P15311: Circuit Board Router (Rev2) Systems Level

Design Review

Team Members and Roles

Devon Monaco (ME)◦ Project Manager

Emily Roberts-Sovie (IE)◦ Safety, Statistics, and Documentation Manager

Joseph Lee (ME)◦ Lead Mechanical Engineer, Facilitator

Thomas Bizon (EE)◦ Lead Electrical Engineer

Nathan Faulknor (EE)◦ Systems Integration

Yevgeniy Parfilko (ME)◦ ME Interface Engineer

Kenny Ung (EE)◦ Electrical Design Engineer

Agenda MSD I Project Background

◦ Review problem statement and deliverables◦ Review stakeholders and use scenarios

Updated List of Needs and Engineering Requirements

Additional Benchmarking

Functional Decomposition

Concept Development◦ Morphological Chart◦ Pugh Analysis

System Level Proposal

Feasibility Analysis

Potential Test Plan

Refined Risk Analysis Chart

Up to Date Project Schedule

Time for Questions

Inherited State of Router, P14311 (Rev1)

Trial Mach3 software for converting Eagle PCB layouts to milling tool path with router

Vacuum table clamp and vacuum/brush debris collection as single subsystem

Manual homing and datum zeroing with computer jog keys

7”x7” max board size

PC, vacuum, and Bosch router enclosed in single roller unit

Monitor and keyboard on separate table

Problem Statement Printed Circuit Boards (PCBs) are expensive to produce.

MSD team P14311 developed a PCB Isolation Router that functioned but needed performance improvements.

Several features are needed for open use to students:◦ Automated tool setup and homing◦ Safe debris collection system ◦ User-friendly controls and operating procedures◦ Low noise level during operation

Refined router must operate predictably and precisely for corporate clients.

Project Deliverables Analyze the design of the current router and identify all improvement areas.

Modify the design to improve operator controls, setup automation, debris and noise management.

Define and document clear procedures from use scenarios and personal experience.

Compile a quick start guide, user manual, troubleshooting guide, maintenance schedule and replacement parts list.

Stakeholders Primary

◦ RIT Students◦ Inventors/tinkerers◦ Jeff Lonneville◦ CAST Electronics Lab

Secondary◦ Investors◦ MSD Team◦ RIT

Use Scenarios

Novice User

Outside Company

Experienced User

Use Scenarios Flow Chart

Prioritized List of Needs (1-3-9)Customer Rqmt. #

Importance Description Comments/Status

CR1 3 Capable of routing traces for finer pitched SMD's Tolerances currently too large

CR2 9Safe and easy to operate by minimally trained (<0.5 hour) user

Took several days to get machine operating

CR3 9Have quick start, service, and detailed troubleshooting/operation manuals

Improvements needed to documentation

CR4 3 Cost less than commercial systems on the marketFactor in lead time and process

costs

CR5 3Require minimal maintenance and part replacement Frequent drill bit breakage

CR6 9

No mechanical, electrical, environmental, or health related hazards to operators of those in the general lab area

Concerns with noise level and particulate matter

CR7 3 Alignment system capable of auto homingNeed for more precision and

repeatability

CR8 1 Automatic tool change and recognition Convenience feature

CR9 3 Visual feedback system for error detection Difficult to see traces through glass

CR10 9 Improve debris removal system Messy and dangerous for operation

CR111

Contain all components of system in one unit Detached monitor and keyboard

CR12 3 Rout PCB rapidly Long setup time

CR133 Ability to flip and zero reverse side of board

accuratelyNo flipping method or ability to re-

zero flipped board

Engineering Requirements

ER Importance Source Engr. Requirement (metric)

Unit of Measure

Marginal Value Ideal Value P14311

1 9 CR6 Noise Generation dBA <100 <65 Marginal pass

2 9 CR1 Minimum Width Between Traces Supported inches 0.020 0.016 marginal

pass

3 3 CR4 Manufacturing Cost $ 2800 2000 Fail

4 9 CR5 Unit Reliability (mean time between failures) TBD TBD TBD

5 9 CR5 Mean to time between maintenance hours 50 100

6 9 CR3, 7 Minimum Tolerance to locating positions on board inches 0.005 0.001 Marginal

pass

7 3 CR5, 8 Bit Replacement Time minutes 2 <1

8 3 TBD Feed Rate in/minute 10 20 Marginal pass

9 3 CR2, 3 Time for initial machine set-up minutes 20 10

10 3 TBD Maximum Compatible Board Size inch x inch 5 x 5 8 x 8

11 3 TBD Minimum Compatible Board Size inch x inch 2 x 2 1 x 1

12 9 CR2, 11 Up to date PC & software for system control Binary No Yes Pass

13 9 CR2, 3, 5 Minimize Operator Training hours 1.5 .5 hours

14 9 CR1 Router Speed rpm 15000 30000 Marginal pass

15 9 C10 Debris Removal (Copper and Substrate) mg ratio 0.90 0.99

16 9 CR1 Total Indicated Runout inches <.0006 <0.0004 Marginal pass

17 9 CR7, 10 Vacuum Table Force lbs force 30 40 Marginal pass

18 9 CR6 Max Power Consumption for entire system watts 1920 1800

19 3 CR6 Aesthetic wiring and schematics Binary No Yes

Current Methods of PCB Routing

Criteria Chemical Etching

Commercial MITS Auto Lab

LaserJet PCB Printing

P14311 PCB Router

Max. Workable Area (in)

Most Sizes 9 x 11.8 8 x 10 7 x 7

Minimum Trace Spacing (mm)

x ≥ 0.1 x ≥ 0.1 x ≥ 0.17 0.51 < x < 0.41

Material Depth Removal

(precision)

Varies on process

0.2 mm; 1.18” maximum

thickness of board

Varies on process

3.175 mm

Cycle time/Feed Rate

Weeks 55 Drill Cycles/min

25 to 60 min (total)

10 in/min

Space Requirements

Room-size 46.7 ft3 32 ft3 40 ft3

Maximum Noise Output (dB)

minimal low minimal 100 < x < 75

Cost Varied $15,200 ~$500 $4000

Additional Benchmarking- RIT’s ME Lab PCB Router

T-Tech PCB router system- limited specs on site

Mobile X-Y axis bed

Z axis solenoid control with hard stop pad

Separate vacuum unit with individual debris vacuum and vacuum table pump

EXPENSIVE◦ For all of the features we wish to have on our router,

this unit costs upwards of $20,000

Functional Decomposition

Morphological Chart for Concept Development

Pugh Analysis for Concept Selection:Securing Board

Pugh Analysis for Concept Selection:Auto Homing

Pugh Analysis for Concept Selection:Debris Collection

System Level Proposal New vacuum debris collection system

◦ Redesign vacuum inlet assembly◦ Include improved vacuum with more powerful motor and higher flow rate◦ Separate vacuum table and debris collection unit

Redesign vacuum table assembly◦ Include vacuum pump with high sealing pressure◦ Separate vacuum table and debris collection to eliminate interface losses◦ Make single standard size vacuum table top

Implement automatic homing◦ Eliminate need for user jogging to home position◦ Set permanent global zero in mach3 code◦ Include proximity sensors for home location verification◦ Improve limit switches for hard stop backup

System Level Proposal Maximize tool life and trace width capabilities

◦ Provide predetermined ideal drill bits and sizes◦ Enable spindle speed and feed rate selection for tool optimization

Improved user experience◦ Quick start guides◦ Troubleshooting documentation◦ Visual feedback◦ Intuitive user interface◦ System contained in single unit◦ Dampen noise generated by system

System Architecture (Block Diagram)

Revised from P14311 documentation

Board Architecture (Block Diagram)

Revised from P14311 documentation

Power Distribution

Revised from P14311 documentation

Feasibility Analysis Test

Observe

Analyze

Demonstrate

Current Working Router

Completed Work, Tests, and Updates

Locker inventory

Running old PC and software

Purchasing full software license and installing

Updating to new PC

Including 2nd monitor and allowing for video feed

Investigating drill bits and deciding on best styles for purchasing and testing

Sourcing and purchasing PCB material

Sourcing and purchasing monitor brackets

Hands on time with machine running test profiles and routing boards

Investigating background code in mach3 and implementing custom macros

Performing and compiling student interviews for refined requirements

Vacuum Table Calculations

When analyzing the ShopVac system calculations from the last group:◦ The team failed to account for the maximum holding pressure of ShopVac◦ The team incorrectly assumed that there would be ~1CFM of flow

ShopVac Specs Vacuum Pump Specs

Cleaning power is a measurement unit of the effectiveness of vacuums referring to airflow and amount of power a vacuum cleaner produces and uses:P = 0.117354 x F x S

where: P = cleaning power (air watts) 290 Assuming 16 x 0.25" Diam holesF = flow rate (CFM) 170 A ≈ 0.785 inS = suction capability (in H20) 60 max Assume coeff friction for copper-table0.117345 = conversion factor 0.117345 µ ≈ 0.4Note- 1 airwatt = 0.9983 Watts Assume mass of board

m ≈ 0.2 lbFor a vacuum pump that has achieved a steady state pressure differential:

CFM Pressure (in H20) Pressure (PSI) Holding force z (lb)

Holding force x-y (lb)

Pressure (PSI)

Holding force z (lb)

Holding force x-y (lb)

170 14.537 0.525 0.412 0.245 8.7 6.830 2.812160 15.446 0.558 0.438 0.255150 16.476 0.595 0.467 0.267140 17.652 0.638 0.501 0.280130 19.010 0.687 0.539 0.296120 20.595 0.744 0.584 0.314110 22.467 0.812 0.637 0.335100 24.713 0.893 0.701 0.360

90 27.459 0.992 0.779 0.39180 30.892 1.116 0.876 0.43070 35.305 1.275 1.001 0.48060 41.189 1.488 1.168 0.54750 49.427 1.786 1.402 0.64140 61.784 2.168 1.702 0.76130 82.378 2.168 1.702 0.76120 123.567 2.168 1.702 0.76110 247.135 2.168 1.702 0.761

5 494.269 2.168 1.702 0.7611 2471.345 2.168 1.702 0.761

ShopVac Vacuum Pump

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Vacuum Debris Collection Calculations

Reasons For Loss• Support structures left in 3D printed parts• 3D printed joints do not create a good seal• Air is leaking out of the sides of the vacuum table

Drill Bit Tool Life Calculations

10,000 linear inches of cut expected at 20 in/min feed rate

Roughly 100 boards per tool life

Breakage caused by high feed rate + deep plunge

Four tools needed to cut board:

1: Drill for through-holes

2: Fine-tip trace isolation tool

3: Wide-tip rubout tool

4: Deep-plunge cutout tool

12

34

Budget EstimateProposed Purchases/Budget

Item Use/Description Supplier Worst Case Most Likely Case Actual (Team Spending)Alignment System Auto Homing with Precision Unknown $500.00 $200.00 TBD

Wire Rewire to color code, and design for service Unknown $300.00 $250.00 TBD

Mach 3 License Improve bugs with program, z-axis precision ArtSoft $200.00 $200.00 $175.00

Drill Bits For testing, bit analysis, and selection Think & Tinker $200.00 $200.00 $101.06

Misc Parts, Hardware, 3D Printing, Etc.

Unnaccounted for extra expenses, sacrificial material, etc. (to date) Unknown $200.00 $200.00 $0.00

New Vacuum More powerful to improve debris removal, quiet ShopVac $200.00 $150.00 TBD

Replacement Router Bausch router has been discontinued Unknown $150.00 $100.00 TBDPCB Boards For testing and machine familiarity DigiKey/Mouser $100.00 $100.00 TBDMisc Labor Machining, etc. RIT/Other $100.00 $50.00 TBD

Computer Monitor Dual Mount Make the machine one unit TaoTronics $100.00 $50.00 $55.00

Wire Duct, Heat Shrink, Etc. Wire management, improve reliability Unknown $50.00 $35.00 TBD

Vacuum Pump Hold PCB board onto table unknown $75.00 $40.00 TBD

Sound Absorbing Material Reduce noise and impove working environment Unknown $75.00 $35.00 TBD

New Computer/Monitor Upgrade computer and provide for camera view RIT $0.00 $0.00 $0.00

Total: $2,250.00 $1,610.00 $331.06

Budget Estimate

Alignment System

Wire

Mach 3 License

Drill Bits

Misc Parts, Hardware, 3D Printing, Etc.

New Vacuum

Replacement Router

PCB Boards

Misc Labor

Computer Monitor Dual Mount

Wire Duct, Heat Shrink, Etc.

Vacuum Pump

Sound Absorbing Material

New Computer/Monitor

$0.00 $100.00 $200.00 $300.00 $400.00 $500.00 $600.00

Cost Analysis

Actual Cost Most Likely Case Worst Case

Refined Risks Assessment

ID Risk Item Effect Cause

Likelihood

Severity

Importance Action to Minimize Risk Owner

1

Breaking Bits Circuit board ruined, extra costs, time spent on maintenance

Improper feed rate, uneven surface, wrong material

9 3 27 Documentation of bit use, statistical study, (bit selection option?)

Team

2 Dusting Issues

Respiratory issues, OSHA compliance issues, can get into small parts and cause mechanical failure

Vacuum not powerful enough or close enough to routing, user not using PPE if needed 6 6 36

Get a stronger vacuum, find a way to get the vacuum as close to the dust as possible, find the particle size of the dust, do not have the operator clean it off by hand

Mechanical Team/Safety

3 Controls FailureCircuit ruined, extra time

Unable to control z axis, programming issues 9 6 54

Update Mach 3, investigate z-axis motor, analyze drill bit fit and slip

Electrical Team

4 Operator Error

Injury, machine breakage, RIT shuts machine down, circuit board ruined

Improper training, unclear instructions, unlabeled parts, poor user interface 6 6 36

Standard Work, Instructions posted on machine, training before use, poka-yokes, improve user interface Safety

5 Electrical Failure

Shortage, loss of power, blow fuse, cannot use machine, broken wall plug

Movements, overheating, improper wiring 6 9 54

Standard Inspection/Replacement of wires, reorganize wires, rewire any improperly done wires

Electrical Team

6 Computer/Software Failure Cannot use machineOlder hardware, outdated software 3 6 18

Inspections of hardware, regular software updates Team

7 Router FailureRuins board, cannot use machine Over use, overheating 3 9 27 Buy extra router

Mechanical Team

Potential Test Plans Produce machine troubleshooting/errors data sheet and analyze

◦ Determine machine reliability◦ Compile troubleshooting requirements

Produce drill bit data sheet and analyze tool life, tool wear, breakage◦ Optimize tools and maintenance requirements

Use load cell to confirm breaking force of vacuum table hold in x,y,z◦ Ensure board security and trace spacing

Use flow meter to analyze vacuum debris inlet flow rate◦ With and without HEPA filter

Experiment with mach3 customized macros◦ Improved functions◦ Extended tool life

Measure change in board weight vs debris collected by vacuum◦ Minimize interference of debris with routing◦ Mitigate airborne particulates

Measure sound produced with decibel meter

Updated Project Schedule

Upcoming Project Schedule

WBS Inspired Weekly Tasks

Task Member(s) TargetInvestigate T-Tech (PCB router company) Dev TuesdayProduce Functional Decomp Emily TuesdayDebug Edge Dev WednesdayUpdate Project Schedule Dev WednesdayFix CNC Controller Issue All (Dev) Wed-ThursCreate Budget Sheet Nate ThursdayProduce Morphological Chart Joe ThursdayProduce Pugh Analysis Tom, Yev ThursdayMove Machine to EE Lab Kenny (Dev) ThursdayUpload Use Scenarios Nate ThursdayInvite Jeff & Safety to Design Review Dev, Emily ThursdayCreate Issues/Troubleshooting Doc Emily FridayInterview CAST Students Joe FridayInvestigate Mach3 Background Code Tom, Nate (Dev, Yev) FridayCreate Powerpoint All FridayProduce Feasibility Analysis All (Dev)PPT Practice Runs & Send Out All Weekend/Next WeekCompile and Review Student Interviews All Next WeekTake Team Pic All Next WeekUpdate Edge Emily Next WeekEagle/Mach3 Familiarization Nate (All) Next WeekRun T-Tech Machine Dev, Kenny Next WeekDrill Bits Testing All Next WeekVac Table Substrate Research Yev OngoingMnifold/Standard PCB Size Research Dev OngoingVacuum Research Dev OngoingBase PCB Template Layout Nate OngoingWiring Schematics/Wire Cleanup Tom, Nate Ongoing5s and Labeling Machine EmilyLimit Switch Research TomMonitor Brackets Joe

Questions?