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SUS304 Stainless Steel Multi-Step Reciprocating Plunger Shaft
This integrated three-stage stepped plunger core is precision CNC turned and cylindrical ground for fluid dispensing valves, quantitative filling equipment and miniature automation positioning fixtures, composed of mirror polished sliding mandrel, two transitional limiting shoulders and flanged base with radial side flow hole. It acts as reciprocating drive core for micro fluid control and linear indexing systems.
- Material: SUS304 Stainless Steel
Hardness: HB 150–185
Tolerance: ±0.0015 mm
Surface Finish: Mirror Polished Upper Sliding Shaft + Matte Brushed Base Body
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Multi-Step Plunger Linear Motion Engineering
Three concentric stepped segments integrate sliding guiding, stroke limiting and fixed mounting into one single piece. The ultra-smooth mirror polished top mandrel enables low-friction reciprocating movement inside valve sleeves, effectively preventing liquid leakage and metal galling during high-speed cycles. Two diameter transitional shoulders form hard stop limits to precisely control plunger travel distance without extra limit accessories. The radial through hole on the bottom flange serves as liquid inlet for internal fluid circulation of dispensing valves. One-piece solid stainless steel structure resists hydraulic pressure and reciprocating impact deformation, sustaining stable flow output and repeated positioning accuracy over millions of working strokes.
Anti-Corrosion SUS304 Stainless Steel Construction
SUS304 stainless steel delivers core advantages for fluid and precision positioning plunger shafts:
- Fully resistant to glue, solvent, disinfectant and weak acid liquid corrosion, suitable for medical, food and electronic fluid automation equipment
- Non-magnetic substrate eliminates magnetic interference with micro electronic components during assembly and inspection
- Excellent ultra-fine grinding performance to achieve mirror smooth sliding surface, reducing friction coefficient and cutting down regular lubrication maintenance
- Non-toxic metal composition meets food contact and medical hygiene standards without heavy metal precipitation pollution Ideal for precision dispensing valves, medical reagent metering pumps, miniature mold ejector pins and robotic indexing fixture plungers.
Custom Plunger Shaft Machining Support
- Custom mandrel outer diameter, total shaft length, step shoulder dimensions and side hole position based on customer valve/fixture 3D CAD drawings
- Optional surface upgrades: Hard Chrome Plating, DLC Anti-Friction Coating, Anti-Fingerprint Passivation
- DFM consultation: sliding clearance matching, fluid flow channel optimization, stroke limit shoulder stress reinforcement
- Fast single-piece prototype sampling and mass interchangeable plunger batch delivery
Key Features & Advantages
- Mirror Polished Ultra-Smooth Sliding Mandrel: Low friction, anti-galling, avoids fluid leakage during high-speed reciprocating movement.
- Integrated Multi-Step Limit Shoulders: Built-in stroke limiting structure simplifies valve and fixture assembly by reducing separate limit parts.
- Radial Side Fluid Inlet Hole: Integrated flow passage for internal liquid circulation of dispensing valves, compact integrated design.
- Full Anti-Rust Stainless Steel Body: Stable performance in damp, chemical splash and hygienic production environments without oxidation rust.
- One-Piece Monolithic Forming: Zero assembly gaps, high concentricity to guarantee consistent fluid output and micron-level positioning precision.
Technical Specifications
| Parameter | Specification |
|---|---|
| Base Material | SUS304 Stainless Steel |
| Alternative Materials | SUS316 Stainless Steel, SUJ2 Bearing Steel |
| Hardness | HB 150–185 (SUS304); HRC 60–64 (SUJ2 quenched) |
| Dimensional Tolerance | ±0.0015mm for mandrel OD, step length and flange flatness |
| Coaxiality of Sliding Shaft | ≤0.002mm over full shaft length |
| Surface Roughness | Ra ≤0.02μm mirror polished mandrel; Ra ≤0.4μm brushed base |
| Manufacturing Processes | CNC Turning, Precision Cylindrical Grinding, Side Hole Drilling, Deburring, Surface Polishing |
| Surface Treatments | Anti-Rust Passivation, DLC Low-Friction Coating, Hard Chrome Plating |
| Customization | 100% Fully Customized via CAD Drawings & Fluid Working Parameters |
Applications
Consumer Electronics Precision Dispensing Valves
SUS304 plunger shafts for conductive glue, UV glue micro dispensing equipment. Corrosion-resistant stainless steel avoids chemical reactions with special adhesives, mirror smooth shaft ensures consistent micro-volume glue output.
Medical Reagent Quantitative Filling Pump Core Parts
Medical-grade plunger pins for vaccine and reagent micro-filling production lines, non-toxic stainless steel meets medical hygiene standards, stable reciprocating performance guarantees accurate liquid dosing.
Miniature Plastic Mold Ejector Pins
Multi-step plunger shafts for small cosmetic and electronic plastic molds, anti-rust surface resists corrosion from mold cooling water, smooth shaft lowers ejection friction.
Food Packaging Liquid Metering Machinery
Food-grade passivated plunger shafts for syrup and flavor quantitative filling machines, resistant to long-term grease and water erosion.
Robotic Automated Indexing Fixtures
Non-magnetic stainless steel plungers for chip and connector robotic positioning stations, ultra-high concentricity realizes micron-level repeated positioning accuracy.
