For Christmas I got a fused filament rapid prototyping machine specifically an XYZprinting DaVinci Pro 1.0. This wasn’t something I asked for or specifically wanted, in reality my opinion was that this type of machine is only useful for making non structural “art” parts, but all the same I have one now, so I have to figure out what to do with it.

I had recently made tweeter brackets for my car out of sheet metal over the Christmas holliday and one of the guys from a local car club suggested that I should make those with the machine (probably because he was hoping for a set)

I remembered the dimensions from when I made the sheet metal ones, so I knocked out the model in a few minutes and proceeded to manufacture it in the laziest way possible with incredibly low expectations.

And here’s how it came out:

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Not bad, the supports were a bit of a pain to knock off and left a bit of a rough surface. Time for a fit check with the old tweeter:

Also, not bad, looks like my ears are a little short. Time to tear my car apart and how it fits in-situ:

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It fits! but as I suspected the ears are a bit short, the mounting hole for the tweeter in the center is a bit oversized and I really feel like the part overall could use some beefing up. All of those were pretty easy changes. I spent some time thinking on the best way to beef it up over all. Additive manufacturing means that it’s easy to do a lit of clever things, but unfortunately a lot of those clever things interfere with the mounting interfaces, so I went with the worst option from a mechanical perspective and just widened the bracket a tenth

of an inch. Here it goes, revision 2:

The fit is much better and I was happier with the way the part feels overall. Here it is fitting much tighter with the old tweeter:

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Then I went away skiing for the weekend I was thinking maybe I could sell these to locals at 10$ a pair I’d make enough money to fund filament for further work with the machine. The fit is good and would make installation preposterously easy, as in a 5-10 minute job if you soldier the pigtail to the tweeter before hand (tweeters are a huge improvement for 15+wrx/sti’s). However, I’m still not sure of the strength. I’d love to have gone about testing with some kind of scientific method, but the fact is the loads on these in service are pretty hard to define and also really low. The highest chance of breaking is probably during installation.

So anyway this morning I was feeling particularity unsympathetic so I started twisting on the part until I broke it. The base and ears are X-Y planar and are surprisingly strong in bending, the legs that are X-Z planar suffer from the classic problem with fused filament machines, poor layer to layer bonding and snapped pretty easily.

So, what’s next?

Well I think I’m going to try printing the bracket on its side, the hole and slots are going to get screwed up with support material and I’m not sure how I’ll clean that, but that will definitely solve my legs breaking and hopefully the loss in strength for the rest of the part won’t be as much of an issue since it doesn’t have as much of an “arm” to be bent on.

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We’ll find out how that goes in a couple of hours!