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Simulation for Electronics

Tom MelloSimulation Specialist

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Informative Design PartnersCollaborative CFD consulting Provide insight from simulation to drive product development

Blue Ridge Numberics Inc.Develop, maintain, and support Cfdesign

Acquired by Autodesk Inc. 2011 Engineering Lead – Electronics Group

Focus on implementing simulation into the electronics product development process

Mupac, Carlo Gavazzi, SIE Computing SolutionsSpecialized in rugged electronic systems deployed in the worlds harshest environments Electronics packaging designer

CAD, CFD, & Physical testing

Speaker BIO

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Product Development Process Typical flow Cost

Time & Money

Simulation Technology Required resources Value

Return on Investment

Simulation in the product development process

Overview

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Product Inception

• Product Specifications

• Marketing & Sales Requests

Source Components

• Meet Specification• Cost• Lead Time

Package Components

• “Get everything in the box”

• Develop “envelope”

• Understand component relationships

Freeze Design

• Detail drawings• Send to

manufacturing

Product Development Process

Testing:

Pass or Fail?

FAIL: ECO

Produce Product

Prototype Cycle

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Prototype cycle How many cycles? How much time is allocated to test? 1-3 months?

Cost of Outsourcing Development

Outsourcing–Manufacturing

•Cost to change tooling•Cost to re-manufacture components•Turn around time

–Testing•Lab fees•Turn around time•Insight?

–Don’t meet specification! WHY?

Manufacture Parts

AssembleTesting:

Pass or Fail?

FAIL: ECO

Produce Product

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Example Outsourcing Development Costs

Service $ value Time Notes

Manufacturing :Rapid Prototyping

2-15k 2 weeks

Manufacturing :Tooling

10-60k 6 weeks Die-Cast

Manufacturing:Machine Shop

1-5k 2 weeks Typically Aluminum

Independent Laboratory 20-50k 3-5 weeks Specification validation, certification

Numbers taken from various actual product development outsourcing Costs can vary based on component material, size, complexity,…etc. Numbers meant to convey there is a COST to prototyping

Outsourcing manufacturing and product validation for a “prototype” (First off the line product) can cost 2-100K & up to 6 weeks! Important to get it right the first time!

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Manufacturing Cost of material Man hours

Each “round” of prototyping produces scrap material and wasted man hours

Manufacturing: In-house Product Development

CNC Sheet metal BrakePlastic Injection Molding

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Physical Testing Equipment

Don’t forget your lab coat!

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Physical Testing

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Correlation

High level of correlation Consider standard deviation / physical testing accuracy

0

10

20

30

40

50

60

Temperature Correlation

Simulation Physical Testing

°C

0

50

100

150

200

250

Velocity Correlation

Physical Testing Simulation

LF

M

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Electronics Industry Mature

Digital prototyping common “Pushing the Envelope” with “State of the Art” technology

Introduces design challenges More Power Smaller Envelope! Specifications

Mil-spec, ATCA, compact PCI,…etc.

Implementation “Up Front” Design Verification

ATCA, compact PCI, ….etc.

Simulation

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Simulation Requirements Software

CAD & CAE Hardware

Examples: M6500 – 16 GB RAM Super Computer! Cloud

General understanding Historical product knowledge Proficiency with tools

“picks and clicks” Understanding of fundamentals

Fluid dynamics Heat transfer

𝑄=�̇�𝑐𝑝∆ 𝑡 𝑅=𝐿𝐾𝐴

𝑄=𝐾𝐴∆ 𝑡𝐿

𝑄=h𝐴∆𝑇

CatiaCoCreateInventor

NXPro/EngineerRevit

Solid EdgeSolidWorksSpaceClaim

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Upfront simulations 2D analyses

Identify variables Asses impact of modification

Positive or negative

Increase complexity Account for 3D phenomena Gain confidence in design as solution

Verify Design

Simulation Process Overview

You Are Here

Conceptual IdeaProject

Completion

• Traditional Design Verification– Dedicated analyst– Fully detailed CAD model– If design doesn’t meet specification

– Recall– Rework– More prototyping

Traditional Design

Verification

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Compress the process of development Non-simulation is a reactive process

design, test, iterate Time consuming and costly to represent products environment Results and conclusions are significantly limited

Simulation Easily define & vary product environment and operating conditions

Ambient temperature Heat dissipation to understand thermal cycling Passive or active cooling

Infinite number of thermocouples Thermal imaging camera output Can decrease product development prototyping time from weeks and months to days! Less scrap & man hours Increase product knowledge thought insight

Increase confidence in design Evaluate component reliability by understanding operating junction temperatures Optimize NOT OVER design!

Business Impact

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Real World Examples

ATR Design Evolution Cold Plate Design

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Design goals set by:1. Marketing

Standard product New market

2. Sales Customer requirements Cost concerns

3. Management (CTO, CEO, VP Engineering,…etc.) Company directives Technology driven

Considerations Form

Geometric envelope (HxWxL) System integration

Shelter Cabinet

Function Environmental concerns Milspec IO Packaged components

ATR Design Constrains

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Inlet & Outlet Momentum sources?

Fans at inlet and outlet? Location in chassis?

IO concerns Card Cage Power supplies

General System Layout

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Design Evolution

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2D Key Results

Highest velocities occur at fan max or min positions

Volume flow rate for all runs < 1% of each other

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Fan size and number

• Highest flow rate recognized with a single evacuation fan– Operating points (pressure rise and flow rate) are a function of system impedance

• less fans equates to less fluctuations in pressure field and less overall system impedance

• Is redundancy required?– If not; a reduction in complexity, manufacturing, & BOM costs are recognized with an increase in system performance by

eliminating inlet fan

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Intuitively makes sense Reinforce known phenomena

Flow fields, recirculation, stagnation

Identify relationships with geometry Inlet / Outlet positions vs. velocity & pressure drop

Guide fan selection Single evacuating fan

2D Discussion

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2D model drives 3D model Skeleton Layout “Master model” “Top down approach”

Increase complexity Add components

Baffles Metering Plates Heat Sinks

2D to 3D

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Main component of concern close to highest velocity in system

Main Component

Celsius Celsius Celsius Celsius CelsiusMain1 Max Temp Main2 Max Temp Main3 Max Temp Main4 Max Temp Main5 Max Temp

0

5

10

15

20

25

30

35

5IN_5OUT6IN_6OUT

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Metering Plates Perforated metal plates Increase pressure drop across center

Air takes path of least resistance Promote flow to slots furthest from fan

Drive 2D analysis from 3D analysis Tune response of system

Increase Flow Uniformity in Card Cage Slots

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Tuning Metering Plates

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Power Supply Temperatures Exceeding maximum allowable operating temperature rise

Connect heat sinks in front of fan

Power Supply

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Objectives met Components operating below maximum allowable limits Cost reduced

Final Design

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Why? High power density Compact design

Applications Military Aerospace High-powered electronics Medical Numerous others

Main Types Internal Tube

Typically designed / developed by cold plate vendors Internal Fin

Cold plate vendors System level designers

Cold Plates

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Typical Design Constraints Maximum allowable operating temperature

limits Mounted components Internal ambient

Fluid Air Water Heat transfer fluid

EG WEG (50/50) Others

Fluid pressure drop Fluid temperature rise Cost Manufacturability

Design Variables Internal construction

“Folded” fin Machined fin

Speed & Feed # of “passes” Gap thickness Fin thickness Inlet / Outlet

Size location

Envelope Component “footprint”

Design

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Fluid gap size maintained Velocities consistent Isolate Conduction

More fins / less fins under chip Total conduction area Conduction paths

Bottleneck?

Machined Fin – Constant Fluid Gap SizeMachined Fin

Fin Thickness

Ch

ip T

em

pe

ratu

re R

ise

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Fin thickness maintained Isolate convection

Smaller Gaps Lower Temperatures Higher pressure drops

Fluid gap larger influence than fin thickness

Machined Fin – Constant Fin ThicknessMachined Fin

Fluid Gap Thickness

Ch

ip T

emp

erat

ure

Ris

e

Machined Fin

Fluid Gap Thickness

Pre

ss

ure

Dro

p

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Correlation between fluid spacing and temperature evident Higher velocities = lower temperatures & higher pressure drops

Fold Fin

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Product Development Process Typical flow Cost

Time & Money

Simulation Technology Required resources Value

Return on Investment

Simulation in the product development process

Discussion

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Informative Design Partners Collaborative consulting business model to

deliver CFD simulation services for confident design decisions.

Our model is built on leveraging strengths: The analysis process is left to our analysis

experts Design process is left to your design experts. 

The insight we provide empowers our clients to create robust designs faster and more reliably without distractions to their current development process.

www.informativedp.com

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Questions?

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Autodesk, AutoCAD* [*if/when mentioned in the pertinent material, followed by an alphabetical list of all other trademarks mentioned in the material] are registered trademarks or trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA and/or other countries. All other brand names, product names, or trademarks belong to their respective holders. Autodesk reserves the right to alter product and services offerings, and specifications and pricing at any time without notice, and is not responsible for typographical or graphical errors that may appear in this document. © 2011 Autodesk, Inc. All rights reserved.