How to design moving parts

[Ogrre84]

Hey guys i am very new here and have had a 3d printer for about 6 months. I have designed some of my own simple projects with out issue and glued them together after printing. What i am fascinated with is how people are designing things that print all as one piece but have moving parts. I have tried looking for some good resources on this subject but have been unsuccessful. Does anyone have a good source that they can share or and sort of guidelines that would help out?


The first thing that i have been tinkering with is a simple box with a gear in it that will turn. i have left a gap between the top and the bottom but it always seems to fuse the gear to the base and the top. Thanks for the help I have attached my STL gear_box_5_fixed.stl

[Marm]

Very carefully.


Check out a lot of the moving items on thingiverse, and see how they are designed and printed.

You may have to use supports and a needle file set to get them out to keep parts free.

[LambdaFF]

look at how intentional3D made their jack. it's a real beauty

[Sebastian Finke]

Personally I would prefer to print single properly toleranced items and assemble them as opposed to fudging tolerances so that something can turn.

Not answering the question but worth mentioning in this kind of thread.

[Grindeddown]

Personally I would prefer to print single properly toleranced items and assemble them as opposed to fudging tolerances so that something can turn.

Not answering the question but worth mentioning in this kind of thread.

i would imagine that this method would also have the benefit of leading to much more accurate prints. In some circumstances it should lead to better characteristics like tensile strength as well as you an much more easily optimize which axes to print each part on. As an example, filament on the XY axes are usually much stronger the on the z axis.

[Ama-fessional Molder]

1. Clearance is very important when designing mechanical parts for 3D printing.
2. Parts have to be cleaned also. You must allocate space for this. 3d printing service delhi-NCR bangalore
3. Powder is trapped in enclosed spaces. If you do not design so that it can be removed your part will not work.
4. Two surfaces(printed in the same orientation) that rub against each other cause more friction than one would expect due to the layerwise production in 3D printing("hooking").
5. If you design some kind of mechanical device such as a coil spring please keep in mind that since it is produced in an integrated fashion(ie part of the housing) there is no(or not much) pre-load in the spring. It will be weaker than a traditional spring made out of two parts and then compressed in the housing.
6. Paint changes the mechanical properties of your model.
7. You could manually correct your model with a file but this is tough going.

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This... is a really good post.

Nice work.

I would only clarify number 3, in the case of FDM there is no powder but the same still applies, support structure material must be able to work it's way out of the joint or it will bind up in operation.

Number 5 is especially nice. Not something most people consider, spring preload is the difference between a sagging part and a nice high quality function that feels solid.

[curious aardvark]

it is fun trying to get parts within parts. Particularly if like me you don't like using supports.

This is my best part within a part design to date:

Well it would be but uploading pictures is definitely not working.
I'll be back ...







basically I wanted a spool to wind 10-20 metre sample lengths of stiff filaments on. Figured was quicker to print one that expanded and locked than just make one big spool.

Works really well :-)
I can print the parts seperately as well, but they print together and just pull to lock with no problem.
I think the smallest gap I've used is 0.5 mm.

This is the mark 2 - mark one has holes in the shaft and locked with a bent paperclip :-)

Print these at 0.3mm layer height and around 65mm/s speed - which is quick for my creator :-)

[awerby]

It looks like you've reinvented the wheel...

[Ama-fessional Molder]

That's a freakin genius design.

Must remember, steal, and patent.

-Edison

[curious aardvark]

It is nice.

But not a pretty artistic model, so no money in it :-(
lol

In fact that one in the pic the left arm didn't print that well - but still locked in place without any problems.

Beauty is it gives you a good width to wind stiff filaments round.
Once wound you leave it for a few days to get used to the bend and viola.

The clever bit is getting the top rim to print without supports.

You got to love openscad :-)