| Quantity: | |
|---|---|
Production Discription
The mandrel is a positioning and supporting functional component in mechanical processing and forming processes. Its core role is to ensure the precision and stability of workpiece processing/formulation.
On one hand, through its rigidity, it provides radial constraint and axial load-bearing for slender shafts, thin-walled parts, etc., counteracting deflection deformation during cutting, forging, and other processes.
On the other hand, in transmission and mold scenarios, it undertakes torque transmission and mold cavity forming benchmark functions, serving as a key fixture base component that "maintains shape and ensures process stability" in precision part manufacturing.
Visibly, this mandrel features a multi-step cylindrical shaft structure, presenting an overall symmetrical long shaft form with diameters varying stepwise (to accommodate clamping/matching dimensions of different workpieces). The surface undergoes precision machining (e.g., grinding), achieving high roundness, high straightness, and low surface roughness. Mounting interfaces (such as the hole system on the right end face of the mandrel shown in the figure) are provided at the ends or specific locations for rigid connection with machine tools, molds, and other equipment. Rounded corners/chamfers are optimized at step transitions to reduce stress concentration and enhance structural fatigue resistance.
Mandrel
Mandrel
Precision instruments: Shaft-type transmission/positioning components for medical equipment and optical instrument.
Mandrel
Mandrel Machinery Process
1,Raw Material Preparation
Select 56NiCrMoV7 alloy structural steel forged round steel, cut it according to the mandrel's design dimensions, and reserve a 1–2mm machining allowance. The forging process can refine grains, eliminate segregation, and improve the material’s density and comprehensive mechanical properties.
2,Rough Machining
Use a lathe to perform rough turning on the blank for the outer circle, end face, steps, etc., leaving a 1–2mm unilateral machining allowance. Clamp with a four-jaw chuck or centering device, and use cutting fluid to dissipate heat and reduce friction—this quickly removes most of the allowance to form the basic shape.
3,Quenching and Tempering Heat Treatment
After rough machining, execute the "quenching + high-temperature tempering" quenching and tempering process to obtain a uniform tempered sorbite structure. This balances the mandrel’s strength and toughness to meet the needs of heavy load and fatigue resistance.
4,Stress Relief Treatment
After quenching and tempering, perform low-temperature tempering or natural aging to eliminate internal stress, avoid deformation caused by stress release during subsequent finishing, and ensure dimensional stability.
5,Semi-finishing
Turn the outer circle, grooves, steps, and other features again, reducing the allowance to within 0.5mm. Process auxiliary structures (e.g., keyways, threads) simultaneously, and strictly control geometric tolerances like coaxiality (≤0.05mm) and cylindricity.
6,Finish machining
Improve the outer circle accuracy to IT6–IT7 grade via grinding, achieving a surface roughness of drawing requirement. If internal hole machining is involved, use a boring machine/reamer to ensure the fit accuracy and positional tolerance between the internal hole and outer circle.
7,Surface Treatment
Perform processes like copper plating, phosphating, or bluing according to the application scenario to enhance corrosion resistance and lubrication during assembly. Precisely control the plating thickness and uniformity during the process.
Final product
Final Product
Quality Inspection
1,Appearance Quality Inspection
Conduct visual inspection + tactile check of the surface to identify scratches, dents, rust, deformation, etc. If coated (e.g., golden coating), verify color uniformity, ensuring no missed plating, runs, color difference, or other defects.
2, Dimensional Accuracy Inspection
Use measuring tools (calipers, micrometers, inside micrometers, etc.) to measure key parameters (total length, segment diameters, step/chamfer dimensions, etc.). Compare with drawing tolerances (e.g., ±0.02~0.05mm) to determine compliance.
3,Geometric Tolerance Inspection
Using instruments like a roundness tester, detect core geometric tolerances:
Cylindricity: Roundness error of the shaft’s cylindrical surface (ensures rotational accuracy);
Coaxiality: Overlap of multiple axis lines (avoids eccentricity after assembly);
Perpendicularity/Radial Runout: For parts with flanges/steps, measure perpendicularity of the end face to the axis.
4, Surface Treatment Verification (Coated Types)
Coating Thickness: Use magnetic/eddy current thickness gauges to confirm anti-corrosion/wear-resistant design values;
Adhesion: Rate via cross-cut test + tape peeling (or circle test);
Corrosion Resistance: 48h/96h neutral salt spray test (observe rust/bubbling).
5, Mechanical Property & Material Verification
Hardness: Test with Rockwell/Brinell/Vickers hardness testers to match heat treatment (quenching, tempering) requirements
Metallographic Analysis (Sampling): Observe grain size and tissue uniformity (e.g., quenched martensite grade);
Load Test (As Needed): For alternating load scenarios, sample tensile/yield strength (destructive tests require reserved samples).
6, Internal Defect Detection (High-Precision Shafts)
Ultrasonic Testing (UT): Detect internal pores, slag inclusions, and looseness in the shaft body;
Magnetic Particle Testing (MT): Check for surface/near-surface cracks (e.g., forging/grinding stress cracks).
7, Assembly Compatibility Test
Simulate working conditions, assemble the mandrel with tooling, gears, etc. Use feeler gauges/dial indicators to measure axial/radial clearance, and manual/torque meters to test rotational flexibility (no jamming, abnormal noise).
Packaging & Shipping
Adopt transparent PE plastic film to fully wrap and coil around the mandrel, forming a sealed layer. Its core functions are: isolating moisture to prevent metal rust, blocking dust to maintain surface cleanliness, and reducing friction/scratches during transportation with the tight film.
2,Outer Packaging
Select solid wood/plywood wooden cases, internally equipped with colorful woven pads or foam shock-absorbing materials. Its core functions are: the wooden case frame resists compression and impact, withstanding stacking and handling mechanical forces; the buffer layer fills gaps to disperse vibrations, preventing the mandrel from damage due to jolting; the rigidity of the wooden case adapts to forklifts/cranes, meeting warehouse storage needs.
