RPI Pencil SharpenerSophie Connor and Katy Mix

Schoharie Central School

SME Contest Presentation

Pencil Sharpener

Why Make This Product?

• Practical and widely used• Variety of processes • Says “RPI”• Elegant and efficient design

Overview of Processes

• Injection Molding• Abrasive Waterjet Cutting• CNC Machining• Laser Cutting and Engraving•Ultrasonic Welding•Heat Treating

Measurements (Basic)

5 ½”

1 ¼”

3”3”

2 ¾”

Gear Bank

Handle: Injection Molding

Handle

Gear Bank

Handle Pin

Handle

Handle Pin: CNC Machining

Gear Bank

Handle Lever

Handle Pin

Handle

Handle Lever: Abrasive Waterjet

Gear Bank

Handle Lever

Handle Pin

Shaft

Handle

Shaft: CNC Machining

Gear Bank

Handle Lever

Handle Pin

Shaft

Planetary Gear (attached to blade)

Blades

Handle

Blades and Attached Planetary Gear: • CNC Machining • Possible Heat Treating

Gear Bank

Handle Lever

Handle Pin

Large GearShaft

Planetary Gear (attached to blade)

Blades

Handle

Large Gear: Abrasive Waterjet

Gear Bank

• CNC Machining• shaft• blades w/ planetary gear• handle pin

• Abrasive Waterjet Cutting• large gear• handle lever

• Injection Molding• handle

Handle Lever

Handle Pin

Large GearShaft

Planetary Gear (attached to blade)

Blades

Handle

½” Diameter

¾” Diameter

2” Length

3 ¾” 1 ½” Diameter

½” ¾”

2”

Sand/Garnet Base

Base

”

Cover

3”

3”1”

Sand

• Injection Molding • base

• Laser Cutting• cover

• Ultrasonic Welding• connect cover and

base

Filled with sand or recycled garnet from waterjet machine.

Drawer

Injection Molded

”

2 ¾” 2 ¾”

1 ¼”

Case

1 ½”

3”

3”

• Injection Molding• two cover pieces

• Ultrasonic welding• to connect the two and

base cover• Laser Engraving• RPI Lettering

Shaft Hole Diameter:• Front – ”• Back – ”Large Gear Diameter – 1½”

Cost

Material Amount Needed

Cost/lb Total Cost

Aluminum 110 lbs $5 $550

Steel 100 lbs $1.50 $150

Large Molds 2 $500 $1000

Small Molds 3 $250 $750

Sand (Optional)

200 lbs $0.07 $15

Plastic Donated $0

Cost/Unit $6.00

Total $2500

Thank you! Any questions?