End Stops (Video 17)

Recap: I'm building a Prusa Mendel 3D printer from a kit I purchased from nwreprap.com using a series of videos.

Video 17 walked me through the process of installing the end stops.

First, gather the parts: you'll need three of each: end stop switches, end stop holders and 24 gauge wire pair.  If you can, you might want to test that the switches function properly using a DVM.  Start by drilling out the hole in the end stop switch that is closest to the terminal marked "NC".  Use a 3 mm drill bit.

Components needed for end stop assembly

 Strip the wires and solder them to the terminals marked "CO" and "NC".

Ends of wires have been stripped and soldered to "NC" and "CO" terminals

Attach two of the three end stop switches to end stop holders as shown in the two photos below:  use an M3 locknut with a 14mm M3 bolt.  The bolt passes through the middle hole on the switch holder and through the hole that you drilled out on the switch earlier.  You'll use this configuration for the Y and the Z switches.  The X axis will have to be set up a bit differently as described later.



 



Mounting Y and Z switches on holders (2)

Mounting Y and Z switches on holders (1)







 Mount the Y axis switch as shown below using an M3 locknut, an M3 washer and a 25mm M3 bolt.  The Y axis switch will be activated by one of the Y bushings when the MDF bottom plate slides all the way forward.

Y end stop holder has been mounted to a smooth rod

The X end stop had to be mounted somewhat differently than the Y and Z end stops.  The X end stop will be activated by the head of one of the bolts that attach the fan to the X carriage.  Use a 25mm M3 bolt, an M3 washer and an M3 locknut.  Pass the bolt through the washer, then the switch, then the two holes in the holder and tighten so the holder clamps around the X axis smooth rod that is closest to the stepper motor that moves the X carriage.

X end stop installation.  The X end stop holder appears inside the blue rectangle.

The Z end stop holder is mounted to the smooth rod underneath the stepper motor that moves the X carriage.  The Z end stop will be activated by the  printed part that holds the X motor.  Do not tighten it yet - the exact positioning will be finalized in a later step.

Mounting the Z end stop holder (1)

Mounting the Z end stop holder (2)