Dadio's 3D Printing Stuff

[Dadio]

More good and bad today , firstly the good news is that i got a 5 min run till the battery went flat with the single resin gear in the gearbox , so the battery is on charge and i'll go again , i wasn't holding back either , i was jumping it and even had a front shaft pop out and lock the transmission , again on grass so its looking better with the new resin .
Now the bad and its probably my fault again , i manually placed supports and that worked well but i ran the print late last night and it finished about midnight and i left it till morning to clean it up , i think the long wait till clean up is the problem , some of the resin had pooled between the bottom gear teeth as it hung over night and seems to have partially cured cured there , i'm not sure yet why it cured as it was not exposed to light , it could be the way i've printed the part that's to blame , this is a transparent resin so potentially the pooled resin could have been cured from light spill from the next layers , this did not occur with the grey resin so i don't know yet how to solve the issue ? I'm printing a single gear now that I've used slightly shorter exposure on the layers and I'm planning on taking out the moment it finishes to see if that makes a difference .
meanwhile i was able to clean up the latest gears by using a metal pinion gear and using the edge of the teeth to carve out the pooled resin between the teeth , laborious and i don't want to do it again but i think it worked .
next is to put a whole pack through the gearbox with the single resin gear in it , if it stands up to it then i'll rebuild with two or three gears in there , i'll leave the diff for now as its a ball diff and more involved to swap about .

[Dadio]

After another run of nearly 10 min the single gear failed so I'm going to put this on hold for a bit , my feeling is that I need to learn (mess about) more and come back to it , I've only had the printer a few days so I'm very green about the whole process .

[XLR8]

Hmmm, I'm sorry. That's very disappointing but maybe there's a way.

For what it's worth... I'm really not qualified to comment on this topic but I'll toss this out there for consideration.
What about using the printer to make a mold to cast the gear from some kind of high strength chemical cured epoxy plastic?
Again, I have no experience with casting plastic but maybe it's worth consideration?

[Dadio]

Been playing again , i decided to try doing the gears flat with manual more minimal supports with one gear and flat onto the bed without support , i used 75% ABS like resin and 25% blue engineering resin for these prints .
Firstly this is the gear printed flat with supports , the first picture is of the upper surface as it prints and the second is of the bottom , the teeth are perfectly formed and the bottom is perfect like an injection moulded part but the top surface is a little less defined but tolerably formed . If it were strong enough then this would work .


Secondly is the gear printed flat on the bed without support , again the first picture is the top surface that faces the bed and the second picture the bottom . again the bottom face is like an injection moulded part and the gear teeth are 95% perfectly formed , the top/bed face exhibits elephants foot , this is where the bottom layers spread out and you lose fine detail and at this point only the teeth lose their shape , its only affecting 0.25 mm and would clean up with a little work .


So what we learn from this is that printing flat with supports although it leaves the top cosmetically less than perfect overall it could be used functionally but the unsupported gear would need some clean up .

[Dadio]

I fitted up the gearbox again with two resin gears , the first gear and the third , the second gear that i printed un-supported just would not clean up and run smooth but i had printed the third gear a knuckle and a top arm so i fitted the gear and other parts . I also de-tuned it to run with a brushed silver can that I've had kicking about for 35 years , some bald tires and ran it on road ,so far I've had two 5 min runs and still going strong , i did jump it off the kerb into the road a few times as well .



Its much less stressed now on the transmission and the top arm and knuckle have had no mishaps yet so I'll keep running it till bad things happen .

[Dadio]

Had another two 5 min runs today and its all still running smooth , the old brushed silver can is probably only half the power but I s still good , what I'm more surprised by is the top arm and knuckle still holding up and I've been jumping this off the path onto the road a lot , not a big jump and its had no impact testing yet but I'm still pleasantly surprised .

[Dadio]

Just another little project I've had in mind for a while , this is a British WW2 era Universal Carrier (Bren Gun Carrier) in 1/12 scale , just designs as yet .

[XLR8]

Cool!
RC or for display?

[Dadio]

RC , I have an old Heng Long Tiger 1/16 scale that I'm gutting for electronics , ideally this would be better in 1/16 but its got to fit gearboxes for a much larger tank so I've up scaled to 1/12 so it fits , I'll be using tracks from a Panzer III 1/16 so again they should look reasonably close to how they should , I may gear it up a bit as I want it to be reasonably agile like the real thing , the down side to that is the Heng Long combo ESC/RX may not take it , they are renowned for not having much extra capacity in the FETs so it might be a pair of ESCs and an RX on the bill .
The real Universal Carriers had a unique steering system , not only did they have the tank style skid steer but also both the front road wheel bogies were linked by a cross beam that moved left to right with the steering and warped the tracks contact patch with the road to give very fine steering control ,I'm hoping to try and do that as well but that all in the future yet .

[Dadio]

A few more details for the rear , quite pleased with the oil can

[Dadio]

Started printing some of the detailed parts in resin and there are also some pictures of an early 1/24th scale test print of the hull , a lots changed since though .

[coxbros1]

can u print the two sprockets for the 834B since u have a car for reference? i really need them for my restoration....thanks!

[Dadio]

I have the whole car model ready to print https://www.rc10talk.com/viewtopic.php?f=29&t=44144&hilit=yo+clone+oh PM me

[Dadio]

Found time for a little more detail , rear seating and some wood surround for the top edge on the rear , I also assembled the bits for the picture .

[XLR8]

Awesome work Dadio!
Still using Fusion 360?