Coffee grinder
From DDL Wiki
Contents |
Executive Summary
Primary Stakeholders and Product Needs
The primary stakeholders for this product are consumers, retailers, distributors and shippers, and manufacturers. The needs of these stakeholders are outlined below.
Coffee Consumers:
- Longevity
- Quiet operation
- Aesthetically pleasing
- Small footprint/Easy to store
- Easy to clean
- Dishwasher safe parts
- Intuitive and fast operation
- Versatility
Retailers:
- Space efficient packaging
- Light
- Aesthetically pleasing
- Low unit cost
- High demand
- Stackable
Distributors and Shippers:
- Light
- Durable packaging
- Stackable
Manufacturer:
- Easy mechanical assembly
- High volume parts
- Inexpensive materials
- Low overhead costs
Product Function and Use
User Study
The coffee grinder is powered by a typical 110V power outlet. To free the power cord, pull down on the black cover on the bottom of the device. Unwrap the power cord, then replace the black cover. Unlock the top plastic cover by rotating it counter-clockwise.
Remove the inner cup and notice the marking lines on the side. These pertain to the number of cups of coffee you intend to brew. Fill the cup with whole coffee beans or raw spices to the desired level. Place the cup back in the device and lock the top cover. The device will not function if the cover is not locked in place.
Select the quantity of coffee you desire (4, 8, 10, or 12 cups) using the switch on the front of the device. Turn the knob to the desired grind. Press the on button. The device will stop automatically, or you can manually stop the device by pressing the button again.
Mechanical Function
The coarseness and size selection control the motor speed (driving the blade) and the duration of operation. As one would expect, the larger quantities require longer run times. Interestingly, the finer grinds require slower motor speeds. We suspect that because the more coarse grinds run for a shorter time, a higher speed is required to get a good quality grind. We took some preliminary data to characterize the device.
Run Time in Seconds:
Quantity | Percolator | Drip | Espresso |
---|---|---|---|
12 cups | 10 | 18 | 30 |
10 cups | 10 | 16 | 30 |
8 cups | 9 | 14 | 25 |
4 cups | 9 | 13 | 20 |
Motor Speeds in rpm for 12 Cup Setting:
Percolator | Percolator/Drip | Drip | Drip/Espresso | Espresso | |
---|---|---|---|---|---|
Speed [rpm] | 25,000 | 23,000 | 22,600 | 22,600 | 22,500 |
List of Parts
The following details the list of parts of a hands-free coffee grinder.
Bill of Materials
Part Number | Name | Quantity | Mass (g) | Function | Material | Manufacturing Process/ Purchased Component | Image |
---|---|---|---|---|---|---|---|
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 |