RPI Force 1 Final Presentation

MPS Student Team: Fall 2021-Spring 2022

Content

• Project Summary
• Overall Challenges
• Manufacturing
• Assembly
• Budget

Our Team

Aksen, Michael

Assembly Engineer

Barbee, Ammar

Information Manager, TDP Co-Manager

Bhimani, Kevin

Co-Assembly Manager, Plastics Engineer

Deiros, Eric D.

Co-Assembly Manager

Gallagher, Ava S.

TDP Co-Manager, Robot Programmer, Plastics Engineer

Grinberg, Benjamin

Plastics Engineer

Interian, Gabriela

Assembly Engineer

Pirovano, Alex

Financial Manager, Packaging Manager

Raheb, Joseph S.

Manufacturing Manager

Sarmiento, Aaron

Manufacturing Engineer, TDP Co-Manager

Stotz, John

Project Manager

Project Overview

Semester Overview

Overall Challenges

• COVID
• Multiple team members caught COVID and had to isolate
• Transferred responsibility to in-person students
• Delays
• Many parts had oversights that the team corrected
• As a result project fell behind schedule
• Team members worked extra time to get on schedule
• Scheduling
• Team members had other commitments, making scheduling difficult
• Created weekly schedules with input from team members

Manufacturing

Top Fuselage

Bottom Face Machining

• Run Time: 4:09
• Material: 1 Inch Square 6061 Aluminum Bar Stock
• Machine: Haas VF2 CNC Mill
• Fixturing: Standard Vice
• Tooling:
• 3” Face Mill
• ⅛” Carbide Drill Bit
• #10-24 Threadform
• #18 Drill
• ½” Flat End Mill

• ¼” Flat End Mill
• ⅛” Ball End Mill
• ⅛” Flat End Mill
• ¼” Ball End Mill

Bottom Face Machining

• Notable features: Two ¼”-20 �threaded holes for interfacing �with the 4th axis fixture
• Post Process: Break and deburr all�sharp edges
• 100% inspection of locator holes
• .125” and .130” pin gages
• Go/No-Go style
• 100% inspection of PCB cutout
• Digital calipers to check width
• 1 part per operation

4th Axis Design

Subplate

Mitee-Bite

Problems:

• Chatter
• Clamping Force

4th Axis Design - Modifications

• Locator pins installed on main body
• Greater locational constraint to reduce chatter
• Countersunk screws (shown) replaced with cap head bolts
• Allowed for more thread engagement with the subplates

4th Axis Design - Modifications

• Mitee-Bite clamps found to not apply adequate force to hold part
• Replaced with ¼-20 cap head screws for more clamping force

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4th Axis - Top Fuselage Machining

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• Run Time: 34:00
• Machine: Haas VF2 CNC Mill
• Fixturing: 4th Axis
• Tooling:
• 1” Face Mill
• ¼” Ball End Mill
• ⅛” Ball End Mill
• ¾” Ball End Mill

4th Axis - Top Fuselage Machining

• Notable features: Window and �windshield for aesthetic purposes
• Post Process: Break and deburr all�sharp edges
• Qualitative visual inspection of all �parts
• 4 parts per operation
• Lead to inconsistent surface finish
• Rock tumbled for 3 hours to provide�even finish and darker coloration

Lessons Learned

• Design for manufacturing
• Bottom face surfacing operation was long and could have been eliminated by modifying wing subassembly
• Value of time
• A difference of 6 seconds per part means a half hour of labor, this scales up quickly
• Optimized MasterCAM to minimize machining time

Plastic Injection Molded Parts

Mold

• Runners were placed close together
• Easier to mold in one shot
• Injection pressure > clamping force
• Decreased shot size

Flashing from Injection Pressure → Clamping Force & Oversized Inserts

Effect of Undershot Parts

2 Wings Assembled Together

Bottom Fuselage Challenges

• Design changes were not incorporated into the mold
• Screw hole height interfered with wing placement
• Required an extra facing operation on the mill

Decreased height

Turning

Spinner & Wheels

• Machine: ST-10Y Lathe
• Tools:
• T2: 35° Facing Tool
• T4: Grooving tool
• T8: #7 Drill (spinner)
• T10: #29 Drill (wheels)
• T12: .118” Angled Parting Tool
• T13: Bar Puller
• 0.5” Collet
• Material: 6061 Aluminum, OD 0.5”

Turning: Drilling:

Mastercam

Spinner

Wheel

Cycle Time: 3 minutes

Output: 3 spinners

Cycle Time: 1 minute, 33 seconds

Output: 3 wheels

Quality Control

Spinners

• 100% inspection of drilled hole
• .200” and .202” pin gages
• Go no-go style
• Every cycle hole depth
• 1 spinner per cycle
• Digital Caliper
• Every 1st, 10th, 25th, 50th, 75th, 100th… cycle spinner height
• 1 spinner per request
• Digital Calipers

Wheels

• 100% inspection of drilled hole
• .1295” pin gage

Design Changes

Spinner

• Machining to a point is difficult, forces cause the part to break-off
• Spinner is flat on both ends
• Requires a sanding operation

Wheels

• Inner fillets are difficult to cut
• Changed to flat inner groove
• Initial parting speed forces causes premature breaking
• Reduced parting speed to compensate

Lessons Learned

• Small Part Collection is Not Easy
• Parts were often lost in the lathe area among the shavings
• Basket and holed sheet metal helped mitigate issue, but parts still fell into chip conveyor

Lessons Learned

• Faster Turnaround Time = Less Time for Quality Check
• Quality control was done while another cycle was running
• The short run times made the more intensive quality checks pile up parts
• Small Errors on Small Parts = Big Changes
• For the wheels, the through hole drill bit was incorrectly set for the first runs resulting in wheels with off-centered holes
• An incorrect insert for the spinners vibrated the tool causing every 2 parts to be smaller in every dimension

Wheel Wire Forming

Wheel Wire Forming: Altair Inspire Simulation

• Support planes fuselage
• Steel vs Aluminum
• Simulation demonstrates no failure points for Steel

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Wheel Wire Manufacturing

1. Cut ⅛” dia SS 304 wires from spool using Foot Shear

2. Grind wire ends to smoothen the ends

Wheel Wire Manufacturing Continued

3. Place wire in die and bend the wire using Arbor Press station

4. Quality check: place through two quality control gauges to inspect quality of the wire

Tooling: Wheel Wire Die

Components:

• Top Die Components
• Base Die Components
• Alignment Brackets
• Alignment Wall
• Arbor Press End Rod
• Base Plate
• Fasteners

Wheel Wire Calculations

Die Clearance Equation [1]

S₀=Surface Thickness (⅛”)

Springback Equation [1]

1. “Metal Working Lab - Deep Drawing.” RPI MANE, Troy, NY.

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Sample Die Clearance Calculation: U_D=(1.1-1.2)So=1.12*0.125=0.14"

R_i = 0.396”, α_i=89.04^o

Sample Springback Calculation:

Assembly

Spinner Propeller Subassembly

Overview

• Staubli Robot Arm
• Feeder Tooling
• Spinner Pallet
• Propeller Pallet
• Press Fit Tooling
• Pallet
• Plate
• Piston
• Bracket

Force to Press:

Feeder Tooling

Press Fit Tooling

Press-fit Pallet

Locator Pins

Piston

Bracket

Piston Connector

Press-fit Plate

Press-fit Bars

Process Overview

1. Press fit pallet will arrive at location 1
2. Robot will begin to load spinners onto press fit pallet
3. Robot will load propellers on top of spinners
4. Press fit pallet is released from location 1

Process Overview

5. Operator ensures that propeller pegs are aligned with the spinner hole

Before & after alignment

Process Overview

6. Press fit pallet arrives at location 2

7. Piston presses propellers into spinners

8. Press fit pallet is released from location 2

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Process Overview

9. Operator checks gap

Quality Control

• 100% inspection of spinner propeller interface gap
• Feeler gage to 0.050”
• Go no-go style

Challenges

• Weighing gap versus quantity per cycle
• Finding location for best press
• Losing air pressure due to tubing available at the MILL

.013” gap

.035” gap

Lessons Learned

• Importance of aligning components
• Importance of testing set-ups
• Break up goal into smaller tasks
• Makes testing and debugging easier

Wheel Wire Subassembly

Assembly: Parts and Fixture

Alignment Block

Assembly Die

Assembly of Wheel wire

Assembly of Wheel wire: Continue

Assembly of Wheel wire : Quality Check

Octopuz Simulations

• Simulation demonstrates the process can be fully automated at industrial scale

Wheel Wire: Lessons Learned & Future Improvements

Manufacturing

• Designing a forming die
• Continuous improvement design process

Assembly:

• Designing the alignment block to accommodate the wheel

Future Improvements:

• Use pistons for forming, design a progressive die, use tool steel
• Add longer lever arm for easier forming, Add thinner shims to reduce misalignment
• Instead of 3D printing fixture can be made using steel to avoid wear

Wings & Horizontal Stabilizer Subassemblies

Overview

• Adept cobra robot arm
• Feeder tooling
• Wing pallet
• Horizontal stabilizer pallet
• Welding Tooling
• Wing welding fixture
• Stabilizer welding fixture
• End effector
• Welding horn

Feeder Tooling

Welding Tooling

Process Overview

• Pallets will be loaded with wing halves
• Pallets will be checked for quantity and secured on the workspace using 3-2-1 fixturing
• Robot will load a concave up wing in the welding fixture
• Robot will load a concave down wing on top of the previous wing

Process Overview

• Welding horn will lower to weld the wing halves
• Robot will wait for prompt to remove welded part
• Robot will place part in a box for QC and final assembly
• Robot will iterate through pallets yielding 30 welded wings

Process Overview

• Operator check hole diameter with gauge pin
• Operator performs cosmetic QC

Quality Control

• 100% inspection of welded parts
• Gaps in wing interface
• Visual
• Excessive flashing
• Visual
• Hole diameter
• Gauge pin
• Go no-go style

Proper

Gap

Misaligned

Challenges

• End effector design
• Must reach under the welder to place the part
• Rigidity
• Quantity of pins in the feeder for greatest repeatability
• Losing air pressure due to tubing available at the MILL

Lessons Learned

• Importance of aligning components
• Quality control
• Repeatability
• Greater tolerance for locator pins
• Height of alignment components
• Limit robot’s movements
• Ensure welding horn doesn’t touch the fixture

Pre-weld

Post-weld

Electronic Subassembly

Electronic Subassembly Overview

Safety Concerns Prevented Soldering from Being Automated

Circuit Diagram

Physical Subassembly

• Assembly Machines
• Soldering Iron
• Third Hand Fixture
• Wire Length Gauge Block

• Parts:
• DC Motor
• USB-B Breakout Board
• 10 Ohm Resistor
• Wires (Red and Black)

Assembly Steps and Quality Control

• Cut Wires and Resistors to Length and Strip Wires
• Red = 4.25 Inches; Black = 3.25 Inches; Leads = 0.25 Inches
• Solder the Resistor to the Black Wire
• Solder the Red and Black Wire to the Breakout Board
• Leads Must solder through the BOTTOM of the Breakout Board
• Solder the Red Wire and Resistor to the DC Motor
• Fit the Subassembly into the 3D Printed Bottom Fuselage
• If the Subassembly does not fit, Scrap
• Plug the USB-B Cable into the Breakout Board
• If the Motor does not turn, Scrap

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Challenges Faced

• Solder on the top of the PCB could cause a short with the top fuselage
• Had to solder only from bottom or trim down lead
• Implemented rework procedure during final assembly in case the short was detected
• Subassembly Sometimes Break in Full Assembly
• Overstretching sometimes break soldered areas
• Implemented rework procedure during final assembly also covers broken subassemblies

Lessons Learned

• Assemblies Interact with Each Other
• Remember this for other Projects where Electronics and Metal are Close Together
• Slack Between Wires is Important for Final Assembly
• Do Not Trim Wires to their Shortest Length Possible
• Pre-Cut and Pre-Soldered Wires Speed Up Assembly
• Adapt the SOP for Future Work

Main Assembly

Challenges

• Significant force was required to install the top fuselage
• Discovered that tumbling left a dry powder coat that reduced the size of the hole, significant force required to assembly
• Deburring the holes reduced the force required to assemble

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Packaging

Budget

Thank you!

Q&A