1. Spindle Speed of the Hob (Cutting Tool)
1.1 Definition
Spindle Speed (n): The rotational speed of the hob (the cutting tool) in revolutions per minute (RPM).
1.2 Importance
Cutting efficiency: Affects the rate of material removal and overall cutting efficiency.
Surface Finish: Influences the surface finish and dimensional accuracy of the gear teeth.
Tool Life: Higher speeds may reduce hob life due to increased wear and heat generation.
1.3 Determining Spindle Speed
Formula: The hob spindle speed is determined based on the cutting speed and the diameter of the hob.
Where is the cutting speed in meters per minute (m/min).
Cutting Speed (V): Typically provided by the hob manufacturer based on material and cutting conditions.
Mild steel: ~100 m/min
Alloy steel: ~50-80 m/min
Cast iron: ~30-50 m/min
1.4 Example Calculation
For a hob with a diameter of 100 mm cutting mild steel:
Cutting Speed (V): 100 m/min
2. Workpiece Speed
2.1 Definition
Workpiece Speed (ω): The rotational speed of the workpiece (gear blank) in RPM.
2.2 Importance
Synchronization: Must be synchronized with the hob spindle speed to ensure accurate gear tooth generation.
Gear Quality: Affects the quality and precision of the gear teeth.
2.3 Determining Workpiece Speed
Gear Ratio: The relationship between the hob spindle speed and the workpiece speed is defined by the gear ratio.
2.4 Example Calculation
For a gear with 20 teeth (Z) being cut by a hob rotating at 318 RPM:
3. Synchronization and Control
3.1 CNC Machines
Automated Control: Modern CNC gear hobbing machines can precisely control both the hob spindle speed and the workpiece speed. The synchronization is handled automatically by the machine's control system, ensuring accurate gear cutting.
3.2 Manual Machines
Manual Adjustment: On traditional, manually operated gear hobbing machines, the operator must carefully adjust and synchronize the hob spindle speed and the workpiece speed based on calculations and gear ratios.
4. Factors Affecting Speed Selection
4.1 Material of Workpiece
Hardness and Type: Materials with different hardness and properties require different cutting speeds to optimize tool life and quality.
4.2 Type of Cutting Tool
Tool Material: High-speed steel (HSS), carbide, and other materials have different optimal cutting speeds.
4.3 Desired Gear Quality
Tolerance and Finish: Higher precision and smoother finishes may require slower cutting speeds to reduce vibration and ensure accuracy.
4.4 Machine Capability
Maximum Speed: The maximum allowable spindle speed and workpiece speed, as well as the machine's stability at high speeds.
By understanding and correctly setting the spindle speed of the hob and the workpiece speed, efficient and precise gear production can be achieved, resulting in high-quality gear teeth that meet design specifications.
About Zhejiang Toman Intelligent Technology Co., Ltd. (Toman)
Toman is a company that adheres to the strategic vision of to be the leader in the professional field, with the mission of innovation to drive customer value enhancement, and the business philosophy of WISE, ALWAYS KEEP STEP AHEAD. In operation since 2006, the company includes the complete range of gear hobbing machine, gear cutting machine, gear machining compound machine tools, gear shaving machine, automatic production units, automatic turning production lines, and MES manufacturing execution system, etc. TOMAN today, is recognised as an industry leader for machines in China.
Toman cutting machines:
CNC high precision gear hobbing machine, gear chamfering machine, gear shaving machine, gear hobbing machine with integrated chamfering station etc.
-Profitable -Intelligent -Accurate
Our machines are suitable for commercial vehicle gear, passenger vehicle gear, construction machinery gear, especially for the processing of new energy vehicle gear.
For more information about cnc gear cutting machines, please visit our website:
www.zjtoman.com
www.tomanmachines.com
For further information, please contact:
Sharon Gong
Master of Mechanical Engineering
Whatsapp/Wechat: +8613589398142
Mail: sharon@zjtoman.com
Skype: sharon.gong525