Looking for someone to create 3D files for a project (and poss print)

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Looking for someone to create 3D files for a project (and poss print)

This topic has 11 replies, 7 voices, and was last updated 16 July 2023 at 13:35 by DC31k.

Viewing 12 posts - 1 through 12 (of 12 total)

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15 July 2023 at 16:57 #652396
Ian P
Participant
@ianp
Title says it all really. I have tried Fusion and Freecad but the steep learning curve (and senility!) have defeated me.

I am involved in an interesting project that I would describe as commercial, its low budget but beer tokens.

The printed parts are to create the augers for a remotely controlled screw driven vehicle. Several identical components would make up one assembly about 140mm dia and 400mm long.

Last thought. I know there are 3D print houses but presumably they do not do design, hence asking here.

Ian P

Ian P
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15 July 2023 at 16:57 #34245
Ian P
Participant
@ianp
From sketches and 2D CAD drawings.
15 July 2023 at 17:32 #652401
lee webster
Participant
@leewebster72680
Oddly enough I was recently thinking that those of us with 3D printers could offer to do this for those who don't own one.

If you could post a sketch with dimensions I would be interested in seeing it. Are you thinking of using the 3D printed parts themselves, or casting them in metal? Most 3D print materials are fairly weak, unless you go for exotic materials which come with their own problems.

I like a challenge. More details please!
15 July 2023 at 17:45 #652405
SillyOldDuffer
Moderator
@sillyoldduffer
A sketch would help enormously. Something like the Screw-propelled vehicles described on wikipedia? The animation is theirs:

Dave
15 July 2023 at 20:22 #652420
Ian P
Participant
@ianp
Dave's nailed it!

The 'parts' forming the would be two bullet shaped ends with several thin wall cylindrical rings between them, all stacked together.

PM sent to Lee

Ian P
16 July 2023 at 07:19 #652450
DC31k
Participant
@dc31k
Posted by SillyOldDuffer on 15/07/2023 17:45:41:

The animation is theirs:

Reading the page to which you refer, it says that the helices on either side need to be opposite hand and that the screws should counter-rotate.

I am not sure the animation reflects this – to my eyes both are going in the same direction and the same hand.
16 July 2023 at 07:40 #652452
JasonB
Moderator
@jasonb
This one has it right

There are also a couple of sites with ready modelled ones that you can download STL files and presumably scale to suit, whole vehicle in some cases.
16 July 2023 at 09:50 #652464
Grindstone Cowboy
Participant
@grindstonecowboy
Posted by DC31k on 16/07/2023 07:19:12:

Posted by SillyOldDuffer on 15/07/2023 17:45:41:

The animation is theirs:

Reading the page to which you refer, it says that the helices on either side need to be opposite hand and that the screws should counter-rotate.

I am not sure the animation reflects this – to my eyes both are going in the same direction and the same hand.

Must be the NASCAR version, for racing on left-hand oval tracks

Rob
16 July 2023 at 10:45 #652476
DC31k
Participant
@dc31k
Posted by Grindstone Cowboy on 16/07/2023 09:50:42:

..for racing on left-hand oval tracks

I wonder in which direction the animation would go. If sat in the cab, I think it would go roughly north west.

I suspect that the helix angle of the screw would influence it but have not quite understood how. If the helix went directly front to back (if it were a bolt, it would be a very coarse thread), I think it would go mostly west, quite fast, but if the thread were very fine, would it go mostly north but very slowly?

—

On the 3D print issue, if the parts are supposed to be modular, you have to think about how to join them together. It would not be possible to have just an 'end cone' and a 'middle cylinder' unless a straight, flat butt joint were used.

Possibly, you could have three parts – the cone, the cylinder and a joining piece. The cone and cylinder could have an internal groove and the joining piece a double external projection. The parts would snap together like the toy container from a Kinder egg.

The other issue to think about when designing the parts is how to print them. The cylinders should be OK, but the conical ends might need internal support material. Printing the helix tapered ends on the cone would not be too bad, but trying to incorporate them into the cylinder might be challenging.

There are rules of thumb concerning overhangs when 3D printing. If the design (as in required geometry) is mindful of those rules, it will make manufacturing considerably easier.
16 July 2023 at 11:55 #652490
noel shelley
Participant
@noelshelley55608
From a practical point of view I would consider a cone at both ends to enable the vehicle to reverse ? Noel.
16 July 2023 at 13:06 #652499
JasonB
Moderator
@jasonb
Biggest issue will be getting the spiral to stay on the cylinder, layer orientation will play a big part as will type of resin
16 July 2023 at 13:35 #652501
DC31k
Participant
@dc31k
Posted by JasonB on 16/07/2023 13:06:23:

Biggest issue will be getting the spiral to stay on the cylinder

When welded steel augers are made, the flights are cut in the same shape as a washer, with a straight cut from OD to ID and then pulled/bent into shape.

It is an interesting problem in geometry going from a helix to a flat piece with the correct dimensions. See:

https://www.eng-tips.com/viewthread.cfm?qid=489908
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