Detailed Design & Component Selection

Detailed Design Phase

• Portion of the engineering design process where the engineering team can completely describe a product or process (through “design output”) before building & testing.

We’ve broken into 2 sub-phases

1. “High and medium technical risk” areas (wk 10-12)– Design Reviews w/ selected faculty (wk 11): YOU

schedule time with subject-matter-experts (short & focused)

– Design Review (wk 12): standard format

2. “Low technical risk” areas (& action items from 1st phase) – complete detailed design (wk 13-15)– Design Review (wk 15): standard format (focus of this

presentation)

Questions to answer• What is your evidence that your design will meet requirements (inspection,

reference, analysis)?

• Have you demonstrated proof-of-concept (all critical areas)?

• Have all factors influencing operation been considered? What can the user do "wrong" and how will your design respond?

• Are all drawings, schematics, flow charts, and other artifacts complete (everything needed to physically and functionally realize your system)?

• Have long lead items and vendors been identified and reviewed against budget?

• How are you going to test for each requirement?

• What is your most challenging subsystem to build, and have you ensured enough time to complete it?

• What is each team member planning to work on during MSD II??

Deliverables (see rubric)

• Complete design output including BOM (see previous presentation & questions to answer) – sufficient information to order long lead time parts and implement the design

• All design documentation (complete & up-to-date on EDGE). See P13026, P13011, P12361 websites

• Engineering requirements (complete)

• Test plan (rev 1 complete, addresses all requirements, equipment & procedures defined, traceable to engr. rqmts)

• Risk assessment, mitigation plans & triggers

• MSD II plan (rev 1 but with project-specific detail)

Detailed Design Review Objectives

• Déjà vu:– Catch mistakes and improve design, now

– How? Critically review your design with subject matter experts

• Verify readiness to spend money and build prototype:

– Engineering requirements are addressed

− Risk mitigations are being deployed

− Feasibility is demonstrated for critical areas

− Design documents and Bill of Materials are ready

The Cost of Changes

Bad Outcomes

• It is week 13 of MSD II, you are implementing a new process on a production floor, and management is acting as if they have never seen this before

• Week 12 of MSD II, you have built your electro-mechanical device, and a series of moves that you thought would occur on a 10 second cycle, are taking 18 seconds (this happened to a team in 2012-13)

We want to avoid these outcomes!

Evidence

Preparation

• Identify what you want help with– Aspects of the design you are least confident in

– Subsystems or design elements with the highest risk scores

• Design input – requirements– Complete, unambiguous, testable

– Link customer requirements to engineering requirements to systems architecture to test plans

Design Output

• Key focus – evidence that your design will meet the requirements through:– Inspection: measuring dimensions to see if part fits,

examining schematic for certain components

– Reference: utilizing a prior tested design or proven process

– Analysis: FEA, Matlab simulation, time study, software prototype, physical simulations, etc.

Design Output

• System architecture – subsystems address all requirements

• Detailed drawings, schematics, flow charts – everything needed to physically and functionally realize your design, from component to subsystem to system

• Feasibility analysis – simulations, engineering analysis, prototyping

• BOM – long lead items and vendors identified, review against budget

• Risk Assessment – updated

• Project Plan - updated

Example design documents

• ME: 3D CAD drawings, mechanical simulations, LabView “algorithms”

• EE / CE: final ORCAD schematics, detailed SPICE, Matlab simulations, development tools. For software: UML/use cases, algorithms, state diagrams, AD/DA mapping for controllers, etc.

• ISE: work center layout, process flow diagrams, value stream maps, ergonomic analyses, operation process chart, DfX analysis, statistical tables

• All: step-by-step plan to fully characterize system against all specs

P13026 PEV

• Detailed design review – 59 slides!– Engrg Requirements

– Many detailed examples of custom designed and purchased parts – includes functionality, characteristics, specs – grouped by sub-system

– Subsystems and systems interactions – e.g. pneumatics

– Mass flow sensor analyses (pages….)

– Thermal analysis

– Test plans

– User interface issues

– Updated risk assessment and project plan

More sketches and numbers than text…

Postulate QuestionsFunction

Will customer needs be satisfied as defined/measured by target values (specs)?Will the architecture and functions be fulfilled? Will they produce the desired effects?What other supporting functions are needed?

Layout, geometry & materials

Will the chosen layout, component shapes, materials, and dimensions provide adequate robustness, adequate durability, permissible deformation, adequate stability, impact resistance, unimpeded expansion and heat transfer?

Energy & kinematics

Will the chosen layout and components provide acceptable transfer of energy, adequate transient and steady state behavior, and appropriate motion, velocity, and acceleration profiles?

Safety Have all factors affecting the safety of the user, components, functions, operations, and the environment been taken into account?

Ergonomics Have human-machine relationships been fully considered?Have unnecessary human stress or injurious factors been predicted and avoided?Has attention been paid to aesthetics and the intrinsic “feel” of the “product”?

Quality control Have standard tolerances been chosen (not too tight)?

Assembly Are assembly operations defined and can they be performed simply, repeatedly, and without ambiguity? (not due yet)

Operation Have all factors influencing operation (such as noise, vibration, handling, software states) been considered? What can the user do “wrong” and how will your design respond?

Costs Will stipulated cost limits be observed?Will additional operational costs arise?

Schedules Will delivery dates be met?What design modifications might reduce cycle time and improve delivery?

Preliminary Test Plan• Documents how you are going to verify satisfaction of

requirements – how to test the features and functions that constitute your implementation

• Important components:– What you’ll test (and what you won’t test)– How you’ll test: equipment and materials needed, test

configurations and procedures, pass/fail criteria– # of repetitions, conditions– Responsibilities and the approval process– Risks and contingencies

• See MyCourses for more detailed format, links to samples, and a template

• Preliminary plan now; finalize early MSD II

Prelim-DDR

• Wk 11: meet w/ faculty who can critically review key design elements (same faculty as previous phase)– Be prepared – bring appropriate design documentation

– Provide feedback form to faculty

– Follow-up with Guide to review outcomes and actions

• Wk 12: standard format design review w/ Guide and other appropriate attendees

DDR (wk 15) – Who You Should Invite

• All team members should contribute• Guide• People who can help you by critically reviewing

your design:– Technical experts – faculty, others

– Customer – if appropriate – technical expertise, or to represent the user(s)

DDR – Logistics• SCHEDULE REVIEW w/ GUIDE: 90 – 120 min. recommended

• Prepare detailed agenda – allocate time to most critical areas and highlight times for specific (discipline) attendees

• Invite participants in advance and distribute materials w/in 48 hrs

• All appropriate documentation on laptop or hardcopy (examples: P13026, P13011)

• Manage agenda

• Emphasis is on review, NOT on “presentation”

• Take notes! Questions, critiques, action items, decisions

• Ask experts if your design is ready for build & test phase

• Update EDGE with notes and design documents

Your Mindset