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SUS304 Stainless Steel Multi-Step Linear Plunger Shaft
This integrated stepped plunger pin is precision CNC turned and cylindrical ground for fluid dispensing valves, automation positioning fixtures and miniature mold ejection mechanisms, consisting of mirror polished sliding mandrel, two-stage transitional shoulders and flanged base with side fluid inlet hole. It acts as reciprocating core plunger for micro fluid control and linear positioning systems.
- Material: SUS304 Stainless Steel
- Hardness: HB 150–185
- Tolerance: ±0.0015 mm
- Surface Finish: Mirror Polished Sliding Shaft + Matte Brushed Base Body
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Multi-Layer Composite Guide Sleeve Engineering
Three-layer nested integrated structure separates friction, load-bearing and anti-corrosion functions independently: inner high-hardness steel sleeve provides wear-resistant sliding surface for reciprocating shafts; intermediate bronze ring acts as self-lubricating buffer to eliminate direct metal-to-metal contact and reduce friction heat; outer stainless steel flange base provides rigid fixed mounting and corrosion isolation. Multi-step concentric stepped outer profile ensures precise positioning inside mold plates and fixture holes, tight clearance fit guarantees ultra-high coaxiality during high-speed linear reciprocation. Closed annular matching structure prevents liquid, dust and debris from entering the sliding clearance, effectively reducing jamming and abrasion failure. Solid layered assembly resists axial impact and radial extrusion deformation, maintaining stable positioning accuracy over millions of operating cycles.
Triple Composite Material Performance Advantages
The matched combination of bearing steel, bronze and stainless steel balances wear resistance, self-lubrication and anti-corrosion performance:
- SUJ2 Bearing Steel Inner Sleeve: Full quenching ultra-high hardness, extreme abrasion resistance against long-term shaft sliding friction; nitriding surface further improves anti-galling performance
- C932 Tin Bronze Intermediate Washer: Natural self-lubricating property, low friction coefficient, quickly dissipates sliding friction heat to avoid thermal expansion jamming
- SUS304 Stainless Steel Outer Base: Complete rust and chemical corrosion resistance, adapts to humid mold workshops and chemical splash automation lines; stable compressive rigidity for long-term fixed installation Ideal for precision multi-cavity injection molds, high-speed stamping dies and robotic linear positioning automation equipment.
Custom Composite Guide Sleeve Machining Support
- Custom inner bore diameter, multi-step outer diameter, overall height and flange thickness based on customer shaft and mold CAD drawings
- Optional surface upgrades: Mirror Polishing, Hard Chrome Plating, Anti-Fingerprint Passivation, DLC Anti-Friction Coating
- DFM consultation: sliding clearance tolerance matching, heat dissipation optimization, bronze wear ring thickness customization
- Fast single-set prototype sampling and mass batch interchangeable guide sleeve delivery
Key Features & Advantages
- Three-Layer Separate Functional Design: Wear-resistant sliding layer + self-lubricating buffer layer + anti-corrosion fixed layer, prolong overall service life and reduce maintenance frequency.
- Multi-Step Concentric Stepped Outer Profile: Multi-stage positioning shoulders prevent sleeve displacement under high pressure and vibration.
- Bronze Self-Lubricating Buffer Ring: Eliminates frequent grease filling, avoids shaft galling and reduces sliding noise.
- High Hardness Nitrided Inner Sliding Surface: Withstands long-cycle high-speed reciprocating friction without dimensional wear drift.
- Full Anti-Corrosion Outer Stainless Steel Shell: Reliable operation in damp, cooling water splash and chemical production environments without rust.
Technical Specifications
| Parameter | Specification |
|---|---|
| Inner Sliding Sleeve Material | SUJ2 High Carbon Bearing Steel |
| Intermediate Wear Buffer Material | C932 Tin Bronze Alloy |
| Outer Base Material | SUS304 Stainless Steel |
| Alternative Materials | Cr12MoV Steel, BeCu Beryllium Bronze, SUS316 Stainless Steel |
| Hardness | HRC 60–64 (SUJ2 quenched); HB 110–130 (Bronze); HB 150–185 (SUS304) |
| Dimensional Tolerance | ±0.001mm for inner bore, outer stepped diameter and total height |
| Inner Bore Coaxiality | ≤0.001mm per sleeve length |
| Surface Roughness | Ra ≤0.4μm nitrided steel sleeve; Ra ≤0.2μm polished bronze ring; Ra ≤0.6μm brushed stainless base |
| Manufacturing Processes | CNC Turning, Precision Cylindrical Grinding, Heat Treatment, Nitriding, Bronze Ring Press-Fitting, Deburring |
| Surface Treatments | Gas Nitriding, Hard Chrome Plating, Anti-Rust Passivation, DLC Low-Friction Coating |
| Customization | 100% Fully Customized via CAD Drawings & Matching Shaft Samples |
Applications
Precision Multi-Cavity Injection Molds
Composite guide bushings for ejector pins and core pins in electronic and cosmetic multi-cavity molds. Bronze heat conduction ring dissipates ejection friction heat, stainless steel outer shell resists rust from mold cooling water.
High-Speed Stamping Auxiliary Dies
Locating shaft guide sleeves for continuous thin metal strip stamping molds. High-hardness inner steel sleeve withstands millions of high-speed reciprocating positioning friction.
Robotic Automated Assembly Equipment
Linear positioning guide bushings for robotic feeding and connector assembly stations. Non-magnetic stainless steel outer body avoids magnetic interference with micro electronic components.
Medical Disposable Molding Tools
SUS304 stainless steel outer base meets medical hygiene standards, used for guide sleeves of medical tube and syringe plastic molds, resisting erosion from medical plastic additives and mold cleaning agents.
Food Packaging Conveying Machinery
Food-grade passivated composite guide sleeves for food filling and sorting equipment, compliant with food contact safety standards and resistant to grease and water corrosion.
