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Discussion Starter #1
your R33 wheel center caps looking drab? perhaps you want to add a little swag to those old rims!

from this:


to this!

bcnr33 wheel cap front.png
bcnr33 wheel cap back.png

the printing has begun, this time tomorrow ill do a fitment check and post the link for the .stl file for all to enjoy!

est. material cost= approximately $1.04 USD!
 

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Discussion Starter #3
I had three crappy prints and the last one fit but the dimensions were off. That's the fun with 3d printing I guess! I squirted some crappy acrylic paint on it to get an idea of what it will look like while the revised version is printing. Do you guys think it's too bland? Thoughts?
 

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Discussion Starter #6
fitment is good but ran into trouble due to the brittleness of PLA (polylactic acid) plastic. apparently it doesnt do so great at push to fit applications like this, so i gave my first crack at annealing in a temperature controlled water bath in my oven at 80 Celsius (175 Fahrenheit) but it warped all to heck. i need to reprint in either PETG or ABS, but im reprinting one last PLA model to give another trick a shot, acetone softening. i figure if i get a dish prepared with enough acetone to cover the flexible bits, it just might work without swapping materials.
 

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Hey Evosnipe,
I think they look great on the wheels even just black with the coloured letters.
In the last week I have been attempting to print caps for my wheels and after 5 versions of the model, I have one that I like.
To fix the problem with them being brittle I made everything 4mm thick and printed with wall thickness of 3mm so everything is solid. Using ABS as it is harder. I am not sure if PETG will work as it melts at quite a low temperature.
If you don't mind me asking, what printer are you using? I have a cheap eBay one and the print quality is not very good. To the point where the final print is not round in the top half. Perhaps it is my calibration but this thing does not calibrate very well.
 

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Discussion Starter #8
I'm using a flashforge finder, pretty cheap but surprisingly accurate. The wheels are going to be plast-dipped black until I can get them pwdercoated. Do you have a picture of your model? What printer are you using, maybe I can help with your settings
 

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https://photos.app.goo.gl/GJihASGQpjTKshtk1

See how it is out of round where my finger is? It is the same on the oposite side. I have read through forums and watched videos. The only thing that really applies in my case is to lube up the shafts on the X and Y axis. The rest is pretty crappy too but it can be fixed with some sandpaper, primer, sandpaper, primer etc. What you see is a draft (0.2mm) layer height and 1mm wall thickness, I just wanted something quick (2h 15m).
 

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I figured it out. As I was oiling the shafts for the Y axis, I noticed the shaft of the stepper motor is bent. Tomorrow I will swap one of the Z axis motor with the bent one. Hope that solves my problem as I just made a really nice looking model for tweeter bases and want to check it out for real.
Thanks for offering your help. Did you manage to try the acetone softening method?
 

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Discussion Starter #11 (Edited)
yea the acetone works great but everything i have read indicates that once the acetone evaporates from the PLA it will re-harden. its good for installation purposes on snap fittings though, they are just gonna break if i ever take them back out

heres the link for my v3 wheel caps, they fit pretty good now and i think the look will come together. will post pictures after the plasti-dip dries in a few hours. https://www.tinkercad.com/things/aYx5UoFfw3n
 

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BTW, I have no idea about plastics....Its JM2PW!

it just might work without swapping materials.
What are these materials your using like after repeated heat cycles Evosnipe? I spent a fortune on genuine Irmscher/ATS 80mm wheel centres because the plastic they were made out of would over time (sometimes quite rapidly too) change its shape ever so slightly due to the brakes normal operating temperatures heat soaking into the Cars alloy wheels.

All it took was just a few spirited drives or a Track day or two and I'd be back to my local Vauxhall Dealer buying four more expensive Zi 61 10 135 replacements for my now missing wheel centres...Well until they became "No Longer Serviced" items that is!:(

Maybe material choice is a much harder consideration (in regards to longevity) if you don't want to be re-printing wheel centres on a regular basis.

On a side note, Grey wheel and painted centre look awesome!
 

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Discussion Starter #15
The final prints are most likely going to be done in either ABS or PETG. I'm leaning more towards PETG after seeing a few independent heat wattage tests on youtube. I'm going to seal and smooth the top in two batches, one using cheap UV and heat warp resistant spar polyurethane and another in epoxy, have not decided on the epoxy yet though. I'll pop the finished product in my oven at 200F degrees and see what happens
 

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Discussion Starter #16 (Edited)
EDIT: Low temp PLA annealing attempt severely warped the caps, additionally the acetone bath significantly softened the material but the snaps were still too weak to insert into the wheels. PETG, polyurethane casting, or ABS seems like the best bet now

Still waiting on PETG filament to arrive, but I'm beginning to consider casting solid aluminum caps that thread in to a retainer on the inside, since properly removing the caps require unmounting the wheels anyway. Also considering going an extra mile and doing a carbon fiber inlay, some small kits are pretty cheap on amazon.
 

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Discussion Starter #18
The filament has arrived! Just in time to pair it with my new all-metal hotend. Once I crank out the caps I'll be sure to post the results!

I wouldn't mind making LM GT1 caps but I'd have to get someone to give me some dimensions or loan me one
 

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Discussion Starter #20
That would be fantastic!

Update: after swapping in a new all metal hot end to support the much higher 245C printing temperature, I gave the cap another print in PETG filament. First impressions, I REALLY like this stuff! Extremely strong and smooth surface, i will need to tweak the settings but I feel like it has a lot of potential over ABS and PLA!

The bad/the epiphany: after taking the new PETG cap off the printer I could tell it was a lot more durable from the get go, good luck trying to break a 6mm thick solid infill piece of this stuff! However after giving the locking tabs the finger test I was sad, they flexed more readily than the PLA but would still snap if significant force was applied! Then I had the epiphany, it wasn't the material that was creating the problem, it was the layer distribution!

3D printing bonds subsequent "2D" layers in order to create your end product, it is between these layers that the strength is the weakest, due to incomplete fusion when compared to a traditional process like injection molding. Thus, with such a thin bit of material being printed horizontally, you will find that regardless of the material used the locking tabs are always going to be the weakest point of the print.

However! If I rotate the print on the side and allow it to print the tabs with parallel layers, I should in theory gain a substantial increase in strength, flexibility and durability. The downside is I will use a lot more material due to the amount of supports required to print vertically, but on the bright side I could potentially print 30 or more caps at once. I will post with the updated results!

P.S. I am due to invest in an ULTEM/PEEK capable printer in the near future, with a DRASTIC increase in build volume, this is all practice for the big hitter, an ultra strong, ultra lightweight, custom printed intake manifold
 
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