The acrylic frame of the Anet A6 is stirdy but bends, if y-belt is tightened the way i wanted it.
So I was planning to stabilize the frame with some kind of frame-brace and found the very simple but obviously perfect working solution by Jhedstrom (thank you so much for the idea!): http://www.thingiverse.com/thing:1517525
It keeps the printer movable not tying it to another surface / table and exploits the simple force-counter-force relationship between the rod and the belt. Perfect.
The only downside I could see was, that I would have to drill some holes in the nice printer of mine. But if that's what it takes, so be it - I thought.
I was about to go to a hardware store to buy some threaded rod and nuts when my wife said: You go and buy some parts? Isn't your nerdy printer able to BUILD those things?
And that was, when it hit me: I can build something, that will fit and support without irretrievably altering the material of the printer, if I design something that keeps itself in place by simply clipping-on!
The outcome you can see on the photos above.
Another problem I addressed was, that the y-belt is ridiculously far off the attachment at the heated bed (most probably due to the cheep development efforts of Anet - but that comes with that kind of price-tag-level).
To bring the belt closer to the bed I picked three measures:
1) I aligned the "y-belt-mount-bed" on the bottom of the bed to the center of the lead-rods (about 6mm down). I wanted a non-screw-solution for attaching the belt to the mount.
I found the same approach after I designed mine at member kaseat, never the less I give him credit by listing him as one of my "sources" to point to his development: http://www.thingiverse.com/thing:1842296 .
2) I altered "y-motor-mount" (integrating the part of the frame-brace in the back) and the "y-motor-L-support" to bring motor and belt up at one end and
3) I altered the "z-belt-bearing" at the front to also gain 5mm of hight.
Because I did not want to buy a longer belt for my quick bed-mount-solution (i needed more belt-lenght to do that) I took about 10 mm of horizontal debth by making 2) and 3) a bit longer than they originally were. This space is not needed for the nozzle is leaving the heated bed surface before and it gets not in the way of the moving hot-bed.
My special improvement of the y-motor mount: the hole to guide cables through is now open, so one can add lines without unplug them. The opening is small to let the bigger 12v cables pass but to not let them fall off again.
Simple supports only for the front and center mounts of the brace rod.
How to mount this thing:
When mounting the frame-brace to the Anet A6 you would want to loosen the y-belt and the four big outer nuts and re-tighten them, when the printed "brace-rod" is in place.
If you haven't done that already, alter the order of the aluminium plates, the hot-bed is mounted on. It will bring you less risk of damaging the PCB-hotbed with long screws from below and also bring the belt 2 mm more away from the bed.
Anet describes the mounting of the H-shaped part the wrong way in their videos.
So just look at my picture below and find the simple difference :)