Making a few tweaks here and there. Printing a few shells so that I can do durability testing soon!
Here's a silver Shoe with speedfeed and halo lid. With the speedfeed installed, the height goes from ~90mm to ~96mm.
Some people were asking for smooth surface. Bottom shell looks pretty good. Top printing right now.
Top shell came out pretty good =)
Now that I see it, smooth is good.
It's been a while since my last post. I've been printing shells with tweaks here and there so that I can run some durability tests. Still printing a few more. All these pictured below are in PLA plastic.
I'm starting to print several shells in ABS plastic so that I can test the difference. PLA is a stiffer but more brittle material. ABS is slightly softer and potentially more durable.
For those unfamiliar with the 3D printing process, ABS takes a little bit more work and is a bit more prone to warping during 3D printing, so I'm hoping that my design can still work.
I think I'll be applying enamel coats to some of these shells so I can see if any post-printing processing will help the shells stay intact.
Yikes. This is what happens with improper setup trying to print ABS.
There goes 15 hours of printing..
Getting ready for this weekend's testing, I've coated a few of the shells with some protective coating.
If anyone has any suggestions for other coats I can use let me know!
I'm thinking the automotive one should be pretty good.
Hooray. ABS material, much better than the previous print. Had to do quite a bit of stuff to my print setup in order to get this right.
And here's getting ready for my durability tests tomorrow. Going to shoot these til they break I think. I hope they don't break.
<--- a lot in here, just read in link
Lots of pics and videos!
Oh boy. Went to the field for testing. The people running the paintball park were kind enough to let me use one of their older fields to test. I wanted to make it as controlled an environment as possible so that I could get useful results. I brought with me 6 printed Shoes and came home with one. So yeah. My super awesome wife was my assistant and camerawoman today. We were able to capture pictures and videos of all the tests.
The two main tests I did today were feeding and durability.
For this test, I wanted to see if the hopper would feed consistently and if there would be any jams. ROF was not as high of a concern, considering the purpose of this hopper.
I tested with semi and ramp at the range and while shooting during the durability tests. There were minor ROF hiccups and one major jam, but no ball breaks. Anti-jam fin works pretty well. There are a few changes that I'll be making to the design of the interior so that it is less prone to jams. A few flat spots that can slow/stop a ball.
Here's a video of the hopper feeding
Overall, I'm happy with how it fed. A few minor adjustments should get it to be even more consistent.
Yikes. This was not as successful. For these tests, I wanted to see how the hoppers would hold up to impacts in the front as well as on the sides. I also wanted to see if coatings would make a difference. Lastly, I wanted to see if ABS plastic would hold up better than PLA. All hoppers were mounted on a rental, which was clamped to a wooden barrier. I stood about 16ft away from the gun and was shooting 280.
For the most part, all the hoppers withstood frontal impacts very well. Even at high ROF, they stayed intact (as you can see in the vid below). There's a weak point on the lower shell in the front that will be addressed in the next iteration.
Unfortunately, the same cannot be said about side impacts. There are some clear weak points that break pretty much on first few impacts. I'll have to consider how to beef up and/or add ridges and other geometries so that they can withstand impacts. Clearly, any spot that was on the thin side gave way very quickly.
It doesn't seem like the enamel coatings made much of a difference
The lid lip broke on almost all shells. I'll have to beef that part up.
Also unfortunate, I ran into more printer issues while working on ABS, so I only had one hopper in that material for this test. That hopper did not last. 3d printed ABS, while more durable and flexible than PLA, has poor layer-to-layer adhesion. Apparently paintball impacts are a great way to expose this weakness. Layers began separating after just a few shots.
While happy that the hoppers were able to take frontal hits, it looks like I still have a lot of work to do. I'm quite disappointed that ABS did not hold up well. I'll be looking into other plastics that have different properties to see if any of them can do any better. I have my eye on PET+, which boasts strength, impact resistance, and good layer adhesion. It's about 2.5x the price of PLA or ABS but if it works, it works.
If you have a weak stomach, now's your chance to stop reading.
For everyone else, here's the damage.
So one thing I realized when taking a closer look through the carnage of my shells was that I may have weakened the shells with a setting in the 3D printing process.
For anyone who is familiar with 3D printing or would like to learn, my slice settings were set so that I didn't have a very high number of perimeters. This led to what were thinner outer shells at the thicker spots in the model. I noticed on several of my broken shells that they broke where the slices starting doing infill (which was set to 10%).
I'll be adjusting the slices a bit and printing a few more PLA shells for testing.
I also received the PET+ filament I've been looking at, which boasts layer adhesion and impact resistance. I'm very excited to try a few shells in this material =).
Here's a pic of of the updated model compared to the old model. Not only is the shell thicker, the 3D printing algorithm (slicing) is set up so that there should be no more hidden weak spots (much higher perimeter count). I have to admit, that was a tremendous oversight on my part of a very basic print setting that a fellow 3d printer hobbyist might scoff at. Live and learn.
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Redesign printing as we speak! First hopper is complete and feels way stronger. Again, I made a few embarrassing modeling and printing blunders on the previous version, so I have high hopes for this one. I hope to get at least 5 hoppers ready before i head out for more durability tests.
Here's a pic of the design so you guys can understand a bit better what I mean when the tray is incorporated into the shell.
This geometry would not be possible using traditional molding, which is why 3D printing is a very cool technology!
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So an unfortunate misprint happened (most likely due to a tangle in the 3D filament spool) that messed up a print of the upper shell.
Cool thing is it happened at a spot that now lets you see inside the hopper. Almost looks like I did it on purpose. I guess it wasn't a total waste of time.
For giggles, here's a hi-cap comparison
Slowly but surely I'm printing my next test subjects.
Krylon True Seal
I think it's kinda like plastidip, flex seal etc
Looks really chunky though. I swear, I shook the can for the 3 minutes they told me to =)
I have a jar of plastidip I'll be trying too.