Lesson 108 of Industrial Engineering ONLINE Course.
Refer to Industrial Engineering Case Studies Collection for case studies and productivity engineering applications
Lesson 111. F.W. Taylor - Productivity Engineering of Belting - 1893
Complete analysis of the mechanics of cutting have to use temperature-dependent constitutive models of cutting conditions. Cutting temperatures increase with cutting speed. As temperature in the primary deformation zone increases, temperature on the rake face of the tool increases and tool life decreases. At high cutting speeds, the tool-chip interface temperature approaches the melting temperature of the work material and chip starts melting.
The rise in machining temperature is different for different materials. Cutting temperatures are higher for harder materials at the same cutting speeds. For materials of similar hardness, cutting temperatures increase with ductility.
MANAGING THERMAL LOADS IN MILLING PROCESSES
https://www.secotools.com/article/21483?language=en
Effective Ways to Reduce Heat Generation
October 25, 2018
https://www.harveyperformance.com/in-the-loupe/reduce-heat-generation/
Makino's Research and Development Work in the Area
Makino, the machine tool builder made special studies in the area of cutting temperature to use the results in productivity engineering.
2013 Cutting Speed Maximization subject to temperature constraint
In the paper "MODEL DEVELOPMENT FOR CUTTING OPTIMIZATION IN HIGH-PERFORMANCE TITANIUM MACHINING" by DR. ZHIGANG WANG, SENIOR PROCESS DEVELOPMENT ENGINEER, MAKINO INC. and MARK LARSON, MANAGER OF TITANIUM PROCESS DEVELOPMENT, © 2013 Makino, Inc., the following conclusions were made.
An analytical cutting-force model for milling processes in Ti64 has been developed that provides good accuracy in predicting the cutting forces when compared to experimental cutting data.
• Numerical simulation was performed to estimate the temperature distribution at the tool/chip interface.
Cutting speeds and radial depth of cut have more dominant effects on cutting temperatures than do feed rates.
• Average cutting temperature at the tool/chip interface was measured in experimental testing and was found to be controlled within the characteristic temperature of WC material to maintain reasonable tool life in a stable finishing operation optimized to achieve high productivity as well as long tool life.
• Physical experimentation has verified that the proposed theoretical modeling approach can achieve high-performance machining of titanium alloys.
For a test job, test cuts were conducted at 1,174 rpm (optimal according to model) to check surface finish and tool wear under actual cutting conditions. During testing, the average temperature at the tool/chip interface reached 650°C (1202°F), below the 800°C (1472°F) critical temperature threshold, and the flank tool wear was less than 0.1 mm after 16 passes.
Makino FB127 Thermal Control Features
To ensure consistent accuracy over long cycle times, the FB127 machine is equipped with the following features:
Core-cooled ballscrews on all axes, including temperature control of the bearings support bracket area and motor mounting area, to maintain component temperatures.
Temperature control of the machine saddle and spindle carrier using oil passageways and temperature-controlled oil, ensuring tight control over saddle and carrier temperatures.
Addition of a separate oilmatic unit for tight temperature control of the machine elements.
Guideway hydraulic circuit (Nano slideway) on the X-axis to reduce friction and heat generation, yet also maintain stringent control over geometries and accuracies.
The FB127 spindle features Makino’s unique core-cooling and under-race lubrication system, minimizing thermal distortion at high spindle speeds.
https://www.makino.com/machine-technology/machines/vertical-machining-centers-3-axis/fb127
Parametric Optimization of Heat Generation during Turning Operation,
Journal of Mechanical Engineering and Automation, 2016; 6(5A): 117-120
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