Printed my slightly modified version of the bed holders with flat bottoms: https://www.thingiverse.com/thing:2778006
Followed most of Pergo's upgrade suggestions
- 20" 8mm chrome rails with extensions
- 600w Kenovo 110v heater with solid state relay
- Firmware updated to set build area Y max to 365mm and enable PID control for the new heated bed (I also updated the auto-level positions to probe the whole bed. Done in the Configuration.h file before uploading the Arduino sketch)
I printed the bed holders in cheap PLA (a mistake) with 5 perimeters and 30% infill at .3mm layer height. I will likely reprint this in ABS or at least in better quality PLA once I dial in my print settings a bit more.
- The ROBO has no issues printing over the entire build surface (I'm getting an effective size of about 9"x14" - a bit less actually heated)
- The 600w heater is an absolute monster compared to the stock bed heater. Heats to 80C in under a minute, often overshooting its target by 10% and then dialing back. The power draw really is 600w at full blast as measured with my Kill-a-Watt.
- PID temperature control and calibration highly recommended. With the default Bang-Bang control, the bed temperature varied a lot more.
- The increased flexibility of the bed is causing significant auto-leveling calibration problems. Because the bed bows further before the end stops trigger, the end result is the nozzle smashed too far into the glass after auto-leveling. I ended up setting a manual Z-offset of .35mm in Simplify3D to account for this. This doesn't seem like quite enough yet, but it's at least extruding the first layer properly. Further tuning is required.
If you're willing to put in some time to do this properly, this upgrade is just awesome. Giant heated bed for under $100, doesn't get any better!
Also - It took me far too long to track down the actual ROBO 3D R1 Plus firmware, so here it is: http://download.robo3d.com/firmware/R1Plus/ROBO3DR1PLUSV2.zip
Printed with 5 perimeters, 30% honeycomb infill with Simplify3D. Used cheap PLA, will reprint with something better. I always have good luck with Hatchbox. Should have stuck with that.