TM — Trusted Machinery

Shut height (often referred to as 閉合高度 or 装模高度 in the sources) is a critical vertical dimension of a stamping press that determines the space available for installing a die.

Based on the provided sources, shut height is defined and utilized in the following ways:

1. Basic Definition

In a press machine, the shut height is the distance from the face of the slide (ram) to the top of the press bed when the slide is at its Bottom Dead Center (BDC) position.

There is often a technical distinction made between two similar terms:

• Shut Height (SH): The distance from the bottom of the slide to the top surface of the press bed (without the bolster plate installed).
• Die Height (DH): The distance from the bottom of the slide to the top surface of the bolster plate (the plate mounted on the bed) at BDC.

2. Adjustment Range

Most mechanical presses allow the vertical position of the slide to be adjusted to accommodate dies of different heights. This creates a capacity range:

• Maximum Shut Height (Hmax​): The distance when the slide is at BDC and the adjustment screw is retracted to its highest position.
• Minimum Shut Height (Hmin​): The distance when the slide is at BDC and the adjustment screw is extended to its lowest position.

3. Die Closed Height (H模​)

For the stamping tool itself, the closed height is the total vertical distance from the top surface of the upper shoe (punch holder) to the bottom surface of the lower shoe (die shoe) when the die is in its fully shut position at the bottom of the stroke.

4. Selection and Compatibility Guidelines

When selecting a press for a specific die, the die’s closed height must fit within the press’s adjustment range.

• Compatibility Formula: To ensure there is enough room for adjustment and to prevent the press from “sticking” at BDC, the die height (H模​) should ideally follow this relationship: Hmax​−5 mm≥H模​≥Hmin​+10 mm.
• Adjustments: If a die is too short (shorter than the minimum shut height), a bolster plate or spacer blocks must be added to raise the die into a reachable position.
• Design Limitations: If a die is built taller than the press’s maximum shut height, it will be impossible to install or operate without modifying the tool or using a larger press.

5. Technical Importance

Properly set shut height is essential for maintaining precision, protecting the machine from overload, and ensuring the safety of the die components. Operating a press with an incorrect shut height can lead to “sticking” the machine at BDC or causing structural damage to the frame and crankshaft.