First Article Inspection Protocols for Custom Pack Stamping Dies
First article approval for pack stamping dies requires free-state optical scanning coupled with micro-sectioned edge burr verification below 0.03 mm.
Edge Burr Height Limit
Meaning
This engineering specification defines the maximum allowable vertical protrusion of metal at the cut edge of a stamped or sheared component. It establishes a boundary for the ragged or sharp deformation that occurs as the material is separated by a punch and die. The measurement is taken from the base of the cut surface to the highest point of the burr.
Designers apply edge burr height limit to prevent mechanical interference, internal short circuits, or damage to insulating layers within a battery assembly. It stops being the primary quality check if the edge is intentionally rounded or deburred through a secondary process. The limit is essential for ensuring the safe handling and long term reliability of the electrochemical cells.
Dimensional Control
Measurement of the protrusion occurs using optical profilometers or specialized mechanical gauges that can detect microscopic height variations. Because edge burr height limit is sensitive to the clearance between the punch and the die, it provides a direct indication of the state of the tooling. A larger burr usually signifies that the tool has become dull or that the clearance has shifted due to thermal expansion.
This specific dimension is often restricted to less than ten percent of the material thickness to prevent issues during the assembly phase. The relationship between the burr height and the burnish zone is used to optimize the stamping process for different metal alloys. Proper control of this height ensures that the parts fit together perfectly without the need for manual rework.
This precision is necessary for the automated assembly of battery modules.
Safety Implication
Risk of internal damage is significantly reduced when the metal edges are kept within the defined height limits. Since edge burr height limit prevents sharp metal fragments from piercing the thin separator material, it is a primary safety metric for cell manufacturing. Excessively high burrs can also create localized points of high electrical stress that might lead to arcing or thermal runaway.
This safety requirement also extends to the people who handle the parts during the manual stages of production. Small metal flakes that break off from a high burr can contaminate the cleanroom and cause defects in the chemical coating process. By strictly enforcing these limits, the manufacturer ensures that the battery pack remains safe throughout its entire operational life.
This focus on safety is the core reason for the rigorous inspection of stamped components.
Tooling Influence
Maintaining a sharp cutting edge and a consistent clearance is the most effective way to keep the burr height under control. While edge burr height limit is a part specification, it drives the maintenance schedule for the entire stamping press. Sourcing teams evaluate the tooling capability of their suppliers by reviewing the burr measurements across thousands of cycles.
The selection of high quality tool steels and specialized coatings can extend the time between regrinds while maintaining a low burr height. It is also necessary to consider the lubrication strategy which reduces the friction and heat that contribute to burr formation. Proper tool management reduces the overall cost of production by minimizing the volume of rejected parts.
Choosing the right tooling setup ensures that the edge quality remains consistent even at high production speeds. .