When sourcing a used press, the most critical factor is the nominal pressure (tonnage), typically ranging from 600 to 10,000 tons, which determines the maximum tile size and density. You must verify the effective clearance between columns and the maximum stroke of the mobile beam. Additionally, inspect the hydraulic system's integrity, specifically looking for signs of wear in the main cylinder seals and the accumulator's nitrogen pressure levels. Ensure the PLC control system (e.g., Siemens or Omron) is functional and that the software version is still supported for troubleshooting.