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3d printing fun. trying Postimage now

Self explanatory...

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tamiyadan
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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Sat Jul 29, 2017 12:44 am

intentionally clipped a wall today, snapped axle in half, and popped a servo saver.
this axle had a defect in it also, this was when my filament twisted up on the spool during print and i got a small gap in the part.

So since it broke remake it in something stronger. 910 nylon.
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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Sun Jul 30, 2017 8:35 pm


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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Fri Aug 04, 2017 5:13 am

transformers robots in disguise
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the STLs were massively damaged so i had to remake a bunch of the pieces to work in my slicer
the mechanical for the robot are not very good but i made it work and added some decals.
its less than 2" long (45mm) 1" (25mm high)

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Re: 3d printing fun. trying Postimage now

Post by RC10th » Fri Aug 04, 2017 10:04 am

Aside from the terrible sounding gear that monster truck looks pretty fun.
I was old school - when old school wasn't cool !

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Fri Aug 04, 2017 4:23 pm

most people don't know how to design gears. there are special programs to generate them but it costs lots of money.
there are all kinds of variables in gear design. the free software to make bevels is really limited and is terrible. the Free straight spur software is actually pretty good but you have to know the dimensions you want precisely. the SVGs it makes are REALLY hard to deal with because it has so many vector faces it freaks out the render engine when you go to extrude it. I learned about this when i designed the new lower ratio for the truggy. what i found was people tried to get around this limitation by copying a simplified version of the generated SVG and what happens is they lose all the slight curves and pressure points and end up with a gear that functionally works but is noisy.

In this case the STL shape of the main gear is flat and the pressure face on the gear isn't right. the bevels are also not 100% correct either.
the driveline is actually very free moving it will spin without the motor and keep going, but it generates a funny not normal noise when under power. lapping gears can reduce the funny noise but it really isn't needed.

all the R/Cs i printed out have similar issues. on the Truggy i redesigned the Spur gear and used a traditional .6 pitch pinion gear so the gear noise on the truggy is almost normal as i didn't go into the bevel gears to fix them. the bevel gear diffs were remixed from another designer as a demo of how a 3d printer could make a gear diff however the designer copied the design without understanding all the little curves and what they meant on the face of the gears. then the truggy was just built around that original demo design. functionally it works fine but it isn't correct.

There are TONS of people that have tried to simply fix the 3d gears in some of these models and most don't improve things other then strength.
some people attempted a Herringbone design to strength the gears but it doesn't help the meshing issues. the herringbone plug in is free on autodesk's website which is why you see it. Autodesk really needs to internalize simple gears in fusion 360.


otherwise on the monster truck another issue i've run into is the stiffness of the PLA is softening over time under stress. so items like the servo savers are spreading and causing more and more steering drift.
I tried them with 910 and ABS and they have also loosened up and spread. in this case they require a mechanical hold addition and i'm toying with some ideas. the short of it,,, the more you drive the MT the worse the steering centering becomes.

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Wed Aug 09, 2017 2:28 am

New blue body with some familiar one off decals
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better rear window i made up
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playing with ninjaflex i don't recommend going below 2 perimeters, i tried a single perimeter and it was a disaster.

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Fri Aug 11, 2017 1:25 am

bigger tires Finally arrived. go china
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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Thu Aug 17, 2017 4:09 pm

I don't know if this was a mistake or not
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27 hours in at this point. i can tell i messed up also and the model is too narrow.

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Re: 3d printing fun. trying Postimage now

Post by jwscab » Thu Aug 17, 2017 4:12 pm

is that hollow? i guess that uses up practically a whole spool per tire?

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Thu Aug 17, 2017 5:52 pm

i came up with a honeycomb 9% infill that is under extruded on purpose this gives you a similar texture to the inside of a sponge or foam insert.

It uses 2 perimeters all around, this was to try and make the tires softer.
each tire (narrow) uses about 160 grams of material.
The spool is .5KB (500grams) which is about enough for 3 narrow tires barely.

The wider tires are going to use up about 1/2 a spool each.

The biggest draw back is time. the narrow tire simulated at 48 hours of continuous running.
Lots of time for something to go wrong. but i had to at least try it.

i spent the last 2 weeks trying to get my flex settings to work better. I made new softer versions of the tires for the F1 car because of it.

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Thu Aug 17, 2017 10:42 pm

39 hours 56mins to complete.
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it is almost 100% correct. i had an issue with the infill it was a little too loose and the nozzle was dragging it into balls which caused some perimeter problems. but it was not enough to murder the tire during layering. by scaling up the problem became apparent.

the tire weights 130 Grams which is lighter then expected. the china tire is 160grams. width wise the narrow version is ok it matches within a few mm of the china tire. it is very soft softer then the china tire. the infill is acting just like i want as like a foam insert.

better then i hoped really considering the time and problems involved. i'll make a change on the infill for the next one and try again.
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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Sat Aug 19, 2017 2:15 pm

Tire finished at 33 hours 34 mins. And still not right. The infill went down too well and effected the stiffness like I hoped it wouldn't. Just a .05 change made a big difference so I had to go back to the original infill width setting. I changed a few parameters on the surface thinking about some fan cooling changes. The tire came out looking a little better but similar surface defects are still present. I watched the infill go down cleaner but it just didn't do what I wanted.
What I'm doing is wrong on purpose to trick the material into laying down softer.

I don't think I have enough material for another go have to check that as well.

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Mon Aug 21, 2017 3:33 pm

i'm days into just trying to improve a tire.

I tried a bunch of tests many of which failed and caused the extruder to jam during a print. anytime i tried to reduce Ooozing it manifested in a jam. There was too much retraction motion back and forth and it would deform the Filament such that it would start to wrap around the loader and jam.

The problem is i'm attempting to force a mistake in the layering to produce a softening effect in the final product.

So far on this last print i'm getting less clumping of the infill material. if it comes out at least softer then the second tire i tried then i will call it a success and move forward. I burned through an entire roll of flex and i ordered more since i will need to do this 3 more times.

so far i made 3 tires all with different material settings and a couple of failures due to jams early into the print.

the first tire is very soft however the surface could of been better and it had large clumping of the infill material
the second tire looks a little better but it is harder, now it still isn't as hard as the made in china tire but i liked the feel of the first one and wanted to try and maintain it.
the third tire is 24 hours in and appears to have less clumping then the first tire but still has some surface defects. won't know the results for another 15 hours.

if this last one is decent then i will commit to the other 3 with this slicer formula. which is another roll of filament.

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Tue Aug 22, 2017 2:14 pm

it failed. the print finished but was much worse then i hoped.

well at least i learned a little about what not to do.
back to the drawing board. i might have to just go with the harder tire and call it a day.

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Re: 3d printing fun. trying Postimage now

Post by tamiyadan » Wed Sep 13, 2017 3:29 am

the cry of the mentally ill.
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