In Jet Interferometry for Ultra Precise Electrolyte Jet Machining

Lead Research Organisation: Loughborough University
Department Name: Wolfson Sch of Mech, Elec & Manufac Eng

Abstract

Ultra-precision machining techniques permit the manufacture of the most high value components. Component complexity continues to develop and researchers are challenged to remove smaller volumes of material in a more precise manner while maintaining work piece integrity. Micro-machining, micro electrical discharge/electrochemical machining and high speed laser processes are now commonly used for micro component manufacture for the microelectronics, biomedical and aerospace industries. Electrolyte Jet Machining (EJM) is a newer process which is yet to be embraced in a meaningful way by these industries. The process itself has several attractive capabilities, such as the ability to process difficult to machine materials with no resulting thermal loading of parts and no induced residual stress. A particularly interesting aspect of the technology is that, with simple modifications, the process may also run in reverse as an additive manufacturing technique to precisely deposit materials.

The work to be undertaken here will make use of a custom built MkI prototype EJM tool at the University of Nottingham which was recently completed by the Investigators. As well as being able to perform material surface machining, this has unique capabilities and represents a significant advancement in terms of the state-of-the-art. The investigators have demonstrated a new functionality in terms of computer controlled signal generation which is capable of creating so called 'dial-up-surfaces' or surface manufacture against a specification for surface texture/morphology as opposed to surface roughness alone. Surface texture control within a machining process is notoriously difficult to achieve, commanding a premium price for high value components since surface condition often dictates performance. Typically, micro surface textures are of interest to several groups of researchers outside of engineering. These include biomedical researchers who study cell/surface interaction and aerodynamicists who look to enhance the performance of surfaces interacting with fluid flow.

To unlock the full potential of EJM, novel on machine instrumentation must be created. This instrumentation must allow fast, accurate, high precision process data to be collected to support real-time adaptive process control. It should also allow for on-machine surface metrology to be undertaken which is increasingly an essential requirement for successful industrial processes. For EJM to be successfully exploited in both a research environment, and critically as a viable production technology this novel set of process instrumentation must be investigated and then developed to allow accurate and timely metrology to be undertaken on the machine while the process is under way.

The instrumentation to be investigated here will be split into two key areas. Firstly, a novel form of in-jet laser interferometer will be designed and optimised for use with EJM. The sensor will provide high speed, high precision process control measurement data. This will allow the material removal rate of the process and the form of the material removal area directly in line with the jet to be measured. In addition a fibre optic arrangement will be included to allow beam delivery. Since stand-off distances are short within EJM this will be possible with a high brightness source (laser) to deliver a spot to the work piece. In addition to the in-jet laser two additional sensors will be deployed to the machine head, external to the jet. These will be custom designed single line coherence scanning interferometer devices, configured for single line based detection (to allow increased acquisition rates).

These techniques will allow the collection of disparate data sets in real-time which will be manipulated through control algorithms to perform online processing and adaptive machining. This represents a step change in the viability of this process for the production of complex and high value parts.

Publications

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Hovell T. (2018) Low coherence interferometric fibre based in-situ measurements of surface roughness in air and in water in European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 18th International Conference and Exhibition, EUSPEN 2018

 
Description The research has developed the use of a form of optical sensing using a bare (lens-free) fiber. In previous work this type of sensing has been used for biological samples, however it has not been investigated for use on metals or other manufactured surfaces in significant detail. The key findings are that the sensor is able to measure manufactured features with high accuracy allowing both the shape and surface finish of objects to be measured. The system is also well suited for use on machine tools, and it has been demonstrated working in both air and liquid environments to demonstrate the possibility of using the sensor in non-ideal measurement environments. In addition the sensor has been deployed within a jet of liquid electrolyte to make measurements from within the jet, a capability that will be useful for applications in processes such as electrolyte jet machining systems.
Exploitation Route The work is ongoing with follow-on funding in the form of an institutionally awarded PhD student. Publications are being prepared by the student to further disseminate findings from the original project. In addition, the optical components are being integrated into a fully packaged demonstration system, this is being undertaken as part of an undergraduate dissertation project in Product Design Engineering. The prototype instrument will then be used for on machine trials of the sensor.
Sectors Manufacturing, including Industrial Biotechology

 
Description PhD Studentship
Amount £195,000 (GBP)
Organisation Loughborough University 
Sector Academic/University
Country United Kingdom
Start 09/2017 
End 01/2021
 
Description CIRP Meeting 2016 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Attended CIRP meeting, to take part in technical discussions related to precision engineering, metrology, and manufacturing.
Year(s) Of Engagement Activity 2015,2016
URL http://www.cirp.net/meetings-conferences/winter-meetings.html
 
Description Engineering Experience Day - Sixth form students from Leicester 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A one day workshop consisting of a range of activities and presentations was delivered to a group of Sixth Form students. Examples of research activities in robotics and sensing were presented, and an engineering design challenge activity was run. The aim was to enhance uptake of STEM subjects and encourage applicants to continue HE or FE studies in STEM related subjects.
Year(s) Of Engagement Activity 2017
 
Description Lab tours and technical demonstrations 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Lab Tours with demonstrations of equipment were given to visitors from the EPSRC funded 'Light Controlled Factory Project' (EP/K018124/1). As part of the tour the OCT measurement test rig we created was demonstrated.
Year(s) Of Engagement Activity 2017
 
Description Poster presentation at European Society for Precision Engineering and Nanotechnology Conference, EUSPEN 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A poster was presented at the EUSPEN international conference, held in Venice in June 2018.
Year(s) Of Engagement Activity 2018
URL https://www.euspen.eu/events/18th-international-conference-exhibition-4th-8th-june-2018-2-2-2/
 
Description Presentation of the results to members of the HVM catapult at the AMRC in Sheffield 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The work completed and results achieved were presented to initialize discussions with the aim of submitting an application for continuation funding.
Year(s) Of Engagement Activity 2018
 
Description Presentation of the work undertaken to the EPSRC Future Advanced Metrology Hub 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Members of the Future Advanced Metrology Hub attended a one day meeting at Loughborough University and recent relevant research conducted at Loughborough was presented to them.
Year(s) Of Engagement Activity 2018
 
Description Presentation to the Midlands Regional Board of the EEF 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact I presented research related opportunites for industry and businesses to work more effectively with universities in general, but also highlighted specific projects and opportunities for engagement with relation to my work at Loughborough University
Year(s) Of Engagement Activity 2017
URL https://www.eef.org.uk/
 
Description Research Seminar Loughborough University Wolfson School: Sensors and metrology for intelligent automation & High Value Manufacturing 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact A lecture and seminar discussion was given on the subject of sensors and metrology for intelligent automation & high value manufacturing.
Year(s) Of Engagement Activity 2017
 
Description Robotics and metrology in advanced sensor manufacturing 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact This was a scoping workshop conducted with employees from GE Digital Solutions to discuss future collaborative research activities, and how they might benefit from future use of cobots
Year(s) Of Engagement Activity 2018
 
Description Talk at the SPIE Optical Sensing and Detection, Strasbourg, France, 22 Apr 2018 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A presentation was given covering the creation of a lensless fibre-based sensor.
Year(s) Of Engagement Activity 2016,2018
URL http://spie.org/EPE/programtrackdailyschedule/optical-imaging-and-sensing