This is an example of designing something that I won't be using.
I'm very happy with my aluminum solution for my retractable casters, but I've had many people complain that they aren't comfortable working with aluminum.
So I designed a 3D printed PETG caster bracket.
It works well enough, but it does flex a tiny bit which it probably not good long term.
I've run this through 10 up down cycles and dragging my rig around the floor between them and left this caster supporting the entire left side over night and it hasn't flexed past where it started.
Since flexing will lead to fatigue, I've redesigned this mount with two additional M8 bolts near the bottom of the caster plate where the maximum force pulling away is located. I've been testing with only 30% infill, but will recommend 60% infill for people who decide to use this.
Since most of this is sheer and the bolts are compressing the layer lines, I don't expect it to come apart at the layer lines. PETG has some give but handles higher temperatures, so I think it stands a good chance of working for a very long time. PLA is stiffer, but more brittle and it tends to conform over time especially in warmer temperatures. So I think PLA would tend to fail by cracking and bolt holes would elongate over time.
I'll continue to stress test the weaker mount for a little while longer and then verify that the new beefier design is solid with only 30% infill. This is the first time I've tried to use 3D printed material in a structural capacity. Hopefully it will work well for some people.