P14311: PCB Isolation Routing System Systems Design Review

Agenda ItemTime Allotted Introduction 2 minutes Review Problem Definition 5 minutes Benchmarking 5 minutes Functional Decomposition 5 minutes Concept Development 10 minutes Engineering Analysis10 minutes Test Plans 3 minutes Risk Analysis 5 minutes Schedule Update 3 minutes Questions?12 minutes

Team Introductions NameMajorRole Matthew ClarkMELead Mechanical Engineer Marley Collier Sears MEME Interface Manager Sarah DumanIEProject Manager Richard KalbEELead Electrical Engineer Joseph PostEEEmbedded Controls Zoe RabinowitzMEDocumentation Manager Kevin RichardEEEE Interface Manager Our Senior Design Team

Problem Statement  RIT students need rapid prototyping for creation of unique circuit boards  Requires multiple revisions to perfect each circuit board  Currently each iteration must be created off campus  Long lead times  Expensive  Limits circuit refinement  Students not involved in process

Problem Statement (Continued)  Isolation Routing System  Rapid prototyping  Inexpensive  In-house fabrication  Students control production process  Proposed System  Create boards to accommodate through hole components  Ex. Improved Radiation Meter (Elektor PN )  Debris management system

Benchmarking- Scott Systems Isolation Router  Able to produce double-sided Board  Smallest bits used -.016”  Minimum width between traces - 5mm  Stepper control for Z-axis  Stepper control for X-Y movement  Alignment pins and double sided tape used to secure board  Sacrificial plastic layer  Uses an air gun to blow dust out during the drilling  PVC with shop-vac sucks up debris  Data Flow – Eagle design file  G-code  Flashcut CNC  Motors

Benchmarking- Scott Systems Isolation Router

Pros, Cons, Potential Improvements  Pros:  Can etch double-sided boards  Easy to switch bits  5mm minimum trace width  Cons:  System lacks real time feedback sensors  X,Y, and Z, axis alignment is done manually.  Improvements  Improve debris management  Replace or repair Z-axis motor  Enclose system

Benchmarking- RIT Robotics Lab  Milling set-up is not used regularly because it’s a pain  Zeroing the plane is highly mechanical  Smallest tolerance is 10 mil  Floor of the mill is warped  Difficult to change drill bits  Interface software include expensive Isopro  Manual debris management  Utilizes two alignment pins  Board is secured down with tape

Pros, Cons, Potential Improvements  Pros:  Relatively Inexpensive  Cons:  Difficult to swap bits  Poor board alignment process  Z-axis solenoid  Improvements  Debris management system  Z-axis zeroing

Customer Requirements

Most Critical Customer Requirements

Engineering Requirements

Most Critical Engineering Requirements

Functional Decomposition

Process Flow Chart Turn on Device / Computer Open Design File Align / Secure Bare Board on Base Run Program Program Prompts For Drill Bit Change Program Pauses / Swap Drill Bit Program Prompts for Mill Bit Change Program Pauses / Swap Mill Bit Program Alerts User it has Finished Flip Board Remove Completed Etched Board Is There Another Side to Etch? YES No

P14311 Morphological Analysis

Pugh Analysis

Concept #1 X-Y axis Control of Spindle Assembly Spindle Assembly Vacuum Nest with Alignment Pins Upper and Lower Acrylic Guards Z axis Control of Base Cyclone Separator Electronic Waste Collection + Combination nozzle/vacuum with cyclone separator effectively manages debris + Straight forward design easy to understand + Vacuum nest and alignment pins ensure accuracy and repeatability Pressurized Air Nozzle - Minimal guards allow access to moving parts during operation - Difficult to relocate, much larger than Ryan’s and Rob’s systems - Large weight of gantry limits maximum accuracy - Redundant systems increase complexity

Concept #2 + Collet for holding tooling + Suction debris removal + Alignment Template system - DC motors with encoders for X,Y,Z - Horizontal Vice for mounting

Concept #3

Concept #4

Concept #5

Concept #6 + X- and Y-axis control using steppers and lead screws, which offers great resolution + Fully enclosed unit provides a much safer operating environment + Interlock would safely disconnect power in case of emergency/unit malfunction + Unit is overall very easy to use (assuming board is aligned) - Incineration not a feasible method of debris management - Rack and pinion Z-axis movement control would cause unnecessary backlash - Board alignment not very easily performed with electromagnets

Concept #7

Hybrid Design

Pugh Total Scores Scott Systems Robotics Lab Concept 1 Concept 2 Concept 3 Concept 4 Concept 5 Concept 6 Concept 7 Hybrid Design Total Total S Total Total Score Total Rank

Hybrid Solution- Selected Concept Stepper Motor with Lead Screw for Y Axis Control Stepper Motor with Lead Screw for X Axis Control Stepper Motor with Lead Screw for Z Axis Control Vacuum Clamping w/ Replaceable Sacrificial Layer Guide Rails Vacuum Attachment Pressurized Air Nozzle Spindle Motor and Collet Assembly Vacuum Clamp Sourced From Main Vacuum X and Z Axis Wire Management Debris Management Vacuum Assembly

Emergency Kill Switch Door Interlock Acrylic Door Assembly To Spindle VFD and X, Y, and Z Axis Stepper Motor Control To Vacuum Assembly with HEPA Filter To Pressurized Air Source Metal Casing Door Handle Hybrid Solution- Selected Concept

System Block Diagram Motor X Motor Controller Computer Design file G-code Motor Z Motor Y USB, serial, Ethernet, etc GUI Power Source Main Logic Board USB, serial, Ethernet, etc Debris Management System Interlock Power conditioning Motor Theta

 A system that creates negative pressure to hold down work pieces during machining  Will allow for easy set up by user  Work pieces will be held down after being cut  Collect debris being cut from board. Engineering Analysis – Vacuum Table

Engineering Analysis – Spindle vs Router Commercial Routers High Speed (~25,000+ RPM) but with manual control Large run out, not published as they are typically hobbyist and woodworking Run directly from 120 VAC line power Heat problem, not designed to be run continuously Low average cost (Free - $200) Brand specific collets Loud

Low to Medium Speeds (usually 400 to 24,000 RPM) Extremely low run out (typically less than 0.005mm/0.0002”) Need an inverter (capable of producing Air or Water cooled options available Higher average cost ($100 - $700) Standardized collet sizes (ER11, ER20, R8, 3MT, etc.) Quiet Spindle Motors Engineering Analysis – Spindle vs Router

Higher cost of spindle motor justified by advantages Inverter vs. speed control, ~ equal complexity (VFD) More professional look and results from spindle Justifies laser centering upgrade in the future Engineering Analysis – Spindle vs Router

Engineering Analysis- Direct Material Cost Estimate

Future Engineering Analysis  Weight analysis  Can the Z motor handle the weight of spindle?  Vacuum Analysis-  Can one shop vacuum both collect debris and secure board?  Does the vacuum have enough suction to keep the board secure while milling the outline?

Potential Test Plans  PCB Trace Accuracy Analysis  Attach pen to Gantry to draw board on paper  Test movement of carriage  Check condition power

Risk Analysis

Project Schedule Update

Problem Definition Systems Design Subsystems Design Detailed Design MSD I Gate Review

Project Schedule Update Problem Definition Systems Design Subsystems Design Detailed Design MSD I Gate Review

Subsystems Schedule

Questions?