Everyone knows that getting your first layer right is 90% of the battle to getting a successful 3D print. Even if your temperatures and everything else are correct, if your nozzle height is off you will get bad adhesion on the first layer.
Setting it up is actually pretty simple, but it can be confusing. In this video I explain, in very deep detail, what all the parameters and settings do that control nozzle height on your first layer so that you can get perfect first layers. In this video I am using a Cartesian style machine, a Prusa i3 MK2, and Marlin as the firmware – but the principles will remain constant for most printing systems.
I power on the printer for the first time and set up the Limit Switches, Axis Movement, End Stops, Bed Extents, Bed Levelling, Z Probe/Bed Sensor and do the Extruder Calibration!
I spent quite some time going through the Marlin documentation to see what each possible configuration instruction could do. I had already done a very basic run through of the Configuration.h file in this video/post but now it was time to get it spot on.
One side benefit of the exercise is that I can see I will need to change the way I mount the heated bed. Most importantly the nyloc nuts sitting on top reduce the Y axis extents by nearly 25%!!!!. But secondly the ply wood under the bed allows the nuts to squash the edges down too much, resulting in the opposite bed bend to that I had before! Still, good enough for a first print 😉
As I am not sure yet exactly where the RAMPS will end up, I am just going to wire everything long and hook it all up temporarily to get the printer up and running. I will revisit the wiring once everything is working and tidy it all up. But this is good enough for now!
I cover a few little things that I needed to look up, pin outs etc. The rest was an easy job… so long as you have the right crimps to hand!!!
If you have a Z probe that needs more than 5v to operate, then you can run it directly from the 12v supply and run the signal wire (usually black) through a voltage divider and from there into the RAMP Z Min Endstop connector.
The values for the voltage divider are R1=10kOhm and R2= 6.8kOhm. This will drop the 12v to 4.9 and result in a power loss of only 85mW.
I didn’t end up needing to do this – although the probe was spec’d for 6-36 Volts (if I remember correctly) it worked fine with just 5v.