pic: Finally Done!

[EricH]

Originally Posted by 75vs1885

I like the idea of 3-D printing the plates. I don't know why everybody is so against it, last year we (1885) used 3D printed parts to join an axle for our intake, it worked very well and only "broke" when we didn't check it and a shaft collar was loose.

If they were using metal 3D printing, I think most people wouldn't bat an eye. The problem is that those machines are generally 6-7 figures, not counting material, and most schools won't go for that.

Now, note this, I'm not against 3D printing, or even necessarily against 3D printing gearbox plates. I'm against 3D printing gearbox plates WITHOUT accounting for all the stresses and loads in the design, and "just because it's the next thing". If you think the plates should be 3D printed, please, by all means, print a set of plates for a given gearbox--just make sure to document the process and the failure.

A coupler sees very different stresses from a gearbox sideplate. I've seen 'em used in very high-load applications when 3D printed, but as I recall that particular coupler broke about a month after it entered service, due to a combination of factors that were not necessarily directly related to the loads it was seeing, and was replaced by a machined part.

Now, in case you need help reading a block of text, here's a list of reasons not to print the plates:

• 3D printing can't hold as tight of a tolerance as machining, and tight tolerances are REQUIRED in gearboxes.
• The printer prints in layers. If you orient them right, you can get away with the built-in failure modes this creates. Otherwise, ouch.
• Press-fits can damage the plates. What exactly is press-fit? Only about every bearing in the gearbox!
• If extra spacers will cause an issue, you don't want to print, because the screws to hold the gearbox together will need washers, which will act as spacers.

tl;dr: I wouldn't 3D print a gearbox plate unless I had specifically designed the gearbox for 3D printed plates, and specifically designed the plates to be 3D printed. This gearbox is, as far as I know, NOT designed for 3D printing. Therefore, it is a very BAD idea to 3D print this gearbox.