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CNC Eccentric Shafts Technical Specifications
| Sleeve Types | Twin-Tube Outer Sleeves, Mono-Tube Cylinders, Strut Housings, Reservoir Tubes |
|---|---|
| Primary Equipment | Star CNC Swiss-type Lathes, Heavy-Duty CNC Lathes, Internal Cylindrical Grinders |
| Dimensional Tolerance | Inner Bore (ID): H8-H9 (±0.02mm); Outer Diameter (OD): ±0.05mm |
| Geometric Tolerances | Coaxiality (ID to OD): 0.05mm; Straightness: 0.02mm/100mm; Cylindricity: 0.01mm |
| Common Materials | 20# Carbon Steel, STKM-13A, 40Cr, SAE 1010, Stainless Steel |
| Heat Treatment | Normalizing, Quenching & Tempering (HB 180-220 for core toughness) |
| Surface Roughness (Ra) | Inner Bore (Honed/Ground): Ra 0.2 - Ra 0.4; Turned Surfaces: Ra 1.6 |
| Machining Features | Seal Grooves, Mounting Brackets, Cross-Drilled Ports, Threaded Ends |
| Surface Treatments & Cleaning | Black Oxide, Phosphating, Electrophoretic Deposition (E-coating), Ultrasonic Washing |
| Inspection Equipment | Japanese/German CMM, Air Gauges, Bore Scopes, Surface Profilometers |
High-Precision CNC Eccentric Shafts for Smooth Ride Dynamics
At Xierge Precision Machinery Co., Ltd., we leverage over 30 years of operational experience since 1990 to manufacture premium CNC Eccentric Shafts for the global automotive and industrial machinery sectors. Shock absorber sleeves, or cylinder tubes, are the critical outer housings and guiding cylinders for the piston rod and damping fluid. These components must withstand immense internal hydraulic pressure, lateral loads, and continuous thermal cycling. They require extreme cylindricity, superior surface finishes on the inner diameter, and flawless coaxiality. Even a microscopic deviation in the inner bore geometry or a slight surface defect can lead to oil leakage, accelerated piston seal wear, and a compromised ride experience.
To achieve flawless results, our state-of-the-art facility is equipped with Japanese imported Star CNC Swiss-type lathes, heavy-duty domestic CNC lathes, and high-precision internal cylindrical grinders. The guide bushing technology on our Swiss lathes provides continuous, rigid support, completely eliminating deflection when machining long, thin-walled sleeve geometries. This specialized equipment allows us to turn complex outer profiles, machine precision mounting grooves, and bore the inner cylinder in a highly rigid setup, ensuring absolute coaxiality between the inner fluid chamber and the outer mounting body.
Following our core principle of "Integrity Oriented, Quality Foremost," we strictly adopt premium raw materials, such as 20# steel, STKM-13A, and 40Cr alloy steel, to ensure maximum structural integrity and burst resistance. To guarantee reliable product performance, we apply strict quality inspection protocols utilizing a complete set of testing instruments imported directly from Japan and Germany, verifying inner bore tolerances, straightness, and surface hardness. We keep innovating to maintain sound business development and warmly welcome domestic and overseas clients to visit our factory and explore custom OEM/ODM cooperation opportunities.
Core Advantages of Xierge CNC Eccentric Shafts
- Ultra-Precise Inner Bore Control: Through advanced internal cylindrical grinding and honing, we achieve strict cylindricity and micro-tolerances on the inner diameter, ensuring smooth piston travel and preventing hydraulic oil bypass.
- Zero-Deflection Thin-Wall Machining: Our Japanese Star CNC Swiss-type lathes utilize continuous guide bushing support, enabling the machining of long, thin-walled shock absorber sleeves without bending or ovalization.
- Superior Burst Resistance: We strictly select STKM-13A and 40Cr seamless steels, applying precise normalizing treatments to provide a tough, uniform microstructure capable of withstanding high internal gas and fluid pressures.
- Single-Setup Coaxiality: By turning the outer profile, grooves, and boring the inner cylinder in highly rigid setups, we maintain strict coaxiality, preventing uneven piston seal wear during high-speed oscillations.
- Advanced Anti-Corrosion Coatings: To withstand harsh underbody environments, we apply phosphating followed by electrophoretic deposition (E-coating) or black oxide, ensuring long-term rust prevention without altering critical bore dimensions.
- Industrial-Grade Cleanliness: Shock absorbers are highly sensitive to particulate contamination. We utilize multi-stage ultrasonic cleaning machines to remove 100% of machining chips and honing debris from the inner bore.
- 3-Decade Automotive OEM/ODM Expertise: Since 1990, we have continuously innovated, providing DFM (Design for Manufacturing) optimization and full PPAP documentation for custom strut housings, scaling seamlessly from prototyping to mass production.
Payment Methods & Global Logistics Solutions
Secure International Payment Terms:
To facilitate smooth B2B international trade, we offer flexible and secure payment options. For mass production orders of CNC Eccentric Shafts, we accept standard T/T (Telegraphic Transfer) with a 30% advance deposit and 70% balance before shipment. For large-scale automotive Tier-1 supply contracts, we are fully capable of processing Irrevocable Letters of Credit (L/C) at sight. For initial prototyping, sample orders, or custom tooling fees, PayPal and Western Union are also available to expedite the process.
Global Logistics & Protective Packaging:
We provide comprehensive end-to-end shipping solutions under FOB, CIF, and DAP Incoterms. For urgent prototypes or small batches, we utilize expedited international couriers such as DHL, FedEx, and UPS. For bulk mass production, we offer highly competitive sea freight (LCL/FCL) and air cargo rates through our trusted global forwarder network. Recognizing that shock absorber sleeves are thin-walled, hollow precision components with critical inner bore finishes highly susceptible to impact, crushing, and oxidation, we utilize specialized packaging: all open ports are capped with plastic plugs to prevent debris entry, and components are coated in anti-rust oil and wrapped in VCI (Volatile Corrosion Inhibitor) paper. To prevent point contact and oval deformation, parts are separated by custom multi-layer EPE foam slots or nested horizontally in sturdy export-grade cartons on heat-treated wooden pallets, ensuring zero deformation during international transit.
FAQ
Thin-walled tubes naturally deform under clamping and cutting pressure. We mitigate this by using custom collets and expanding mandrels that distribute clamping force evenly across a larger surface area. Additionally, we utilize sharp carbide tooling with optimized shallow depth of cuts and minimal radial forces, ensuring the cylindricity of the inner and outer diameters is maintained.
The inner bore must provide a smooth path for the piston seal. After CNC boring, we utilize precision internal cylindrical grinding or horizontal honing machines. This removes any tool marks, corrects microscopic taper, and creates a specific cross-hatch pattern (Ra 0.2 - 0.4) that retains hydraulic oil for lubrication, significantly extending seal life.
Contaminants in the bore will instantly destroy the piston seal upon operation. We use a dedicated multi-stage industrial washing process. High-pressure flushing removes honing grit and chips, followed by immersion in industrial ultrasonic cleaning machines to dislodge micro-debris from internal grooves. Finally, we use borescopes to visually inspect the inner chamber before applying protective end caps.
For high-pressure mono-tube applications where the cylinder is subjected to extreme internal gas pressure, we highly recommend STKM-13A seamless carbon steel or 40Cr alloy steel. These materials undergo precise normalizing and tempering to achieve a uniform, tough microstructure (HB 180-220) that prevents catastrophic burst failures under heavy road impacts.
Yes. For strut housings, we can machine complex geometries on the outer diameter. Using our 4-axis CNC machining centers, we can mill mounting ears, drill cross-holes for mounting bolts, and machine precision circlip grooves. We perform these operations on forged blanks or thick-walled tubes to ensure structural rigidity at the mounting points.
Yes. With over 30 years of experience supplying the automotive industry, we are fully compliant with PPAP (Production Part Approval Process) requirements. We provide complete documentation, including dimensional layouts, material mill certificates, capability studies (Cpk/Ppk), and measurement system analysis (MSA) to ensure seamless integration into your automotive supply chain.
