think your biggest issue will be shifting that heavy bed around at speeds and accelerations that allow you to print at acceptable times!
Chris
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Offline John Stevenson

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #9 on: June 30, 2012, 08:00:49 PM »
PM sent
John Stevenson

Offline NickG

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #10 on: July 01, 2012, 08:17:46 AM »
Chris,

I was going to suggest the printed engine!! If it works you could rattle a few sets out and sell on ebay! Can't wait to see...

Nick
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Offline David Jupp

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #11 on: July 01, 2012, 11:21:30 AM »
Parts printed to be assembled later, or printed as a (near) complete assembly?

Offline NickG

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #12 on: July 01, 2012, 11:44:37 AM »
 Oh yeah, didn't think of doing it as an assembly, didn't think that type of thing was possible until I saw that bearing! Guess you could so lots as long as you were prepared to do a certain amount of finishing off though? You mentioned not being able to do a wobbler or slide valve but is that because of the way it's built up or just because you intended on being able to assemble immediately? If you tried top lap a valve with a printed part would it give a smooth finish?
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Offline raynerd

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #13 on: July 01, 2012, 03:42:20 PM »
No no no! I never intended to print a full assembled engine!!! No, just parts and put it together. I thought a wobbler won`t be possible because of the poor surface finish on flat parts. That being said, typical me in that I`ve said something and not tried it! It might just be worth me printing off two blocks of plastic and trying to lap them flat together and see if it can be done. If it can, a simple wobbler might be the way forward.

My problem is the drawing...I`m so slow!! I`m definately going to give this a go.

Chris

 :update:  On my thrird attempt at a bearing and I`m half way through and it is looking ok!!!
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Offline j45on

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #14 on: July 01, 2012, 04:23:04 PM »
Chris  have you seen the engines on thingiverse ?
http://www.thingiverse.com/thing:25624 and http://www.thingiverse.com/thing:14990
Jason

Offline shipto

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #15 on: July 01, 2012, 04:31:58 PM »
j45on stole my thunder so to speak, posted as i was looking for http://www.youtube.com/watch?v=yNW0m6YCkxA
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
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Offline machineshed

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #16 on: July 02, 2012, 03:21:07 AM »
if you are going to lap things, i think it should work :thumbup:

Offline NickG

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #17 on: July 02, 2012, 01:05:11 PM »
Looks good, the only problem with that one on youtube seems to be the flywheel is too light.
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Offline Raggle

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #18 on: July 02, 2012, 05:17:03 PM »
I wonder if embedding metal inserts is feasible, as in the case of injection moulding? In the case of a flywheel it could be made of lead at a predestined pause in the printing, for instance a half depth cavity then place the insert, then a finish to completely enclose the lead.

That could possibly work for bushings at conrod ends, allowing for reaming in situ.

As usual, I may be talking rubbish, but Chris was doubtful about a wobbler at the beginning of his thread so I maybe in good company

Ray
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Offline John Stevenson

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Re: Building a Plastic 3D Printed Engine - junk idea or possible?
« Reply #19 on: July 02, 2012, 05:59:35 PM »
How did the bearing come out Chris ?

The UP ones seems to print a disposable support, does the reprap ?

John S.
John Stevenson