At the time I solved this by taping the edges of the panels down to the knife edge table, but that was really inconvenient so I came up with a solution for next time. (A knife-edge table is a row of triangles - points up - that you lay a material onto when laser cutting it.)
I designed and 3D printed some clips that would snap down and grip a section of the table, and a little tab that would keep the edge of material held down tight. It's specifically sized to work with 1/8" thick material, but they are low-profile and re-usable.
|Printing on my Raise3D N2.
|The top of the "V" has a tab to hold material down, the mouth of the "V" snaps over the table support.
This shows the knife table from the side. You can see how the clip goes on. Press it straight down, and the feet grab onto the flat bottom of the bar. You can pull the legs apart to take it off.
This shows the top side. The top little "hook" clips onto the edge of the material and keeps it pulled down.
Download the .STL file here (but be warned it is sized to work with my knife table and might not be 100% right for yours. Modeled in millimeters.)