Card shuffler 3
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[[Image:Turned Card.jpg|thumb|right|A turned card.]] | [[Image:Turned Card.jpg|thumb|right|A turned card.]] | ||
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=List of Parts= | =List of Parts= | ||
Revision as of 20:05, 31 January 2014
Contents |
Executive Summary
Primary Stakeholders and Product Needs
Distributor Needs
Distributor needs are concerned with the ease and safety of transport.
- Packed with smallest possible box to save space
- Packed with rectangular box to stack efficiently
- Packed robustly enough to withstand bumps and slight drops
- Batteries either not included or shipped according to U.S. Department of Transportation
Retailer
Retailers have the same needs as distributors for stocking purposes, plus some needs unique to the seller of the product.
- Packaging is colorful and intriguing to costumers
Consumer
The product is primarily aimed at amateur card players who require a system for their home. Taking this into account, consumer needs are mainly related to portability, performance, maintenance and safety.
- Small
- Light
- Small table footprint
- Battery powered
- Shuffle quickly and thoroughly
- Minimal jamming
- Quiet
- Easy to load/unload
- Shuffle anywhere from 1 to 6 decks
- Work with brand new and used cards
- Long batter life
- Easily replaced batteries
- Easily fixed jams
- Robust
- Minimal Assembly
- Affordable
- Aesthetic product
- Safe to use and store
Product Function and Evaluation
Usage
Mechanical Function
Both sides of the card shuffler are mirrored and work independently. Their only connection is through the electrical circuit which closes once the bar is depressed. The following is a description of one independent side of the card shuffler.
The main mechanical function of the card shuffler comes from the motor/gearbox components. When the circuit is completed, the motor pinion turns the gearing system shown in figure 1. The pinion gear turns the first gear on the far right. This gear then translates its motion in two ways: 1) It directly rotates the agitator gear attached behind it on the same shaft 2) It translates its motion through the second gear to turn the third gear. The third gear is attached to a rubber wheel that grips a card from the feeder tray and slides it into the collection chamber. The agitation gear is a quarter gear that slightly protrudes above the feeder tray. This facilitates a steady flow of individual cards by vibrating the stack so that no cards stick together.
Upon entering the collection chamber, the cards encounter a routing surface (Part #adsf in Figure #adfasdf) which angles the cards downwards towards the base of the collection chamber. The base of the collection chamber sits on springs which compress as more cards are shuffled. This prevents the cards from flipping over on their way down the collection chamber by keeping the top of the stack close to the entrance of the chamber. Figure #adfs shows the platform of the collection chamber in its fully extended position; as cards stack in the collection chamber, the springs compress and the platform lowers.
Preliminary User Study
Step-by-Step Product Use
1. Retrieve shuffler from storage location and place on playing table.
2. Place clear retaining shield into appropriate position through:
- a. rest base on top of spring-loaded platform
- b. depress fully
- c. release ensuring retaining shield slots into guide clips
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3. Load half of cards into each feeder tray.
4.Depress bar labeled “push down to operate” until no cards remain in feeder trays.
5.Lower and remove retaining shield.
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6.Enjoy your freshly shuffled cards.
User Commentary
Overall, we believe that the product worked well for its reasonable price and relatively compact design. Through thorough testing of our 6-deck model, we were able to recognize key pros and cons that have been outlined below.
The product saved time shuffling the cards especially when using multiple decks. The product exhibited a small table footprint which definitely was an advantage of its design as it allowed ample room on the playing table for the users and the game being played. Moreover, the simple design also meant that the product was easy to use. A bar was the only part that needed to be pressed to make the shuffler function and this simplicity also meant that the design looked sleek and non-intrusive on the table.
The product did, however, have room for improvement in many categories. Firstly, when operated, the shuffler was surprisingly loud which distracted players and interfered with conversations between users. When a single deck needed to be shuffled, the product was not very time efficient and was not significantly faster than shuffling by hand. This was primarily down to the retaining shield which needed to be first inserted then removed from the product. We also experienced multiple instances of cards flipping or getting stuck in the collection chamber when being shuffled. This was very time consuming since the whole deck needed to be reshuffled. In one instance, when trying to repair a jam that occurred, one card was damaged in the process which is another area of improvement. Finally, the product required uncommon “C” batteries which was not expected of a device that is meant to be used at home.
List of Parts
Parts list table
| Part Number | Name | Quantity | Mass (g) | Subassembly | Function | Material | Manufacturing Process/ Purchased Component | Image |
|---|---|---|---|---|---|---|---|---|
| 1 | Battery cover | 2 | 7 | Base | hides and holds the battery | plastic | injection molded |  |
| 2 | Retaining shield | 1 | 31 | Card catcher | holdes cards in the card catcher | plastic | injection molded |  |
| 3 | Screws (plastic top) | 4 | <1 | Top | holds the top assembly in place | steel | Catalog Purchase |  |
| 4 | Clear plastic top | 1 | 24 | Top | To view card catcher from above | plastic | injection molded |  |
| 5 | Sticker | 1 | <1 | Top | Aestetic | NaN | NaN |  |
| 6 | Shiny metal bracket | 2 | 5 | Top | Allows single card flow | Aluminum | NaN |  |
| 7 | Triangle card angler | 1 | 7 | Top | angles cards downward | Plastic | NaN |  |
| 8 | Screws (triangle and clear top) | 2 | <1 | Top | holds the triangle and clear top together | Steel | Catalog Purchase |  |
| 9 | ^Associated washer | 2 | <1 | Top | Distribute load from screw | NaN | Catalog Purchase |  |
| 10 | screws (Battery compartment) | 4 | <1 | Base | holds base to motor assembly | NaN | Catalog Purchase |  |
| 11 | screws (long) | 4 | <1 | Base | holds base to main structure | NaN | Catalog Purchase |  |
| 12 | base | 1 | 88 | Base | holds motor assembly and battery compartment | NaN | NaN |  |
| 13 | screw (operating lever + base) | 1 | <1 | Base | holds the operating lever to the base | NaN | Catalog Purchase |  |
| 14 | lever washer top | 1 | <1 | Base | top washer in top of lever mechanism | Al | Catalog Purchase |  |
| 15 | lever spacer | 1 | <1 | Base | separates metal contacts | plastic | Catalog Purchase |  |
| 16 | rivots (battery spring) | 4 | <1 | Base | connect spring to metal battery contact | brass | Catalog Purchase |  |
| 17 | springs (battery) | 4 | <1 | Base | negative pole of battery | NaN | Catalog Purchase |  |
| 18 | lever metal contacts | 2 | <1 | Base | completes circuit when lever is depressed | Al | NaN |  |
| 19 | large battery contact plate | 2 | <1 | Base | contacts battery(+ and - pole) to circuit | Al | NaN |  |
| 20 | small battery contact plate (+ end) | 2 | <1 | Base | contacts battery(+ pole) to circuit | Al | NaN |  |
| 21 | small battery contact plate (- end) | 2 | <1 | Base | contacts battery(- pole) to circuit | Al | NaN |  |
| 22 | Operating lever | 1 | 4 | Base | User operated lever to activate shuffler | plastic | NaN |  |
| 23 | screws (holds gear casing together) | 4 | <1 | Gear | Holds gear casing together | steel (yellowish coating) | Catalog Purchase |  |
| 24 | screws (holds gear box to the gear stand) | 4 | <1 | Gear | Holds gear box to the gear stand | steel (yellowish coating) | Catalog Purchase |  |
| 25 | white wires | 4 | <1 | Gear | connected battery contact to motor and lever to battery | NaN | Catalog Purchase |  |
| 26 | black wires | 2 | <1 | Gear | connected motor to motor | NaN | Catalog Purchase |  |
| 27 | outside housing | 1 | 252 | Housing | contains all sub-assemblies | plastic | NaN |  |
| 28 | platform springs | 4 | <1 | Card catcher | holds up platform on which the shuffled cards rest | steel? | Catalog Purchase |  |
| 29 | gear stand | 2 | 10 | Gear | holds up gear assembly | plastic | NaN |  |
| 30 | gear box (L-shaped) | 2 | 6 | Gear | holds gears | plastic | NaN |  |
| 31 | gear box (planar) | 2 | 6 | Gear | holds gears | plastic | NaN |  |
| 32 | gear shafts | 6 | <1 | Gear | Holds and provides axis of rotation for gears | plastic | NaN |  |
| 33 | Gear | 2 | <1 | Gear | Changes torque/rate of rotation from motor output | plastic | NaN |  |
| 34 | Gear | 2 | <1 | Gear | Changes torque/rate of rotation from motor output | plastic | NaN |  |
| 35 | Gear | 2 | <1 | Gear | Changes torque/rate of rotation from motor output | plastic | NaN |  |
| 36 | Gear | 2 | <1 | Gear | Changes torque/rate of rotation from motor output | plastic | NaN |  |
| 37 | Gear | 2 | <1 | Gear | Changes torque/rate of rotation from motor output | plastic | NaN |  |
| 38 | Platform | 1 | 2 | Card catcher | Holds shuffled cards | plastic | NaN |  |
| 39 | Wire leads | 2 | <1 | Motor | connects to power | aluminum | NaN |  |
| 40 | Brushes | 2 | <1 | Motor | completes the circuit while the motor is turning | copper | NaN |  |
| 41 | Housing, case | 1 | <1 | Motor | protects components | steel | NaN |  |
| 42 | Housing, cap | 1 | <1 | Motor | protects components | plastic | NaN |  |
| 43 | Magnets | 4 | <1 | Motor | spins core | NaN | NaN |  |
| 44 | Core | 1 | 1 | Motor | creates | NaN | NaN |  |
| 45 | Retaining clip | 1 | <1 | Motor | holds in magnets | steel | NaN |  |
| 46 | Washer (red) | 1 | <1 | Motor | Distribute load from screw | plastic | NaN |  |
| 47 | Washer (white) | 1 | <1 | Motor | Distribute load from screw | plastic | NaN |  |
| 48 | Shaft ring | 1 | <1 | Motor | tighter tolerance for shaft | brass | NaN |  |
| 49 | L-bracket to piece we couldn't disassemble | 3 | <1 | Motor | idek | aluminum | NaN |  |
Design For Manufacturing and Assembly [DFMA]
Design For Manufacturing [DFM]
This card shuffler was clearly designed for cheap and effective mass production. The following highlight both clear applications of DFM and areas where DFM was lacking.
Successful DFM implementations:
- Mirrored design
- Identical design to other models
- Slide-in battery contacts
- Drafted internal screw mounting posts + drafted card chamber
- Motor drives feeder + agitator (only 1 motor per side)
- Almost exclusively injection molded plastic
- Gears, motors, fasteners can be purchased cheaply pre-assembled
- Loose tolerances
- Stickers and colored plastic remove need for paint
Potential Improvements:
- Riser for gear box unnecessary
- Outer casing 5 components, possible to make with fewer
- Undrafted support posts resulted in irregular finish.
- Injection molds have complex features
Due to the low price point the manufacturers of the card shuffler are targeting, DFM is extremely important for high volume/low cost production. One of the simplest ways the manufacturers streamlined their process is by utilizing identical components on each half of the shuffler, halving the unique parts required. Furthermore this shuffler uses identical internal electrical and mechanical components and basic structural components from other models designed for fewer decks of cards, allowing for established high-volume production to be used across all product lines. More complex components (like gears and motors) were likely purchased inexpensively in large quantities from other vendors saving time for the shuffler manufacturer. The vast majority of the shuffler is made from injection molded plastic components with some attention to draft angles for mold releasing, increasing production rates. Additionally, loose tolerances are required throughout the product making it even easier to produce. By using colored plastic and decorative/instructional stickers, the manufacturer avoids having to paint the device.
No device is perfect and the shuffler manufacturer had room to improve in a few areas. The motor/gearbox assemblies stand on risers to accommodate the additional height of the 6 deck shuffler, adding additional components. This design choice was made to preserve the use of existing motor/gearbox assemblies across all shufflers but complicates the 6 deck model. The outer casing could be made with fewer individual components instead of the current five separate components. The battery cavities in the base of the shuffler have many complex features and cutouts, increasing manufacturing difficulty. Of particular note were four cylindrical support posts in the base with straight sides. When pulled from the mold, the outer layers of the posts wrinkled and bunched irregularly. These components are internal and this defect does not affect the shuffler's appearance or operation.
Design for Assembly [DFA]
Alongside effecting manufacturing processes, streamlining the shuffler's assembly reduces cost and production time. The following highlight both clear applications of DFA and areas where DFA was lacking.
Successful DFA Implementations:
- 2 motor/gearbox system avoids complex transmission system
- Motors wired in series (less wires than parallel)
- Ultrasonic welding between parts
- Complex motor/gearbox combo can be independently assembled/tested
- All mechanical components operate without outer shell in place
- Screw posts have lip that function as guide pins for the enclosure and base
- Shuffler built bottom-up
- Loose tolerances allow for quick assembly
Potential Improvements:
- Screws could be replaced by snap-fit fixtures
- Gearbox stands add additional assembly steps
- Sticker requires careful placement to preserve aesthetics
- Spring attachment points used hand-melted rivets
One of the main DFM features of the shuffler is it's mirrored design. This also has positive assembly ramifications. By providing a unique motor/gearbox system for each half, the manufacturer avoids a complex and potentially labor intensive assembly for a power transmission system from a central motor to each card feeder. Another feature of the motor/gearbox assemblies is that can can be tested and assembled independently of the rest of the system, increasing assembly and QC efficiency. By wiring the motors in series rather than in parallel, less wires need to be soldered, also saving time. The entire internal structure is built from the base up. This allows for the shuffler to remain in the same orientation for the vast majority of its assembly and conveniently allows the electromechanical systems to be fully tested without the external enclosure in place. The system as a whole is constructed with loose tolerances, meaning parts can quickly be placed together without significant regard for precise positioning.
A major oversight in the shuffler is the extensive use of screws which add complexity (and therefore cost) to the assembly process. Integrating snap-fit fixtures into the plastic design would simplify assembly. Mentioned in the DFM section, each motor/gearbox is placed on an individual stand to allow compatibility with smaller models. Integrating this stand into the motor/gearbox would remove an assembly step. Judging by their rough finish, the springs which support the card tray are hand-melted onto the enclosure. This is a time consuming process and creating a special spring attachment point may be a better solution, even if it costs more upfront for additional tooling and R&D. Finally, the sticker on top of the shuffler, while serving no practical purpose, has the some of the tightest tolerances of the entire product. Any tilt or skew will immediately be apparent and negatively impact the product's aesthetics.
Failure Mode and Effect Analysis [FMEA]
Design for Environment [DFE]
Team Members
FMEA Lead:Rodrigo Bergamasco
Role:Allen Kim
DFMA Lead:Alexander Kozhemiakov
Role:Angela Nawrocki
DFE Lead:Pranay Sharma
Process & divisionf alkdsjf
