Friday, April 18, 2008


One more RepStrap...

I finally finished my machine and as proof, I have a minimug!

This picture (above) shows the minimug printing the last few layers.

The print is finished here and the machine is going back to it's start position.

As you can see I have something taped to my MDF stage. It's actually a grocery bag (HDPE) and I'm printing in ABS. The black bits are electrical tape. I've since switched to an all electrical tape stage which works a whole lot better. I get really good adhesion from this setup. No problems with objects detaching themselves from the stage mid-build.

There were some alignment issues to deal with. Mainly this was a matter of getting my prefs set right in the host and aligning my head more fully with the stage. Can't have one side higher than the other. I fiddled some more with that and called it good.

Upon successful first printing--and after the minor celebration that ensued which only involved me and my friend Noah--we immediately started looking for other things to print. Well, Vik's wine glass looked nice and friendly so we gave that a go.

Minimug for size comparison for those of you who have printed a minimug.

Things were going well up until this last photo at which point we started noticing that the extruder wasn't extruding. We had lost pump preasure due to the bolts loosening--I never installed lock nuts on my pump body, stupid. We frantically fixed this while the machine continued to print and got it back on track...sort of. We were left with a ring about a half cm high of less than bonded material. No problem. The shape is still there and we continued to the end.

Sorry that's sideways. Couldn't figure out how to rotate it in Blogger. Feh... Anyways, the form came out great and I'm really happy with how the machine performed. I used a 1 mm extrusion tip on all of these prints. My longest build time was 1 hour, 20 minutes for the wine glass and 30 minutes for the minimug. I've subsequently printed several failed minimugs--one successful one too!--and another failed wine glass.

My next task is to install springs and lock nuts to the pump so that I can print without loosing pressure. After that, I'll get an aluminum body for my pump to replace the cast one and then I'll begin printing a set of parts. I'm really stoked that Vik replicated finally and I really would like to follow close behind him. I've got about 5 people who want a set and I would like nothing better than to give them one for a birthday or for Christmas.

Regards to all

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It looks as if you could start building parts pretty quickly. Besides the 5 people who'd like parts I assume you want parts yourself as well to build a Darwin? That's six kits already. I think your RepStrap is going to be busy for a while, but there's of course no use for idle time, on the contrary if you build 5 kits that will really help RepRaps growth rate!
Yup, all those people will be building RepRaps too.

Things come out rough at the start as you discover inaccuracies, wear off dodgy plating and stretch slightly elastic parts out. Something hidden away in a corner will come adrift over time, and you'll lock it down. This process repeats for a while, but eventually you end up with a working system.

Congratulations on achieving minimug status, and cheers!

Vik :v)
Congratulations Demented,

They look really great for the first prints!

What temp did you use for ABS? What speed did you manage to go up to with the extruded filament?

So you are doing a McWire? Cool! I look forward to hearing more about your experiences with that design. :-D
My temp says it's at 180 C but I'm not really sure I believe that. I don't have a real good way to verify the temp yet. I get good adhesion so it's not really an issue. I set my extruder at 230--I think. Seems pretty fast and I might need to slow it down a bit. I haven't tested for dimensional accuracy yet.
Wow mucho impressed.

And ABS too.

RM it is. How were the pieces for dimensional stability and warping ??
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