What exactly does labor energy saving mean?

Complex: Introduction to the topic of market conditions: Market requirements: Competitive through:


1 Complex: Introduction to the topic 1. How do you justify the statement production technology is a determining economic competitive factor? Enables the production of capital and consumer goods, still coveted export articles of the respective country 2. Name characteristic market conditions and requirements under which a manufacturing company has to assert itself! Market conditions: globalization of the markets, market saturation, shorter innovation cycles, cost and time pressure, turbulent change, high labor costs, short working hours, location factor Market requirements: increasing product individuality and complexity, increasing number of variants, decreasing lot sizes, high demands on quality and adherence to deadlines Flexibility, innovations, increased productivity and quality, reduced costs, increased reliability, short processing and delivery times, customer service 3. How can a manufacturing company gain competitive advantages? Innovations, special features compared to the competition (economic efficiency, work and operating safety, workpiece size, processing variety), price, etc. 4. Characterize the economic importance of machine tool construction (in general)! Enables the production of capital and consumer goods, still coveted export articles of the respective country 5. Characterize the German machine tool industry! Predominantly medium-sized, high export volume compared to total production (70%), high quality standards, production according to customer orders, highly qualified and experienced staff, high added value per employee, innovative 6. What requirements are placed on machine tools from the customer's point of view? - high work accuracy - high volume output - short production times - high reliability - low space requirement - low investment and operating costs - great flexibility - low production costs - good integrity - easy to repair and good service - simple operation and attractive appearance 7 Supervision of production facilities? Give examples! Supervision of the production systems by the machine tool manufacturer over the entire life cycle. Examples: inspections, delivery and installation of spare parts, training, maintenance, emergency services 1

2 8. Name the four groups of technical properties of machine tools with 3 examples each! How do these groups of technical properties affect the machine user? Working accuracy: Examples: static, dyn. And thermal behavior, geometrical and kinematic working accuracy Impact: Manufacturing accuracy Capability: Examples: speed, acceleration, force, torque, footprint Impact: Productivity Environmental behavior: Examples: Safety, ergonomics, recycling Impact: Customer acceptance Reliability: Examples: Maintenance and service friendliness, reproducibility Impact : Process capability 9. Name the four properties of machine tools that have a direct effect on their working accuracy! Which properties determine which defects on the workpiece? Geometric accuracy Cause: Manufacturing and assembly errors -> (dimensional, shape and positional deviation), static behavior Causes: elasticity of materials -> (dimensional, shape and positional deviation), thermal behavior: Causes: Material behavior when there is a change in temperature, heat sources, -senken -> (dimensional, shape and position deviation), dynamic behavior: cause: elasticity v. Wstoff, dyn. Load-> (imbalance of the workpieces, surface defects) 10. How can the designer of a machine tool reduce the future production costs on this machine tool? Reduction of time / piece (higher cutting speed -> selection of tools for higher cutting speeds), avoidance of time-consuming tool changes, automatic workpiece feeding 11. What characteristics are machine tools classified according to? Name at least 6 characteristics with two examples each! Purpose: single-purpose, special, universal machines number of produc. Process Single process, several processes Degree of automation manually operated, NC machine, cell, center, ... Type of drive conventional, direct drive Accuracy Heavy machining, precision machines Main spindle position horizontal, vertical Number of NC axes 3-axis BZ, 5-axis machining center Machine kinematics: serial, Hybrid, parallel 12th Describe the levels of automation of machine tools! Machine drives for cutting and feed movement, movement, size, workpiece and tool determined by the operator 2

3 NC machine Machine with numerical control, automatic sequence of cutting, feed and infeed movement center tool storage, manual change of cell workpiece storage and automated workpiece change (series production possible without operator intervention) System consisting of one or more machine tools, workpiece flow system, tool logistics, supply and disposal systems , connected to production control, computer with parts assortment takes over control 13. Name the components that machine tools consist of with their tasks and 2 examples each! Frame: bed frame, angle frame, C frame, portal, gate or frame frame Tasks: determines the machine tool structure, supports and secures other assemblies, absorbing forces and torques Main spindle: air-bearing HS, magnetically bearing HS, hydrostatically bearing HS Tasks: holding WZ or Wst. Adapter, realize the rotary movement, transfer of forces and torques Drives: main drive, auxiliary drive Tasks: generation of main, auxiliary and auxiliary movements, provision of services Guides: roller guides, sliding guides Tasks: enable linear movement between assemblies, transfer v . Force and torque Foundation: Isolation plate, leveling shoe, hydr. Damper Tasks: Stability, adjustment, alignment, insulation of tool or tool holder and changing devices: tool turret, pallets, chuck, double gripper, chain store 3

4 tasks: picking up, fixing, changing, provision of tool control, measuring and regulating equipment: control panel, dial gauges Tasks: information processing, guaranteeing the program flow, supply and disposal equipment: cooling, lubricating equipment, chip disposal Tasks: securing energy supply, guaranteeing d. Required auxiliary processes Machine cladding: Sliding door, sheet metal cladding Tasks: Occupational safety, design accessories: Lubrication, ejector, energy supply Tasks: Functional assurance, extended range of functions 13. Using the example of a machine tool (horizontal or vertical milling machine, lathe), describe the structure of the NC coordinate system according to DIN 66217! Right hand rule. middle finger = z axis, goes into the main spindle, index finger = y axis thumb = x axis Movements of the workpiece: x, y, z opposite to the tool coordinate system Movement tool: x, y, z for rotations: right-hand screwing rule. Designation a, b, c, complex: Function-determining assemblies of machine tools 14. Explain the term vertical integration! Depth of production = in-house production / entire production Production: = Transformation of production factors into goods 15. Name the 3 components of the machine setup with their tasks and requirements! Subsoil absorption of the load -> load-bearing capacity, rigidity foundation static rigidity -> perm. Inclination & deflection dynamic behavior -> dynamically soft or stiff vibration-isolated, hall floor as a foundation or special foundation block close to the building site. rigid -> foundation bolts, adjustable -> wedges 4

5 Elastic, damping, insulating-> insulating plates 16. Explain the three installation principles for machine tools! without foundation (for machines with sufficient inherent rigidity, small machine tools) with foundation (for fine processing machines -> foundation block for low natural frequency, possibly isolated installation natural frequency reduction) (for machine tools with insufficient inherent rigidity or open frictional connection between the frame components. 17. Name the tasks and requirements for machine tool frames! Tasks: -capture all assemblies -secure the position in operation -secure d. accuracy and productivity requirements: -sufficient static rigidity -good dynamic behavior -high economic efficiency -favorable in production and assembly 18.Which designs and types of machine tool frames you know? Name essential properties! Types of construction: -open construction: bed- L- C-construction -closed construction: O-construction types of construction: welded steel construction -cost-effective with small number of pieces -low mass compared to cast iron (iron) with the same stiffness -light Possibility to change -good and targeted contact damping cast construction (iron) (in the cf. to Ssk) -favorable production in large quantities (sometimes from 2 pieces) -no annealing treatment necessary - good material damping (cf. to Mgk) -material inexpensive -thermal conductivity better -stiffness at same mass higher mineral cast constr. -Short production time -clean casting surfaces, x -better material damping 19. Enter the definition of the static stiffness! For the machine tool, is it linear or non-linear (and why)? Static stiffness = (change in load / change in deformation) C = dF / dx linear because in the elastic range. only non-linear at connection points 5

6 20. Name the constructive influencing variables on the static rigidity! - Material (E, G module) - Dimensions (component length, force application point), - Cross-sectional shape (moments of inertia), - Ribs, bulkheads, openings - Clamping conditions (contact surfaces good flatness, size number of contact points) (screw connections many small screws instead of less large) 21. Explain the causes and properties of the three types of vibration occurring on machine tools! For which is the dynamic stiffness defined and how? Free oscillation: -Not under the influence of external forces, occurs when the oscillator (hammer) is deflected once. Tooth meshing joint, changing cutting forces Self-excited Schw .: -Energy source from which Schwinger absorbs energy, e.g. Basic noise of the cutting forces Dynamic stiffness = (amplitude of the excitation force / amp. Of the generated vibration) for separately excited and forced vibrations; or: (amplitude of the load / amplitude of the deformation) 22. What is meant by thermal behavior on machine tools and which measures have a positive effect on this property? Every Wst shows a certain behavior at different temperatures. (expands or contracts) Measures: -Heat emission v. lower heat sources in the machine - move heat sources to the outside - materials with the same coefficient of thermal expansion 23. Divide the guides according to their surface contact! Explain the functional principle and the existing properties! Slideway: -hydrodynamic, hydrostatic, aerostatic, magnetic -WZM with high rigidity, good damping, medium accuracy, problems with heavy loads at low speeds. Roller guide: - limited or unlimited displacement path - machine tool with high uniformity of movement, feed and guidance accuracy Combined sliding roller guide: sliding guide with hydrostatic lubrication 24. Sketch a rectangular guide and explain the terms: support guide, open guide system, play adjustment in the sides - or circumferential guide, wide and 6

7 narrow guide! Carrying guidance:? Open management system:? Siel setting in the side or. Circumferential guide:? Wide guide (above), narrow guide (below) 7

8 25. Which elements are assigned to the main group main spindle? actual component main spindle the bearings for radial and axial position determination and force transmission the seals the elements arranged on the HS for their type of drive tool or workpiece mounting surfaces possibly quill for axial displacement of the HS elements for control, automation such as: tool clamping devices, coolant supply, measuring sensors 26. What is meant by main and auxiliary bearings, drive without lateral force, cantilever arm, optimal bearing spacing for machine tool main spindles? Main bearing front radial and axial bearing secondary bearing rear radial bearing cantilever arm bearing on one side of the HS flange transverse force-free drive only transmits a torque from a separately mounted drive element, e.g. with a belt drive 27. Why do roller-bearing main spindles dominate over slide-bearing ones? 8th

9 - higher rigidity (due to stiff rolling elements and thin lubricating film) - pretensioning, therefore even stiffer - lower wear (due to lower friction) - lower friction (rolling friction instead of sliding friction) -> faster speeds possible - no increased start-up friction, no running-in time - inexpensive, because standardized purchased parts 28. Which functional principles can be used to build non-contact seals? - Capillaries - Sealing air (mostly used) air pressed from the outside inwards 29. Divide the drives of cutting machine tools according to their tasks! Main drive (red e.g. of the tool), power take-off (transl. E.g. of the tool), auxiliary drive (tool / workpiece change, etc.) 30. Name requirements and evaluation criteria for main and power take-offs! HA: Conversion of the rotary motion into translatory motion through e.g. Crank gear, spindle / nut gear NA: speed adjustment through e.g. Conversion gearbox 31. What is meant by dependent or independent feed in cutting machine tools? see Specify in a block diagram how dependent or independent feed rates can be implemented in cutting machine tools! 9

10 33.What are stepped and what are steplessly adjustable main drives? The speeds of the main drive can be adjusted continuously (e.g. by means of a bevel gear, shell gear) or in fixed steps (gearbox). 34 Why is the efficiency of the main drive of a machine tool particularly important? Most powerful drive, does the actual work, energy saving 35. Draw the basic variants for the power speed and the torque / speed design for cutting machine tools! Under what conditions are these variants used? 1 0

11 36.What frame designs are typical for presses? Explain their advantages and disadvantages! C-frame: Advantages: -good accessibility of the work area -simple construction -inexpensive O-frame: Disadvantages: -asymmetrical spring-back - only usable up to medium-high forces Advantages: -symmetrical spring-back - can be used for all force ranges -higher accuracy of the bearing guidance Elaborate production - poor accessibility of the work area 37. Sketch a C and a gate frame! Enter the position of the forming forces and the resulting deformation of the press frame! 1 1

12 38.What is the role of expansion anchors in press frames? -Tensioning of the frame -Improving the static strength -Reduction of the non-linear due to the influence of joints 39. Explain the operating principle of presses that are bound away! Which drives are used for this? 40. Explain the relationship between nominal force angle or nominal force path and pressing force in crank presses! What is the effect of changing the nominal force angle? 1 2

13 41.What difference is there in terms of the force-displacement relationship between crank presses and crank-toggle presses? 1 3

14 42. Explain the advantages and disadvantages of the top and bottom drive for presses! 43. Sketch the basic structure of a motor flywheel drive and explain the function! 44.What machine-side options do you know of realizing deep drawing with hold-down devices? -The movement of the hold-down device can be derived from the main movement-this is done using cams, crank mechanisms or a combination of the two-hold-down devices with hydraulic or pneumatic drive are adjustable 1 4

15 45.Which assemblies protect path-bound presses from overloading due to excessive forces, excessive torque, excessive labor required by the forming task? Slipping clutches against torque overload, tilt locks against force overload, in the event of work overload the motor simply stops because the energy of the flywheel is no longer sufficient. 46 Which drive options for hydraulic presses do you know? Explain the advantages and disadvantages! 1 5

16 Complex: Machine tools 47.What do you understand by row-structured or parallel-structured machine tools? Row-structured machine tools: one axis per x-y-z-coordinate Parallel structured machine tools: all positions in space can be reached (strut drive) 48.What are the main parameters of turning, milling and grinding machines? Lathe: maximum turning length, maximum diameter Milling machine: Wst clamping surface, edge dimension d. Wst grinding machine: maximum tool size, maximum workpiece size, edge dimension, diameter 49.Why and why do conventional lathes have a lead screw and a pull spindle? Pull spindle: -Implements feed drive leading spindle: -compliance with d. kinematic relationship between main spindle and longitudinal feed 50.What are the advantages of the inclined bed design on lathes? Better accessibility, higher rigidity, improved chip evacuation, in principle also improved expandability by, for example: Robot 51. Sketch an inclined bed lathe and designate the necessary frame and drive assemblies! 52.Name the frame and drive assemblies of the illustrated NC machine! Specify the possible movements between the workpiece and the tool with the associated guides! Various examples in script 1 6

17 53.Draw a console milling machine in which all feed and setting movements are carried out through the workpiece side! Identify the rack assemblies! The top left. 54.What is the difference between an NC milling machine and a machining center? 1 7

18 55.What is the gantry design for bed-type milling machines? 56. Explain the terms tool change time and chip-to-chip time Tool change time: Time that is required to carry out the tool change Chip-to-chip time: Time between the last chip with the old tool and the first chip with the new tool 57 What are the special features of grinding machines that differ from other cutting machine tools? 58. What assemblies does a universal external and internal cylindrical grinding machine consist of? 1 8

19 59. How is a grinding cycle usually structured when grinding with or without measuring control? -without measuring control: rapid infeed, roughing, finishing without readjustment -with measuring control: linear rapid infeed, roughing and finishing then time and value discrete (digital measurement and readjustment), when the dimension is reached, the grinding wheel retraction is initiated (= automatic dimension control)

20 60.What is sparking? 61.Which dressing tools do you know? Depending on which sizes is the dressing process initiated? 62. Name types of surface grinding machines! -Machines with vertical main spindle for face grinding -Machines with horizontal main spindle for peripheral grinding 63. Sketch a surface grinding machine with vertical main spindle and rotary table! Specify possible movements between the workpiece and the tool! Identify the necessary frame and drive assemblies! 2 0

21 64. Which assemblies are used to hold the workpiece in centerless grinding machines and which are used to set the workpiece in motion? What is the design of the axial workpiece feed? 65.What types of parameters must be taken into account when using forming machines? 2 1

22 66. Name the three different types of forming machines with regard to the provision of force and energy parameters! 67. Explain the basic structure of the hybrid drive in presses! What are the advantages? Crank drive with 1 or 2 hydraulic cylinders that prevent the tool from tipping and can also use brake cylinders to brake the pressing process, i.e. influencing the s-v curve 68. Name important types of screw presses! Flywheel screw press Clutch screw press Wedge screw press 69. How can overloading be prevented with screw presses? Slip between the frictional connection between the drive pulley and the flywheel 70 Explain the different types of hammers and their areas of application! Scratch hammers: for open-form and drop forging Counter blow hammers: heavy and heaviest die parts (crankshafts for ships) 71.What special features do automatic cutters have compared to normal presses? Very precise guidance of the cutter bar, knife free wheel necessary, inclination of the cutter bar 72. Explain the structure of a transfer press (transfer press) and its advantages when using it! Fast processing, uniform, continuous material flow, several processing steps automatically one after the other 73 Describe the operating principle of a multi-stage press for massive forming and name typical areas of application! 2 2

23 74.What are the special features of flow-forming and flow-forming machines compared to presses? Complex: Devices 75.What are devices in manufacturing technology? Production resources with the help of which a defined position of one (or more) workpieces in relation to the machine tool is determined. secured by clamping forces. 76. Name the classification features for devices and underline them with examples! 1. According to the application and the structure: ie either a standard device (e.g. vice), a modular device (groove or drilling system) or special device (e.g. ne drilling device) 2. Construction principle: casting, welding or screwing device Number of workpieces to be clamped (one or more) 4. and a purpose, i.e. whether it is a production (drilling, turning, milling, welding device), assembly, magnet or transport device. 77. Name the main tasks (5) of devices and the functions which these tasks carry out in the devices! 2 3

24 Positioning to fix the position in a statically determined position (FG = 0) Determination of the position fixation with a slight force Clamping for the final position fixation with the process forces occurring in production, if necessary, imposition of a forced movement, if necessary, parts when assigning several workpiece positions 78. Understand what one under determining, tensioning, supporting, guiding and dividing in devices? Determination: Defined and reproducible position fixing of one (or more) workpiece (s) in a device with the accuracy required for machining. Clamping: Safe holding of the workpiece under all machining conditions in its intended position within the device. Support: Allocate an additional fixture contact surface in order to enable the determination of a workpiece or the clamping and / or machining. Guiding: Imposition of a constrained movement. The Wst is preferably determined and stretched on a movable Wstträger, over which each determined position is indexed and locked. (enable the same processing several times on the workpiece through different workpiece positions) 79. What are the goals of using devices in manufacturing technology ?! Accuracy, reliability, rigidity, automatability, 2 4

25 80.What are the requirements for devices and how are they assessed? 81. Which assemblies is a device made of ?! 82. Use an example to describe the methodical procedure for realizing the determination function in a device 2 5

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27 83.What do you understand by reference plane and determination plane in the context of the construction of a device? What is the connection between the two? The reference plane is the plane to which the dimension and tolerance calculations refer. Ideally, the determination plane is the same as the reference plane, otherwise tolerance calculations are necessary 84. Explain the terms support surface, guide surface and contact surface! Support surface = production dimension or surface to be removed or determination plane is in the x-z plane Guide surface = production dimension or surface to be removed or determination plane are on the y-x plane Contact surface = production dimension or surface to be removed or determination plane is in the y-z plane 85. Overdetermination occurs when more than one determination plane has been defined for each coordinate direction to the reference plane of a dimension. 86. Sketch the determining principle for a given workpiece! 2 7

28 87.What to watch out for when designing support surfaces! Stiffness of the material. Determination surface on the material. Force application (inside, outside) As flat as possible and parallel to the tool ?! 88.What should be considered when using a prism as a determining element? The position of the reference plane in the device depends on the diameter of the workpiece, see Sketches show 6 clamping principles! 90. Classify the clamping function according to the force acting on the workpiece. Give an example of this! 2 8

29 91. How can the clamping force be generated in devices? 92. Name important requirements for the design of the clamping force in fixtures! Machining must not be hindered No shift from a certain position Largest force component in the same direction as the cutting force Small elastic deformations on the workpiece and fixture No clamping marks occur 93.What constructive calculations can be required in the context of the development of a fixture? Security against shifting, twisting, ... of the workpiece during the process, security against breakage at risk of components, security against permissible surface pressure on the workpiece, permissible deformation of materials. And device tolerances for the position of the determining elements and tool guides in relation to tolerances on the workpiece 94. What is the fundamental difference when using a spiral or eccentric as a clamping element? The manufacturing costs of the spiral are higher. Spiral independent of the angle, workpiece tolerance independent of v. Clamping force 95.What task do drill bushings fulfill and what should be considered when using them? Drill bushes are used to guide the drill in the drilling device. This results in a true-to-size drilling pattern and prevents the drill from drifting. 2 9

30 In order to achieve optimal chip evacuation, the distance between the drill bushing and the workpiece surface should be 1/3 of the drilling diameter. Drill bushings do not guide reamers and taps. 96.Describe the functional sequence in a device with the divide function! 3 0