From DDL Wiki

Contents 1 Customer Needs 2 Function 3 FMEA 3.1 Components:

Customer Needs

The customer’s primary need is to cool a room by circulating air. More air circulation provides greater air movement and cooling potential. The fan’s noise level is a concern of the customer. Quiet operation, with little to no vibrations is preferred. The customer must also be able to adjust the fan’s rotational speed to best suit the surroundings. This allows for quieter, lower energy, operation when maximum air circulation is unnecessary. Another necessity is the ability to vary the direction of where air is being. This includes altering the vertical orientation as well as providing horizontal oscillation. The fan should also be safe for the user. This involves shielding the fan blades, while still allowing air to pass through. This shielding prevents objects and body parts from coming in contact with the blades. Fans are generally only used during warm times of the year. As a result they must be easy to move and store while not in use.

Function

An oscillating fan cools an area using forced convection thus increasing heat transfer. This is accomplished by spinning three plastic blades which circulates air in the desired direction. The blades are spun by an AC brushless motor, which is powered from a standard 120V wall outlet. The motor’s rotational speed can be adjusted by the user using a circular knob. The fan is also capable of horizontal oscillation. The user starts this movement by pushing a button at the top of the fan casing. This engages a gear train which spins a small plastic linkage. This linkage is connected to an aluminum bar which is attached to the casing. This simple mechanism translates circular motion to oscillatory horizontal motion. The gear train is powered by the same motor and shaft that spin the blades, thus requiring no additional motor.

FMEA

Item and Function Failure Mode Effects of Failure S Causes of Failure O Design Controls D RPN Recommended Action Responsibility and Deadline Actions Taken S O D RPN Motor/Shaft Inhibited Rotation Inefficient Operation 5Debris (e.g. dust) in Fan 4 Run Under Extreme Dust and Debris Conditions 2 40Filter, Accessibility for Cleaning, Better Protection of Rotating Parts Motor Housing - 53230 Swivel Mount Nut Stripping, Plastic Fracture Cannot Adjust Vertical Directoin Fan Cannot Effectively Circulate Air 8 Overtightening, Material Failure 3 Overtightened Screw, Force applied on Swivel Area 1 24 Use Torque Limited Fastening, Using Stronger Plastic Swivel - 8 2 1 16 Oscillation Button Dislocation of Button Cannot Toggle Oscillation 6 Stripped Gear, Button Disengaged 5 Stronger Gears, Improved Connection 2 60 Fatigue Testing Gears and Button - 6 3 2 36 Blade Cover Inhibited Rotation, Blade Fracture Complete Inoperable8 Penetration of Cover 4 Penetrate Repeatedly 1 32 Warning Label, Redesign Cover User - 8 3 1 24 Shaft Non-concentric Rotation Vibration and Noise 5 Broken Bearing, Unbalanced Weight, Shaft Non-Uniformity 2 Quality Control 3 30 Vibration Testing Assembly - 5 1 3 15 Electronics Short Circuit Completely Inoperable 8Exposure to Water 3 Water Exposure Testing 2 48Waterproof Housing of Electronics Housing - 81216

Components:

As part of the first stage of disassembly, we documented the inner workings prior to removing each individual component. The first image shows the shredder with the top removed and certain key components labeled. The second is a detailed close-up of the gear train. Refer to the table below for more details on individual components identified in these pictures.

The following table contains each individual part present in the product. A brief description of each part and its function will help determine whether any of the components can be refined for future designs to make it less expensive or possibly remove it all together. It can be also be seen that a large, important part of the system is purchased (the motor and electronics).

Part #	Part name	QTY	Function	Materials	Manufacturing Process	Picture
001	Front Fan Cover	1	Protect the user's body parts Protects fan blades Aesthetics	??	Merging of Extruded Parts	Image:Fan Front Cover.jpg
002	Switch Housing	1	Sets desired functionality Houses child safety button	Plastic	3" x 1" x 1"	Injection Molding
003	Base	1	Houses main components Light bulb Motor Gear train Blades Operation safety switch Dispense of shredded paper	Plastic	12" x 5" x 3"	Injection Molding
004	Feeder Lip Top	1	Guides paper Protects user	Plastic	8" x 2" x 1"	Injection Molding
005	Feeder Lip Bottom	1	Guides paper Protects user	Plastic	8" x 2" x 1"	Injection Molding
006	Child Safety	1	Prevents unintentional use	Plastic	2" x 1" x 1"	Injection Molding
007	Electrical & Motor Sub-assembly	1	Drives gear train (motor) Automatic safety switch (must be sitting on basket properly) Shredding cutoff time-delay Ready LED Off/auto/reverse switch Light bulb Provides electrical power to the system	N/A	N/A	Purchased
008	Helical Gear	1	Component of gear train Connects to motor Quieter than spur gears	Plastic	1" x 1"	Injection Molding
009	Large Spur Gear	1	Component of gear train Reduce Speed/Increase Torque	Plastic	3" x 1"	Injection Molding
010	Small Spur Gear	1	Component of gear train Reduce Speed/Increase Torque	Plastic	1" x 1"	Injection Molding
011	Output Spur Gear	1	Drive shaft	Plastic	1" x 1"	Injection Molding
012	Light Bulb Reflector	1	Increases intensity of light	Plastic+Aluminum	.5" x .5" x 1"	Injection Molding and Sheet Foil
013	Delay Trigger Housing	1	Houses the shredding cutoff time-delay	Plastic	3" x 1" x 1"	Injection Molding
014	Cutoff Switch Time-Delay Trigger	1	Triggers cutoff switch time-delay	Plastic	1" x 1" x .5"	Injection Molding
015	Spring for Child Safety Switch	1	Hold the safety switch in position	Spring Steel	1/8" x .5"	Winding
016	Bow-Tie Washer	1	Attaches automatic safety switch to the base cover	Plastic	1" x 1" x 1/8"	Injection Molding
017	Main Shaft Base Plate	1	Hold axes aligned	Plastic	3" x 3" x 1/4"	Injection Molding
018	Cover Plate for Shaft Alignment	1	Hold axes aligned	Plastic	2" x 2" x 1/4"	Injection Molding
019	Gear Train Housing Base Plate	1	Holds gears Holds axes aligned	Metal	4" x 2" x 1/4"	Stamped
020	Gear Train Housing Top Plate	1	Holds gears Holds axes aligned	Metal	3" x 1" x 1/4"	Stamped
021	Attachment Aligner for Motor Base Plate	1	Holds motor to gear train housing top plate	Plastic	1" x 1" x 1/4"	Injection Molding
022	Screws	31	Fastening	Steel	#10-20	Machined	In the background
023	Helical Blade	104	Cut paper in diamond shape Feeds paper	Steel	.5" x 1\32"	Stamped
024	Flat Blade	8	Feeds paper	Steel	.5" x 1\32"	Stamped
025	Paper Aligners	54	Ensures proper feeding of paper	Plastic	1/2" x 1/4" x 1"	Injection Molding
026	"Paper Aligner" Aligning Rod	2	Aligns aligners	Metal	1\4" x 8"	Extrusion	Gold rod
027	Long Main Shaft	1	Driven by gear train Turns blades Aligns blades	Steel	10" x 1/4"	Machined	Center rod
028	Short Main Shaft	1	Driven by gear train Turns blades Aligns blades	Steel	9" x 1/4"	Machined	Center rod
029	Basket	1	Collect shredded waste Houses tab Shredder assembly rests on top of basket Keeps shredder assembly aligned	Steel	12" x 12" x 5"	Stamp
030	Tab	1	Press safety switch	Steel	1/2" x 1/2" x 1/2"	Stamped	On the basket