How It’s Made

Step One

Stock Strip Layout & Design

The first step in a stamped part’s production involves designing the progressive die or “tool.” The designer must optimize the positioning of each punch, bend and hole in the blank strip. CAD/CAM engineering is used to design the strip and determine dimensions, tolerances, feed direction, scrap minimization and more.

Knowledge-based engineering tools offer representations of design rules on the computer, allowing engineers to analyze and model the design to specifications. All part specs and necessary data are included in the design for the part to be accurately stamped.

Step Two

Tool Steel and Die Set Machining

Once the stock strip is complete and all the tool materials are ordered, the die blocks are machined using the final CAD drawing. CNC ensures a higher level of precision and repeatability for even the most complex dies. Equipment like 5-axis CNC mills and wire EDM machines can cut through hardened tool steels with extremely tight tolerances.

The video here shows the die block that ESI designed getting machined for Ford’s Anchor Bracket. ESI utilizes 5-axis CNC milling, which offers five axes of movement to machine multiple sides of the die for faster and more accurate results.

Step 3

Secondary Processing: Grinding & Heat Treating

Heat treating is applied to metal parts to enhance their strength and make them more durable for their application. Metal alloys are heated above the material’s critical transformation temperature, then cooled rapidly to improve their dimensional stability and toughness.

Grinding is used to finish parts requiring high surface quality and dimension accuracy. The abrasion generates a significant amount of heat, as seen by the sparks in the video below, so the process also requires a coolant to be applied.

Step 4

Wire EDM

Wire electrical discharge machining shapes metal materials with an electrically-charged strand of brass wire. The wire carries one side of the electrical charge and the workpiece carries the other, creating a controlled spark that results in a fine surface finish with no burrs. Wire EDM can cut the most intricate shapes, including small angles and contours. ESI’s Swiss-made wire EDM machines can achieve cutting tolerances of ±2 µm and surface quality as fine as Ra 0.1 µm, as well as taper cuts at full height up to 45 degrees.
As shown in the video here, the die is submerged entirely in deionized water to continuously cool the metal, while a high-powered flushing nozzle clears away scrap during the process.

Step 5

Die Assembly

Once all tool components are manufactured, the die is assembled to match the design. High precision is necessary to ensure the tool can stamp the parts to exact measurements.

Step 6

Stamp Parts

The next step following tool assembly can utilize a variety of techniques to manufacture the part. This particular automotive part from ESI leverages progressive die stamping, a process that features a number of stations with a unique function. As the metal strip progresses through the press, each station performs a different cut, punch or bend, adding onto the work of the previous station

Step 7

Package and Ship

Following production, the parts are packaged and shipped to the customer. Manufacturers like ESI utilize packaging equipment that automatically opens boxes and weighs and counts bulk parts to precisely fill cartons. This automated process allows for faster and more accurate packaging before delivery.