RepRap Masterclass | Part Three
RepRap Masterclass | Fabmoment #3
29th of September, 2009
this week we’ve focused our attention on ‘more of the same’, but also on new developments.
on one hand we continued with casting the poly-urethane parts and laser cutting the necessary gears.
on the other hand we started drilling out the holes in the poly-urethane parts that were accidentally covered during the casting process, and we began carving screw thread from the metal rods.
• continuing the process of poly-urethane casting
o about seventy-five percent of the total volume has now been realized
o the process speeds up once a ‘casting rhythm’ has been developed
o there were still some imperfect parts coming out of some two-sided molds, this was due to the temperature of the
molds. when they’re overheated, the viscosity of the casting fluid decreases significantly when it’s poured in,
thereby cluttering the air release vents.
• laser cutting the gears
o material: 6mm acryl panels
o laser settings: speed 3, power 100
o for part size, take into account that the laser melts away about 0.1mm from the part diameter
o produce one, test it, then produce more
• drilling through the partly covered holes of some cast parts
o carefully fasten the parts on a flat surface to make sure the holes are cut straight
• carving screw thread
o first drill through the holes with a 4mm drill (M4)
o then carve the screw thread with a 5mm carving tool (M5)
o beware that the carving tool is positioned in such a way that it’s prolonging the direction of the hole at all times
