3D printing in UK

[AbsolutelyN]

I'm looking to make an aperture ring to sit above the primary mirror of my 250PDS but I've never 3d printed anything before. Any recommendations for where to get stuff printed and what software to make things in please? 

It's just a simple item - inside diameter 249mm and outside diameter 273mm

Any suggestions much appreciated as completely new area to me.

Edited March 22, 2021 by AbsolutelyN

[Dr_Ju_ju]

The basic design can be done in a number of websites\applications etc. and depending how 'good' you want the part to be, e.g. Tinkercad (https://www.tinkercad.com/), OpenScad, you may even find what you're after on Thigiverse (https://www.thingiverse.com/).

Once you have the design model (usually either an OBJ or STL file) you then need to prepare the the model for printing. This usually entails 'slicing' the obj\stl file into thin layers for the printer to 'print'. These days I usually just use the free PrusaSlicer (https://help.prusa3d.com/en/category/prusaslicer_204), but I also have paid for software (Simplify3D).

As for getting the resultant 'sliced' file printed, what you are proposing at 273mm external diameter, would be too big for most of the 'home' printers, although I have one capable of 300mm diameter, but you could alter the design to split the model into multiple sections, to make it easier to print. As for printing shops, I'm not sure what is available at a reasonable cost ??  

[AbsolutelyN]

Thanks Julian. Much appreciated. Managed to find one designed for a 6" celestron on the site you suggested so that may do it upscaled. Quote from first printing service I found is about £35 when upscaled 160%. 

I've got an old version of 3d studio max hanging around somewhere so I can probably modify it in that to ensure all dimensions are correct - if I can remember how to use it after 10 years that is.  

 

[Dr_Ju_ju]

You can do the scaling in PrusaSlicer, which I've found to be accurate.

[Jonk]

I can create an .stl file for you using those dimensions. How thick, 2mm?

[Jonk]

Here's the 3d model (2mm thick):

...and here's the .stl file.

Aperture ring.stl

You can get it printed at 3dhubs.com for example, although a 1 off may be pricey.

 

[jvrsluys]

if you need a mask so thin, wouldn't it be easier to get it lasercut somewhere?

Although not in the UK these guys ship EU wide, and the possibilities are really extensive!

https://snijlab.nl/en/

[CraigT82]

You could consider RTV silicone adhesive to glue the mirror onto the cell (3 blobs) and getting rid of the clips. 

On mine I found 3.5mm tall blobs too tall and let the mirror move too much, then I tried 1.5mm blobs which caused funny star shapes, and now I'm on 2.25mm blobs which hold the mirror firmly with no loss of collimation as I slew around the sky and also no diffraction effects from the clips.

[AbsolutelyN]

4 hours ago, Jonk said:

Here's the 3d model (2mm thick):

 

...and here's the .stl file.

Aperture ring.stl 71.57 kB · 1 download

You can get it printed at 3dhubs.com for example, although a 1 off may be pricey.

 

Wow - that's amazing thank you. I've not even had a chance to glance a making a model yet. Really appreciated thank you and yes I see no issue with 2mm as don't want it heavy. Cheers! 

[AbsolutelyN]

2 hours ago, jvrsluys said:

if you need a mask so thin, wouldn't it be easier to get it lasercut somewhere?

Although not in the UK these guys ship EU wide, and the possibilities are really extensive!

https://snijlab.nl/en/

That's a really good idea thanks. Never even occurred to me. 

[John78]

Fractory do some decent pricing on laser cutting.

[AbsolutelyN]

1 hour ago, CraigT82 said:

You could consider RTV silicone adhesive to glue the mirror onto the cell (3 blobs) and getting rid of the clips. 

On mine I found 3.5mm tall blobs too tall and let the mirror move too much, then I tried 1.5mm blobs which caused funny star shapes, and now I'm on 2.25mm blobs which hold the mirror firmly with no loss of collimation as I slew around the sky and also no diffraction effects from the clips.

Thanks Craig. I've never come across RTV silicone adhesive before - it must be seriously strong to hold a mirror in place. Your DIY telescope skills far exceed mine, I'm not sure I'd dare attempt to do this approach in case I made a pigs ear of it. Much appreciated though. 

[happy-kat]

I used the free version of sketchup (which is still available) and had the part I designed printed through the 3Dhub uk site.