T3P3 Kossel Mini Kit - Release 3
Chapter 15 - Printbed
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
1501 Printbed - Parts required
200m diameter x 4mm thick aluminium plate with 3M ™ Kapton adhesive heater pre-applied, complete with a MF58104F3950 thermistor taped to the centre of the aluminium plate.
Heated bed mounts
12mm M3 plated brass male/female PCB standoffs x 3
M3 x 10 countersunk socket screws x 3
M3 penny washers x 3
M3 T-nuts x 3
190 mm diameter pre-cut cardboard insulator disc.
Approximately 1m of self-adhesive aluminium foil tape for covering the cardboard heat insulator
Circular glass plate 200mm diameter x 4mm thick.
Black paper 200mm diameter
3 x 19mm bulldog clips for attaching print glasses to the heat-bed.
NOTE: The aluminium heat-bed as supplied may have some minor surface imperfections and scratches. You may care to rub it down with very fine (600 or 800 grit) emery paper to remove these and provide the smoothest possible surface for contact with the print glass, if used, or for printing on directly. The picture shows the top surface of a prepared plate.
1502 Fit Heated Bed Mounts
Prepare a heat-bed standoff with M3 penny washer and M3 T-nut, …...
…...fit it to the the X-Y upper extrusion top channel, screw up loosely, centralise it on the extrusion, and screw up finger-tight.
Repeat for the X-Z and Y-Z channels to provide 3 mounting points for the heated bed.
1503 Prepare insulator
Apply overlapping strips of aluminium foil tape to the cardboard insulator. Be aware that the aluminium foil is quite springy and will try to roll itself up once the backing is removed. Sticking one end down and removing the backing progressively as you apply the tape will help to prevent this.
Trim excess tape off with scissors or a knife. Do not allow it to wrap round the edge of the cardboard disc onto the underside, as this could cause a short onto the electronics.
1504 Fit Heated bed
Balance the heated bed temporarily on the X-corner, leaning against the X-tower, while connecting its wiring.
Connect the 2 heavy red heater element wires to the heated bed screw terminals on the Duet. Make sure you tighten these fully and firmly because of the large current they carry.
Plug the black thermistor wires onto the adjacent thermistor pins.
Lay the insulator over the electronics while routing the bed wires clear . It should be a slight interference fit between the 3 standoffs and rest on the inner edges of the upper base extrusions.
Lay the heated bed on top of the standoffs and align the bolt holes. You may have to adjust the standoff positions slightly for correct alignment (they should still only be finger-tight). Insert the 3 M3 x10 countersunk retaining screws and do up loosely.
Tighten the standoffs firmly, .
and finally screw the countersunk bolts in fully
1505 Fit print glass
Early kits were supplied with the black paper uncut - if so you need to cut a 200mm disc using the glass print bed as a guide.
Place the black background paper on the aluminium heated bed , fit the glass and clip it to the printbed with the bulldog clips provided, spaced approximately 120 degrees apart. We suggest you place the clips about halfway between the standoffs and the towers, rather than in front of the towers where they may get in the way during calibration.
You are now ready to commission and calibrate your printer.