7.62 x 39 mm round
by clintkc, published
This is a 7.62 x 39mm round. This is NOT my design (downloaded from a 3D CAD resource on the net with no designer's name).
I wanted to print it out to test the Thing-O-Matic's ability to print objects that are much taller than they are wide or deep. I printed it with a raft, no support, 20% infill (mainly for weight than stength), and 2 shell layers.
The print went very well, up until about the end of the "casing" section. Since I designed my filament guide, I don't have to baby-sit my TOM nearly as much...so I let the print run while I ate dinner. I visit to my upstairs office found that the base of the bullet was rocking back and forth, fore and aft during the print. My nozzle seemed extra close to the printing object, which caused drag and probably caused this error.
Anyhow, this object printed just about how I expected. The TOM shakes about quite a bit, and I wondered how well it would do with tall, narrow objects like this. ANSWER: Not very well.
I'm relatively new to the MakerBot scene (had mine almost a month now), but very familiar with CAD and CNC. My belief is that objects such as this (if not all objects) should be printed with a moving extruder, not a moving build platform. (I could be wrong... I was once before, back when I believed I was mistaken... heh heh.)
Print (at your own risk) with your own settings, and see what you can do with it. Please note that my print was NOT successful. I have no further ambitions with this design, other to mark it up as a learning process (i.e. "do not print tall, skinny things").
Please note that the STL file name is wrong... on my SD card, it was "7.62..." not "62..." No, I'm not an idiot. :) I did my time as a Marine infantryman, and I definitely know my weapons & rounds. This is NOT a 62mm round! :)
Best of luck! :)