Novel Machine Tool Feed Drive Design for High Dynamic Stiffness and Ultra-Low Vibration

Increasing demand for highly efficient production systems has been one of the primary subjects in the 21st century, this has led to the development of complex and flexible manufacturing systems and in-process measurement tools. The tasks performed on a CNC are complex than ever with an expectation to perform machine dimensional measurement with the help of retrofit probing systems. However, high power requirements of machining operations are the prime attributes that their feed drive system must possess this gives rise to high levels of vibration consequently causing high dynamic errors. This leads to less accuracy during measurement operations hence posing a need to have vibration-free measurement machines or commonly known as Coordinate measuring machines (CMM’S). To solve this problem, there is a need for a novel feed drive system that can help in the reduction of vibration during measurement, this can lead to more accurate machining operations as well as efficient use of scanning probes.

In this thesis, various solutions of high dynamically stiff novel feed drive solutions capable of Nano positioning have been studied in detail. Since the goal of the project is based on feed drive systems two major areas were explored including, Bearings Design and Drive Train Design. Other miscellaneous options were also studied which fall in either of the groups or are just a combination of them. Two parameters are at the core of the research problem, 1) High Stiffness capability of Machining operations and 2.) Precision measurement.

Studies reveal that many possible solutions exist but many of them are not economically viable while others provide Nano positioning but are incapable of having high stiffness required in the machining centre. Also, the Integration of Air bearings in Medium to large-sized machine tool CNC is missing. This results in a gap knowledge, in terms of Bearings Design which was studied thoroughly to result in a novel hybrid feed drive. The study was focused more on the bearing design as it offered many promising solutions. it is deduced in the section 2.5 that the magnetic bearings and air bearing provide an alternative solution.

The problem was understood and further explored by carrying out market research followed by a critical review of various technical papers. Most of the breadth, as well as depth in the field of Feed drive design, was covered and documented in detail for further research. Various Novel Ideas were generated and rated based on their viability leading to novel hybrid bearing design.

All the preliminary Analysis necessary for the validation and verification of Novel hybrid bearing original as well as the prototype design has been set for further validation, Including the Finite element modelling of the original feed drive its validation with experimental modal analysis and detailed design and analysis of the Novel Hybrid bearing design and the prototype.

A prototype that can replicate the physics of the Novel hybrid bearing solution has been Designed and Manufactured with all the plans of experimental Analysis carried out for further research and development.