Progressive Die Stamped 316L Medical Instrument Brackets：

Клиент: MT,Instruments (ISO 13485 certified; USA)

Отрасль: Medical Device Manufacturing

Задача:

The client needed 250;000 units per year of small (65mm × 38mm × 12mm) stamping brackets for a reusable surgical instrument sterilizer rack.
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The bracket held critical alignment pins and was exposed to:

 Daily autoclave sterilization (steam at 134°C / 273°F; high humidity).
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Hospital grade disinfectants (bleach and quaternary ammonium compounds).
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 Physical impact from repeatedly loading heavy surgical trays.
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The original part was machined from solid 316L bar stock.
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While functional; machining had three major problems:

Cost: $4.20 per unit (too expensive for a semiconsumable bracket).
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Lead time: 8 weeks for 5;000 units (machining was too slow).
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Material waste: 65% of the 316L bar was turned into chips and scrap.
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MT requested: stamping brackets alternative at ≤$1.80 per unit; with zero porosity; corrosion resistance equal to machined 316L; and a smooth; cleanable surface (no crevices for bacterial growth).
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The Flow Wing Metal Execution
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Step 1: Design for Stamping (DFS) Engineering

Flow Wing Metal’s engineering team reviewed the 3D model and redesigned the stamping brackets:

 Material change removed: Replaced machined bar with 1.2mm thick 316L stainless steel coil (fullhard temper for springback control; then annealed poststamp).
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 Geometry optimization: Added 0.5mm fillets to all internal corners (previously sharp 90°) to prevent stress cracking during forming.
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 Hole tolerances: Specified punched holes at +0.05mm / 0.00mm for precision pin alignment (achievable with fineblanking techniques).
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Step 2: Tooling Fabrication

 Die type: Progressive die with 8 stations.
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 Die material: Powdered metallurgy tool steel (CPM 10V) with titanium aluminumnitride (TiAlN) coating for wear resistance against workhardening 316L.
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 Press: 200ton Bruderer highspeed stamping press.
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 Stations included:

Pilot hole piercing

Main hole piercing (×4)

Lancing: partial cut for clearance feature

First 45° bend

Second 90° bend

Coining: flattening of mounting surface.

Blanking: part cut from carrier strip

Scrap cutoff

Step 3: Process Development & Testing

 Trial run: 500 parts produced using mild steel (for die validation).
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 Stainless trial: 1;000 parts in 316L with specialized chlorinated extremepressure stamping lubricant to prevent galling.
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 Adjustments: Increased press speed from 40 to 55 SPM (strokes per minute); added air blast to clear small slugs from piercing stations.
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Step 4: Post Stamping Brackets Operations

 Degreasing: Automated threestage spray washer (alkaline wash → rinse → rust inhibitor rinse).
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 Deburring: Light vibratory tumbling with ceramic triangles (15 minutes) to remove punchentry burrs (<0.05mm remaining).
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 Passivation: Citric acid bath (20% concentration; 25 minutes at 55°C) to restore chromium oxide layer – critical for autoclave resistance.
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 Inspection: 100% go/nogo gauge for pin holes; laser micrometer for bend angle tolerance (±0.5°).
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Step 5: Quality Validation

 Результат:

 Cost savings: 64% reduction per unit ($4.20 → $1.52) = $670;000 annual savings for the client.
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 Production speed: From 8 weeks for 5;000 units (machined) to 2 weeks for 25;000 units (stamped).
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 Material utilization: Increased from 35% (machined) to 82% (stamped from coil).
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 Quality: Zero field failures reported after 18 months of hospital use. The stamping brackets survive autoclave cycles without pitting; and the passive layer remains intact.
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 Client outcome: MT converted 14 additional machined stamping brackets to Flow Wing Metal stamped designs over the following 12 months.
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Отзыв клиента:

> “Flow Wing Metal didn’t just stamping brackets – they re-engineered our entire cost structure. The progressive die tooling paid for itself in the first production run. And the part quality? Better than our original machined version.”,
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> – Senior Purchasing Manager; MT Surgical Instruments

Why Choose Flow Wing
 Metal for Stamping Brackets?

Flow Wing Metal transforms sheet metal into precision components – faster; stronger; and more economical than machining.
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