An excellent use / application of 3D plastic printing is creating replacements for small damaged OEM plastic components.
I have an expensive Kerr Ultra Waxer 2 machine that is an electrically heated hand-held wax carving pen tool. It is used to sculpt wax in model and jewelry making. This is the base unit and services two pens. The empty holes in the top are for storing various shaped tool tips.
On each side are brackets for placing the hot pen when switching between pens. The brackets are held in place with a single screw and three plastic locating pins through the side of the case.
The machine fell off a small table where I had placed it as I was moving the table. The plastic bracket on the left side shattered from the two-foot fall to the floor.
It’s a small but rather complicated part. I made a sketch and took very careful measurements. I had a flat bottom, and this gave a good reference for locating the pins and holes.
I’ll admit I made two prints. The first one I missed a side pin placement my a few tenths of a millimeter. Easily corrected in Fusion 360 sketch and a new STL file was printed. About 80 minutes at 0.15mm layer and normal speed on my Cetus printer. Material is white PLA.
I gave some consideration to the hot pen storage and using the PLA plastic. I have a good STL file I could print again in ABS if needed. In use the bracket never gets warm. Should not be a problem.
This is evidence that I occasionally use 3D FDM (plastic) printing for practical applications. Not just Junque “stuff”.