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Selecting the right press machine for a progressive die is critical because these dies typically involve high-speed automation and complex, multi-station synchronized operations. According to the sources, the selection process should focus on tonnage, speed, rigidity, and the ability to handle eccentric loads.

1. Tonnage and Pressure Requirements

• Total Process Force: The press’s nominal capacity must exceed the sum of all forces in the die stations, including blanking, bending, drawing, and stripping forces.
• Safety Factor: It is generally advised to select a press with 1.2 to 1.3 times the calculated total force to protect the machine and die.
• Tonnage Curve Awareness: For mechanical presses, the full rated tonnage is only available near the Bottom Dead Center (BDC). If the progressive die includes deep drawing or thick-plate operations that begin higher in the stroke, the available tonnage at that point will be significantly lower, necessitating a higher-tonnage press or a hydraulic press.

2. Operating Speed (SPM) and Productivity

• High-Speed Requirements: Progressive dies are primarily used for mass production. High-speed automatic presses often operate at 600 SPM or higher, with some specialized models reaching 1,000–2,000 SPM.
• Automation Integration: The press must be compatible with an automated line, including uncoilers (decoilers), levelers, and high-precision feeders. It should have a control system (such as rotary cams) to synchronize these auxiliary devices with the ram’s movement.

3. Machine Structure and Rigidity

• Frame Type: Straight-side (closed-box) presses are preferred for progressive dies because they offer much higher rigidity than C-frame (gap-frame) presses. This rigidity prevents the “angular opening” deflection that can cause misalignment and premature tool wear in complex dies.
• Handling Eccentric Loads: Because progressive dies perform different tasks at different stations along the bed, they often generate off-center (eccentric) loads. To handle this, presses with two-point or four-point suspension (double/four-point crank) are ideal, as they distribute the force more evenly across the ram.

4. Stroke Length and Shut Height

• Stroke Length: The stroke must be long enough to allow for material feeding and part clearance. For progressive dies involving drawing, the stroke should generally be about 3 times the part’s depth to ensure the strip can be lifted and fed forward without interference.
• Shut Height Compatibility: The die’s closed height must fall within the press’s shut height adjustment range. If the die is too short, a bolster plate or spacer may be needed to reach the required height.

5. Bolster Area and Die Dimensions

• Bed Size: Progressive dies are often long due to the number of stations. The bolster area (bed size) must be large enough to support the entire die base.
• Scrap Removal: Ensure the press bed has sufficient openings or chutes to allow scrap (slugs) from multiple stations to fall through cleanly.

Summary Selection Checklist

Feature	Progressive Die Requirement
Frame Type	Straight-side for rigidity and precision.
Tonnage	1.2x – 1.3x total force; check BDC curve.
Suspension	Double-crank or four-point to manage eccentric loads.
Speed	High-speed (600+ SPM) for mass production.
Peripherals	Must interface with automatic feeders and uncoilers.

For high-precision tasks or materials prone to springback, a servo press may be the best choice, as it allows for programmable speed and pressure profiles throughout the stroke.