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: