Machine Design for Packaging Technology - Noppa

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Machine Design for Packaging Technology - Noppa Powered By Docstoc
					          BK50A2200
   Design Methodologies and
    Applications of Machine
        Element Design
                  Lecture 1
Fundamentals of the systematic design approach
                D.Sc Harri Eskelinen
      Common requirements for an effective
         design method are as follows:

n   The method must be applicable to every type of design activity, no matter
    in which specialist field.
n   The method should facilitate the search for optimum solutions.
n   The method should be compatible with the concepts, methods and findings
    of other disciplines.
n   The method should not rely on finding solutions by chance.
n   The method should facilitate the application of known solutions to related
    tasks.
n   The method should be compatible with electronic data processing.
n   The method should be easily taught and learned.
n   The method should reduce workload, save time, prevent human errors, and
    help to maintain active interest.
     MOST COMMON DESIGN
         APPROACHES
n   Systematic Design
n   Reverse Engineering
n   Concurrent Engineering
n   Cross-technological Approach
n   Virtual Engineering ( Virtual Prototyping and
    Manufacturing)
n   Approaches Based on the Use of Integrated
    Product Teams
n   Collaborative Design
         Briefly about Reverse Engineering

n   1 The process of duplicating an existing component, subassembly,
    or product, without the aid of drawings, documentation, or
    computer model is in many cases called as "reverse engineering".
n   2 In reverse engineering the component is measured by a
    coordinate measuring machine or the surface profiles are laser
    scanned. As the geometry is measured, a dimensioned 3-D wire
    frame image is generated and displayed on a monitor. After the
    measuring is complete, the wire frame image is dimensioned.
n   3 The component is then re-manufactured from a cost-effective
    foam or plastics, which could be coated with a specific material to
    test component’s performance.
n   4 If any changes are needed to the geometry, they are easy to
    produce to the soft material. When the new prototype is ready, the
    new geometry can be read either with the CMM-technique or laser
    scanning again.
n   5 The exact geometry can be optimised by filtering the data to the
    CAD-modeller. Finally the required CNC-code for a real product is
    compiled with the CAM-module.
n   In mechanisms design one way to apply reverse
    engineering is to start e.g. from the required motion path
    of the mechanisms needed in the specific function of a
    machine.
n   If we are able to draw at least a raw draft of the motion
    path, it usually gives the first ideas of adequate
    mechanism types . So the designing process starts from
    the "results" of “mechanisms analysis” (= one way to
    carry out mechanisms synthesis) - this could be called
    "reverse engineering".
n   If the motion path and the selected mechanism type are
    known, it is possible to use computer aided means to 3D-
    simulate the mechanisms construction and its
    components and carry out the final dimensioning process.
      Briefly about Concurrent Engineering Design
  n   The simultaneous interest of design and manufacturability makes up
      the CE Design. The transition from design to manufacturability is
      also reflected in the interaction of different CE Design intellectual
      activities (such as marketing).

 Traditional
consecutive
  process
   stages               Traditional Design Process.




Simultaneous
 and parallel
   process
   stages


                         Concurrent Engineering (CE), Simultaneous Engineering (SE), Parallel Engineering.
Briefly about Cross-Technological Approaches

 n   The design engineer
     meets different areas of
     science, different human
     views, various industrial
     and technical goals and
     many environmental
     opinions. à See an
     example of mechatronics
     on the right.
        Briefly about Virtual Engineering

n   Virtual Engineering includes at least virtual
    prototyping and manufacturing
n   Different kinds of simulations and visualisations
    are used to illustrate the propagation of the
    design process.
n   By using virtual models it is possible to combine
    geometrical, physical, functional and
    manufacturability simulations of the product.
n   In mechanical engineering also the main
    functions of the machine or the flow of the
    process could be simulated.
Worm gear




            Springs
Approaches Based on the Use of Integrated
             Product Teams
n   Use of IPT’s is a practical way to carry out the
    cross-technological approach
n   The key members of the team for mechanical
    engineering are e.g. as follows:
    n   experts on mechanical engineering
         n   designers (e.g. strength calculations and mechanisms design)
         n   experts on material science
         n   experts on pneumatics and hydraulics
    n   experts on optics
    n   experts on electrical engineering
    n   experts on material science
    n   experts on related industrial areas (medicine, paper and
        wood industry, steel industry etc.)
     Briefly about Collaborative Design




   WBS=
   Work
Breakdown
 Structure
        SYSTEMATIC DESIGN
n   Different researchers have emphasised either their own
    weightings of specific steps and phases of the design
    process and they have presented their own
    methodologies for the “systematic approach”.
n   The most common way to understand "systematic
    design approach" of technical systems and products is
    presented in VDI 2221 (1987).
                The flow of work during
           the systematic design process
     n   Traditionally the flow of work during the systematic design
         process is dealt in following main phases:
n   1 The first phase is the task clarification and finding the general
    functions to be performed.
n   2 The method moves on step by step from one phase to another
n   3 The solution is developed from qualitative to quantitative product
    properties
n   4 The solution can be found also by developing or combining the
    existing product or component variants
n   5 The purpose is to find algorithms or rules to describe the design
    process
n   6 usually the problems for manufacturing or manufacturability
    analysis are met in the end of the process
A generalized model of the systematic design approach
A detailed modelof the
systematic design approach by
Pahl & Beitz

The flow of work during the
systematic design process is
dealt in four main phases:

1. Planning and clarifying
the task: specification of
information
2. Conceptual design:
specification of principle
3. Embodiment design:
specification of layout
(construction)
4. Detail design:
specification of production
 Requirements to pack a new product are
 collected and the main task is clarified:
 Shatter- and waterproof packing




One principal solution is found to be the
use of a wrapping machine combined with
some type of padding elements or
protective film


A new wrapping film material (new layered      A simplified and rough
plastic/foil) is evaluated to be the best
(both its economic and technical properties)   example from
if wrapped tightly enough                      packaging technology


Angular direction of each wrapping cycle
should be varied 5 degrees so that
adequate sealing properties are achieved.



Detailed changes needed to the
commercial wrapping machine to enable
the use of new film material and angular
positioning of the wrapping head are listed
The requirement list for the
systematic design approach
             System requirements vs.
             component requirements
                             General requirements
                             of packaging
                                  Requirements of the
                                  packaging line
                                       Requirements of the
                                       conveyor unit
                                            Requirements of the
                                            rolling bearings


The main task is to derive
the requirements of each
component from the general
and system requirements.
  General requirements of packaging
       Costs                      Product inside                Laws and degrees
                                        -Foodstuff
                                      -Fragile items




                                                                    Logistiscs
Packaging materials                                               -Mechanical handling
                                                                     - Delivery time
       -Sealing
                                                                      -Temperature
                                                                         -Light


                                                                    Marketing
                                                                     -Appearance
    Environment
                                     Consumer
                               -Information about the product
                                       -Functionality
                                -Amount of waste and refuse


            Derived general requirements of the packaging equipment:
            -Label and marking facilities of the equipment
            -Total process time needed for the packaging process
            -Possible packaging technologies and processes
        Contents of the requirements list

n   When preparing a detailed requirements list,
    either for the system or for its mechanical
    units or components, it is essential to state
    whether individual items are
    n Demands (must me met under all circumstances)
    or
    n Wishes (should be taken into consideration whenever it is possible)
n   Further on demands and wishes can be
    classified into to groups: Quantitative and
    qualitative aspects.
    n   Quantity: All data involving numbers or magnitudes,
        such as “maximum weight”, “power output”,
        “throughput”, “volume flow rate” etc.
    n   Quality: All data involving permissible variations or
        special requirements such as “waterproof”, “corrosion
        proof”, “vibration or shock proof” etc.
n   Notice, that requirements should, immediately
    when possible, be quantified.
Main headings of the requirement list

n   Geometry
    n   Size, height, width, length, diameter, space requirement,
        number, arrangement, connection, extension
n   Kinematics
    n   Type of motion, direction of motion, velocity, acceleration
n   Forces
    n   Direction of force, magnitude of force, frequency, weight, load,
        deformation, stiffness, elasticity, stability, resonance
n   Energy
    n   Output, efficiency, loss, friction, ventilation, state, pressure,
        temperature, heating, cooling, supply, storage, capacity,
        conversion
n   Material
    n   Physical and/or chemical properties of the initial and final
        product, auxiliary materials, prescribed materials (food
        regulations etc.)
n   Signals
    n   Inputs and outputs, display, control equipment
n   Safety
    n   Direct safety principles, protective systems, operational, operator
        and environmental safety
n   Ergonomics
    n   Man-machine relationship, type of operation, clearness of layout,
        lighting, aesthetics
n   Production
    n   Factory limitations, maximum possible dimensions, preferred
        production methods, means of production, achievable quality
        and tolerances
n   Quality control
    n   Possibilities of testing and measuring, application of special
        regulations and standards
n   Assembly
    n   Special regulations, installation, sitting, foundations
n   Transport
    n   Limitations due to lifting gear, clearance, means of transport
        (height and weight), nature and conditions of dispatch
n   Operation
    n   Quietness, wear, special uses, marketing area, destination (e.g.
        sulphurous atmosphere, tropical conditions)
n   Maintenance
    n   Servicing intervals (if any), inspection, exchange and repair,
        painting, cleaning
n   Recycling
    n   Reuse, reprocessing, waste disposal, storage
n   Costs
    n   Maximum permissible manufacturing costs, cost of tooling,
        investment and depreciation
n   Schedules
    n   End date of development, project planning and control, delivery
        date
How to derive the requirements of
each individual machine element?
n   It is necessary to know the fundamentals
    and criteria of dimensioning of each
    machine element included to the
    construction or the equipment.
n   Requirement list should include enough
    data for calculating the initial values to
    make it possible to select the right type
    and size of the machine element.
         A simplified case example
n   Requirements of the roller conveyor
    n   Size and weight of the packet à width of the conveyor, strength and
        diameter of each roller element
    n   Type of motion (backward-and-forward, high speed, continuous use,
        easy to move the load) à number of roller elements, low friction
    n   Forces (critical position of the packet) à maximum vertical load and
        bending moment of each roller element
    n   Environment (dusty) à non-adhesive surface properties of roller
        elements
    n   Operation ja maintenance (twenty-four-hours use, long servicing
        intervals) à high wear-resistance of roller elements
n   Requirements of the bearings
    n   Diameter of each roller element à Possible bearing sizes
        (diameter)
    n   Type of motion, low friction à Possible bearing types, speed limits
    n   Maximum vertical load and bending moment of each roller
        element à Allowable axial, radial and bending loading of bearings
    n   Environment (dusty) à Double-sided sealing of bearings
    n   High wear-resistance à Carbide or nitride based materials of the
        roller elements of bearings
    n   Twenty-four-hours use à Self-lubricant bearings
n   A conveyor belt of
    the pallet handling
    system
    n   Required belt speed
        due to process
    n   Maximum load

                              Required properties of the power
                              transmission unit
                              -Gear ratio
                              -Speed and torque
                              -Power



                              Dimensioning of
                              worm gears
n   Some problems when systematic design approach is
    applied:

    n   In systematic design approach, especially according to VDI
        2221, it is typical that the functional design of a product and its
        modular construction are followed by the documentation for
        manufacturing and assembly. Because these two stages are
        presented in design scheduling flowcharts to be consecutive (not
        parallel), it is possible that the designer does not give enough
        attention to manufacturing aspects during modularization.
    n   Another problem from the designer’s point of view is that there
        is a lot of subjective information available during different design
        stages and development of the solution is, however, based on
        this “facts”.
    n   The third problem might be that “new” products or designs are
        too easily tried to be developed only by combining already
        existing modules or other “old” technical solutions
                               Exercise 1
n   Exercise 1A.
     n Select any machine element or component of a worm gear (e.g. bearings, shafts,
       gears etc.) illustrated in the figure below and try to derive detailed requirements
       (and wishes) of this component to make it possible to select the appropriate
       type, size and material of the component.




n   Exercise 1B.
     n Make a comparison table about the advantages and opportunities vs.
       disadvantages and difficulties, which could be met, if the following design
       methodologies or approaches are applied in machine design:
         n Reverse Engineering
         n Systematic Design Approach
         n Virtual Engineering
         n Concurrent Engineering
         n Cross-technological Approach

				
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posted:5/5/2014
language:English
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