Back to 4-point bed mounting, switching to Cura

My printer bed is warped!

I submitted my PhD thesis (accepted with minor editorial revisions ;D)! I am back to printing between doing those revisions, and I was happy to find my printer still chugging along reliably after years of being stuck in a room and mostly untouched (my last printer post was nearly 3 years ago!). However, I found that my build platform had warped quite badly in that time, with a change of almost an entire layer height from the ‘base’ of the triangle of my 3-point bed mounting to the apex of that triangle. I took the bed off the machine and indeed, when laid on a flat surface it had a noticeable diagonal bow from one corner to the other.

I have to conclude that because I rigidly mount my bed to the carriage with screws and lock nuts and not a spring anywhere, that the bed was constrained from expanding and contracting with the seasons, and all of that stress had to go somewhere.

In an ideal world of perfect planes, a 3-point bed mounting system is the best, and it really was before this happened to my bed. But now that I have a warped bed I need to pull it back into shape, so I have gone back to a 4-point bed mounting system with the same aftermarket carriage plate. The stack at each corner is, starting from above the printer bed and going down:

M3 cap-head screw
Heat-resistant fibre washer
Printer bed
Heat-resistant fibre washer
Nyloc locking nut, finger-tight so that the screw has no vertical play but it can still be turned with a hex key
Large thumb-nut, which controls the height of the bed from the carriage
Y carriage plate
Metal washer
Wing-nut, for locking the height of the bed.

Adjusting this system involves:

Unlocking the wing-nut (9).
Turning either the large thumb-nut (6), or holding it and using a hex key to turn the cap-head screw (1).
Tightening the thumb-nut (6) and wing-nut (9) against each other to lock the screw height on the Y carriage (7).

To actually tram the bed, I use the ‘feeler gauge then dial indicator’ method I outlined in my comparison of bed levelling techniques.

Switching to Cura from Simplify3D

Years ago, Simplify3D was the king slicer for general audiences that wanted power and accessibility. However, even back in 2017 they were noticeably lagging in implementing new and desirable features that other slicers were showing off. These are things like adaptive layer height (variable layer heights based on the amount of detail needed in that layer), gyroid infill (inspired by biological structures, fast to print and gives good strength in all directions), non-planar layer deposition, ironing of top surfaces, and tree supports. Returning to Simplify3D in 2020, it felt like nothing had changed. This is good if you don’t want to learn anything new, but bad if you were hoping for some great new features. On the other hand, Cura has changed a lot from the time I used it last, and looking through the full settings list had me going “Oooh!” several times. I’ve now been slicing with Cura for about a month and it’s been great, no complaints here.