EPT 221 CONFIGURATION DESIGN. Objective of This Lecture Describe the configuration design phase...
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Transcript of EPT 221 CONFIGURATION DESIGN. Objective of This Lecture Describe the configuration design phase...
EPT 221
CONFIGURATION DESIGN
Objective of This Lecture
• Describe the configuration design phase
• Describe ways to generate product and parts configurations
• Describe and apply ways to analyse, refine and evaluate alternative configurations.
What is configuration design?
Alternative Configuration - parts arrangement
Alternative Configuration-different parts/features
Alternative Configuration-different parameters/dimensions
What is part design?
Physical principleForces in equilibrium
Alternative Configurations
What is configuration design?
• The phase of product development when we determine the number and type of parts or geometric features in our design, how they are spatially arranged or interconnected, and approximate relative dimensions of the parts or features, and develop a list of design variables.
• Deals with: Product architecture the selection and
arrangement of components on a productPart configuration the selection and arrangement
of features on a part.
Configuration Decisions
How do we create different configurations? By changing one or more of these
How to start configuring a product?
Product Configuration
The goal is to prepare a rough layout/sketch of the product.
Layout sketches: Sketches drawn roughly to scale to show the geometric
or spatial arrangement of the selected components and illustrate their relative shapes and sizes.
Contains no dimensions or tolerances.
Product Architecture
• Develop product architecture: Product architecture according to Ulrich and Eppinger (1995) is
how the physical elements and functional elements of a product are arranged or clustered into physical building blocks called chunks and how the chunks interact.
Physical elements: the physical concepts developed during the conceptual design phase, and/or the components such as standard or special-purpose parts and/or assemblies.
Functional elements: the functions that a product performs.
Why do we need product architecture? Because before we determine the details of a product, we need to know the general layout of a product.
2 types of product architecture:i. Modular architecture:
chunks implement one or a few functions, and the interaction between chunks are well defined.
ii. Integral architecture: a single chunk implements many functional elements or many chunks implement or share one function, and the interaction is ill-defined.
Modular Architecture
Integral Architecture
Steps for Developing a Product Architecture(Ulrich and Eppinger Procedure)
• Step 1: Create a schematic (of the product elements), including physical elements that have not been reduced to a physical concept. Keep the number of elements under 30. separate the others to be worked on later.
• Step 2: Cluster elements into chunks. Start with a single element and cluster it with another when it is beneficial to:
Share functions Enable standardization (use or create standard parts or modules) Integrate geometry (i.e., dimensional precision between features) Exploit vendor capabilities (e.g., such as injection moulding expertise) Fully utilize manufacturing process capabilities Accommodate consumer variety (options, customization) Exploit common interfaces (120 VAC, air duct connectors, PC bus) Manage changing technologies or components Provide for wear, upgrades, maintenance, consumables
• Step 3: Make a rough geometric layout. Use either 2D or 3D sketches and/or CAD drawings or build a physical prototype. Arrange chunks so that the interfaces remain feasible. Recluster any element to maintain feasible interactions and interfaces. Discuss the layout with others on the team. Refine the layout as necessary.
• Step 4: Identify the fundamental and incidental interactions. Examine the flow of matter, energy, and signal between chunks. Are the desired functions preserved? Identify incidental interactions such as unwanted vibration, or heat generation, or EMI, and show on incidental interaction graph
Printer Example
Step 1: Create a schematic
Step 2: Create elements into chunks
Step 3: Make a rough geometric layout
Step 4: Sketch interaction diagram
Part Configuration
• Part a single-piece component that is made out of one material and needs no assembly.
• Has geometric features• Arrangement of features: locations, orientations• Contiguous features: features that are
connected to each other • Relative dimensions: features that have different
widths and heights with respect to each other.
Part Configuration Decisions
How do we create different configurations? By changing one or more of these
How to generate alternative configurations?
Example: Sponge Holder
Sponge holder
Step 1: Prepare configuration requirement sketch
Step 2: Prepare alternative noncontiguous part configurations
Step 3: Prepare alternative contiguous configurations
Step 4: Refine configurations
Configuration Design Analysis
How to analyze configurations?
• We asks the following questions:
• Thus developing these 3 criterion categories:
Will the product function as it should?Will the product be able to be assembled?Will the product be manufacturable?
Design for functionDesign for assemblyDesign for manufacture
Design for function checklist
Design for Assembly
• A name used to describe a set of practices that aim to reduce the costs of part handling, insertion, and fastening.
• Assembly: a process of handling components and to bring them together (inserting) and then fastening them.
Reduce handling
• Handling: grasping, moving, orient, place • Influenced by part features or attributes.• So, part/ product must be designed to reduce
handling:
Reduce insertion and fastening effort
• Insertion and fastening: mating of a part to another part or sub-assembly
• So, insertion and fastening of a part/ product is influenced by:
Design for Assembly Principles by (SME)
Using standard parts
Minimise part count
Encouragingmodular assembly
Eliminate reorientationFacilitating
parts handling
Eliminatingcables
Stacking subassembliesfrom the bottom up
Based on the principles/ guidelines by SME
• Varying product architecture by:
i. Encouraging modular assembly
ii. Using standard parts
iii. Stacking from bottom up
iv. Minimising the number of parts
• Varying part configurations by:
i. Self-fastening features
ii. Self-locating features
iii. Eliminating reorientation
Design for Manufacture
• Is the set of practices that aim to improve the fabrication of individual parts
Will the manufacturing processes produce the configured part features?
Will the processes be economical with respect to materials, processing, and tooling costs?
Checklist for Parts Made by Molding/ Casting
• Design for molding/ casting
Checklist for Parts Made by Sheet Metalworking
• Design for sheet metalworking
Checklist for Parts Made by Machining
• Design for machining
Obtaining the best configuration design - evaluation
Example : Evaluate the sponge holder configuration
Evaluation using the Weighted-Rating Method
Can also use Pugh’s Method such as that in the conceptual design phase
Weighted-Rating Evaluation of Sponge Holder Configurations
Configuration Design Summary
Using Graphics in Configuration Design: Computer-Aided Design
• The goal of using solid modeling packages is to generate, analyse, and evaluate alternative configurations; not to document the design efforts.
• Advantages: