Hi all,
I’ve had an i3 for about 6 mos and had mostly dialed in my slicing profile to get pretty good quality on my prints (PLA).
Recently my prints started getting a wavy pattern on the sides, I found a loose screw on one of the mounts for the x axis rods and tightened that, but am still getting terrible print quality. I’m not even sure what to call what is happening to my prints and so have been unable to properly look for solutions. I am currently printing the recommended z brace mod in the hopes that it will help, but I don’t have high hopes. Pics attached.
Looks like z-axis issues
Check the lead screws. clean them and re-oil using light machine oil.
Check the screw on x-axis which the print head is on, do not move on z -lead screws.
Last check wires leading to z motors
Replace Z motors 
Cheers
Garth
I think the Z braces may fix some of that. But you need to be sure all your axis are moving right. I don’t recommend anything but superlube to lubricate the axis. Print a XYZ cube 2x2 cm to check where you have the problems.
Also let us know if you are printing directly to the bed or some mat, or glass. Sometimes if you print on a loose glass you may enconunter some layer missalignment.
Check the bearings of the axis. I had the toothless one on the X axis badly damaged and had to replace it.
Hope that helps. Sorry for my english. 
Gerardo.
Decrease print temp and use a better cooling fan
I’m printing to the stock bed sticker that came with the printer. The first layer looks great and I have good adhesion.
Have you tried tightening your belts?
The belts all appear to be properly tightened. I did remove the y-axis pulley briefly to check that and retightened the belt afterwards.
So I installed the z-brace mod and ended up removing the print bed to check the y-carriage (it’s flat and level). After reinstalling the bed and leveling, my prints were coming out much better despite having leveled the bed recently. After setting my printer to ‘coast’ .1mm, prints were drastically improved.
Anyways, the only problem that remains is some bulging at corners. I thought it might be related to acceleration or jerk, but after minimizing both of those there was no meaningful effect on the print. When I printed a test cube (2cm) with 100% infill, my print came out amazing. With any lower amount of infill, however, I experience this bulging effect.
Thoughts?
Here is the cube with the problem.
