In the process of making metal badges, avoiding stamping deformation requires strict control over multiple aspects such as equipment debugging, mold design, material selection, and operation techniques. The following are the specific key points and solutions:
I. Optimization of Mold Design and Processing
1. Design the mold structure reasonably
The gap between the punch and die: If the gap is too large, it can easily cause tensile deformation of the material; if it is too small, it will lead to extrusion fracture. The gap needs to be precisely calculated based on the thickness of the metal material (usually 5% to 10% of the material thickness, for example, the gap of a 0.5mm aluminum plate is approximately 0.03 to 0.05mm).
Fillet of the cutting edge: The cutting edges of the punch and die should be ground to an appropriate fillet (generally 0.1 to 0.3mm) to prevent stress concentration when the sharp edge directly cuts the material, which may cause the edge to warp or tear.
Demolding slope: Design a demolding slope of 3° to 5° in the mold cavity to facilitate the smooth demolding of the workpiece after stamping and reduce deformation caused by forced demolding.
2. Mold material and hardness
Select high-hardness and high-wear-resistant die steel (such as Cr12MoV, SKD11), and carry out quenching treatment (hardness should reach HRC58~62) to prevent the die itself from wearing or deforming during stamping, which may affect the accuracy of the badge.
Ii. Material Selection and Pretreatment
1. Suitable metal materials
Give priority to choosing materials with moderate strength and good ductility (such as aluminum alloy, brass or stainless steel with a thickness of 0.3 to 1mm). Pure copper has low hardness and is prone to deformation. Copper-zinc alloy can be used instead. Stainless steel has high hardness and requires greater punching force, which needs to be matched with the power of the equipment.
The material must meet the flatness requirements (flatness error ≤0.1mm/mm) to avoid uneven stress after stamping due to raw material bending.
2. Annealing treatment of materials
For materials with high hardness (such as stainless steel), annealing treatment (heating to 600-700℃ and then slowly cooling) is carried out before stamping to reduce hardness, improve plasticity, and decrease resistance and deformation during stamping.
Iii. Commissioning and Operation of Stamping Equipment
Pressure and speed control
Pressure matching: Calculate the required stamping force based on the material thickness and die design (formula: stamping force = Material shear strength × stamping circumference × material thickness), ensuring that the equipment pressure is sufficient and stable to avoid incomplete stamping due to insufficient pressure or material extension deformation caused by excessive pressure.
Stamping speed: Low-speed stamping (typically ≤50mm/s) is adopted to allow the material sufficient time for plastic deformation and reduce distortion caused by impact loads.
2. Install a material pressing device
Install a blank holder or blank holder ring on the die. During stamping, first press the edge of the material tightly (with a pressure of approximately 10% to 15% of the stamping force) to prevent the material from deforming due to sliding or wrinkling in the unfixed areas during the stamping process.
Iv. Process Route and Subsequent Treatment
1. Step-by-step stamping process
Complex-shaped badges can adopt “step-by-step stamping” : first, the outline is punched, and then the details (such as concave and convex textures, text) are punched to avoid deformation caused by the superposition of stress in multiple areas during one-time stamping.
For deep-drawn structures (such as three-dimensional badges), multiple drawing processes are adopted, with each drawing amount controlled at 20% to 30% of the material thickness, gradually forming.
2. Leveling treatment after stamping
After stamping is completed, the workpiece is leveled with a flat leveling machine (with uniform pressure distribution and speed ≤20mm/s), or the deformed area is gently tapped by hand with a wooden mallet (a soft rubber sheet should be placed underneath to prevent surface scratches) to eliminate internal stress.
3. Cool the mold in time
During continuous stamping, the die is prone to heat up, causing the material to soften and deform. The mold temperature can be controlled below 50℃ through the mold cooling system (such as water cooling or air cooling) to maintain the rigidity of the material.
V. Quality Inspection and Feedback
1. First item inspection
Before each batch of production, the first piece is made. The dimensional accuracy is inspected with a two-dimensional image measuring instrument (error ≤±0.1mm), and the surface flatness (warpage ≤0.2mm) and edge quality (no burrs or cracks) are checked visually or with a magnifying glass.
2. Process inspection
After each stamping of 50 to 100 pieces, random inspections should be conducted, with a focus on checking the wear of the die (such as whether the cutting edge has become blunt) and whether there are scratches on the material surface. If any deformation problems are found, the machine should be stopped immediately to adjust the die or replace the material.
Post time: May-25-2025