3D CAD drawing drafts

[Astrofriend]

At last I have started to practicing how to make 3D CAD drawings. I really need these 3D printed parts for my astronomy projects.

For you who want some insight I have my first simple drafts of CAD drawings here with some links of information:
http://www.astrofriend.eu/3d-printing/cad-drawing/01-cad-drawing.html

It will be a revolution for me to be able to make my own special designed parts.

/Lars

[saac]

Good luck with it Lars - once you get the hang of it it can be very satisfying.  Have you tried Fusion 360, it's good but usual learning curve ?

Jim

[PeterW]

I’m an OpenSCAD user, does most of what I want if I keep my wits about me. I use 3D-tool free to section and take measurements off stl to ensure I’ve not messed up critical dimensions.

good luck

Peter

[Astrofriend]

Hi,

Yes It's really exiting.

How about Fusion 360 and OpenSCAD, is it possible to create pulleys, worm gears, sour gears and other complicated shapes ?

In FreeCAD it's only a macro and some parameters to set.

/Lars

[PeterW]

Thingiverse has a lot of SCAD files that you can build off (creative commons), have a look. I’ve used wide threads before, so worms and pulleys should be easy.

To use OpenSCAD you have to think how to add/difference to make shapes. I tried sketchup and a few other options years back and none were so easy to get something useful. I see fusion has a free version I ought to check it out, though I have tried solidworks and found the learning curve rather steep.

 

peter

[Astrofriend]

Hi Peter,

Good that there are other alternatives if I get stuck in FreeCAD. Today and yesterday I have working on a CAD drawing to a motor fouser bracket. Almost finished I hope.

http://www.astrofriend.eu/3d-printing/focus-motor-bracket/01-focus-motor-bracket.html

/Lars

[PeterW]

If you’re polymer 3D printing then I’d be careful about potential areas of weakness and printing orientation to maximise the strength. Interesting to see a CAD layout, given many people use CNC you don’t need a drawing produced to make anything.

 

Peter

[Astrofriend]

Yes the strength concern me, have to print and test and reinforce when needed. And how does the plastic material behave at -15 degrees Celsius ?

 

/Lars

[MaJiC79]

Big fan of OpenSCAD here - I print almost exclusively in ABS (comes with it's challenges, but as with everything there are Pro's and Con's)

ABS is a little flexible for some applications, but you can overcome that by making walls thicker to compensate. Wall thickness on your slicer has a big impact on performance, and some infills can add or remove strength (most infills are strong only in one direction, if you need strength in multiple directions, take a cubic or gyroid which is strong in all directions, but not as strong as a dedicated direction of strength)

Material wise - there's lots to choose from. As I said, I'm using ABS, which is convenient for storage, has a medium yield strength and is long lasting (operating temps good for -20c to 80c). PLA is popular (lower print temp, slightly higher yields strength, more brittle, hygroscopic  - so you need to treat the storage environment if you don't use it immediately, lower operating range - reduced maximum temp, but lowest temperature is probably the same), as well as PETG, Nylon and Polycarbonate

Interestingly, depending on how you measure the strength (impact, tension, compression?) you might find things are stronger at lower temperature (tension) or weaker (impact)

 

Edited December 25, 2020 by MaJiC79

[Astrofriend]

Interesting, what do you suggest for printing gears, pulleys, worm gears ?

 

I have made some progress on my 3D-printer the last days. It's much easier now with updated software. Some notes from my progress, see page 12, working on page 13:

http://www.popularastronomi.se/wp-content/uploads/2012/06/2006_3_blom_ogon_pa_solen.pdf

 

/Lars

[MaJiC79]

I'd use any of the materials I listed above for those applications - of them all, PLA is biodegradable, so not really suitable for long term outdoor use exposed to moisture. Nylon is common in real world manufacture but has an exceptionally high print temperature (300c+).

Personally I'd use ABS (I have it already, I'm setup to print it, it's good for outdoor work, it's the great all rounder)

[Chriske]

I use PLA all the time to make outdoor projects.
BUT exclusively white because it reflects the heat of the sun. Some of these projects stay outside all day long, winter/summer.
And no, it does not degrade or deform at all during these very hot summers/heat wave. Some of these projects are already seven years old.
Still, PLA cannot be used for projects inside your car. They will deform when the inside of your car get to hot during a heat wave.

[MaJiC79]

I think the upper temperature limit for PLA is around 50c - yes, temps in cars can get well above that. Choosing white is a good idea for sun exposed stuff anyway (no matter the material) - a suitably dark material will probably exceed 60c on a hot bright day anyway

[Astrofriend]

I wish we had that problem with too much heat. In Sweden we can only do astronomical observations during the winter season. We have temperatures from zero degrees Celsius to minus 30 degrees Celsius.

 

Welcome to Sweden 🙂

 

/Lars

[MaJiC79]

On the bright side, you don't need to try so hard to cool your imaging sensor down! I've flown into Skavsta airport many times, drove on Swedish roads and paid high prices for 500ml of beer. I quite like Sweden

Edited December 28, 2020 by MaJiC79