Sustainable manufacturing: modern machine tool technologies to improve productivity, resource and energy efficiency

Transcription

1 Sustainable manufacturing: modern machine tool technologies to improve productivity, resource and energy efficiency Prof. Dr.-Ing. Jürgen Fleischer International Conference on Sustainable Manufacturing, ICSM 2014 Shanghai, 2014/10/23 wbk Institute of Production Science KIT University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

2 Outline Introduction Enabling key factors for modern machine tools Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 2

3 Outline Introduction Enabling key factors for modern machine tools Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 3

4 Introduction Demands on modern machine tools The magic triangle of modern production Demand Reality Quality Capital Investment 20 % Operating costs 80 % Time Costs Rising costs lead to new enabling key factors for modern machine tools Slide 4

5 Introduction - Costs of a machine tool Life cycle costs of a machine tool (10 Years) based on MATTES, K.: Bewertung der wirtschaftlichen Potenziale von ressourceneffizienten Anlagen und Maschinen / Effizienzfabrik - Innovationsplattform Ressourceneffizienz in der Produktion Forschungsbericht Rising energy costs Capital Investment 20 % Operating costs 80 % Higher product price but no higher product value Rising operating costs Rising prices in the energy market promote the use and the development of energy and resource efficient machine tools Slide 5

6 Outline 1 2 Introduction Enabling key factors for modern machine tools Productivity Energy-efficiency Resource-efficiency 3 4 Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 6

7 Enabling key factors for modern machine tools Productivity High Output High Quality Only value-adding processes Energy efficiency Low energy consumption Optimized use of energy Reutilization of energy Resource efficiency High life-times No waste Optimized maintenance Slide 7

8 Outline 1 2 Introduction Enabling key factors for modern machine tools Productivity Energy-efficiency Resource-efficiency 3 4 Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 8

9 Productivity Productivity High Output High Quality Only value-adding processes Energy efficiency Low energy consumption Optimized use of energy Reutilization of energy Increase productivity by: Selecting new cutting parameter Changing the machine behavior Resource efficiency High life-times No waste Optimized maintenance Slide 9

10 Axial depth of cut [mm] ICSM 2014 Productivity Strategies for chatter prevention Selecting stable cutting parameter combinations Out-of-process methods: 1. Prediction of stability lobes in stability lobe diagram: Analytic calculation, Simulation, Measurements, etc. chatter In-process methods: 1. Online chatter detection by monitoring of vibration, sound, power, etc. 2. Algorithm which analyses the signal and takes action on cutting parameters, if chatter just begins Stable zone source: Zabel Revolution speed of spindle [rpm] 2. Selection of cutting parameters: feed, spindle speed, depth of cut, Accelerometer PC Slide 10

11 Productivity Strategies for chatter prevention Passive strategies: Redesigning the (weakest) component structure Changing the system behavior Active strategies: Spindle speed variation Disrupt regenerative effects Input shaping method One control law for all feed drives simultaneously Increase damping Friction dampers, mass dampers, tuned dampers Non-Standard cutting tools, i.e. with variable pitch and variable helix milling tools Double sided milling Superimposed vibrations with effect of avoiding chatter Magnetorheological fluids Adjust stiffness Slide 11

12 Productivity Basic idea New Approach: Adaption of natural frequencies Fluid for mass addition Moved component with chamber design Filling chambers with liquid f~ c 0 m 0 +m fluid f~ c 0 m 0 + m liquid Carbon fiber reinforced plastic Reduction of basic component mass m 0 Carbon fiber reinforced plastic: High ratio between stiffness and density High damping capabilities Carriage with chambers Pump Liquid tank Liquid enables change of natural frequency m liquid m 0 f = f 0,empty f 0,filled Increased range for shift of natural frequencies with light-weight CFRPconstruction Slide 12

13 Stiffness S [N/m] Acceleration Sensor [100mV/g] ICSM 2014 Productivity New Approach: Adaption of natural frequencies Filling +m Fluid Constant m Fluid Emptying -m Fluid Time t [s] Modal analysis: frequency response f 1, empty f 2, empty f 3, empty empty full f 1, full, max f 2, full, max f 3, full, max Frequency f [Hz] Slide 13

14 Outline 1 2 Introduction Enabling key factors for modern machine tools Productivity Energy-efficiency Resource-efficiency 3 4 Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 14

15 Energy efficiency Productivity High Output High Quality Only value-adding processes Energy efficiency Low energy consumption Optimized use of energy Reutilization of energy Reducing energy use by: Resource efficiency High life-times No waste Optimized maintenance new controlling units based on the Riccati equation Slide 15

16 Energy-efficient feed axis controller State of the Art The control of feed axes is mostly done with a cascaded position control loops. The design of the controllers focuses on dynamics and positioning accuracy. Deficit: In this type of design, the power consumption of the control axis and the actuator required for the motors is currently ignored Goal: Creation of a new controller control strategy based on the Riccati equation for the feed axis Approach: cascaded position control loops Riccati equation X is the unknown n by n symmetric matrix and A, B, Q, R are known real coefficient matrices. Design of a multicriteria controller Modelling of a feed axis Model verification Definition of a test cycle Results Slide 16

17 Energy-efficient feed axis controller multi-criteria controller High positioning accuracy Power consumption minimization. Respect of the manufacturing tolerances Respect of the process dynamics Feed axis modelling The model is mechanically constructed as a twomass model in state space representation Model verification verified and parameterized by measurements on a test board Design of a multicriteria controller Modelling of a feed axis Model verification Definition of a test cycle Results Test cycle divided into 3 phases to differentiated evaluation of control strategies Test cycle The difference in power consumption between Ricatti and cascade control is 5.75 Wh. Results Cascade control Energy savings of 1,380 kwh / year Ricatti control Slide 17

18 Outline 1 2 Introduction Enabling key factors for modern machine tools Productivity Energy-efficiency Resource-efficiency 3 4 Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 18

19 Resource efficiency Productivity High Output High Quality Only value-adding processes Energy efficiency Low energy consumption Optimized use of energy Reutilization of energy Resource efficiency High life-times No waste Optimized maintenance Reducing resource use by: Adequate and adaptive lubrication of ball screws Slide 19

20 Ball screws and friction State of the Art In feed axis technology, ball screws are a widespread element for transforming rotary motion into translatory motion During the transformation, a friction torque arises The friction torque results in wear and has a clear influence on the life time of ball screws An adequate and adaptive lubrication shall optimize balls screw ś friction and wear Applications ball screw machine tools servo steerings Hypothesis Images: HIWIN, DMG, Arburg, TRW, Looser Adequate and adaptive lubrication can optimize the friction torque of the widespread construction element balls screw and thereby raise its resource-efficiency due to reduced wear Slide 20

21 Dosing unit and lubrication algorithm Dosing unit Lubrication based on temperature and friction torque Developed lubrication algorithm Actual friction torque (t n ) Temperature (t n ) Load (t n ) Revolution (t n ) Lubricant store Pneumatic cylinder Comparison: Comparison between actual and simulated friction torque Friction model: Simulated optimum friction torque (t n ) Consideration of temperature development lubrication? Torque [Nm] lubrication! Temperature [ C] Objective Mechatronic dosing unit detects demand for lubricant and starts an adequate lubrication. cycle Decision Results Dosing unit for the individual, adaptive lubrication of ball screws and a lubrication algorithm which allows the comparison of a simulated optimum with metroligically detected actual values. Slide 21

22 Temperature [ C] Friction torque [Nm] ICSM 2014 Life cycle detection - Results Results Individual, sensitive friction torque End of life criteria: Particles in grease particles Position [mm] Temperature as additional criteria Standard Adaptive End Position [mm] Lifetime nom. [%] 43.5 % higher lifetime due to adaptive lubrication Significant raise of lifetime due to adaptive lubrication shown for constant operating conditions. Lubrication demand only 1/3 of manufacturers recommendation. Slide 22

23 Outline Introduction Enabling key factors for modern machine tools Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 23

24 Cyber-physical Systems Definition A cyber-physical system (CPS) is a system of collaborating computational elements controlling physical entities CPS can today be found in automotive, manufacturing, consumer appliances Automation pyramid CPS-based automation Motivation The commissioning of components in machine tools includes high manual effort Manual input during configuration of components leads to failures Slide 24

25 Cyber-physical Systems Approach Extending the machine elements with communication module Transfer of configuration data during installation No communication modules Component transmits configuration data Result Improved procedure for commissioning using self-describing, networked machine components. Shorter commissioning duration Avoid data entry errors Support to specialists Slide 25

26 Cyber-physical Systems BMBF Secure-Plug-and-Work Description of the components The data for the commissioning of the components are stored in a standardized data format based on AutomationML (XML-based). Standardized interface Transfer of data via the standardized open bus system OPC UA (client-server) Storing the data Microcomputers-based storage and processing of commissioning data RFID-based storage of data Project sponsor Project supervisor Project consortium Slide 26

27 Outline Introduction Enabling key factors for modern machine tools Future trend: Machine tool as a Cyber Physical System Summary and Outlook Slide 27

28 Summary Increase of the productivity and the energy efficiency of a maschine tool thanks enabling key factors: Productivity Energy efficiency Ressource efficiency Adaption of natural frequencies with mass shifting Carriage with chambers Creation of a new controller control strategy to reduce the energy consumption Cascade control adaptive lubrication of the balls screw element Pump Liquid tank Ricatti control The future of machine tools are Cyber-physical Systems with: machine elements with communication module improved procedure for commissioning Slide 28

29 Outlook Productivity Adaption of natural frequencies Carriage with chambers Energy efficiency adaptive lubrication of balls screw Pump Liquid tank development of new carriage with more chambers Validation of approach during cutting process, e.g. milling Further investigation of the adaptive lubrication by dynamic process states Cascade control Resource efficiency Ricatti control Ricatti controller Extension of the existing studies for energy Optimal control in function of operating scenarios CPS Cyber Physcal Systems Slide 29