Could one of the more experienced friends of Mendel tell me why I should use a heated printbed (sorry, I am a newbie)? Is the heated printbed controlled by the standard G6 electronics?

The heated print bed allows you to print parts with out having to worry about warping them. (Mainly the larger parts)

You can find more details here: http://reprap.org/wiki/Mendel_heated_bed

More importantly... A heated bed solves adhesion issues with the print...

ABS will stick to Acrylic at room temperature but you solve both warp and adhesion by heating a Kapton surface to 100 degrees C..

PLA will stick to kapton at 30ish degrees.. but it sticks better and slight warp issues are solved if you run PLA bed at 60 degrees C

Just heating the bed doesn't solve all warp issues... for larger items, you need to try to keep the whole part warm as well.. this can be done with a heated print chamber, or you can make walls around your print that get printed along with it... keeping the heat in.

Al...

Thanks for the addition. I was just going off of some IRC chatter the other day.

Just to reiterate the OP, can the GEN6 control a heated bed?

Ive noticed the recent update (v2.0 mendel) kit comes with a heated bed and GEN6 electonics. Will this require an addition to our batch 1 boards?

Nope. While you can use electronics to control your bed-heat.. you can simply do it by adjusting your Power supply.

Obviously this requires a multi-voltage power supply with enough current capability.

Al...

Can someone experienced with them suggest a good type of variable voltage supply to use for the heating?
I very much like the idea of printing on glass that adrian demonstrated, I'm hoping that any heated printbed kits supplied here will allow a glass plate to be easily fitted without losing too much of the workspace height...

I am also interested in how to heat the bed. I have recently received AL printbed and I got the set of 4ohm heater blocks the fit perfectly. I hooked up to a variable regulated power supply that only goes to 12v DC. It only raises the temp by 2deg C. 31c or so. How many volts at how many amps do I need to raise the temp to 100 - 120 C?

Thanks
erby

I'm not sure I understand here... you have fitted a set of 4 ohm resistors to the bottom of the platform?

IMO you need 4x 1 ohm resistors in series.. or you need to wire up your 4 ohm resistors in parallel..


If you have 4 ohm resistance on your heater array in total.. you should achieve about 60 degrees at 12v

Al...

As for Variable Voltage power supplies..

Anything will do.. if you want to be able to achieve 100 deg C.. then I recommend a 125W 12 to 25(ish) volt laptop PS...

If you are happy with only 60 degrees, then 70W with voltages arrayed around 12V is fine...

Al...