The bed on the K40 is terrible. There is a spring clamp (which is not very accommodating to begin with) in the center to hold a work piece, but it’s only a fraction of the travel area of the head. After spending a good deal of time trying to align the mirrors to be able to cut consistently across the entire area, I realized that since the bed was connected to the bottom of the case with standoffs rather than joined to the frame of the linear rails, the height on one side of the table varied by .8cm depending on which direction the diaphragm of the sheet metal on the bottom was popped. So, all of it came out.
On a forum that I spend a good deal of time looking at there is a regular that has a quote in his signature: “I used to spend my time to save money but now I’m willing to spend my money to save time”. As I began to think about designing and building a motorized Z table, that quote came to mind. Rather than reinvent the wheel and spend more hours designing, purchasing parts, and building my own.
LightObject.com has a bed made for the K40. The hours I worked to earn the $155 it costs is fewer than what I would spend designing and building my own. Plus, it will be here in a matter of days. Another A4988 driver on the RAMPS board and a few settings for the motor should all I need to get it operational. I will need to figure out how to mount it properly to avoid the issues of the case not being ridged, but that should be rather simple.