A new jumbo 300mm cube,

adapto is cleaner.

做那么大,加热床那么小

good job!but May be you need a large heatbed

The beige thing off to the left of the frame is a 300mm heated bed. :stuck_out_tongue:

Is that a PCB heater or a silicone one?

Why did you build a CUBE, when you have a Y-axis (or X depending how you look at it) moving bed? The prism design of the rep-rap is superior for that type of printer.