$6 flexible print bed for Monoprice Select Mini

Last weekend I got tired of having to use a putty knife to chisel prints off of my Monoprice select mini V1, so I DIY'd a removable flexible print bed.

It's based on an inexpensive thin piece of plexiglass from Home Depot.

Cutting this kind of plastic sheet is pretty easy.  You score it with a utility knife and a straight edge, hang it over a sharp edge of a table or countertop, press down hard on the part on the table possibly using a book or board to spread out the force, and karate chop the overhanging piece.  I cut it to match the existing dimensions of the print bed and drilled some holes so I could reach the bed height adjustment screws.  Drilling the holes isn't technically necessary, but I like to be able adjust my bed height while the first layer is printing if I see a problem.

The MPSM came with masking tape as a print surface, and I'm using that now.  I haven't tested printing directly on the acrylic.  The internet says that this print surface is good up to 70C.  I don't print that hot so it's not a limitation for me.  To hold the bed in place I'm using some tiny binder clips I from our school supplies cabinet.  I think these are the same ones I used for the glass bed, but I'm not sure.

Last but not least, I changed the starting G-Code in Cura for the printer so it doesn't burn a hole in my shiny new removable plastic bed while the hotend is warming up.  Here's the new code.

M140 S{material_bed_temperature_layer_0}

M104 S{material_print_temperature_layer_0}

G21;(metric values)

G90;(absolute positioning)

M82;(set extruder to absolute mode)

M107;(start with the fan off)

G28;(Home the printer)

G92 E0;(Reset the extruder to 0)

G0 Z5;EG Move up off the print bed while heating

M190 S{material_bed_temperature_layer_0}

M109 S{material_print_temperature_layer_0}

G0 E5 F500;(prime the nozzle)

G0 X-1 Z0;(Move outside the printable area)

G1 Y60 E8 F500;(Draw a priming/wiping line to the rear)

G1 X-1;(Move a little closer to the print area)

G1 Y10 E16 F500;(draw more priming/wiping)

G1 E15 F250;(Small retract)

G92 E0;(Zero the extruder)

Explaining what this does, it starts the bed and extruder preheating

M140 S{material_bed_temperature_layer_0}

M104 S{material_print_temperature_layer_0}

Then it homes the printer

G21;(metric values)

G90;(absolute positioning)

M82;(set extruder to absolute mode)

M107;(start with the fan off)

G28;(Home the printer)

G92 E0;(Reset the extruder to 0)

Moves up off the Bed

G0 Z5;EG Move up off the print bed while heating

Waiting for the bed and nozzle to come up to temperature 

M190 S{material_bed_temperature_layer_0}

M109 S{material_print_temperature_layer_0}

Primes the printhead and zeros the extruder

G0 E5 F500;(prime the nozzle)

G0 X-1 Z0;(Move outside the printable area)

G1 Y60 E8 F500;(Draw a priming/wiping line to the rear)

G1 X-1;(Move a little closer to the print area)

G1 Y10 E16 F500;(draw more priming/wiping)

G1 E15 F250;(Small retract)
G92 E0;(Zero the extruder)

The crack when a print pops off is super satisfying.

  Happy Thanksgiving!