Fine Blanking vs Conventional Blanking: Process Differences, Tooling and Economics

When your customer drawing calls for a flat, burr-free, smooth-shear part with ±0.02 mm positional tolerances, conventional blanking with its inherent fracture zone cannot deliver. Fine blanking was developed for exactly this situation — producing near-net-shape functional components in a single press stroke without secondary milling, grinding, or reaming operations.

The two processes look identical on the surface: both use a punch forcing material through a die. The engineering underneath is fundamentally different. Conventional blanking is a controlled fracture process — the punch initiates a crack, and the material separates when fracture zones from both sides meet. Fine blanking suppresses fracture entirely. Material flows in full plastic shear from top to bottom of the sheet, producing a cut edge that is smooth, perpendicular, and dimensionally consistent over hundreds of thousands of strokes.

This distinction has cascading consequences for tooling design, press selection, material requirements, and part economics. Choosing the wrong process — applying fine blanking where conventional blanking suffices, or using conventional tooling where fine blanking is required — is a costly mistake that shows up in scrap rates, secondary operation costs, or outright customer rejects.

This article covers the complete engineering comparison: process mechanics, V-ring geometry, force calculations, die design differences, material selection, tooling costs, and the decision framework production engineers use to select between these two processes. Real worked calculations are included throughout.

What Separates Fine Blanking from Conventional Blanking

The Fracture Zone Problem

In conventional blanking, the cut edge consists of four distinct zones: rollover (plastic deformation at the punch entry), burnish zone (clean shear), fracture zone (rough crack propagation), and burr. Typical proportions for 3 mm carbon steel at 10% clearance per side:

  • Rollover: ~0.3 mm
  • Burnish zone: ~1.2 mm (40% of thickness)
  • Fracture zone: ~1.3 mm (43% of thickness)
  • Burr: ~0.2 mm

The fracture zone creates functional problems when the cut edge is a precision surface — gear tooth profiles, ratchet pawl faces, cam contours, or hydraulic spool lands. These surfaces require secondary machining, which adds cost, cycle time, and fixture investment.

Fine blanking eliminates the fracture zone by maintaining hydrostatic compressive stress around the cutting zone throughout the entire stroke. Three simultaneous actions achieve this:

1. V-Ring (Impingement Ring) on the Blank Holder — A serrated ring pressed into the sheet surface surrounding the blank contour before cutting begins. The V-ring locks material flow laterally and generates hydrostatic compression in the shear zone. Without it, material flows outward and fracture initiates from both cut faces before shear is complete.

2. Counter Punch (Opposed Punch) — Presses from below against the blank face during cutting. It provides back pressure that prevents sheet bulging, maintains flatness, and controls rollover on the punch entry face. Counter punch force is applied before metal engagement and maintained throughout the stroke.

3. Ultra-Tight Die Clearance — Fine blanking uses 0.5–1.0% of material thickness as total clearance (both sides combined). Conventional blanking uses 5–15% per side. This narrow clearance forces the material into full plastic shear rather than crack initiation.

The result: a burnish zone that extends 100% through the material thickness, surface roughness Ra 0.4–1.6 μm, flatness within 0.01 mm per 100 mm, and part-to-part repeatability of ±0.01–0.03 mm without secondary operations.

Engineering Calculations: Fine Blanking Forces and V-Ring Geometry

Understanding force requirements separates engineers who can specify equipment from those who overload presses and damage dies.

Shear Strength of Common Materials

All blanking force calculations depend on shear strength τ_s:

τ_s = K × UTS

Where:

  • τ_s = shear strength [MPa]
  • UTS = ultimate tensile strength [MPa]
  • K = material factor

Fine blanking uses a higher K factor than conventional blanking because full plastic shear (no fracture relief) mobilizes more of the material’s shear resistance.

MaterialUTS [MPa]K (conventional)K (fine blanking)τ_s fine blanking [MPa]
DC04 mild steel270–3500.600.70189–245
S235 structural360–5100.620.72259–367
C45 medium carbon600–8000.650.75450–600
304 stainless515–7200.650.80412–576
Brass CuZn30290–4200.650.70203–294
Aluminum 5052-H32228–2830.600.65148–184

Main Blanking Force

F_blank = L × t × τ_s

Where:

  • F_blank = blanking force [N]
  • L = perimeter of cut contour [mm]
  • t = material thickness [mm]
  • τ_s = shear strength [N/mm²]

Blank Holder (V-Ring) Force

The blank holder requires substantially more force than conventional due to V-ring indentation and hydrostatic pressure generation:

F_BH = C_V × F_blank

Where C_V = 2.0–4.0. Use 2.5–3.0 for standard circular or simple contour blanks. Use 3.0–4.0 for complex gear or cam tooth profiles with many re-entrant angles.

Counter Punch Force

F_CP = (0.20–0.30) × F_blank

Use the upper end for thick material (t > 6 mm) or materials prone to dish formation.

Total Fine Blanking Press Force

F_total = F_blank + F_BH + F_CP

This total is the force rating required from the triple-action fine blanking press. Selection margin: F_press_rated ≥ 1.25 × F_total.

Worked Example: Automotive Sprocket Blank

Part: Sprocket blank with 12 teeth, net perimeter of cut = 340 mm (measured along tooth profile) Material: C45 medium carbon steel, t = 5 mm, UTS = 700 MPa Operation: Fine blanking, full burnish required on tooth faces

Step 1 — Shear strength:

τ_s = 0.75 × 700 = 525 N/mm²

Step 2 — Main blanking force:

F_blank = 340 × 5 × 525 = 892,500 N = 892.5 kN ≈ 91 metric tons

Step 3 — Blank holder force (complex tooth contour → C_V = 3.0):

F_BH = 3.0 × 892.5 = 2,677.5 kN ≈ 273 metric tons

Step 4 — Counter punch force:

F_CP = 0.25 × 892.5 = 223.1 kN ≈ 23 metric tons

Step 5 — Total press force:

F_total = 892.5 + 2,677.5 + 223.1 = 3,793 kN ≈ 387 metric tons

A fine blanking press rated at 500 tons is the minimum selection, providing approximately 29% safety margin. A conventional blanking press for the same contour blank would require only ~100 tons (blanking force only, no V-ring or counter punch). The total press force ratio is approximately 4.2:1 — fine blanking vs conventional blanking for the same part.

V-Ring Geometry Specification

The V-ring is the most critical fine blanking tooling element. Incorrect V-ring dimensions are the primary cause of fracture initiation and shear zone collapse.

V-ring height (h):

h = (0.10 to 0.15) × t     for t ≤ 4 mm
h = (0.15 to 0.20) × t     for t > 4 mm

V-ring position from cut edge (a):

a = (0.8 to 1.5) × t

Use the smaller value for soft materials; larger value for harder alloys.

V-ring base width (w):

w = (2.5 to 3.0) × h

V-ring flank angle: 45° per side (90° included) — do not radius the tip.

For the C45 sprocket example (t = 5 mm):

  • h = 0.17 × 5 = 0.85 mm → specify 0.9 mm
  • a = 1.0 × 5 = 5.0 mm from the nearest cut edge
  • w = 2.8 × 0.9 = 2.5 mm base width
  • Flank angle: 45° each side

Die Clearance Specification

Fine blanking clearance is specified as total gap (punch diameter relative to die diameter):

c_fine = (0.005 to 0.010) × t     [total clearance, both sides]

For t = 5 mm: c_fine = 0.025–0.050 mm total → 0.013–0.025 mm per side.

Conventional blanking clearance per side:

c_conv = (0.05 to 0.12) × t     [per side, depending on material]

For t = 5 mm, carbon steel: c_conv = 0.25–0.60 mm per side.

The difference is one order of magnitude. Fine blanking punches and dies require surface finish Ra 0.1–0.2 μm on cutting faces and dimensional tolerances of ±0.003–0.005 mm, compared to ±0.01–0.02 mm acceptable for conventional dies.

Decision Framework: Selecting the Right Process

Use this structured six-step evaluation before committing tooling investment.

Step 1 — Assess Edge Quality Requirements

Identify whether the cut edge is a functional surface (gear tooth face, pawl engagement surface, valve land, bearing seat) or a non-functional edge (structural bracket, cover panel, shim). If functional — fine blanking is the primary candidate. If non-functional — conventional blanking is the baseline; upgrade only if secondary machining cost justifies it.

Threshold: parts requiring burnish ratio > 80% of thickness cannot be reliably achieved in conventional blanking without subsequent machining.

Step 2 — Evaluate Dimensional Tolerances

Dimensional Tolerance ClassTypical IT GradeRequired Process
±0.3–0.5 mmIT11–IT12Conventional blanking
±0.08–0.20 mmIT9–IT10Conventional + secondary
±0.03–0.08 mmIT8Conventional + precision secondary
±0.01–0.03 mmIT6–IT7Fine blanking
±0.005–0.015 mmIT5–IT6Fine blanking + light coining

Step 3 — Check Flatness Specification

Fine blanking holds flatness to 0.01–0.03 mm per 100 mm due to counter punch restraint throughout the stroke. Conventional blanking typically produces 0.3–1.5 mm dish or bow from unrestrained elastic springback.

If the drawing specifies flatness ≤ 0.10 mm over 100 mm, conventional blanking will not comply without secondary leveling or coining.

Step 4 — Evaluate Annual Volume and Break-Even

Fine blanking tooling costs 3–5× more than conventional dies due to:

  • Precision-ground cutting edges (±0.003 mm vs ±0.015 mm)
  • V-ring machining on blank holder
  • Hardened counter punch insert
  • Tighter assembly tolerances throughout

Break-even calculation:

V_break-even = (C_fine_die - C_conv_die) / (C_secondary_per_part)

Where C_secondary_per_part = cost of all secondary machining operations replaced by fine blanking.

Typical range: Fine blanking becomes economically favorable above 50,000–150,000 parts/year when replacing 2+ secondary machining operations. Below 20,000 parts/year, secondary machining on conventional blanks is almost always cheaper.

Step 5 — Verify Material Suitability

Fine blanking works with materials that have:

  • Uniform, fine-grained microstructure (ASTM grain size 7 or finer)
  • Elongation A50 ≥ 8%
  • Hardness ≤ 250 HB (for carbon and alloy steels)
  • Spheroidize annealing for carbon steels with C > 0.35%

Problem materials for fine blanking:

  • Cast iron (insufficient ductility — immediate fracture)
  • Air-hardening tool steels in hardened condition
  • Sheet thinner than 0.5 mm (V-ring cannot develop sufficient force)
  • Sheet thicker than 13 mm (requires specialized presses, severe tooling wear)

Step 6 — Count Secondary Operations Eliminated

List every secondary operation that fine blanking replaces: gear hobbing, broaching, reaming, edge milling, grinding, deburring, leveling, flatness checking. Each eliminated operation saves: direct machining cost + fixture amortization + work-in-process floor space + inspection cost.

If fine blanking eliminates 3 or more operations, the economics favor it at moderate volumes (50,000+ parts/year). Document this analysis before tooling approval.

Fine Blanking vs Conventional Blanking: Side-by-Side Comparison

ParameterConventional BlankingFine Blanking
Cut edge quality40–60% burnish, fracture zone, Ra 6.3–25 μm95–100% burnish, no fracture, Ra 0.4–1.6 μm
Dimensional tolerance±0.05–0.30 mm±0.01–0.05 mm
Flatness0.3–1.5 mm per 100 mm0.01–0.03 mm per 100 mm
Die clearance (per side)5–12% of thickness0.25–0.5% of thickness
Press type requiredSingle or double actionDedicated triple-action fine blanking press
Tooling costBaseline (1×)3–5× conventional
Tooling life300,000–1,000,000 strokes100,000–400,000 strokes
Thickness capability0.1–25+ mm0.5–13 mm practical
Secondary ops neededOften required for functional edgesUsually none — near-net-shape
Material requirementsStandard commercial specSpheroidize-annealed, ±1% thickness tolerance
Press force vs blank force1× blanking force3.5–4.5× blanking force
Setup complexityLow to mediumHigh — V-ring, counter punch, closure force all critical
Typical production speed60–400 SPM20–80 SPM
Primary applicationsBrackets, panels, gaskets, structural partsGears, sprockets, cams, pawls, safety components
Burr height0.05–0.3 mm≤ 0.05 mm inherent
Break-even volumeAny volumeTypically > 50,000 parts/year

Common Mistakes and Failure Modes

1. Incorrect V-Ring Height

The most frequent fine blanking scrap cause. V-ring height too low: the ring fails to lock material flow, fracture initiates before full shear, and the edge shows a partial tear zone starting from mid-thickness. V-ring height too high: the ring perforates surrounding material before blanking completes, tearing the scrap web or leaving embedded ring impressions on functional part surfaces.

Diagnostic: Inspect V-ring impression on the scrap skeleton. Correct impression depth is 0.7–0.9 × h, with no cracking at the base of the impression. If the web tears at the ring, reduce h. If the impression is shallow and part shows fracture, increase h.

2. Counter Punch Pressure Set Too Low

When counter punch force falls below 15% of blanking force, the punch-face side of the blank dishes under load. Parts fail flatness requirements, and rollover depth increases measurably. This failure mode is frequently misattributed to material variation.

Diagnostic: Check part flatness immediately after press setup. Flatness deviation beyond 0.05 mm on a 100 mm part with t > 3 mm points to counter punch pressure deficiency, not material.

3. Running Fine Blanking Dies in Conventional Presses

Some shops attempt fine blanking in hydraulic presses with tooling modifications. The critical requirement is simultaneous triple action — blank holder must be fully closed under V-ring force before the punch begins to descend, and counter punch must be at pressure before metal engagement. In sequential-action presses, fracture initiates before V-ring develops sufficient hydrostatic pressure. Press modification does not replicate the control logic of a purpose-built fine blanking press. The result is partial burnish (50–70%) with intermittent fracture.

4. Using Material Without Spheroidize Annealing

For carbon steels with C > 0.35% (C45, C55, 42CrMo4), pearlitic microstructure creates hard carbide plates that act as crack initiators. Fine blanking in pearlitic condition produces a rough, torn edge with visible carbide pull-out. Specify spheroidize annealing (750–800°C, slow cool) on all order documentation. Verify microstructure on incoming inspection for high-volume production.

5. Incorrect Lubricant Viscosity

Fine blanking clearances (0.013–0.025 mm per side) are of the same order as lubricant film thickness. Using conventional stamping oil (ISO VG 100 or higher) in fine blanking dies causes hydraulic pressure buildup in the narrow die gap, deflecting the punch laterally and producing taper in the cut edge — visible as a “wedge” shape across the burnish zone cross-section. Fine blanking requires low-viscosity (ISO VG 15–32), chlorine-free EP lubricants that can flow freely through sub-0.05 mm gaps.

6. Tolerancing the Die Like a Conventional Die

Toolroom machinists unfamiliar with fine blanking will grind cutting edges to conventional tolerances (±0.015 mm) and wonder why burnish ratio is 60% instead of 95%. Fine blanking punch and die diameters must be ground to ±0.003–0.005 mm. Cutting face surface finish must be Ra ≤ 0.2 μm. Specify this explicitly on die component drawings, and require grinding reports for all critical cutting dimensions.

7. Ignoring Snap-Through (Reverse Tonnage) Loads

At the moment blanking completes, elastic energy stored in the press and tooling releases suddenly as reverse tonnage. In fine blanking, the blanking force is 3–4× higher than conventional (same perimeter), which means reverse tonnage is proportionally greater. Reverse tonnage can reach 20–30% of blanking force, creating tensile stress in crankshaft bearings and die components. Specify staggered punch heights or angular shear where possible to reduce snap-through, and verify that the fine blanking press is rated for the reverse load.

Industry Applications: Where Fine Blanking Wins

Automotive Powertrain

The highest-volume fine blanking application globally. Transmission components — multi-disc clutch plates, reaction plates, parking pawls, planetary gear carriers, shift forks — require 100% burnish edges for torque transmission and precise pack clearances. A 6-speed automatic transmission contains 30–60 fine blanked components. Fine blanking a C35 steel shift fork (t = 8 mm) produces the functional fork face at Ra 0.8 μm and flatness 0.02 mm — zero secondary operations on the engagement surface. Compared to milling from solid billet, fine blanking saves 40–60% total part cost at volumes above 200,000 parts/year.

Hydraulic and Pneumatic Components

Hydraulic valve spacer discs, orifice plates, and flow metering discs require tight thickness control and smooth bore surfaces. Fine blanked orifice discs in C45 steel at t = 3 mm achieve internal bore diameter accuracy of ±0.015 mm, eliminating reaming. The smooth burnished bore also reduces flow turbulence compared to conventionally blanked holes.

Power Tools and Hand Tools

Ratchet pawls, socket drive dogs, saw blade tangs, and chuck mechanism components are produced by fine blanking in large quantities. Pawl engagement geometry demands 100% burnish on the engagement face — a conventionally blanked pawl with 40% fracture zone at the engagement face will wear rapidly and generate noise under cyclic load.

Medical Devices and Surgical Instruments

Surgical instrument components — forcep jaws, scissors blades, clamp mechanisms, staple cartridge components — require burr-free edges (burr ≤ 0.05 mm) and dimensional repeatability across production runs. Fine blanking in 304 or 17-4 PH stainless steel delivers these requirements, with the additional benefit that the work-hardened cut edge resists micro-fracture during sterilization cycling.

Electronics and Connectors

High-precision lead frames, electrical contact springs, and EMC shields in copper alloys (CuSn6, CuBe2) use fine blanking for edge perpendicularity and coplanarity. In high-frequency connectors, edge taper greater than 0.003 mm/mm causes impedance variation and insertion loss. Fine blanking consistently achieves taper below 0.001 mm/mm across the burnish edge height.

Safety-Critical Fasteners and Locking Components

Aircraft secondary structure lock tabs, seat belt ratchet plates, and brake caliper adjuster ratchets are fine blanked components in safety-critical assemblies. The regulatory requirement for burr-free, full-shear edges without secondary deburring — which could leave loose material in the assembly — drives fine blanking selection regardless of volume.

Frequently Asked Questions

Q: What is the practical maximum material thickness for fine blanking?

Most production fine blanking shops process up to 13 mm thickness. Above 10 mm, V-ring forces become very large, material must be strictly spheroidize-annealed, and tooling wear accelerates. Some dedicated fine blanking press builders (Feintool, Schmid) offer equipment capable of processing 16–20 mm in selected materials, but this requires custom process development and is not standard practice. For thicknesses above 13 mm, consider fine blanking followed by light coining on functional surfaces only.

Q: Can fine blanking produce internal holes smaller than the material thickness?

Yes, but with limits. The minimum recommended pierce hole diameter is approximately 0.7–0.8 × material thickness. Below this ratio, the pierce punch operates under excessive compressive stress from the triple-action blanking load and risks buckling or fracture. For holes with d < 0.7t, design the fine blanking tool to leave a web, then use a separate pierce operation or secondary drilling.

Q: How does fine blanking affect cut edge hardness?

Full plastic shear work-hardens the cut edge significantly. For C45 steel (220 HV base hardness), the fine blanked edge typically measures 320–380 HV — a 45–70% increase over bulk material. This work-hardened zone is confined to 0.1–0.3 mm from the cut face and is beneficial for wear resistance on functional surfaces. For parts requiring post-blank heat treatment, the work-hardened layer re-integrates during austenitizing without adverse effect.

Q: Is fine blanking practical for stainless steel?

Yes, for austenitic grades (304, 316L). These work-harden rapidly during blanking — use C_V = 3.5 for blank holder force calculation and expect 30–40% higher tool wear compared to carbon steel at equivalent thickness and contour complexity. Martensitic stainless (420, 440C) is problematic in production-hardened condition. Use only in fully annealed condition and validate with process trials before committing tooling investment.

Q: What causes “orange peel” texture on fine blanked edges?

Orange peel is a grain-size effect. When material has a coarse ferrite grain structure (ASTM grain size 4–5 or coarser), individual grains shear sequentially rather than as a continuum, leaving a faceted surface texture resembling orange peel under magnification. Specify ASTM grain size 7–8 or finer on material purchase orders. Reject incoming coils with hardness variation greater than ±15 HB within a coil — wide hardness spread indicates microstructural non-uniformity.

Q: How do I correctly specify fine blanking edge quality on engineering drawings?

Use ISO 1302 / ISO 4287 notation on the cut edge surface. Typical specification:

  • Shear face (burnish zone): Ra ≤ 1.6 μm
  • Rollover: maximum depth ≤ 0.15 × t (specify if functional)
  • Burr height: ≤ 0.05 mm
  • Edge perpendicularity: per ISO 2768-m or tighter class

For gear-quality components, add: “Burnished zone ≥ 90% of edge height, measured per cross-section at 5 locations around perimeter.” This prevents tooling shops from delivering partially fine blanked parts that pass visual inspection but fail functional use.

Q: What production speed should I plan for in fine blanking?

Fine blanking presses run at 20–80 SPM for single-station tools, and 10–40 SPM for compound tools producing multiple parts per stroke. Compare this to conventional blanking lines at 60–400 SPM. The productivity gap is real and must be factored into annual capacity planning. However, fine blanking often eliminates 2–5 secondary machining operations, each with its own cycle time, WIP handling, and machine time. The net throughput comparison — parts per machine-hour including secondary ops — is frequently favorable to fine blanking at medium-to-high volumes.

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Conclusion

Fine blanking and conventional blanking are not competing technologies — they serve different engineering requirements, and the correct choice depends entirely on the functional demands of the part.

Conventional blanking remains the right process for structural parts, cover panels, brackets, and any component where the cut edge carries no dimensional or surface finish requirement. It is faster to run, simpler to set up, and an order of magnitude cheaper to tool. For the majority of sheet metal components produced globally, conventional blanking is correct.

Fine blanking is correct when the cut edge is a precision functional surface, when flatness must hold within 0.05 mm, when secondary machining would otherwise be required, or when burr-free edges are a safety or assembly requirement. The 3–5× tooling cost premium pays back at volumes where secondary machining cost per part exceeds die amortization. For automotive powertrain parts at 100,000+ parts/year, fine blanking consistently wins the economic comparison.

The force calculations are not optional. A fine blanking process for a C45 steel part demands 3.5–4.5× the press force that a conventional blanking engineer would specify. Undersizing the press leads to overload trips, deflection, and poor edge quality regardless of die precision.

V-ring geometry, ultra-tight clearance, spheroidize-annealed material, low-viscosity lubricant, and triple-action press control are the non-negotiable requirements. Miss any one of them and fine blanking degrades into expensive conventional blanking with smaller clearances — fracture zone intact, flatness deficient, and scrap rate high.

Run the economic model. Calculate secondary operation cost per part, multiply by annual volume, compare against fine blanking die investment amortized over die life. That number gives an objective answer to a decision that is too often made on familiarity rather than cost data.

Work with Demirezen Engineering

Demirezen Engineering provides process selection consulting, tooling design review, and fine blanking feasibility analysis for stamping shops and OEM procurement teams in the Middle East and global markets. If your parts require precision cut edges and you are evaluating fine blanking against conventional blanking plus secondary operations, contact us before committing tooling investment.

WhatsApp: +90 543 341 6183 Website: demirezenengineering.com

External References

  1. Feintool International (feintool.com) — Process engineering data, fine blanking press specifications, and application notes from the leading fine blanking press and tooling manufacturer.
  2. DIN 8588 / ISO 16092-1 — International standards for shear cutting processes and press safety, covering fine blanking process classification and equipment requirements.
  3. Society of Manufacturing Engineers — SME Technical Paper MS90-372 — “Fine Blanking: A Powerful Method for Metal Forming” — foundational reference on V-ring design, force calculation methods, and tooling requirements.

Suggested Images and Diagrams

  1. Fine blanking tool assembly cross-section — Show punch, die, V-ring blank holder, counter punch, workpiece, and scrap web in cross-section with labeled dimensions: V-ring height h, position from edge a, base width w, die clearance c. ALT: “Fine blanking tool assembly cross-section showing V-ring blank holder, counter punch, and ultra-tight die clearance.”

  2. Cut edge quality comparison macro photo — Side-by-side images of conventional blanked edge (labeled rollover, burnish, fracture, burr zones) vs fine blanked edge (100% burnish, no fracture zone visible). ALT: “Cut edge cross-section comparison between conventional blanking showing fracture zone and fine blanking showing 100% burnish.”

  3. V-ring impression on scrap web — Top-view photograph of scrap skeleton showing correct V-ring indentation pattern after blanking. ALT: “V-ring impression on fine blanking scrap web showing correct indentation depth and sharpness.”

  4. Triple-action force sequence diagram — Timeline graph with x-axis = press stroke position, y-axis = force [kN]. Three overlaid lines: blank holder force, counter punch force, main punch force. Shows all three forces active simultaneously during the blanking phase. ALT: “Fine blanking triple-action press force sequence diagram showing simultaneous blank holder, counter punch, and blanking force.”

  5. Fine blanked automotive sprocket — Photo or CAD rendering of a fine blanked sprocket or cam showing the smooth tooth flank surface with no secondary machining marks. ALT: “Fine blanked automotive sprocket showing precision tooth profile and smooth burnished edge surface.”