TI-99 Cart shell on Thingiverse - needed changes

+acadiel · July 24

Finally got to print my shell now that I have a somewhat reliable 3D printer. (Bambu A1 Mini.) I made this shell 14 years ago in Inventor and still have the original project. The model is in Thingiverse, in inches (which I need to fix), and I’m going to place it fixed in Makerworld too using metric, and will save that also back to Thingiverse:

https://www.thingiverse.com/thing:2296281

I have found several issues with it:

For the industrial 3D printer I used 14 years ago, the top roughness, especially the part that slides into the console and the front, bothers me. The roughness of the square “label window” on the bottom is also an issue. Solution: Identify and fix the cause of the uneven printing on the top and bottom.
The front part needs screws for better tension as the label alone is insufficient. Solution: Extend the cartridge slightly to add screws.
The UberGROM and other cartridges barely slide in due to the front supports. The nubs on the top interfere with the 1284 socket. Solution: Consider removing the nubs and making the front slightly taller and without an angle.
The original unintended angled printing on the front of the top and bottom parts creates significant roughness and removes space where it is needed. Solution: Address this as part of fixing the top and bottom roughness.
When uploaded to Thingiverse, it was incorrectly licensed with a “no commercial usage” stipulation. This has been corrected to the CC 3.0 Sharealike attribution license, allowing anyone to modify and fix these issues.

If there is anyone good with modeling and wants to help (and maybe be patient with me in a free or very inexpensive mainstream Mac or PC modeling package), I’d like to collaborate on the above (or even let you just respin and I provide feedback). Also, if I can find the original Inventor files, would they help?

thanks!!

—————-

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+Ksarul · July 24

That roughness didn't show up like that when I had them professionally printed, @acadiel.

InfiniteTape · July 24

That roughness looks like maybe your hot end temperature isn't right or your e-steps aren't calibrated well, @acadiel. Do you see this roughness on other prints? What slicer are you using?

+acadiel · July 24

2 hours ago, InfiniteTape said:

That roughness looks like maybe your hot end temperature isn't right or your e-steps aren't calibrated well, @acadiel. Do you see this roughness on other prints? What slicer are you using?

Nope, other prints have been turning out extremely well. Very smooth on surfaces. See attached. Same temps. Using generic PLA profile, Creality PLA. The temps are 220C for the PLA on all builds and 65C for the bed for all below prints. I sliced the C64 connectors below using the defaults too, and they showed up fine. It’s giving me an OK preview in the Bambu slicer for the STL but the surface is not smooth. Note the different gradients.

Edit: Ran them both through this tool: https://www.formware.co/OnlineStlRepair It didn't see any errors, but fixed many angles.

The slicer sees one surface at the top now, but still doesn't see a whole surface - so will see what it does. Still looks rough.

tishell_bottom_fixed.stl tishell_fixed.stl

InfiniteTape · July 24

Cura didn't show either model having an odd top surface (original on the left in the picture below). I wonder if the Bambu slicer has a bug? Cura loads both of the STL files as being 4mm wide, so I had to scale them. I can't recall what issue with your modeling sofware can cause that.

It's almost like your printer is having issues maintaining constant velocity on those long single-axis paths, but it's confusing because I don't see evidence of that in your other models. It's almost like it's binding in that axis, but the A1 has linear encoder rails that should be able to detect that and give an error. The big blobs at one end also made me wonder about hysteresis.

One suggestion would be to try scaling down your object to see if there is something about distance traveled. Or maybe it's print speed? Or, if Bambu slicer has a way to do it, try telling it to do the top layer at a 45 degree angle.

+acadiel · July 25

Tried Mesh mixer to edit the units to inches and generate a more uniform face group. Note the top looks slightly better now. Still a little rough. Bottom still looks unfinished.

ti cartridge top.mix tishell.obj

+Vorticon · July 26

I printed your original design a number of years ago using my original and very primitive 3D printer to house my FinalGrom cart, and it's still in use . The whole thing had a very rough finish and needed some adjustments, so I'm looking forward to version 2.0!

Duewester · July 26

Check out this Guy's YT, it might help.

InfiniteTape · July 26

I just printed the original model. Ender 3 Pro, Cura 5.8.0-beta.1, standard quality, Hatchbox Black PLA, 200C head, 60C bed. So I don't think it's your model design. And it's not your filament since you see odd behavior with at least 2 different filaments. I still suspect something is set poorly in your slicer given the higher quality of your other prints.

Tursi · July 27

I've printed quite a few on my resin printers and they come out pretty even as well.

LASooner · August 2

Try turning on ironing for all top layers

+acadiel · August 9

On 8/2/2024 at 2:35 AM, LASooner said:

Try turning on ironing for all top layers

Yep, that orange one had ironing turned on.

I downloaded a MSX cart shell just for fun and used the same slicer settings as the TI cart shell just for fun. Came out super well. It has to be something with the way the model is setup if I can print other models with the exact same settings and filaments and they turn out OK. This model was made back in 2014 in Inventor, and I am attaching it (and all the inventor files) just on case anyone wants to take a look. (This was the version without the three screw holes; I also attached 2.6 which is the one with the three screw holes.)