Common Stamping Terms and Definitions in Sheet Metal Manufacturing

Stamping production involves a wide range of technical terms related to raw materials, mold structure, feeding systems, forming defects, and press operation. Understanding these terms is important for improving communication between engineers, toolmakers, and production teams.

Below are some of the most common stamping terms used in sheet metal manufacturing and die design.

Basic Stamping Terms

• Stamping Part: A general term for a workpiece after one or more stamping operations.
• Blank: Raw material used for a single stamping operation.
• Coil: Rolled raw material used for continuous stamping production.
• Sheet: Flat sheet material used for multiple stamping operations.
• Strip: Long strip-shaped raw material used in progressive die stamping.
• Step: The feed distance of the raw material for each stamping cycle.
• Feeding: The process of moving raw material into the die for stamping.

Die Structure and Press Terms

• Closing Height: The distance between the upper and lower mold bases when the die is fully closed.
• Stroke: The travel distance of the press slider between its upper and lower positions.
• Upper Dead Point: The highest position of the press slider.
• Lower Dead Point: The lowest position of the press slider.
• Gap: The clearance between the punch and die.
• Single-Sided Gap: Clearance measured from the centerline to one side.
• Double-Sided Gap: The total clearance between both sides of the punch and die.

Material Feeding Devices

• Clamping Feeding Device: A feeding system that uses clamping and reciprocating motion to feed raw material into the die.
• Roller Feeding Device: A feeding system that uses rollers to move material forward.
• Hook Feeding Device: A feeding system that uses a hook mechanism to feed material into the die.
• Hopper: A container used to automatically orient and feed shaped punch parts.
• Chute: A channel that guides workpieces into or out of the die.
• Outlet Device: A device used to eject stamped parts from the mold.

Forming and Drawing Terms

• Drawing Ratio: The ratio used to evaluate the depth of a drawing process.
• Drawing Coefficient: The ratio of the current drawing diameter to the previous drawing diameter.
• Minimum Bend Radius: The smallest bend radius that can be formed without cracking.
• Bending Radius: The internal radius of a bent stamping part.
• Neutral Layer: The layer in the bent material with zero strain during bending.
• Neutral Layer Coefficient: A coefficient used to determine the position of the neutral layer.
• Expanded View: A flat pattern drawing of the formed part.
• Expanded Size: The flat size of the material before forming.

Common Stamping Defects

• Rebound: The difference between the formed part size and the mold size after the part is released from the mold.
• Positive Rebound: Springback where the bend radius becomes larger after release.
• Negative Rebound: Springback where the bend radius becomes smaller after release.
• Pull Marks: Surface scratches caused by friction between the material and the mold surface.
• Arching: A condition where the surface of the stamped part bulges upward.
• Wrinkling: Wavy wrinkles formed in the flange area of a deep-drawn part.
• Stick Mold: A condition where material adheres to the mold surface.
• Chipping: Peeling or breakage at the punch or die edge.
• Burr: Sharp protruding material remaining on the edge of a stamped part.
• Burr Surface: The surface of the part where burrs appear after punching or blanking.
• Collapse Angle: The angled portion formed near the edge of a blanked section.
• Collapsed Surface: The surface opposite the burr side of a blanked part.
• Lug: Ear-shaped protrusions formed on the upper edge of a deep-drawn part.

Other Common Terms

• Glossy Section: The smooth, bright section of a cut edge.
• Matte Section: The rough torn section of a cut edge.
• Edge Distance: The minimum distance between adjacent parts or between a part and the strip edge in the layout.
• Layout: The arrangement of parts on the strip during die design.
• Life: The number of stamping cycles a die can perform before regrinding or replacement.
• Test Run: Trial stamping after mold assembly to verify mold performance and part quality.

Understanding these stamping terms can help improve die design, tooling communication, process control, and production efficiency in sheet metal manufacturing.