above noted hole size is also shown by experiments to be most useful when incorporated in a printbed having a thickness of 3 2 mm such a printbed is formed by two 1 55 mm thick pcbs bonded together as described below this particular hole structure worked better for a 1 55 mm thick pcb allowing prints printed objects to avoid warping but still allowing release of the rafts even more unique to the present invention though is the use of two pcb 39 s thermally bonded or glued together to make a 3 2 mm pcb these pcb 39 s work better with a 1 4 mm 1 8 mm hole size trapping plastic even better for the purpose of preventing warp due to longer holes but stiffer bed and still allowing release in an alternative embodiment a pcb is manufactured to be 3 2 mm in thickness so gluing or thermal bonding is not required the improved performance from an enlargement in hole size as compared with the prior art is an unexpected result intuitively it had been thought and expected that a reduction in hole size would provide better results since less material can get into smaller holes therefore the greatly improved performance with the print bed of the present invention by use of large hole sizes is an unexpected and surprising result fig2 is a top view of a portion of a printbed.