Y-axis Stiffening, Quick and Easy
Squeeze the middle of the front and rear frame brackets towards each other and you will see the y-belt droop a few mm. Yes, you easily can deform those brackets that easily. I stiffened them both easily and cheaply with some L-profile aluminum bar. I could have fashioned angle bracket, but that would be more work and could change geometry if not cut accurately. This way was easy, doable with hand tools, and stiffens front and rear brackets to make them a lot harder to bend. I can't really droop my y-belt by squeezing the brackets after the mod.
Basically, cut two lengths of L-bar. Make them correctly sized to avoid covering mounting holes or interfering with LCD mounting bracket. You don't have to run the entire length of the brackets. Simply laminating the majority of the length makes a big difference. You leave only a small length of bracket un-reenforced. Those short segments are hard to bend compared to the entire bracket. The L-profile's horizontal portion lends its strength against bending the brackets.
Took about an hour and cost $15 max. Clean the brackets and abrade the mating surfaces. The bolts might be enough, but with fully cured epoxy, the lamination is not budging.
Doesn't change printer dimensions much and creates no interference with existing parts.
Yes, a Bear upgrade would be even stiffer, but this stiffens up y-axis quite a bit for easy, fast, and cheap.
My XYZ test cubes are a little bit cleaner after the mod. Sorry, my phone camera does no't capture specular details on PETG well enough to illustrate.
Re: Y-axis Stiffening, Quick and Easy
Think I need to do this as I can see my planes bending slightly and my Y belt tension is still too loose @ 285. I can't imagine bending these plates will help with accuracy..