Product Description

420J2 Stainless Steel Micro-Precision CNC Milled Medical Spare Parts are high-tolerance, miniature components engineered for the most demanding applications within medical devices and surgical instruments. Utilizing 420J2 stainless steel—a martensitic grade known for its excellent hardness, wear resistance, and ability to hold a keen edge after heat treatment—this service specializes in producing intricate, small-scale parts through advanced multi-axis micro-machining. The process achieves exceptional dimensional accuracy, complex geometries, and superior surface finishes, making these components ideal for critical assemblies where reliability, durability, and precision are non-negotiable.

Product Processing

1. Material Verification & Pre-Treatment: Certified 420J2 stainless steel bar or rod stock is verified for chemistry. It is supplied in the annealed (soft) condition for optimal machinability. Blanks are precision-cut and stress-relieved if necessary.

2. Micro-Precision CNC Machining Setup: The soft blanks are fixtured in high-precision CNC machining centers, often 5-axis Swiss-type lathes or micro-milling machines. The setup prioritizes rigidity and vibration control to achieve micron-level accuracy.

3. Multi-Axis Micro-Milling & Turning: Using micro-diameter end mills (down to 0.1mm) and fine-grain tooling, the parts are machined. This includes creating complex 3D contours, miniature gears, threads, slots, and holes with tolerances in the micron range. Features like cutting edges on surgical blades are pre-formed in this stage.

4. Heat Treatment (Hardening & Tempering): After machining to final dimensions in the soft state, the parts undergo a precise vacuum hardening process, followed by multiple tempering cycles. This achieves the target high hardness (typically 50-55 HRC) while relieving stresses and maintaining necessary toughness.

5. Post-Heat Treatment Finishing: Following hardening, critical surfaces and edges (e.g., blade edges, bearing surfaces) undergo precision grinding, honing, or lapping to correct any minimal distortion and achieve the final ultra-fine tolerances and razor-sharp edges.

6. Super-Finishing & Cleaning: Parts undergo specialized finishing such as vibratory tumbling for deburring, followed by electropolishing or micro-blasting to achieve a specified surface finish (Ra < 0.2 µm) and enhance corrosion resistance. Intensive ultrasonic cleaning in a cleanroom environment removes all contaminants.

7. Metrology & Inspection: Each part is 100% inspected using high-magnification vision systems, non-contact optical measurement, and micro-CMMs. Hardness is verified. For cutting components, sharpness is tested.

Product Applications

• Minimally Invasive Surgical Instruments: Jaws, hinges, pins, and trigger components for laparoscopic tools, endoscopic cutters, and biopsy forceps.

• Orthopedic & Dental Surgical Tools: Blades for osteotomes, components for bone rongeurs, drivers for screws/plates, and cutting tips for drills/burrs.

• Disposable & Reusable Surgical Blades: Scalpel blades, specialized cutting inserts for dermatomes, and micro-surgical scissors components.

• Medical Device Mechanisms: Miniature gears, springs, clamps, and connectors for drug delivery pumps, auto-injectors, and diagnostic devices.

• Veterinary Surgical Instruments: Similar small, high-wear components for animal surgery.

Product Technical Parameters (Detailed Table)

Category	Parameter	Specification / Details
Material	Primary Grade	420J2 Stainless Steel (AISI 420J2, UNS S42000) - Martensitic
	Key Properties	High Hardness after heat treat, good wear resistance, moderate corrosion resistance, ability to take a fine polish/sharp edge.
	Condition Supplied	Annealed (for machining) & Heat Treated (to specified hardness, typically HRC 50-55).
Physical & Mechanical (Hardened)	Hardness (Final)	50 - 55 HRC (Customizable via heat treat protocol)
	Tensile Strength	~ 1600 - 1900 MPa (Approx., hardness dependent)
	Corrosion Resistance	Good for medical applications; superior to many tool steels but less than 316L.
Machining Capabilities	Primary Process	5-Axis Micro-Milling, CNC Swiss Machining, Precision Micro-Turning
	Equipment	High-precision machining centers with sub-micron positioning capability.
	Minimum Feature Size	0.05 mm (e.g., micro-holes, thin walls, fine pitch threads)
Precision & Tolerances	Standard Dimensional Tolerance	±0.005 mm (±0.0002")
	High-Precision Tolerance	±0.002 mm (±0.00008") achievable on critical features
	Geometric Tolerances	True Position, Parallelism, Flatness to within 0.005 mm.
	Surface Finish (As-Machined)	Ra 0.4 - 0.8 µm
Part Specifications	Maximum Part Dimensions	Typically up to 25 mm in largest dimension for micro-precision work.
	Complex Geometries	Micro gears, intricate cams, undercuts, multi-start threads, razor edges.
Surface & Finish (Post-Process)	Final Surface Options	Electropolished (Ra < 0.2 µm, enhanced corrosion resistance), Micro-blasted (matte finish), Mirror Polished.
	Edge Sharpness (for blades)	Can achieve cutting edges with edge radius < 1 µm.
Quality & Compliance	Inspection Equipment	Optical Coordinate Measuring Machine (CMM), Laser Scanning Microscope, Surface Profilometer, Rockwell Hardness Tester.
	Material Certification	Mill Test Certificate (MTC) per EN 10204 3.1 with full chemistry. Heat Treat Certificate provided.
	Biocompatibility	Material is considered biocompatible for instrument applications (ISO 10993-1, -5). Surface finish ensures cleanability.
	Cleanliness	Cleaned and packaged in an ISO Class 7 (or better) cleanroom. Can meet stringent particle count requirements.
	Regulatory Support	Manufactured under an ISO 13485:2016 compliant quality management system. Full Device History Record (DHR) for OEM parts.