Impact of Process Variables on Part Quality in Progressive Stamping.

Area of Science:

• Manufacturing Engineering
• Materials Science
• Mechanical Engineering

Background:

• Progressive stamping involves multiple coupled operations (blanking, piercing, bending, drawing) on a single die set.
• Maintaining part quality and dimensional precision is challenging at high production rates due to intricate processing conditions.

Purpose of the Study:

• To investigate the influence of die bottom dead center (BDC) depth, punch-die clearance, tool wear, and lubrication on stamped part precision and bending angles.
• To identify the key process parameters affecting quality characteristics in progressive die stamping.

Main Methods:

• Utilized a thin-sheet steel progressive die with a factorial experimental design.
• Measured quality characteristics using a Coordinate Measuring Machine (CMM).
• Analyzed data using Pareto effect plots and the MINITAB platform; employed Scanning Electron Microscopy (SEM) for material analysis.

Main Results:

• Bottom dead center (BDC) depth was the most significant factor for part bending angles, followed by clearance and then tool condition.
• Lubrication showed interaction effects but was less significant as a main factor compared to BDC, clearance, and tool condition.
• SEM analysis revealed that worn tools and poor lubrication cause material defects like grain boundary separation, while sharp tooling and adequate lubrication promote homogeneous grain structures.

Conclusions:

• Achieving full control of part quality in progressive stamping necessitates consideration of BDC depth, component clearances, punch condition, and lubrication levels.
• Process knowledge of parameter relationships in multi-stage stamping can inform adaptive monitoring systems for stabilizing geometry and minimizing production variation.