Rebuilt build platform for my MakerGear Prusa Mendel RepRap with mirror

I rebuilt the heated build platform on my MakerGear Prusa Mendel. I’ve been having problems with it ‘eating’ glass. I didn’t recess the thermistor enough, so the glass would try to ‘bend’ over it, and break.

These are 3D stereoscopic images. You can look at them crossed eyed and get the full effect. You can click for a larger view as well.

image of Original print bed with broken glass.
Original print bed with broken glass. I used the printer like this for months. Really limits what you can print. I’ve actually not used the printer in 2 months because of it being broken like this.


image original build platform
This is how I’d configured the board to accept the heater. The notches are for the thermistor and wire runs.
image of Lining up the dremel to route out the board
Here I am lining up the dremel to route out the board. I wanted to recess the heater flush with the face of the board. So I used the router fence I had printed on my printer.
image of routed lines and chiseling out the excess
Here you can see my routed lines and chiseling out the excess. Running the dremel-router was a l of fun.
image of recessed area for the heater PCB
I’ve finished the recessed area for the heater PCB. It was fairly easy to use the chisel to chunk out the bits between my routed grooves. I used the grooves as a depth gage and tried to go that deep.
image looking at the bottom of the board
Here we are looking at the bottom of the board. I cut in 2 notches for the belt clamps as well as 4 holes for the bolt heads. This allows the board to set much lower than it could previously and still offer ‘springyness’.
image of installed print platform
I’ve installed the print platform. Notice that the bolts are recessed in so they sit flush to the board as well as the heater PCB. This will allow a full sized piece of glass.
image of installed heater PCB
The installed heater PCB looks pretty good I think.
image of heater PCB sits flush to the print bed platform
You can see the heater PCB sits flush to the print bed platform now. Hopefully I’ve got everything right now, and I will no longer break the glass print surface.
image of print platform height
You you can see how low the print platform is now. I’ve barely enough clearance over the Y carriage pulley. I’ve still got over an eighth inch of give too!
image of a cut mirror for a build platform
I am not very good as cutting glass. I broke my first piece. This is a mirror panel I rescued from the trash. Originally from Ikea. It’s very thin glass. I’ve heard good things about printing on mirror. Going to give it a try.
image of mirrored print bed
You can see my shiny new mirrored print bed. You can see that the mirror edges extend all the way to the edge of the build platform. I think this looks cooler. It also gives me more room to clamp the print surface down and avoid nozzle contact with the binder clips.
image of MakerGear Prusa Mendel RepRap with mirrored print bed
Now to level the print bed. This is going to be tedious as I have to remove the print surface to make any adjustments. I may try to cut my broken mirror piece down to use for leveling. It would expose the bolt heads.

All in all, I am pretty happy with these modifications. I should get a bit more print height. It looks cooler, and maybe I will turn the printer on again soon and start printing again!

The next serious modification will be a water cooling block for the nozzle. I’ve an idea for that…