The Significance of Open Height and Stroke in a Press Brake

The success of many companies projects are dependent on the skills of a press brake operator, which means it is important to understand the significance of open height and stroke when working with tooling.

Open Height

Open height is defined as the distance between the ram and the dies. Open height is rated in terms of both inches and millimetres. It is important to know the tooling open height in order to properly select and order a punch die. Calculations for open height: To calculate the open height of a press brake, the following formula is to be used: Open height = (max. part thickness + 1/2″) + 3/32″
Open height = (max. part thickness + 1/2″) +

Stroke Length

The stroke length of a press machine is selected depending on the details of the job at hand. The stroke length can be anywhere from .010″ to .065″, or longer. Shorter stroke lengths will accommodate smaller parts. Longer stroke lengths will accommodate longer parts. A longer stroke length also affects the open height.

Determining Stroke

The stroke is the amount of travel that occurs from a completely open machine to a completely closed machine. To find the stroke, you simply subtract the closed height from the open height.

Referencing Example 1:

The stroke is 3 3/32″ (20.00″-19.5937). Hand Brake vs Pedal Brake
The stroke length differs between the different types of hand brakes and pedal brakes. Hand brakes have shorter stroke lengths than pedal brakes due to the fact that the dies are mounted directly to the press ram. Pedal brakes have larger stroke lengths because the dies are attached to an axle, allowing them to move farther away from the machine.

With Different Stroke Lengths, if you choose not to load the press brake properly, the punching distance comes into play. If the press brake is not properly loaded, you could end up with damaged tooling and scrapped parts. Prior to loading the press brake, you should determine the proper punching distance. The punching distance is the distance away from the die opening that the part should be punched. The punching distance is affected by the selected stroke length.

Conclusion:

Knowledge of open height and stroke is important when contacting a reputable tooling company for tooling quotes.