Discussion
I went to an interesting company last month on a jolly and came across the new(ish) breed of 3D printing: They can print out 3D parts from a 3D CAD file with clearences built in! That means you can print out a part with moving parts without any extra assembly that you couldn't physically make if it did require assembly!
I'm designing something now that isn't very interesting, but it has got me thinking; they can print in plastic (what I'm having), ceramic and even in metal alloy. They can't mix these materials up during the printout (unfortunately otherwise I'd have printed out a whole engine - including spark plugs
) but that means I could print out a fully working engine that just requires the ancillaries.
BUT I could make it with loads of things that you don't get in a convensional engine... But what? Can anybody think of a way to use a spherical chamber?
I'm aiming to have a flat 2 or 4 cylinder with about 40mm stroke and 20mm diam. I could do some clever stuff with a turbo being built into the engine (if I can get the heat out of it well enough).
I think the max size would be 150-200mm cubed for the print out.
It's a completely blank screen, and just want to do this for a bit of fun when I need to escape from anything in the rest of my life... Any funky ideas guys?
I'm designing something now that isn't very interesting, but it has got me thinking; they can print in plastic (what I'm having), ceramic and even in metal alloy. They can't mix these materials up during the printout (unfortunately otherwise I'd have printed out a whole engine - including spark plugs
) but that means I could print out a fully working engine that just requires the ancillaries. BUT I could make it with loads of things that you don't get in a convensional engine... But what? Can anybody think of a way to use a spherical chamber?
I'm aiming to have a flat 2 or 4 cylinder with about 40mm stroke and 20mm diam. I could do some clever stuff with a turbo being built into the engine (if I can get the heat out of it well enough).
I think the max size would be 150-200mm cubed for the print out.
It's a completely blank screen, and just want to do this for a bit of fun when I need to escape from anything in the rest of my life... Any funky ideas guys?
MTv Dave said:
I went to an interesting company last month on a jolly and came across the new(ish) breed of 3D printing: They can print out 3D parts from a 3D CAD file with clearences built in! That means you can print out a part with moving parts without any extra assembly that you couldn't physically make if it did require assembly!
I'm designing something now that isn't very interesting, but it has got me thinking; they can print in plastic (what I'm having), ceramic and even in metal alloy. They can't mix these materials up during the printout (unfortunately otherwise I'd have printed out a whole engine - including spark plugs) but that means I could print out a fully working engine that just requires the ancillaries.
BUT I could make it with loads of things that you don't get in a convensional engine... But what? Can anybody think of a way to use a spherical chamber?
I'm aiming to have a flat 2 or 4 cylinder with about 40mm stroke and 20mm diam. I could do some clever stuff with a turbo being built into the engine (if I can get the heat out of it well enough).
I think the max size would be 150-200mm cubed for the print out.
It's a completely blank screen, and just want to do this for a bit of fun when I need to escape from anything in the rest of my life... Any funky ideas guys?
I'm designing something now that isn't very interesting, but it has got me thinking; they can print in plastic (what I'm having), ceramic and even in metal alloy. They can't mix these materials up during the printout (unfortunately otherwise I'd have printed out a whole engine - including spark plugs
) but that means I could print out a fully working engine that just requires the ancillaries. BUT I could make it with loads of things that you don't get in a convensional engine... But what? Can anybody think of a way to use a spherical chamber?
I'm aiming to have a flat 2 or 4 cylinder with about 40mm stroke and 20mm diam. I could do some clever stuff with a turbo being built into the engine (if I can get the heat out of it well enough).
I think the max size would be 150-200mm cubed for the print out.
It's a completely blank screen, and just want to do this for a bit of fun when I need to escape from anything in the rest of my life... Any funky ideas guys?
Is this a joke?
Stereolithography does not produce anywhere near the finish and tolerances you will require. The process cuts your 3D CAD model into .003" slices to print so anything round or radiused will have 3 thou steps in its surface. Finished piece parts can have even wider tolerances than that due to shrinkage as the printed plastic cools.
The process can produce very good piece parts as design discussion aids or sales models.
Where it can be very worthwhile is in the production of one off castings. The plastic model is made as above but with all the walls and solid elements made hollow. This plastic piece is then dipped in a ceramic slurry several times the fired to cure the ceramic and burn off the plastic. Molten metal is then pored into the resultant ceramic mould.
In our situation this would be the ideal way to develop a custom inlet manifold or plenum.
Steve
Nope - this isn't stereolithography. The tolerances in that are lower than in this process and trying to make fixed clearances is pretty hard (read impossible) from what I remember of trying to use it a few years back when I worked in rapid prototyping for the auto industry.
This method produces something with around twice the level of precision in all three dimensions. This still may not be perfect, but I'm happy to have a go with it. It also doesn't slice the CAD into little cubes, but rather takes the CAD surfaces and surface normals to work out what the 'inside' of your objects is - sort of like a 'flood fill' tool in a bitmap paint program.
It prints in layers - like on a page - with packing material that melts off at pretty low temperatues. Each layer is cured... I guess it's like building a think brick wall in layers of bricks.
If you keep the radii above ~1mm then you're fine as you get around 25-30 blobs in that diameter. But as the printing method is very similar to an inkjet you get slight steps on the edges. You can pay a lot more for higher dpi but I'm not sure what the upper limit of the technology in what material is yet - I'm checking that out now.
The part I am making is to work along side my CG-Lock in my FTO to use my seat belt as a 3-point harness. This has a main captive bearing and a geared clamp. Nothing flash, but after seeing the little ruber-band car with a rear diff that was made by them to demo the technology, I think my radii on the bearing will be fine (mean 5mm bearing diameter with a mean of .25mm clearance at 200 segments)
Just for a rough giude they told me that if you printed a solid tennis ball of plastic at 600dpi you're looking at about 80 quid to them to do it direct. I'm expecting this to me of roughly the same volume.
Steve - if you want me to pass you the detials of the company, just drop me a mail.
ETA - The plastic prints out from the CAD and finishes the same size - I have no idea about the changes in the alloy they use, and I'm assuming there is also almost none (> 0.01%) in the cermaic printing.
This method produces something with around twice the level of precision in all three dimensions. This still may not be perfect, but I'm happy to have a go with it. It also doesn't slice the CAD into little cubes, but rather takes the CAD surfaces and surface normals to work out what the 'inside' of your objects is - sort of like a 'flood fill' tool in a bitmap paint program.
It prints in layers - like on a page - with packing material that melts off at pretty low temperatues. Each layer is cured... I guess it's like building a think brick wall in layers of bricks.
If you keep the radii above ~1mm then you're fine as you get around 25-30 blobs in that diameter. But as the printing method is very similar to an inkjet you get slight steps on the edges. You can pay a lot more for higher dpi but I'm not sure what the upper limit of the technology in what material is yet - I'm checking that out now.
The part I am making is to work along side my CG-Lock in my FTO to use my seat belt as a 3-point harness. This has a main captive bearing and a geared clamp. Nothing flash, but after seeing the little ruber-band car with a rear diff that was made by them to demo the technology, I think my radii on the bearing will be fine (mean 5mm bearing diameter with a mean of .25mm clearance at 200 segments)
Just for a rough giude they told me that if you printed a solid tennis ball of plastic at 600dpi you're looking at about 80 quid to them to do it direct. I'm expecting this to me of roughly the same volume.
Steve - if you want me to pass you the detials of the company, just drop me a mail.
ETA - The plastic prints out from the CAD and finishes the same size - I have no idea about the changes in the alloy they use, and I'm assuming there is also almost none (> 0.01%) in the cermaic printing.
Edited by MTv Dave on Wednesday 14th February 10:54
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