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Design for Production in Existing Facilities (DPEF). Richard A. Wysk The Pennsylvania State University IE550 Manufacturing Systems. Design for Production in Existing Facilities (DPEF). Given: a product design, the expected production requirements for the new product,
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Design for Production in Existing Facilities (DPEF) Richard A. Wysk The Pennsylvania State University IE550 Manufacturing Systems
Design for Production in Existing Facilities (DPEF) • Given: • a product design, • the expected production requirements for the new product, • a set of production resources and the current configuration (production lines, cells, etc.), and • the expected requirements for the products currently being produced,
Design for Production in Existing Facilities (con’t) • Answer the following questions: • Can the new product be produced in the required quantities given the current production allocation? • if so, what are the expected production costs ? • if not, can the current production be reallocated such that all of the production requirements can be met? • if not, can the design be modified to enable production within the current resource structure? • if not, how should additional resources be acquired to meet the production requirements?
How it’s done today: Parametric-based Feature Information • Feature information (Intra-feature specifics) • Dimensions • Size Tolerances • Surface Finishes • Geometric Tolerances
Product, Process and Production Models Product Engineering Library of features Feature interactions Process Engineering Process / Feature links Inter-feature linkages Inter-process linkages Production Engineering System Specifics Machine Specifics Fixture Specifics Tool Specifics
Production Resource Constaints • Geometric Constraints • Machine Constraints • Jig/Fixture Constraints • Tooling Constraints • Process Constraints
Key Process Planning Features • Plans based on Feature Precedence Graph • Generates AND/OR Graph • Collects the resource data from Databases • Is independent of Decision Table
Example: Threaded hole (.250-20 UNF Class 3) • Process alternatives • Drill -> Tap • Drill -> Thread cut • Drill -> Thread form • Process plans • Drill ---> NxxG00G91X@locY@locZ@locM06 NxxG01Z-@sizeF50 NxxG01Z@sizeF100
Process Planner Process Planning Design Station
SL-20 Turning Center Facing Turning Drilling Reaming Boring Tapping Threading Processes • VF-0E Machining Center • Milling (Face/end-milling) • Drilling • Reaming • Boring • Tapping • Threading • Engraving (Ball-mill)
AND/OR Graph Generator • Creates an AND/OR Graph Representation of a process plan • Fills out Processing Node Information • PNI is used by NC code Generator • Covers MP, MT, MH and AS/RS nodes
Example Part • Cylindrical Part • Center Hole • Bolt Holes • Contour • Thread
Process Plans • Shop level plans Dr Tr1 MT MT MT MT Tr2 Ml
Process Plans • Workstation level plans SL-20 VF-0 MH MH MH MT VF-0 VF-3 Workstation #2 Workstation #1
Process Plans (cont.) • Equipment Level Plans (Drilling) Dr1 Tp1 Tp2 Fx Dr2 Fx Dr3 Tp3 Dr4 Tp4
Decision Maker • Contains the hierarchical constraints • Machine • Fixture • Tool • Process • Feature • Can be updated indendent of Process Planner
IPPE Concept Process Planning System Production Analysis System Design Model Process Model CAD System Resource Model Instance
Machines Jigs/Fixtures Toolings Layout Decision Table Process Planner STEP or STEP-like PSL or PSL-like Feature AND/OR Information Graph Process Planning IBM Compatible IBM Compatible Design Station Manufacturing Resource Model
Multi-facility Planning and Analysis WWW Resource Model Instance Resource Model Instance Resource Model Instance Resource Model Instance Inquiries Production Orders
Technological Hurdles • Process Planning • Given a part design, what are the processes, tools, fixtures, etc. required to manufacture the part. All feasible alternatives should be explicitly represented. • Production Planning and Analysis • Given a set of production resources and a set of production requirements with the associated process plans, how should the production be allocated among these resources in order to efficiently satisfy the requirements.
Resource Model • A set of definitions and symbolic descriptions that are used to completely describe the individual resources in a facility as well as the possible interactions between these resources. • A resource model instance describes a specific facility and its resources.
t =E(t + t ) j j + t + t + t j P m c i setup L/UL A j j t setup j t j t m t c t i the time required for setup for an operation (load fixture, retreive tooling , etc.) the time required to load and unload a product for feature operation j (chuck, fixture, etc..) L/UL the machining/processing time for feature j tool change time/part idle time due to scheduling control
t t t = t t + + + p m ch set l/ul Performance Metrics Production time per piece • The cost associated with new tooling is also a key consideration • for the designer. • For low and medium volume products, the cost associated with • tooling and setup can dominate the total product cost.
Concept of a manufacturing system resource model [ Wysk, R.A., Peters, B.A., and Smith, J.S., “ A Formal Process Planning Schema for Shop Floor Control ” ] • Resource Model - set of definitions and symbolic descriptions that are required to completely describe all of the individual resources in a facility as well as the necessary interactions between these resources
Terminology • Resources (R) : Collection of assets in the facility directed towards the manufacture of the products. Includes equipment, tools, fixtures, transporters, and instruction sets • Locations (L): A precise physical location associated with a port and a part. Locations are used to link the transfer of parts between equipment types. Each location has an owner and a set of clients that can address that location • Ports (P): Ports are nodes in the graph defining the paths parts can follow through the facility (note: Graph shows the connections between the resources in the facilities • Arcs: Show which ports can be directly accessed from a particular port • Facilitator: A device than can move transporters between different ports on the MT system or move parts between a port on a MT system and a port on a MP
Example... MP 3 MT 1 3 3 4 4 1 MH 1 1 MH 1 2 2 MP 2 Ports, Locations : 1,2,3,4 Resources: MP2, MP3 (type MP) MT1 (type MT) MH1 (type MH) Facilitator : MH1 Arcs between : 1-2, 2-1, 1-4, 4-1, 4-3, 3-4, 2-3, 3-2 ( represent connections between the resources )