Tip: How to print real small parts

Hi all,

The reason I have built my Prusa (and dumped my previous CNC for) was to use it to print parts which would be otherwise pretty hard to manufacture.

As my hobby is (well currently) building robots, and I don't like buying parts, one major need is to be able to manufacture gears, small gears, so I can make use of DC motors scavenged from old IT equipment (think old CD-ROM drives for instance).

The below is the result of my struggle:





So how did I manage to print that small? Well here is a little howto:

Preparation:

1. Calibrate the printer - I mean calibrate the hell out of it else you will not get any results - trust me on that

2. Very important !! - Make sure your print bed is flat ... real flat, else at 0.1 mm or lesser layer height the plastic will not stick

3. Setup the Z axis to be as close as possible to the print be - if you need to print 0.1 layers you have to have the nozzle at 0.1 mm from the bed at max, best is to have less.

4. Make sure your temperature reading are correct +-5 degrees C

Now to actual printing:

Disclaimer: I choose to use Slic3r because I like the results I get with it and it is fast. Slic3r does not yet have a cooling feature yet so if you use Skeinforge you might be able to get my results easier.

So my settings in Slic3r to get the results are:

- feed rates 10mm/s everywhere

- temperature 160 degrees (yes that low)

- 1 mm retraction at 10 mm/s

- 0.1 mm layer height

- extrusion width ratio on auto

That's it ! Oh wait, at 160 degrees C you still need at least one fan blowing at the part so do not forget that.

Adding to the above, printing multiple parts at one time, I tried 4 gears, will provide more time for the layers to cool and get you even better results.


More info: I'm using a 0.35 mm J-head nozzle, I do not have a heated printbed and I use PLA from 3d-magic (http://www.ebay.co.uk/sch/3d-magic/m.html?hash=item7dbd8a8a12&item=330659043727&pt=LH_DefaultDomain_3&var=&_trksid=p4340.l2562)

Hope this helps,

Cheers

Edited 5 time(s). Last edit at 02/08/2012 04:48AM by TinHead.

Nice work!

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garyhodgson.com/reprap | reprap.development-tracker.info | thingtracker.net

That IS nice work. What size nozzle are you using?

Oops I knew I forgot to mention something. I'm using a 0.35 mm J-nozzle.

Nice Job, What infill are you using on the tiny gear, or it is just made up of outlines?

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[richrap.blogspot.com]

At this size you get only the outlines from Slic3r with the automatic width calculation which gives about 0.4 mm. I have experimented with setting the Extrusion width ratio to 2 to get 0.2 mm width but that did not lead to anything, I think that regardless of that it was still wider (it is real hard to get a good measurement).

I need to fix my bed as I have trouble keeping it flat, maybe find a replacement for the Z home switch too, then I might attempt lower width and maybe even smaller layer height.