DFM Overview & Injection Molding - MIT - October 7, 2014

DRAGON INNOVATION, INC. !

MIT  EC.729  !

DFM OVERVIEW + INJECTION MOLDING !

OCT 7, 2014 !!!!!!!

SCOTT N. MILLER | CEO | @DRAGONINNOVATE | WWW.DRAGONINNOVATION.COM

Presentation Download

http://bit.ly/DFM-Injection-Molding-Overview

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Agenda

http://en.wikipedia.org

•Survey

•Dragon Background

•How to Select a Factory (RFQ)

•How to Work with a Factory

•Injection Molding Basics

Quick Survey

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DRAGON BACKGROUND

MIT RoboTuna

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Disney Dino

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My Real Baby

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Agenda

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DRAGON INNOVATION HAS HELPED LAUNCH AND SCALE OVER 100 COMPANIES SINCE 2009

HOW TO PICK A FACTORY !

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!*THE MOST IMPORTANT MANUFACTURING DECISION YOU’LL MAKE

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Overview of the CM Selection Process

http://en.wikipedia.org

1. Talk with trusted network connections who have manufacturing experience.

2. Create a differentiated list of 5 - 10 CMs.

3. Down select to 3 - 5 factories based on your product category (why?)

4. Create a Request for Quote (RFQ) Package.

5. Visit!

6. Analyze Results.

7. Negotiate Big Items.

8. Talk with the CM’s customers.

9. Select the winner, and leave the others on good terms.

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RFQ Package

http://en.wikipedia.org

•Company Overview -Team overview -Funding -Product -What’s done -What needs to be done -Factory Criteria

•BOM -Canonical format (A2A) in Excel -Transparent and Formula Driven -Separate Std, Special and Consigned Margins/Markups -Include all costs to Ex-Factory -Fill in the blanks

•Schedule -Gantt chart (Cloud) -Fill in the blanks

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Factory Visit Checklist

http://en.wikipedia.org

Do you like the team? Are they experienced and friendly?

Do they have the right manufacturing capabilities?

Does your intended volume match their volume capabilities?

Are they financially stable?

Do they have enough working capital to get going?

Do they have favorable payment terms?

Are they transparent in their costing?

Do they take IP seriously? Did they show you something they shouldn’t have?

Are they ethical in their treatment of their workers and otherwise?

Do you have access to upper management?

Are they excited about working on your product?

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CM Comparison (A2A Decision Matrix)

http://en.wikipedia.org

•Total Material Costs

•Labor

•Margins/Markup (Std, Special, Consigned)

•Pareto of Top 5 Most Expensive Components

•Fixed Costs (tooling, fixtures, NRE)

•Schedule

•Fit Criteria

HOW TO WORK WITH A FACTORY

POP QUIZ

• Question: What is the biggest challenge in manufacturing ?

Hint

POP QUIZ

• Question: What is the biggest challenge in manufacturing?

• Answer: Communication! • You cannot design in a vacuum (even if you design

vacuums). Strong communication and teamwork skills are critical to success. Engineering is team sport. It’s all about the people. “Us” and “Them” won’t work.

Communication At Work

Bi-Directional Knowledge Flow

Product Designed In U.S.A. Database Sent To Cm Tooling Manufactured

Parts Molded Product Assembled Final Inspection & Shipping

Manufacturing Management Triangle

Quality

Cost

Schedule

Cost of Goods Sold

(COGS)

• Direct costs for goods produced. • Does NOT include Tooling. • Actual price depends on where a

company takes ownership: - Ex-Factory (XF) - FOB (add overland transport to

XF) - Landed (add shipping to FOB) - Inventory (add warehousing)

• Price will vary by date depending on running changes, transportation costs, currency exchange, commodity costs, etc.

Very Simple Retail Costing Model

$

Sell-Through Price (Retail Price)

Sell-In Price (Wholesale Price)

COGS

Retailer Gross Profit

Company Gross Profit

COGS

COGS YOUR DESIGN

• Material and Component Selection

• Fabrication Method • Manufacturing Efficiency

(First Time Yield, machine tonnage, assembly labor, number of operations, etc.)

• Quality Requirements (driven by requirements / Voice of Customer)

• Packout (replaceable vs. rechargeable batteries; packaging; spares, etc.)

MANUFACTURING PARTNER • BOM Transparency • Profit Margin • Labor Rate • Currency • Geographic Location

(shipping, tariffs, etc.) • Capability (in-house vs.

outsourced) • Supply Chain (Purchasing

Power, volume (piggy back), Consigned vs Purchased, etc).

Controlling Costs

1.Deconstruct  the  BOM.  2.Separate  special  components.  3.Transparency  4.Compare  to  standards.  5.NegoEate  Inclusions

Additional COGS Strategies

Cost

•Bill  of  Material  Transparency:    Require  factories  to  provide  an  item  by  item  costed  BOM.    No  mysteries  or  hidden  formulas.  

•Calculate  labor  rates.    Pop  Quiz  –  How???  

•Build  a  “Standard  Cost”  database.    Price  out  cost  reducJons.  

•If  Jme  permits,  develop  relaJonships  with  mulJple  vendors  to  avoid  single  source  suppliers.    Leverage  is  a  beauJful  word.  

•When  manufacturing  in  volume  for  a  CE  product,  it  is  criJcal  to  understand  and  control  COGS.    Focus  here!    Because  of  the  volume,  every  penny  counts  ($10k  @  1M  units)

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ITEM NO. PART NUMBER DESCRIPTION QTY.

1 100132 Heatsink, Aavid 60520 12 PCB 1

100104 Circuit board blank 1 100015 LED, Luxeon LXHL-LW6C 1

3 GATE 1 100110 Film Gate 1 100011 Backgate 1 100024 Film Spacer 1

4 Bottom 1 100144 Bottom Plate 1 100029 Leaf Spring 2

5 Knobreel 2 100106 Cover Bush 1 100151 Dowel .125 dia 2.000 long 1 100009 Driver 1 100153 Gripring .125 dia 1 100149 Knob bush 1 100007 Clutch, one-way, Torrington RC-02 1 100152 Washer, ss .125 id, McMaster 98019A310 1 100017 Knob, plastic McMaster 7354K15 1 100045 Felt washer 1

6 Reel 27 condentube 1

100031 Condenser lens, small Fisher Price 1 100105 Condenser Tube 1 100154 O-ring Buna -120 1 100035 Retaining ring, internal 1.062 dia 1 100031b Condenser lens, large, Fisher-Price 2

8 100162 Spacer, condenser lens, short 19 100136 Spacer, condenser lens, long 1

10 100163 Spacer, projector, short 111 FHMS Phillips M4x20 812 PHMS Phillips M4x8 613 PHMS Phillips M4x6 514 PHMS Phillips M5x16 815 FHMS Phillips M4x12 616 PHMS Phillips M4x12 117 PHMS M4x8 618 100150 Endplate, Right 119 100160 Endplate, Left 120 100100 Front Plate 121 100138 Projector Lens Housing 122 100148 End Spacer 223 100145 Top Plate 124 100158 Window Edmund R39-773 125 100146 Handle 126 100161 M5 Acorn Nut 127 100147 Half Bridge 128 100012 Focus Screw McMaster 92558A170 129 100143 Spacer, .25 dia, .19 long 430 100156 Spacer, projector, long 131 FHMS Phillips M4x8 232 100150 Washer, Nylon, MSC 05401757 133 100159 Detent 134 100101 Bumper, rubber McMaster 9540K35 835 100039 Switch, SPST rocker Carlingswitch 136 100155 Projector lens, concave 137 100157 Projector lens, plano 1

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APPLICATION

DIMENSIONS ARE IN MILLIMETERSTOLERANCES: 0,1MM ANGULAR: 0 30'

MATERIAL

FINISH

DRAWN

APPROVED

DATENAME

TITLE:

SIZE

BDWG. NO. REV

SCALE 2:5

UNLESS OTHERWISE SPECIFIED:

KINKAJOU DELTA100141

DO NOT SCALE DRAWING

REMOVE ALL BURRS AND SHARP EDGES

allen 21july04

Anatomy of a BOM• Plastic • Purchased Parts • Electrical Components • Consigned Components • Deco • Packaging • Assembly Labor • CM Profit, Overhead and Scrap • Overland Transportation

• Does it matter that it is a gear???

• Components (3) 1.Material Cost = Part Weight * Resin Cost 2.Machine Overhead: = Hourly Cost * Cycle Time (sec) / (3,600 sec / hr) 3.Factory Mark-up, Scrap and Overhead (%)

• Total Part Cost: = (Material Cost + Overhead Cost) * (1+Factory M/U)

How to Calculate Plastic

HK Resin Prices (USD/Ton)

Reference: http://www.nhh.com.hk/eng/trading/price_trend.asp (you will need to create a login)

Item Cost (USD)

280 Ton / hr $15.48

220 Ton / hr $10.96

180 Ton / hr $8.38

140 Ton / hr $7.09

100 Ton / hr $5.80

80 Ton / hr $5.16

Example PRC

How to Calculate EE Costs

• Cost = Component * Usage • Separate high cost components over a certain

threshold. Apply a lower mark-up. • Apply Factory M/U

Typical PRC CM Margins (Profit, Scrap, Overhead)

PCBA 6–8%

Toys 12%

Consumer 15%

Medical >40%

Other BOM Costs

• Deco (Tampo, Paint, etc.) • Labor (PRC $2 – 6 / hr) • Packaging (Gift + Master)

Add It Up

• Plastic • Purchased Parts • Electrical Components • Consigned Components • Deco • Packaging • Assembly Labor • CM Profit, Overhead and Scrap • Overland Transportation

Schedule

Schedule

•Many  consumer  products  are  driven  by  the  Christmas  (which  has  a  fixed  date).  Plan  conJngency  in  your  schedule.    Things  never  go  according  to  plan.  

Have  an  onsite  presence.  Track  schedule  carefully  and  take  correcJve  acJons  early.  Avoid:    “There  is  never  Jme  to  do  it  right  the  first  Jme,  but  there  is  always  Jme  to  do  it  again.  ”

The Road to Production

Detailed Milestones‣Hand  Over  /  Kick-­‐Off  

Form  CM  Team  Contact  Lists  /  Roles  and  ResponsibiliJes  

ME  and  EE  File  transfer  Works  Like  /  Looks  Like  Samples  CM  trip  to  the  US  if  possible  (access  to  models  and  team,  relaJonship  building).  

Factory  Input  Components  

Engineering  Quality  ProducJon  Planning  (interface  with  Sales)  

Sourcing  /  MA  /  CosJng  LogisJcs  Process  /  Procedure  Financial  (modeling  and  payments)  

Pre-­‐ProducJon  Milestones  Tool  Release  

Tool  Start  (TS)  First  Shots  (FS)  Engineering  Pilot  1  (EP1)  EP2  EP3  Final  Engineering  Pilot  (FEP)  ProducJon  Pilot  (PP)  

ProducJon  ProducJon  Start  (PS)  Ramp  

Engineering  Change  NoJce  (ECN)  Sustaining  (Quality  Up  /  Cost  Down)  Sunset

Quality

Quality•DefiniJons:  

•Quality  =  Customer  SaJsfacJon  =  Performance  –  ExpectaJons  •“Fitness  for  Use”  Incoming  Quality  Control:    Use  good  ingredients.  Build  and  test  along  the  way.    Use  sub-­‐components.  StaJsJcal  Process  Control  (SPC)  /  Yield.    Find  out  now,  not  later.  Sample  TesJng:    Temp/Humidity;  TransportaJon;  Drop;  T/T;  Small  Parts;  Heavy  Metals;  

Compliance;  FuncJonal;  Life.    How  do  tests  match  reality?    ISTA-­‐3A.  Final  InspecJon  /  Acceptable  Quality  Levels  (AQL)  Walk  the  line.    Get  your  hands  dirty.  It  is  much  easier  (and  less  expensive)  to  make  changes  before  ProducJon  Start.  What  happens  if  something  fails?  Will  make  or  break  a  product  …  and  a  Company!  Quality  is  rarely  considered  in  the  engineering  phase  by  startups  due  to  schedule,  cost  and  

technical  pressures.  Watch  out  for  the  Unknown  Unknowns.  Strong  indicator  of  long  term  success,  etc.  Can  you  answer  the  quesEon  “How  do  you  know  the  product  is  good”?

INJECTION MOLDING

•Overview •Molding Process •Part Design •Materials •Techniques •Shot Nomenclature •Tooling Fabrication

INJECTION MOLDING

Overview

Recommended References

www.matweb.com

Typical Engineering Molded Parts (Examples)

• Housings / Brackets

• Transmissions

• Joints

Injection Molding Advantages

• Supports highly integrated design - Complex geometry and fine details possible

• Low part cost • High volume production • Wide range of thermoplastic materials and fillers • Wide range of sizes • Low scrap rate • High reproducibility & Reasonable tolerances • Little post production required • Good surface finish • Can be fully automated • Reduces piece count • Simplifies assembly

Injection Molding Disadvantages

• High tooling costs and long lead-times

• Difficult to make changes

• Large undercuts are difficult

• Requires nearly uniform wall thickness

• Limited to Thermoplastic materials

• Cannot produce very large parts as a single piece.

Molding Process

Molding Cycle

1. Melt Shot

2. Clamp and Fill

3. Pack (Gate Freeze)

4. Cool

5. Eject

Molding Process

Three Plate Mold

Part Design

Temp and Pressure

12k psi @ 440F

Shrinkage

Design Guidelines

• Design for 2mm uniform wall thickness (0.5mm – 6mm).

• Ribs 80% wall thickness. • Draft depends on texture and resin. Assume 0.5 deg. • Use rounds and fillets. No sharp edges except parting

line. • Shoot for planar parting line if possible. • Tolerance is a function of the resin, part geometry and

mold construction. • ABS: +/- 0.1mm • ABS Hole: +/- 0.05mm up to 6mm diameter.

• Surface Finish: SPI A-1 Grade 3: 6000 Grit Diamond

Reference: Product Design for Manufacture and Assembly. Geoffrey Boothroyd,, Peter Dewhurst and Winston Knight.

Part Features

Use 2mm Uniform Wall Thickness

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Uniform Wall Thickness, con’t

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Gusset Bosses & Avoid Shrink Marks

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Draft Overview

Reference: http://www.diecastingdesign.org/design/basic/draft/

Use at 0.5 - 1.0 Degree Draft Angle (depends on texture)

Avoid Penetrations and Weld Lines

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Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Avoid Undercuts if Possible

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Avoid Undercuts if Possible

Lifter (Undercut)

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Screw Bosses

No Flatheads!

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Use Shut-Offs Instead of Slides

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Use Shut-Offs con’t

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Integrate Joint into Parts

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Living Hinge

Hide Rib Shrink Marks

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Materials

Materials

•Thermoplastic polymers (95%). Can go through molding cycle many times (i.e. similar to ice). No chemical bonds between strands.

•Thermosets (5%). Chemical react during process to form cross linked polymer chains. Irreversible. Excellent creep, dimensional stability, temperate and chemical resistance. Ex: phenolics and epoxies.

Materials, con’t

•Additives - Enhance a specific property (UV, stiffness, color,

flame retardants, etc). All have side effects. - Add chopped fiber (up to 30% volume). Strength

and stiffness, lose on impact, abrasion and tool live (cut down to 1/3). Properties approaching metal.

•Need to operate below 250C (400C max) •Low specific gravity (0.8 - 1.8) Steel = 7. Strength to weight ratio good. Automotive. •Some materials are transparent. •Very sensitive to changes in temperature (vs steel) •Good electrical insulation

Example: Chi Mei Polylac PA-747

http://www.matweb.com/

Resin Comparison

Resin Use Yield (MN/m2)

Modulus (MN/m2)

Heat Deflect (1.8 MPa : C)

Cost ($/kg)

Shrink (cm/cm)

ABS Housings 39 1,800 86 $2.09 0.004

PC Lenses 65 2,400 128 $2.81 0.007

POM Gears 65 2,800 105 $1.48 0.02

Polyamide Strength 123 2,750 65 $3.63 0.013

PP Food 36 1,380 93* $1.76 0.015

Aluminum 276 68,900 $1.75

Steel 435 205,000 $0.39

http://www.matweb.com/ http://www.nhh.com.hk/eng/trading/price_trend.asp

Techniques

Use Moldflow Simulation

Use a clear shot to see mechanism (ABS -> PC)

Other Techniques

• Steel Safe Design

• Add additional ribs after first shots

• Use Inserts around change areas

• Review mold drawings carefully. Watch out for cooling lines.

Other Types of Molding

• Co-Injection / Overmolding (toothbrush)

• Gas Assist

• Low pressure (EE)

Calc Molding Size

• Assume holding 2 - 5 tons / sq. in

• Assume 50% cavity pressure lost due to friction

• Calc surface area of combined parts and runners

• Look up injection molding pressure (ABS = 1k bar)

• Calculate cavity pressure (Molding Pressure * 0.5)

• Calculate Tonnage: F = P * A

Shot Nomenclature

Shot

Shot Nomenclature

Shot Nomenclature

Reference: Plastic Part Design for Injection Molding. Robert A. Malloy.

Shot Nomenclature, con’t

Tooling Fabrication

Tool Shop

EDM

Open Tools

Polishing

Finished Tools

Questions?