The basic knowledge and features of Stamping Parts
2025-05-28
Stamping parts are metal components formed by feeding sheet or coil stock into a stamping press where dies shape, cut, or form the metal into the desired geometry. This high-speed, high-precision method is widely used in automotive, appliance, electronics, and many other industries. Below is a breakdown of the essential knowledge and key features involved in stamping parts:
1. Basic Processes in Stamping
Blanking
Cuts a flat outline (“blank”) from the sheet.
Often the first operation in a progressive die sequence.
Piercing (Punching)
Removes internal holes or cut-outs.
Can produce rounds, slots, or complex shapes.
Bending and Forming
Applies force to plastically deform the blank along a straight axis or into a three-dimensional shape.
Includes 90° bends, hems, channels, and louvers.
Drawing and Deep Drawing
Converts a blank into a cup or box shape by pulling material into a die cavity.
Deep drawing produces deeper profiles with multiple draw stations to avoid tearing.
Coining
High-pressure forming that achieves very tight tolerances and fine surface detail (e.g., gears or medallions).
Compound Operations
Combine punching and blanking in a single stroke of the press.
2. Types of Stamping Dies
Progressive Dies
Multiple stations on a single die strip perform sequential operations on a coil.
Ideal for high-volume production; scrap is handled in coil form.
Transfer Dies
A robot or mechanical fingers transfer parts from station to station.
Suited for very large or complex parts where progressive stripping isn’t feasible.
Single-Hit Dies
Perform one operation (e.g., blanking) per press stroke.
Simpler tooling but lower throughput compared to progressive.
Compound Dies
Combine two operations—typically blanking and piercing—in one station.
3. Press Types
Mechanical Presses
Flywheel-driven; very fast strokes, excellent for piercing and blanking.
Stroke speed often up to 500–1,500 SPM (strokes per minute).
Hydraulic Presses
Slower but offer full-stroke tonnage and precise speed control—good for deep drawing.
Servo-Electric Presses
Precise slide motion control, energy-efficient, and quiet; growing in popularity for specialized forming.
4. Material Considerations
Common Materials
Cold-rolled steel (CRS), stainless steel, aluminum alloys, copper, brass.
Material gauge typically ranges from 0.2 mm up to ~6 mm, depending on part geometry and press capacity.
Key Material Properties
Yield Strength: Determines the force needed to form or draw.
Ductility: Ability to stretch without cracking (critical for deep drawing).
Springback: Elastic recovery after forming—compensated by overbending.
5. Typical Part Features
Flanges: Straight, bent edges for stiffness or mounting surfaces.
Hems: Folded edges to eliminate sharpness and add rigidity.
Lances: Slit and bent tabs for self-locking or venting.
Louvers: Raised vents for airflow or heat dissipation.
Beads: Raised or depressed ridges to increase stiffness.
Embosses: Raised or recessed marking areas (logos, instructions).
Stiffening Ribs: Narrow drawn sections to add rigidity without adding weight.
Drawn Cups: Cylindrical or tapered cups from deep drawing.
6. Dimensional Control & Tolerances
Typical Tolerances
Flat dimensions: ± 0.1 mm (depending on size and material).
Hole locations: ± 0.05 mm in high-precision dies.
Factors Affecting Tolerance
Die wear, press stability, material variability, part complexity.
Quality Controls
In-die sensors, first-article inspection, SPC (Statistical Process Control).
7. Secondary Operations
Stamped parts often require additional steps to meet final requirements:
Deburring (vibratory, tumble, or brushing)
Heat Treatment (stress relief, hardening)
Surface Finishing (plating, painting, powder coating)
Assembly (welding, riveting, clinching)
Inspection (coordinate measuring machines, optical checks)
8. Design for Manufacturability (DFM) Tips
Uniform Wall Thickness: Minimizes drawing issues and springback.
Smooth Corners: Larger radii reduce cracking, especially in deep draws.
Balanced Flanges: Distribute forces evenly to prevent warping.
Avoid Sharp Transitions: Prevent stress concentrations.
Material Selection: Choose alloys with proven formability for the intended depth.
By understanding these fundamentals—process types, die styles, press options, material behavior, key features, tolerance practices, and secondary operations—you can design and manufacture stamped parts that meet performance, cost, and quality targets in high-volume production.
