Stamping Die Fundamentals: Punching, Cutting, and Fixed Matrix Components

Stamping Die Fundamentals: Punching and Cutting Operations

Punching and Cutting: Punching is a consistent operation performed on a sheet metal plate to create a hole with a proper shape using a stamp (punch and die). Cutting operation separates a piece of sheet metal in a specific way. Both operations are typically designated by the names of the punch and dies used in the tooling.

The Stamping Die Cutting Cycle

The cutting cycle involves two main phases:

1. Plastic Deformation: The material is pushed by the punch, undergoing plastic deformation.
2. Shear Cut: The actual cut occurs when tensions in the peripheral zone are so strong that they exceed the shear strength of the sheet metal.

Essential Components of a Fixed Matrix Die Set

Below are the key components of a fixed matrix die set:

1. 1. Die Shoe (Base Plate)

   Its purpose is to support the tools and provide support on the press table.

2. 2. Die Plate (Matrix Plate)

   One of the active elements of the tooling, it remains static but is directly responsible for the cutting of the sheet. The perimeter hole is cut-through and features a taper or angle of departure so that the cut pieces or excess material can drop through.

3. 3. Stock Guide (Guide Bed)

   It consists of two rules (rails) whose thickness is slightly higher than the matrix strip (stock material).

4. 4. Stripper Guide Plate (Extractor)

   This plate has the mission of keeping the punches aligned with the cutting edge of the matrix, while also being in charge of removing (stripping) the sheet metal from the punches.

5. 5. Punch Holder Plate

   This plate houses the punches so that their alternating rectilinear movement of work ensures their solidarity with the plate.

6. 6. Backing Plate (Dolly)

   This plate is located on the punch holder plate to prevent stressed hallmarks or damage to the upper base of the punches, due to the shock efforts that occur during sheet metal stamping.

7. 7. Upper Die Shoe (Base-Up)

   This board serves as the support for the mobile part of the tooling. The punch holder plate and the nose are fastened to it. The stem (shank) used to clamp the die to the press is threaded into the upper base plate. Matrices often do not contain a stem and are flanged to the press on this board.

8. 8. Shank (Rod Subject)

   It is a generally cylindrical piece screwed to the upper base, serving to set the moving part of the tooling to the head of the press. The head carriage body is often egg-shaped and is fitted with screws and a flange. The moving part is securely fastened to the press ram (shopping table).

9. 9. Dowel Pins (Positioning Pins)

   These are cylindrical bodies whose mission is to accurately position the tooling plates relative to each other or any other component whose assembly requires precise positioning over the entire useful area.

10. 10. Punch

    One of the most important components of a fixture, its section corresponds to the shape to be cut. The punch is locked in the punch holder plate and is guided by the stripper guide plate. During the downward movement of the moving part, the punch enters the die plate, cutting the sheet metal interposed between the two.

11. 11. Fasteners (Screws)

    Their mission is to hold the various components of the matrix together.