A suitable replacement can be found on eBay for much less than it can be purchased from Trotec.
Search for:
Aluminum Honeycomb Sheet / Honeycomb Grid Core - 1/2" cell, 24"x48", T=1.00"
- Extricate the old honeycomb from the frame, keeping close track of the bolts.
- Count the cells in the X and Y dimensions.
- Cut the new honeycomb using the same number of cells.
- Re-assemble frame.
- Rejoice! \o/