Abstract: A supporting bed for supporting a stack of sheet material in a cutting machine of the type retaining the material by means of a vacuum applied from below the supporting bed is manufactured from a sheet of reticulated polyurethane foam material which has been compressed under heat and pressure so as to be permanently reduced to approximately 10-35% of its initial thickness. The degree of compression, the temperature and compression time, and the porosity of the reticulated polyurethane foam starting material are selected to provide particular airflow and firmness characteristics for the finished supporting bed. In a preferred embodiment of the invention, the starting material is a reticulated grafted polyether foam having a porosity of 30 pores per inch and a sheet thickness of 5 inches. The sheet of material is compressed to a thickness of one inch and retained under pressure for 10 minutes at a temperature of about 400.degree. F.

Abstract: A supporting bed for supporting a stack of sheet material in a cutting machine of the type retaining the material by means of a vacuum applied from below the supporting bed is manufactured from a sheet of reticulated polyurethane foam material which has been compressed under heat and pressure so as to be permanently reduced to approximtely 10-35% of its initial thickness. The degree of compression, the temperature and compression time, and the porosity of the reticulated polyurethane foam starting material are selected to provide particular airflow and firmness characteristics for the finished supporting bed. In a preferred embodiment of the invention, the starting material is a reticulated grafted polyether foam having a porosity of 30 pores per inch and a sheet thickness of 5 inches. The sheet of material is compressed to a thickness of one inch and retained under pressure for 10 minutes at a temperature of about 400.degree. F.