A hydraulic press cylinder generates axial force, but the workpiece and tool may apply an off-centre reaction. The frame and ram guides should control that geometry. If the rod is forced to act as the machine guide, seals and bearings may wear quickly even when nominal tonnage is within the cylinder rating.
Trace force from oil pressure to the foundation
Start at the piston area and operating pressure, then follow the load through the rod end, ram, tooling, platen and frame. Deflection and eccentric loading change the reaction at the mounting and guide surfaces. Bosch Rexroth’s cylinder configuration guidance includes force, stroke, installation position and buckling length as selection inputs. Press-specific safety and control functions require their own machine review.
Engineering checks
- Record maximum force and any off-centre loading case.
- Check parallelism and guide clearances through the stroke.
- Review rod buckling at the longest compression length.
- Confirm mount and platen stiffness at peak load.
- Define approach, working and return speeds separately.
Common mistake to avoid
Increasing cylinder bore to fix uneven tooling contact can increase force without correcting alignment. The resulting higher load may make frame or guide problems worse.
Data to send with an inquiry
- Press general arrangement and ram guide drawing.
- Force versus stroke and tooling envelope.
- Duty cycle, pressure peaks and speed phases.
- Inspection and test requirements for the final assembly.
Approve the cylinder only after reviewing the complete press load path and its control sequence. For related selection guidance, see our custom press cylinder product page.
Field note
A press acceptance test should record ram position and platen parallelism at defined loads, not only maximum gauge pressure. Measurements at several points in the stroke help distinguish tool setup from machine deflection. The allowable values must come from the press design.
Technical references: Bosch Rexroth hydraulic cylinder selection; Bosch Rexroth machine safety overview. Cover: original conceptual schematic, not a product photograph.