heinzboehmer's 2002 Topaz 6MT Coupe

[heinzboehmer]

I can only imagine the feel of satisfaction Pal! Excellent work

Thanks! Feels pretty great to finally have the real thing in my hands.

Also, was talking to some friends about the parts and Bry5on mentioned that he printed the threads in his super knuckle and then just ran a tap through to clean them up. I usually do this with any plastic printed parts and it works great. Not entirely sure why I chose not to do it for this one, but I bet I was afraid that the bore would expand when cool and the thread fit would have been too sloppy. Anyway, have added threads to the CAD design, which should make it so that others don't need to go down the steel insert route.

[maupineda]

I can only imagine the feel of satisfaction Pal! Excellent work

[heinzboehmer]

Brackets have arrived!




Super happy with how they came out. Think they're gonna look even better once they're painted to look like the stock parts

The surface quality is amazing (much nicer than the stock cast parts), but I still think I should give them a very light skim on the mill. Designed this quick fixture that should let me flatten both the face that contacts the strut tower and the faces under the nut flanges:




Very similar design to last time, except for a couple changes:

1. Ditched most of the stiffening holes. Turns out the printed part was more than strong enough without them, so only added a few to keep it from warping/cracking when clamped in the vise. Chose that funky teardrop shape so that it can print without supports.
2. Added a big hole in the middle. This way I can add some hold down clamps and not just rely on the fasteners to hold the piece flat. Should make my life a little easier.

There are two other surfaces (E86 pickup point and stock strut bar pickup point) that should be flat, but I don't think I trust my skills enough to do those on the mill. There are a ton of features around these faces and I feel like I'm gonna crash into them so quickly. I might just sand those down flat(er) by hand.

But honestly, I don't think these things need too much work. Look at that surface!




The other bit of post processing needed is to tap the threads for the stock strut bar studs. Got to work on that aaaand immediately messed the parts up:



These things are super weird to work with. Not sure if it's the alloy (AlSi10Mg) or the manufacturing method (lots of localized heat on the exterior walls?), but they're incredibly gummy. The chips don't really break, but instead just kinda get smushed around. Very weird.

Anyway, tried tapping the M8 holes and immediately gummed the tap up. Didn't realize it in the moment and destroyed the bore. Here's what the tap looks like now. Those bits of aluminum are really wedged in there. Tap is now in the trash because I was unable to clean it up:



No big deal though. I figured something like this might happen, so I left enough material around the holes for timeserts. Was much more careful with the tapping this time around and managed to get through all four bores without issues:



Think I fully backed the tap out five or so times per hole before I was able to get through. Again, weird to work with.

In hindsight, it seems likely that the original holes were undersized. They're sized for an M8 tap in CAD and I just trusted that they were accurate in real life without measuring. I bet it would have gone way better if I had run a drill bit/reamer through before tapping. Oh well, next time.

Will try to get in the shop sometime next week. I'm excited to put these to the test on the car.

[bavarian3]

Update from the manufacturer:



So cool.

Now just have to wait for them to get to me. I'm excited!

you're the mad scientist. this is awesome

[heinzboehmer]

Man, we're really living in the future.

Right? I'm constantly blown away that regular consumers can just do this type of thing now.

That was fast. Protolabs or somewhere else? I want to re-design all of this myself but ultimately I guess I'll just copy your stuff 1:1.

Got these through Craftcloud. 3DPnxt is the manufacturer making them.

And go for it! Would love to see others iterate on this design. The original CAD document is linked in the documentation I wrote up (https://drive.google.com/corp/drive/...ib65e2dj8d9FKH). It's got a bunch of scans and other references that will likely make your life easier if you want to redesign it

[discoelk]

That was fast. Protolabs or somewhere else? I want to re-design all of this myself but ultimately I guess I'll just copy your stuff 1:1.

[Bry5on]

Man, we're really living in the future.

Many No Longer Available parts almost no longer matter

[0-60motorsports]

Update from the manufacturer:



So cool.

Now just have to wait for them to get to me. I'm excited!

Beautiful

[Obioban]

Man, we're really living in the future.

[heinzboehmer]

Update from the manufacturer:



So cool.

Now just have to wait for them to get to me. I'm excited!

[heinzboehmer]

The three pockets around the bolt holes would need to go. The threaded insert may not fit and probably want some material there to take up anu torque stresses. The others aren't an issue as far as releasing the part.

Yep! Those three pockets are gone in the carbon version.

But cool, I'll get these printed in plastic and sent over to you. No rush or anything, just think it's cool to have some material choices.

[bigjae46]

Let me know what you think of the manufacturability of the design bigjae46

The three pockets around the bolt holes would need to go. The threaded insert may not fit and probably want some material there to take up anu torque stresses. The others aren't an issue as far as releasing the part.

[heinzboehmer]

Never knew about draft angles until I watched this video:

That's exactly the scenario I want to avoid

3 degrees is the good rule of thumb for mold release draft angles. It’ll be cool to see both options! You’re making me want to swap out the Slon brace to make maintenance easier.

Hell yeah! It is quite nice to be able to remove only a few components to get to the engine. Still a bit finicky to deal with the cabin air filter plastics, but I don't think there's a good way around that with how tightly everything is packaged back there.

Removing the Slon firewall mount point sounds like a huuuuge pain though.

The pockets just need to be less than 90 degrees to aid in the release. Maybe 87-88 degrees? It is a compression mold so the pockets are fine except for the smallest pocket near the bolt hole. I can still work around it but that one would be a pain.

Had a go at this and I think all of the pockets on the brace pickup points are gonna have to go for the carbon version. It's kinda hard to show in pictures, but the issue comes from the fact that the three mounting faces are at completely different angles to one another.

Hopefully this is appreciable in the following pics of the 3D printed aluminum version.

Viewing normal to the strut tower mounting surface:



Viewing normal to the stock strut bar mounting surface:



Viewing normal to the E86 brace mounting surface:



For the CF version, I modeled the pockets so that they're all normal to the strut tower mounting surface, since I think that makes the most sense. Unfortunately, after making the pockets at the brace pickup point normal to the strut tower surface AND modifying them so that there's still enough wall thickness around the fastener holes, they become too small to be practical for manufacturing.

I guess I could make ALL the pockets normal to some other surface (e.g. the stock bar mounting surface), but probably not worth the hassle. The volume of the pockets around the brace pickup points in the aluminum versions is ~15 cm3, which would roughly translate to tens of grams in CF. I bet that would be even less once you take into account the now-crooked pockets in the strut tower mounting surface.

Anyway, here's what I came up with for CF. 3 deg draft angle added to all the surfaces that are normal to the strut tower mounting surface (hard to tell, but trust me, the angles are there):



Let me know what you think of the manufacturability of the design bigjae46

Incidentally, I noticed this small oversight in the design I sent out to manufacture:



Min wall thickness there is 0.6 mm, which is not ideal. Fortunately the orthogonal surfaces are more than thick enough, so it doesn't actually impact the strength of the part:



I've since fixed this problem area in the CAD for both the aluminum and CF versions.

I did also try reaching out to the manufacturer to get the fixed version manufactured instead, but I was too late. Oh well. Again, strength of the part isn't affected, so as long as it prints out nicely (i.e. no holes), I'll be happy.

[Slideways]

Never knew about draft angles until I watched this video:

[Bry5on]

3 degrees is the good rule of thumb for mold release draft angles. It’ll be cool to see both options! You’re making me want to swap out the Slon brace to make maintenance easier.