Friction Welding to alter appearances

So, during this rather long and tedious 3D printing process to churn out parts for the BB-8, The 3D model has changed along the way, and as a result, some of my prints are no longer accurate.

I had a part of the “triangle” that holds the rounded panels together that changed recently, making 3 parts out of 6 obsolete.

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Now, these take a good 4 hours and some change to print, and I didn’t want to just waste 12+ hours on printing parts I didn’t need!

Looking at the specs, I realized that there is another part, that has the same basic construction as this (with overlaps and all) but does NOT have the groove that cuts out what is to be a panel in the finished full part.

Only thing I would need to do, is fill that groove that “splits” the part in two!

Sounds like a perfect job for some friction welding!

Friction welding, is really when you use friction to melt plastic together. I have used this on joints inside my R2, using round styrene rods that I put in my power drill, and then simply “drilled” until the plastic melted, and this created a very stable joint.

When doing this on a 3D print, I insert a piece of 1.75mm filament into my Dremel, and crank it up to about 80% speed, and gently push the quick rotating filament towards the area where I want to do the weld.

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As the quick rotating plastic melts, it also melts the surrounding plastic, making the new weld a part of the surrounding material.

First I did one softer go, to fill in as much of the groove as I can in one go..

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Then another go, that really pushes the materials inside, and also tried to erase the edges of the old groove, leaving a small extrusion of material after I am done.

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Now, this might not look pretty, but remember the plastic here is now part of the old print.

Using a break blade knife to first cut away some of the excess material, then using the same knife to scrape across the surface…

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.. and you end up with a groove that is totally gone.

Now, there are still some very small spots here and there, but compared to the layers of the print, they are nothing to worry about. Once I sand this part down properly and spray it with some spray filler, this will be completely invisible!

It only took about 4 minutes to do the three panels, and I saved up tons of time and filament compared to throwing the old pieces out and printing these from scratch!