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Revision as of 17:30, 2 February 2014

1 Executive Summary
2 Primary Stakeholders and Product Needs
3 Product Function and Use
- 3.1 User Study
- 3.2 Mechanical Function
4 List of Parts
- 4.1 Bill of Materials
5 Design For Manufacturing and Assembly (DFMA)
6 Failure Modes and Effects Analysis (FMEA)
7 Design for Environment (DFE)
8 Team Members
9 References

Executive Summary

Primary Stakeholders and Product Needs

Product Function and Use

User Study

Mechanical Function

List of Parts

The following details the list of parts of a hands-free coffee grinder.

Coffee Grinder Exploded View

Bill of Materials

Part Number	Name	Quantity	Mass (g)	Function	Material	Manufacturing Process/ Purchased Component
Grinding Chamber Sub-Assembly
1	Lid	1	66	Contains coffee	Plastic	Blow Molded
2	Flat Head Screws	3	<1	Cup to Scatter Shield	Steel	Catalog Purchase
3	Female Drive Adapter	1	6	Provides Torque to Blade Assy	Plastic	Injection Molding
4	Rubber Nipples	3	<1	Vibration Isolation & Noise Reduction	Rubber	Die Cut
5	Plastic Washer	1	<1	Reduces friction of Blade Assy	Plastic	Catalog Purchase
6	Cup	1	46	Provides References for Coffee Bean Measuring	Plastic	Injection Molding
7	Scatter Guard	1	15	Contains Coffee Beans behind the Blade	Tin	Stamped
8	Dust Shield	1	3	Separates the Grinding Chamber and the Drive Assy	Plastic	Injection Molding
9	Blade-Adapter Shaft	1	2	Transmits Torque from Part 3 to Part 13	Plastic	Catalog Purchase
10	Blade Gasket	1	<1	Seals Blade Assy	Rubber	Injection Molding
11	Blade Washer	1	<1	Reduces friction of Blade Assy and Provides Axial Preload	Steel	Catalog Purchase
Blade Sub-Assembly
12	Blade Hub	1	2	Connects blade to drive shaft	Plastic	Injection Molding
13	Blade	1	3	Grinds Coffee	Stainless Steel	Stamped
Cord Housing Sub-Assembly
14	Tamper Proof Screw	1	<1	Connects cord housing assembly to main body	Steel	Purchased Part
15	Rubber Foot Pad	3	<1	Prevents Device from Slipping	Rubber	Stamped
16	Cord Reel Container	1	17	Contains Cord While Wound	Plastic	Blow Formed
17	Screw	3	<1	Mates Part 19 to Part 28	Steel	Purchased Part
18	Power Cord Reel Center	1	3	Cord Capstan	Plastic	Injection Molded
19	Power Cord Reel	1	26	Captures Cord	Plastic	Injection Molded
20	Internal Motor Gasket	2	3	Seals Motor Components	Rubber	Injection Molding
21	Screw For Part 22	2	1	Mates Part 22 to Part 28	Steel	Purchased Part
22	Power Cord Retention Clip	1	2	Positively Retains The Power Cord Inside The Housing	Plastic	Injection Molding
23	Tiny Spring	1	<1	Provides Preload to the Safety Mechanism	Steel	Purchased Part
24	Safety Paper	1	<1	Reduces Abrasion of Safety Switch	Plastic	Stamped
25	Electrical Switch Cover	1	1	Houses Electric Switch	Plastic	Injection Molded
26	Electrical Switch Lead	2	1	Provides Current to Electrical Switch	Copper	Purchased Part
27	Mechanical Switch	1	1	Actuates the Safety Switch	Plastic	Injection Molded
28	Motor Housing	1	47	Secures motor to device	Plastic	Injection Molded
AC Motor Sub-Assembly
29	Brushes	2	<1	Provides Current to Commutator	Carbon	Electronic Component
30	Motor Shaft Cap	1	<1	Transmits Torque from Part 42 to Part ??	Plastic	Injection Molded
31	Shaft Insulator	1	<1	Provides Mechanical and Electrical Insulation to the Shaft	Fiber	Stamped
32	Spring Washer	1	<1	Provides Axial Preload to locate the commutator with respect to the bushings	Copper	Purchased
33	Small Brown Washers	4	<1	Locates Part 42 Axially	Plastic	Stamped
34	Large Orange Washers	2	<1	Locates Part 42 Axially	Plastic	Stamped
35	Small Metal Washers	2	<1	Locates Part 42 Axially	Steel	Purchased
36	Bearing	2	2	Locates Part 42 Radially	Steel	Purchased
37	Brush Side Bracket	1	17	Locate Part 36 on Brush Side	Steel	Stamped and Bent
38	Non-Brush Side Bracket	1	16	Locate Part 36 on Non Brush Side	Steel	Stamped and Bent
39	Brush Housing	2	1	Constrains Part 29	Plastic	Injection Molded
40	Stator Coil	2	13	Provides Magnetic Poles	n/a	Electronic Component
41	Steel Inductor Plate	30	4	Enhances Magnetic Poles	Steel	Stamped
42	Rotor	1	77	Provides Motor Torque	n/a	Electrical Component
43	Circuit Board	1	28		Assembly	Electrical Component
56	Male Drive Adapter	1	15		Plastic	Injection Molded
Knob Sub-Assembly
44	Power Button	1	2	Allows user to operate grinder	Plastic	Injection Molded
45	Power Button Finger	1	<1	Translate power button movement to connect circuit	Plastic	Injection Molded
46	Knob	1	8	Allows user to adjust fineness of grind	Plastic	Injection Molded
47	Circuit Board Connector	1	<1	Connects fineness knob circuit	Copper	Stamped
48	Power Button Spring	1	<1	Returns power button after press	Steel	Purchased
49	Knob Screws	4	<1	Fastens knob sub-assembly	Steel	Purchased
50	Detent Springs	2	<1	Pushes ball bearings for discrete adjustment of knob	Steel	Purchase
51	Detent Bearings	2	<1	Allows for discrete adjustment of knob	Steel	Purchased
52	Detent Housing	1	2	Contains detent components in knob	Plastic	Injection Molded
53	Brush	1	3	Cleans coffee grinds	Plastic	Injection Molded
54	Body	1	74	Houses inner components	Plastic	Injection Molded
55	Power Cord	1		Supplies electrical current from outlet to grinder	Assembly	Purchased

Design For Manufacturing and Assembly (DFMA)

Failure Modes and Effects Analysis (FMEA)

FMEA Summary: Table summarizes likely failure modes and effects of various components of the coffee grinder.
(S)everity, Probability of (O)ccurence and (D)ectability of Failure ratings are assigned following the standards established in Tables 14.12, 14.13 and 14.14, respectively in Dieter and Schmidt.
Risk Priority Numbers (RPN) are generated by finding the product of SxOxD
Item and Function	Failure Mode	Effects of Failure	S	Causes of Failure	O	Design Controls	D	RPN	Recommended Actions
Lid Safety Switch	Switch stuck	Blade powers on when lid is off	7	Sticktion	2	Friction reducing shim	8	112	Create redundant fail-safe mechanisms
Lid Safety Switch	Switch stuck	Blade powers on when lid is off	7	Return spring failure	2	Positive mechanical engagement	8	112	Create redundant fail-safe mechanisms
Grinder blade	Fracture	Catastrophic failure of grinder resulting in a useless product	7	Misuse: grinding unintentional objects	7	Product warnings and guidelines			Yield before breaking Hardened lid
Grinder blade	Fracture		7	Manufacturing defects	2	Product warnings and guidelines			Yield before breaking Hardened lid
Power cord	Snapping	Faulty electrical wiring Inoperable product	5	Excessive force from pulling	4	Reenforcing bracket	7	140	Better power cord directions
Lid and body	Crack or fracture			Unexpected loads e.g. leaning, dropping		None
Lid and body	Crack or fracture			Placing in dishwasher		None
Electric Motor	Burnt out motor	Inoperable grinder	6	Excessive duty cycle	5	None	5	150	Temperature sensor to force mandatory cool down

Design for Environment (DFE)

Team Members

Phil Aufdencamp - DFE

Justin Barsano - DFMA

Kristen Hauser - User Study, General Organization

Brian Tang - FMEA

References

Dieter, George E., and Linda C. Schmidt. Engineering Design. 4th Edition. New York, NY: McGraw-Hill, 2009. Print.

@@ Line 242: / Line 242: @@
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+|-
+|-
+| Electric Motor
+| Burnt out motor
+| Inoperable grinder
+| 6
+| Excessive duty cycle
+| 5
+| None
+| 5
+| 150
+| Temperature sensor to force mandatory cool down
 |-

Coffee grinder