An-Bri-RC SU-85

[General Jumbo01]

Nice work. I believe that antenna mount is supposed to swivel backwards through 90 degrees, presumably to allow the turret to turn past it. Would be good if you could replicate that, maybe sprung? I'm struggling to authenticate that but I'm looking at doing it on my mod 43 anyway! I did see it somewhere though. If only l could remember. It's an age thing. Wibble wibble...

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[HERMAN BIX]

Nice fuel tanks, I like those-thanks for the extra work !
You dont 'owe' anything mate, I'm just happy to have the shot at correct wheels for that SU which arent going to require a foreign bank loan

Dont get too misty-eyed on that T34, it will only make parting such sweet sorrow

[tankme]

The antenna mounts do swivel down to like 90 degrees, but I think that was mostly for storage. With the spring on it, the turret can pass right by it.

[Raminator]

Printer's been running non-stop for the last week.

Got a whole set for the T-34/76 done, and I'm halfway through a stamped set for Herman's SU-85. A lot of post-processing and curing ahead of me, I should probably be doing it in batches during the week instead of saving it for the weekend.

[igi911]

read the whole thread and it's really great !! good job, bravo

[General Jumbo01]

A question?? Those wheels appear to have been printed on an incline, or was the bed inclined? Any reason for this? Looking good by the way

[Raminator]

read the whole thread and it's really great !! good job, bravo

Thank you! The topic changed from the original build to new wheels for it, hopefully they'll see some good use before too long!

A question?? Those wheels appear to have been printed on an incline, or was the bed inclined? Any reason for this? Looking good by the way

Yep, they're printed at 45° from the build plate. Resin printers work upside-down, the build plate moves down to the bottom of the vat (which has a taut, transparent film as its floor) and UV light is shone up through a screen to cure the layer. The build plate then moves upwards, pulling the solidified resin off the film before moving back down to do the next layer. You don't want to have surfaces parallel to the build plate and film if you can avoid it, it creates a larger cross-section that has to peel off the film and can cause the print to fail (because the attachment to the vat will be stronger than the attachment to the supports).

[HERMAN BIX]

Yeah...........what he said
Im as good as - press go and wait.

[General Jumbo01]

So much to learn! Thanks for the explanation. I'd love to watch it working as l've only seen an upwards build printer - I'll look on YouTube. Does your design have to accommodate the angle or do you just ask the printer software to rotate your drawing?

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[Raminator]

A little bit of both. The parts are drawn in a CAD suite (I use DesignSpark Mechanical), then imported to slicer software (in this case Chitubox) to translate it into something the printer can use. For a traditional filament printer, the slicer cuts the model into layers that are drawn sequentially by the extruder moving along set instruction paths. For a resin printer, the slicer just cuts the model into flat images that are projected into the resin vat one at a time to build the model up.

They're not as interesting to watch as a filament printer where the print head moves around and does stuff, these are mostly stationary. They'll expose and cure a layer, move up a few millimetres, move back down, rinse and repeat. For the Blu resin I'm using, it exposes for 5 seconds, moves 5 millimetres up at one millimetre per second, then goes back down, waits a few seconds for the resin to settle and then does it all over again. It takes about 17 seconds per layer, and for a typical print like these stamped wheels there might be 1200+ layers (I'm printing at 35 µm or 0.035 mm layer height). It takes a little over six hours to print a roadwheel pair. Besides the level of detail, the other big advantage of resin printers is that if the build plate was twice as big you could print twice as many models in the same amount of time because the whole layer is printed at once.

To make sure that everything will print suspended in the vat, it all needs to be supported. This is all upside-down on the printer, the build plate is the blue rectangle, the light blue supports attach directly to it. The wheels can then be separated from the supports with (hopefully) minimal damage.

The orientation of the print and its supports were some of the things I was having trouble with earlier on. It's been a pretty steep learning curve with all of this! I really jumped into the deep end.