3D-printed tools for microscope repair

[MicroBob]

I'm about to clean the prisms in my old Leitz Großfeld-Stereomikroskop. The eyepiece tubes had to be removed for this and they are held by a threaded collar inside of the tubes. Usually I would make a tool from brass, aluminium or steel, in some cases assembled by press fits, soldered or welded.
A while ago I started to learn 3D-CAD and as an incentive I bought myself two 3D-printers. So I designed the tool in 3D-CAD and printed it from PETG material. For the pins I thought that nails would suffice since the tool itself "is just plastics anyway". But I was wrong. When I had to use real force, I bent the nails while the plastics body stayed intact. The pins have a harder life in the plastics body as they are less well supported. Usually I use HSS drill shafts that have just the right properties.
Apart from the nails the tool is working fine. I had to take a small chip of from the outside on the lathe as minus 0,1mm didn't allow to tool to be inserted.
Printing time was 2,5 hours with 50% infill rate. In the tool a cavity is visible to reduce the printed volume. The roof of the cavity is angled because a 3D printer can't print horizontal roofs without an additional support structure. The last image is from the webcam that helps surveying the printer.
Overall it takes about the same time to make the tool but there are no chips and only the least amount of material is used.

Bob

[ImperatorRex]

Thanks for sharing Bob. Surprised that the pins are the week point and not the plastic.
Do you have any advice for an easy to learn 3D drafting tool that can be used for such 3D printing tasks? Maybe will give it a try then. For one off taks the online 3D print services might be an option to avoid the printer investment & maintainance.

[MicroBob]

Hi Jochen,
the pins have a harder job to do in a soft plastic tool boby than in a hard steel body. In a steel body nails might have just been stron enough, but only just.

CAD-software: The cheaper professional programs are about 2k€ to 10 k€, the higher grade programs much more. But the software companies are also interested in having many installations e.g. in universities and startup commpanies and even for the hobby designer because this can lead to sales later on. So they have to find a way to avoid that professionals use the cheaper programs. There are several ways to do this:Regular online registration, useage only in a web browser, not common export file types....
I'm no expert, but for me the market is difficult. I would like to have:
- My own software on my computer, no repeated online registration...
- Feature set not too limited
- Many im- and export file formats to have a way in to the future and be able to share designs
- File compatability over a couple of versions
- Easy to learn
- Not too expensive
- Preferably similar to Caddy ++ Maschinenbau
- Probably around for many years to come

So what can I recommend:
For playing around a bit: Sketchup (0€)
For a usable program with no future safety: DesignSpark, Fusion360
For relatively quick learning, full 2D features and limited but usable 3D-Features: Becker CAD Pro 3D (120€)
For advanced features and many file formats, but not quite as easy to use: Turbo CAD Pro Platinum, older version V21 for 50€

In the last years many programs were available to the hobbyist and then were withdrawn or the license was changed. The software companies are always looking to optimize their profit and future chances and if a marketing move doesn't work out as expected they react.

There are ready-to-go 3D printers on the market like Renkforce RF100 and Anycubic i3 Mega. 3D printing takes some effort to learn. I can imagine, that it is difficult to learn 3D CAD and 3D print design when it is always necessary to have the prints made externally. I wouldn't use it often enough then to become fluent and quick.

Bob

[ImperatorRex]

Thanks Bob for your advise. I guess I will just try Sketchup to see if I can model a Zeiss Dovetail

[MicroBob]

Hi Jochen,
you would make a circular dovetail by making a line drawing of on half of the cross section and rotating it around the central axis. I'm not sure whether the free version of Sketchup has this feature.

Bob

[ImperatorRex]

Hello Bob,
thanks for the hint. I have not installed the software yet, so will check probabely by next week or so.