A SYSTEM LEVEL MODELING FOR SHEET METAL PROCESS PLANNING

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A SYSTEM LEVEL MODELING FOR SHEET METAL PROCESS
PLANNING

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CONTENT

• ABSTRACT.
• 1. INTRODUCTION
• 2. MODELING IN PRESENT WORK.
• 3. FEATURE REASONING.
• 4. PROCESS PLANNING.
• 5. DATA AND KNOWLEDGE MODELING
• 6.CONCLUSION

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ABSTRACT

• Modeling is to specify, visualize and document
  models of application system before actual
  implementation system.

Sheet metal process planning system
Many attempts have been made at implementation
level based on product data models.
In the past

Knowledge
Describes modeling a before actual implementation
with data and knowledge models as a basis.
This paper
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1. Introduction current papers.

• Modeling is to specify, visualize and document
  models of application system including their
  structure.
• Modeling language help in contriving models with
  diagram.
• What diagram? Model diagrams represent
• - static application structure
• - different aspects of dynamic behavior
• - ways to organize and manage
  application modules.
• Integration of process planning with other
  systems is vital to respond rapidly to market
  changes.
• Process planners are currently exchanging more
  knowledge than the data
• Objected-oriented process planning system is
  presented.
• Relevant works

Feature
Neutral file
Process planner
Part model with features
Design
Feature Reasoner
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Overview each Section
For system level modeling of process planning,
describes complete data and knowledge models with
relation among them.
Section 2
describes modeling in present work along with a
process planning framework.
Section 34
discuss feature reasoning and process planning
modules of the process planning system
respectively.
Section 5
discuss data and knowledge modeling aspects
pertaining to the present sheet metal process
planning system.
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2. MODELING IN PRESENT WORK

• Modeling methodology in this work is based on
  the objected-oriented approach.
• In this approach, fundamental construct is the
  object or class that incorporates both data and
  function.

• Identification of object.

Objected-oriented modeling

• Identification of Relationships
• between object and data.

• Function in the object.

• O-O approach advantages
• Easier modeling of large complex objects.
• Reusability.
• Better extensibility.
• Easier integration with O-O programming code.

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Objects structure.
Generalization
Is the grouping of objects with the same data and
function.
Specialization
Establish relationships among the models classes
or objects.
Identify respectively the inheritance-from and
inheritance-to relationships.
Aggregation
Classification
Identifies subset-of relationships.
Association
Identifies dependency relationships.
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OOA OOD

• These structural relationships in models are
  represented by Object-Oriented Analysis(OOA) with
  the help of UML.
• Details of model classes are represented by
  Object-Oriented design (ODD) with UML
• UML(Unified Modeling Language) is used as a
  visual modeling tool for creation model behavior
  diagrams.

• OOA(Object-Oriented Analysis) - what
• is used to provide a detailed description of a
  system using object-oriented notation, concepts,
  and methodology
• OOD(Object-Oriented Design) - how
• concentrates on providing the blueprint for
  implementation
• Design-before-Implementation Software Engineering
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3. FEATURE REASONING

• Feature reasoner recognize and extracts features
  from neutral file of part assumes that component
  design is available as a CAD model.
• Feature reasoner recognize sheet metal features
  and extracts feature related information and
  makes it available to process planner.
• Sheet metal parts are represented as 3D models
  with uniform thickness.
• STEP(ISO10303) neutral files are used here to
  store part feature information.

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Flowchart for Feature Recognition and Extraction
for Example Sheet metal Component
Plate
Hole
Bend
Corresponding objects of corresponding classes
are declared.
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Plate

• Each Plate feature recognized.
• End point of all the plate edges are recognized.
• Store in edge point13 and edge point23
  attributes of corresponding Plate objects.

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Bend

• Each Bend feature recognized.
• End point of all the Bend edges and radius.
• Store in edge point123 , edge point223
  and Radius Attributes of corresponding Bend
  objects.

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Hole

• Each Hole feature recognized.
• End point of all the Hole radius and Hole center
  point are recognized.
• Store in Hole radius and Hole center point3
  Attributes of corresponding Hole objects.

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4. PROCESS PLANNING

• Process planner in relation with various data and
  knowledge models generates the process plan.

Feature data and knowledge model
Can be interpreted as the logical accumulation of
all relevant information.
Resource/process data and knowledge model
Contains information related to manufacturing
resources and manufacturing processes.
Process plan
Is represented by the process plan data and
knowledge model.
Material data model
Is all about modeling of material data.
Data knowledge models
Process planner
Data knowledge objects
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• Process planner accesses knowledge in order to
  get the required data during process plan
  generation.

Process planner

• According to the required of model knowledge.

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Sheet metal feature and process hierarchies

• Based on these hierarchies feature and process
  data and knowledge models can be built up.
• Classes can be constructed for all features and
  process.
• Their instance object can be created.
• Relationships can be identified and established
  among models elements.

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Feature and Resource/process data and knowledge
models for Example sheet metal component.
Objects incorporates both data and knowledge in
the form of attributes and operations.

• For a typical sheet metal in figure 2.
• Drawn with the help of a UML class diagram.
• Classes for shown features and corresponding
  manufacturing processes of the component are
  construct.
• Objects are created from each of these classes.

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Data and knowledge objects Relations for Example
sheet metal component

• Process planner accesses various knowledge to get
  various data and generate process.
• Figure shows data and knowledge object relations
  with the help of a UML collaboration diagram.

Objects of feature data and knowledge model
Objects of material data model
Resource/process data and knowledge model
Objects of process plan data and knowledge model
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5. DATA AND KNOWLEDGE MODELING

• Data and knowledge models consist of interrelated
  data and knowledge objects.

Object
attributes
operation

• Rule Expressions
• Knowledge rules are of IF-THEN
• An actual rule checks one or more conditions

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5.1 Feature Data and Knowledge Model

• Feature data and knowledge model is all about
  modeling of features during manufacturing.
• The modeling includes formalization of features.
• Operations fall into two major groups.
• - knowledge rule checking one or more
  condition for correctness and executes Action
  if they are true.
• - knowledge rules form the basis for
  identifying second group of operations along with
  attributes.
• Ex) CheckDistanceToHole of feature data.

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5.2 Resource/Process and knowledge Model.

• Resource/Process and knowledge Model contains
  information related to manufacturing resources
  and manufacturing processes.
• Sheet metal manufacturing resources include sheet
  metal presses, dies and punches etc.
• Operations fall into two major groups.
• - The first group contains knowledge
  expressions in the form of simple mathematical
  expressions.
• - knowledge expression form the basis for
  identifying second group of operations along with
  attributes.
• Ex) piercing pinches making time,
• no. of different shapes and size of piercing
  punches
• piercing press force (from other attribute)

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5.3 Process Plan Data and Knowledge Model

• Process plan data and knowledge model represents
  the process plan.
• These model reflects the general process plan
  consisting of material, sequenced manufacturing
  features and related data.
• Operations fall into two major groups.
• - The first group contains knowledge rules
  checking one or more condition for correctness
  and executes Action if they are true.
• - knowledge rules form the basis for
  identifying second group of operations along with
  attributes.
• Ex) CheckDie of process plan data
• SequenceOfProcesses, SequenceOfDie,
  SequenceOfPunches (condition check)

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5.4 Material Data Model.

• Material data model consist of material related
  information.
• Material data model is all about modeling of
  material data.
• This contains attribute and operation.
• The knowledge rules or expressions contained in
  operations of other models classes form the
  basis for these attributes and operation.
• Ex) Thickness, CheckDistanceToHole(??? Feature
  Data??? operation)

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6.CONCLUSION

• Modeling a sheet metal process planning system is
  presented in this work.
• The need for system level modeling of process
  planning before implementation, describing
  complete data and knowledge models with a
  relation among them is discussed in detail.
• Chosen modeling methodology along with language
  and diagrams are described in detail
• A framework for process planning for integration
  purpose is presented.