Questions concerning the contents of the lecture Manufacturing Technology

Transcription

1 Questions concerning the contents of the lecture Manufacturing Manufaturing I 1. Introduction to Manufacturing No related questions 2. Measuring and Testing in Production 1. Explain systematic errors and random errors and name two examples for each. How can you minimize the effect of these errors on the work result? 2. What disturbances influence the production process (one example each)? 3. Explain the pneumatic measurement of cylindrical workpieces. 4. Explain the measurment of lengths with a interferometer. What is the comparision standard. 5. Why must measurments of high accuracy and high reproducibility be done in an air conditioned environment? 6. Why can it be necessary to determinate the structure of the boundary layer? With what parameters would you describe the structure (Phases, grain size, texture-anisotropy)? 7. What structure parameters can be determined with a light microscope? 8. How are residual stresses caused and how can they be measured? 9. Why is the structure of the workpiece affected by the production process (arbitrary example)? 3. Principles of Machining with Geometrically Defined Cutting Edge 1. Specify the influencing factors for choosing the geometry of the cutting part. 2. How to increase the stability of the cutting edge? 3. Specify the measures to reduce the passive force respectively the tendency to chatter. 4. Indicate and explain the types of wear at the cutting part. 5. Signify the main measured wear variables. 6. Specify the causes of wear and indicate their dependence of the cutting speed. 7. Explain comb and transverse crack formation. 8. Illustrate the term built-up edge formation and explain the progression of the wear land value and the surface roughness dependent on the cutting speed. page 1 of 8

2 4. Cutting Materials and Lubricants 1. Which are the components in high speed steel (HS), WC-Co-based cemented carbides (HW) and cermets (HT)? 2. Explain, why complex tools such as broaching and gear hobbing mills are made of high speed steel (HS)! 3. Why do cermets (HT) have a higher thermal strength than WC-Co-based cemented carbides (HW)? 4. What is the maximal chip thickness (monolayer) which can be realised by the PVD-coating setup? 5. What are the advantages of CVD-coatings compared to PVD-coatings? 6. Which coating materials are coated? 7. What problems can occur because of the coating of the tool? 5. Cutting materials II 1. Why have cemeted carbides a higher toughness than ceramics? 2. Explain, why steel is not machined by tools made of polycrystalline diamond (DP)! 3. What is the lower limit of workpiece (steel workpiece) hardness (Rockwell HRC) to be economically machined by polycrystalline boron nitride (BN)? 4. Explain the advantages of dry machining! 5. How does the lack of lubricants in machining operations concern the accuracy of the workpiece geometry? 6. Why are milling processes conducted without any lubrication when using oxide ceramics as cutting tool? 6. Cutting Criteria 1. Which heat treatment is used to reduce the hardness of a microstructure? Describe the appropriate temperature control. 2. Which microstructure exists after heating (T=1050 C, 2h) and cooling on air? 3. Which properties has a normalised microstructure? 4. Illustrate the characteristics of hard machining. 5. Why are free cutting steels well machinable? 6. Due to which special feature the machinability of cast iron materials is influenced? 7. Specify the factors influencing the machinability of aluminium alloys. 8. Due to which material properties nickel-based alloys are difficult to machine? 7. Manufacturing Methods with Geometrically Defined Cutting Edges 1. Describe the contact conditions of longitudinal cylindrical turning! 2. Specify the cutting speeds for roughturn and dress-turning! 3. Which benefits result by higher cutting speeds? 4. Which benefits have the high-precision-hardturning compared to grinding? 5. Which alternatives exist for surface-milling? 6. Which cutting materials can be used for milling with a face milling head? 7. Which cutting speeds can be realised in the above mentioned case? page 2 of 8

3 8. Practical use of Manufacturing Methods with Geometrically Defined Cutting Edges 1. Please structure the methods with geometrically defined cutting edges and rotationally main movement. 2. Please term the alternative drilling processes. 3. Which alternative wear types exist by drilling tools? 4. In what way does the twist drill angle and the workpiece hardness correlate? 5. Which alternative sawing types exist and by what properties are they characterised? 6. What is the difference between planing and shaping? 7. Which properties characterise the broaching technology? 8. Which criteria are used to identify the optimal cutting parameters? 9. Which aids are usually being used for the identification of the optimal cutting parameters? 10. Which coefficients describe the manufacturing time and cost? 11. Please give one example for an analytical, an empirical and a numerical model 9. Cutting with geometrically undefined edges: fundamentals 1. Which IT-Classification can be reached by grinding in comparision to other manufacturing processes and why? 2. How can the cutting operation be described for grinding? 3. Describe the energy distribution and the heat flow during cutting edge engagement. 4. Which wear forms does exist for grinding wheels? 5. How is a grinding wheel composed and what tasks does the respective elements have? 6. What are the different grain materials, which properties do they have and for what application do they suit? 7. What are different types of bond, what are their properties and application areas? 8. What is the main difference regarding the indication of conventional grinding wheels and grinding wheel with diamond and CBN? 9. What is the difference between static and kinematic cutting edges? 10. How is the material removal rate Q w defined for surface and for external cylindrical grinding? 11. What is the difference between creep and pendulum grinding? 10. Christmas lecture no related questions 11. Cutting with geometrical undefined cutting edge: Grinding tools and grinding wheel preparation not available so far page 3 of 8

4 12. Grinding with undefined cutting edges processes and application examples 1. What is the material removal-rate a quantum for? 2. How do you assign the material romoval volume? 3. In which procedures for generating a rationally symmetric geometry is the tool feed a) radial b) axial? 4. What is the difference between down-grinding / up-grinding? 5. Name four common grinding procedures! 6. How can you avoid workpiece deflection in the process of external cylindrical grinding? 7. What problems can occur in the internal cylindrical grinding process and how are they caused? 8. What are the advantages and disadvantages in deep- and pendulum-grinding? 9. What are the typical devices, which are machined in centreless grinding? 10. What are the four active principles of the cutting edge engagement in machining with geometrically undefined cutting edges? 13. Excavating: Thermal excavating 1. Why must the wire electrode trail in EDM cutting operations? 2. What electrode materials are generally used for EDM Machining operations? 3. Demineralised water is generally used as a working medium in EDM cutting 4. operations. List the advantages and disadvantages associated with the use 5. of demineralised water. 6. Complex geometries with angles of inclination up to 30 can be produced in 7. EDM cutting operations. Name the two process-related limitations. 8. Name the residual stress condition affecting the area around the surface 9. of workpieces which have been machinend in EDM and ECM operations. 10. List the media used in EDM machining operations and outline their function. 11. Describe the material removal principles on which EDM and ECM are based. 14. Rapid Prototyping and Rapid Tooling not available so far page 4 of 8

5 Manufacturing II 1. Primary shaping - Casting 1. Explain the change of the crystal lattice during cooling down the liquefied material at the example of pure iron! 2. Outline and explain the globulitical, fringe crystal and monocrystalline solidification at turbine blades! 3. Coarse grain contra fine grain! 4. Nominate and explain different casting properties (5)! What is meant with shrinkage cavitation and how does that casting damage arise? 5. How are the moulding and casting processes defined? 6. Nominate and explain different methods of core production! 7. Into which main groups (3) are the casting processes classified? 8. Explain the principal work flow of the casting processes which belong to the three main groups! 9. Nominate and explain the essential parts of a casting simulation! 10. Explain the proceeding of the rapid-prototyping process for production of casting patterns! 2. Primary shaping - Powder metallurgy 1. Describe the difference between ideal crystals and real crystals! 2. Scetch the principle of stationary diffusion. Which diffusion laws do you know? 3. Specify and eyplain the three types of diffusion 4. Scetch - for the three types of diffusion - the temperature dependency of the diffusion coefficient D! 5. Explain the two significant methods for powder production, the methods for the characterization of metal powders and the three different alloying techniques! 6. Scetch the phases of compaction (use a cylindrical compact)! 7. Explain the terms density distribution, ejection force and spring-back! 8. Explain an industrial sintering process on the basis of a sintering conveyor furnace! 9. Explain the reasons for a sizing operation! Explain then a sizing operation, as example use e.g. the ball sizing of bushes! 10. Specify and explain the schematic flow of conventional PM-processes! 11. Which possibilites are provided by PM-technology for producing highly loaded parts? 12. Specifiy and explain the influencing parameters on the produciton costs of PMparts! page 5 of 8

6 3. Principles of forming & bulk forming 1 1. Explain the elastic and plastic deformation in the atomic structure. 2. Outline the progress of stress in a cold forming process with annealing for recrystallisation. 3. Outline the Mohr s stress circles with a uni-, bi- and triaxial compressive stress state. 4. Explain the definition of forward and backward extrusion. 5. Name and explain the requirements on lubrications. 6. What is a shringage ring system and for what are they used? 7. Which production tolerances are achievable in the different production processes forming and cutting? 8. Name and explain advantage and disadvantage in froming processes opposed to cutting processes. 9. What has to be done when the maximum natural strain is reached? 10. Name the influence of forming temperature on material properties. 4. Bulk Forming II 1. What is the difference between a flow curve at low and at high temperatures? 2. What is the transition temperature for hot forming (for steel, for lead)? 3. When do you use hot forging, when do you use cold forging? 4. Why are head and foot taken away from a cast ingot before or latest after the forging operation? 5. Why can only worse tolerances be reached in hot forming in comparison to cold forming? 6. Why are crankshafts not machined from bulk material? 7. What is the purpose of the flash in closed die forging? 8. What types of wear do occur in hot forging tools? 9. Why are forging tools not made of case hardened steel? page 6 of 8

7 5. Sheet Metal Forming I 1. Name and explain briefly the most common tests for analysis of the flow curve in sheet metal forming. 2. Explain the term anisotropy and name the most important types of anisotropy. 3. Briefly explain the most important tests to examine sheet metal quality. 4. How do you analyse the circle grid test? 5. Name the analysing tests to obtain friction coefficients in the sheet metal forming. 6. Briefly explain the principle of deep drawing. 7. Name the most common process variations in deep drawing. 8. Name four parameters that influence the result for a deep drawing process. 9. Name the factors on which the maximum expansion ratio in collar forming depends. 10. Sketch the neutral fibre in a stretch drawn profile. 6. Sheet Metal Forming II 1. Which are the three most common failures that can occur as a result of a spinning process? 2. Which elastic effect is responsible for many workpiece inaccuracies in sheet metal forming? 3. Name three types of bending processes. 4. Which process is particularly suitable for the manufacture of long sheet metal parts with a profiled cross section? 5. Under which conditions can a material be superplastically formed? 6. Give a description for a typical tube hydroforming process. 7. Explain the principle of laser bending. 8. Name three types of magnetic forming processes. 7. Process Design - Methods and Tools used in product - based production planning 1. Give a definition of the expression technology chain? 2. State differences between technology chain and manufacturing sequence? 3. Name the stages of generating technology chains? 4. Describe the evaluation of manufacturing sequences? 5. What are fuzzy data? 6. What is a fuzzy set? page 7 of 8

8 8. Fine Blanking 1. What does the sheared surface look like in blanking? 2. Why is this surface not completely smooth? 3. Please explain the punch force over punch travel for blanking! 4. Why are blanking tools made of hardened and tempered material? 5. Why are sheet metal parts of high quantity made preferably through blanking and not through CNC-wire electro-erosion? 6. What is the maximum stroke frequency of a blanking machine? 7. Why is there an increased fraction of smooth surface in fine blanking in comparison to normal blanking? 8. What is the reason behind the difficulty classes in fine blanking? Why can a protuding part be not arbotrarily thin? Why can a radius not be arbitrarily small? 9. Can hardened and annealed materials be used as workpiece material in fine blanking? 10. What is the maximum plastic strain in fine blanking? 9. Fertigungsfolgen: Seminar no questions available page 8 of 8