【Zhejiang, China】 - In the long journey of a crankshaft from forging to finished product, one process stands as the "ultimate judge"-CNC precision grinding. This process transforms the rough-machined crankshaft from millimeter-level accuracy into the micron-level world, endowing the journals with mirror-like finish and perfect geometry. It is the final and most critical process in crankshaft manufacturing, determining the ultimate quality. Recently, the technical team of Zhejiang Weilin Mechanical Co., Ltd. conducted an in-depth on-site shooting of the CNC precision grinding process for a 3408 crankshaft (example part number: 1W5009) in the workshop, capturing the magical moments of this precision machining through the lens and continuing our Crankshaft Manufacturing Process Series.
CNC Precision Grinding: The Ultimate Pursuit of Micron-Level Accuracy
Precision grinding is the final "shaping" process in crankshaft manufacturing. Before this stage, the crankshaft has undergone rough milling, semi-finishing, and heat treatment, but the journal surfaces still bear machining marks, and dimensional accuracy is far from final requirements. The mission of CNC precision grinding is to push these "semi-finished" products to perfection:
· Final Dimensional Finalization: Precision grinding controls the diameter tolerances of main and connecting rod journals within microns (typically 0.005-0.010mm), ensuring the fit clearance with bearings reaches the optimal design value.
· Perfect Geometric Correction: Precision grinding corrects residual roundness and cylindricity errors from previous processes, presenting journals with perfect circularity and uniform taper.
· Ultimate Surface Quality Enhancement: Using fine-grit grinding wheels and optimized parameters, precision grinding achieves a mirror-like finish on journal surfaces (Ra values as low as 0.2μm or less), creating ideal conditions for oil film formation.
On-Site Shooting: The Art of Precision Grinding Under the Lens
Recently, at Zhejiang Weilin Mechanical's production workshop, the technical team conducted a comprehensive shooting session of the CNC precision grinding process for a 3408 crankshaft (corresponding to part number 1W5009). Through high-definition lenses, we can clearly observe:
· High-Precision CNC Crankshaft Grinding Machine: The crankshaft is precisely clamped between dual centers, with the grinding wheel spindle rotating at thousands of RPM. The CNC system controls the wheelhead's axial movement along the journal while automatically adjusting feed rates based on the crankshaft's phase angle. Under the lens, at the moment the grinding wheel contacts the journal, fine metal chips mix with coolant to form a uniform slurry flowing from both sides of the journal.
· In-Process Measurement and Closed-Loop Control: During grinding, measuring devices monitor journal diameter in real-time and feed data back to the CNC system. As the dimension approaches the target value, the system automatically reduces feed rate for "spark-out" until the preset tolerance is reached. This closed-loop control ensures consistency for every crankshaft.
· Non-Circular (CBN) Grinding Technology: For features like crankpins that are not on the same axis, our grinding machine employs non-circular (CBN) grinding technology. The wheelhead moves synchronously with the crankshaft's rotation angle, achieving efficient and precision grinding of the crankpins. Under the lens, the wheelhead moves like a precise dancer, perfectly coordinated with the crankshaft's rotation.
In the video, each journal of a 3408 crankshaft is precision-ground sequentially. Technicians use pneumatic gauges to measure the ground diameters, with data consistently falling within tolerance bands. The journal surfaces exhibit a uniform metallic luster, smooth as a mirror to the touch.
CAT 3408
CAT 3408
CAT 3408
Technical Value: Equipment and Processes Born for Ultimate Accuracy
CNC precision grinding is one of the most technically demanding processes in crankshaft manufacturing. In grinding the 3408 crankshaft, Zhejiang Weilin Mechanical employs:
· High-Precision CNC Crankshaft Grinding Machines: Equipped with hydrostatic guides, high-speed CBN grinding wheels, and in-process measurement systems, capable of achieving micron-level accuracy and exceptional surface quality.
· Non-Circular Grinding Technology: For eccentric features like crankpins, advanced non-circular grinding processes are employed, significantly improving machining efficiency while ensuring accuracy consistency.
· Specialized Grinding Wheels and Dressing Processes: Selecting wheels with appropriate grit and hardness based on crankshaft material and hardness, equipped with in-process wheel dressers to ensure optimal cutting condition at all times.
· Strict Process Control: Precision grinding parameters (wheel speed, feed rate, number of passes) for each crankshaft are recorded, enabling quality traceability.
Customer Value: Injecting Smoothness and Efficiency into the Engine
For end users, the quality of the precision grinding process is directly reflected in engine performance:
· Reduced Friction Losses: Mirror-level journal surfaces significantly reduce friction with bearings, improving fuel economy.
· Extended Bearing Life: Accurate dimensions and geometry ensure uniform oil film distribution, avoiding localized dry friction, significantly extending the service life of main and connecting rod bearings.
· Reduced Vibration and Noise: Perfect roundness and cylindricity ensure smooth crankshaft operation, reducing overall machine vibration and noise levels.
· Ensured Long-Term Reliability: Grinding removes micro-cracks and stress concentration sources left from previous processes, serving as a critical guarantee for achieving ultra-long crankshaft fatigue life.
Video & Image Access: Feel Free to Contact Us
To more intuitively demonstrate the precise details of CNC precision grinding, we have compiled high-definition videos and images from the on-site shooting into a technical information package. If you are interested in the manufacturing process of the 3408 crankshaft or wish to obtain technical parameters related to 1W5009, please feel free to contact our technical team anytime. We will provide you with detailed technical support and product solutions.
About Zhejiang Weilin Mechanical Co., Ltd.
Zhejiang Weilin Mechanical Co., Ltd. is a National High-Tech Enterprise specializing in the R&D, manufacturing, and sales of high-performance forged steel crankshafts. Our products are widely used in construction machinery, heavy-duty trucks, generator sets, and marine propulsion. Committed to providing reliable and efficient core powertrain solutions to global customers through excellent materials science, precision manufacturing processes, and a complete quality traceability system.