Author Topic: Spring Powered Toy Car  (Read 1622 times)

Offline ddmckee54

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Re: Spring Powered Toy Car
« Reply #15 on: October 04, 2018, 06:12:03 PM »
Toby:

When you printed the parts, what layer thickness did you use?  What sort of tolerances were you using between parts?

I normally print at 0.2mm layer thickness.  This is my compromise between print quality and print time.  I've had to do a lot of playing around with my printed parts but I've found the following tolerances to work for me and my printer:
Less than +0.1mm gives me a very "tight" press fit, almost impossible to use.  Once you mash the parts together, if you can, they are NOT coming apart without a fight.
+0.1mm to +0.2mm will give me a press fit, with +0.2 being a "light" press fit.  The parts will go together with finger pressure and they will come apart without an argument.
I use +0.3mm and above for parts that I want to fit together and move.

3D printing, at least the FDM/FFM processes normally used, is kind of a "sloppy" procedure.  Printing in layers as we do, this can't be helped.  You CAN'T print an absolutely flat side no matter how hard you try.  Under magnification it's still going to look like the side of a log cabin.  It can be minimized, but it can't be eliminated.

Hope this helps.
Don
« Last Edit: October 04, 2018, 06:16:54 PM by ddmckee54 »

Offline TobyTetzy

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Re: Spring Powered Toy Car
« Reply #16 on: October 05, 2018, 10:11:36 AM »
Hello,

yes, it is planned to build the car out of metal.
3D printing was just a first test of whether it works in principle.

I also print in 0.2mm layer height.
I did not customize the STL file, I have e.g. insert a 6 mm shaft into a hole drilled to 6.5 mm. A 6.0 or 6.2 mm bore was still too tight.

As I said, 3D printing was just a first test of whether the model works.

Since I like the size very well with Module 1.5 gears, I will revise the model again.
The side parts and gears e.g. were 5 mm thick.
1.5 times bigger it would be 7.5 mm, the material is bad to get.
It would be better now 6 or 8 mm material.
I will also see if I get sintered metal bushes.
I would adapt the model accordingly.

Greeting Toby