Card shuffler 3

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6 Deck Card Shuffler
6 Deck Card Shuffler


Executive Summary

The purpose of this study was to dissect and analyze a mechanically complex product in order to make recommendations for improvement. We purchased the Brybelly Casino 6 Deck Automatic Card Shuffler for $15.98 because of its low price-point and our interest in card play. Through our product's dissection, we completed a preliminary analysis of Usability, Design for Manufacturing and Assembly (DFMA), Failure Mode Effects Analysis (FMEA) and Design for Environment (DFE). We identified where the manufacturer followed good design practices and also where improvement could be made.

The DFMA study revealed that the manufacturer took advantage of a symmetrical design to minimize the net number of unique components. Additionally, they designed the 6-deck card shuffler with the same inner mechanisms as the 2 to 4 deck shuffler which allowed for a large number of interchangeable parts. For comparison, refer to previous entries in the Design Decisions Wiki. The FMEA study revealed that the mechanical assemblies of the product are very reliable and will not fail dangerously. According to our DFE research, we came to the conclusion that the product's largest impact to the environment is due to playing card production.

To improve the 6 card deck shuffler we focused on manufacturing, assembly, and sustainability concerns. The loose tolerances used in each component allow easy manufacturing and assembly, but cause consistent failures during use. Tighter tolerances would result in a more reliable product. Furthermore, the outer casing of the card shuffler contains a slot that exposes the inner gearboxes. A brushed slot could prevent debris from entering the gearbox and disabling the card shuffler. Last, we would recommend the distributor market this product with sustainably manufactured playing cards that would insure a lower environmental impact throughout their life cycle.

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


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


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.

  • 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

Figure 1:6 Deck Shuffler
Figure 1:6 Deck Shuffler

Mechanical Function

Figure 2: Gearbox from card shuffler
Figure 2: Gearbox from card shuffler

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 2. 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 #2 in Part #7) which angles the cards downwards towards the base of the collection chamber. The base of the collection chamber suspended by springs which extend 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 1 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 by:

a. resting the base on top of spring-loaded platform
b. depressing fully
c. releasing while ensuring the retaining shield slots into guide clips
Step 2a
Step 2a
Step 2b
Step 2b
Step 2c
Step 2c

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.

Step 3
Step 3
Step 4
Step 4
Step 5
Step 5

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.

A turned card.
A turned card.
A damaged card.
A damaged card.

List of Parts

Exploded view of card shuffler
Exploded view of card shuffler

Although the motor was most likely purchased off the shelf from a outside vendor, it is still considered an assembly and was therefore dissected to it's individual components.

Exploded view of motor assembly
Exploded view of motor assembly

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 Holds 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 Paper Printing
6 Feed Regulator 2 5 Top Allows single card flow Aluminum Stamping
7 Routing triangle 1 7 Top Angles cards downward Plastic Injection molded
8 Screws (triangle and clear top) 2 <1 Top Holds the triangle and clear top together Steel Catalog Purchase
9 Washer (triangle and clear top) 2 <1 Top Distribute load from screw Aluminum Catalog Purchase
10 Screws (Battery compartment) 4 <1 Base Holds base to motor assembly Steel Catalog Purchase
11 Screws (long) 4 <1 Base Holds base to main structure Steel Catalog Purchase
12 *Base 1 88 Base Holds motor assembly and battery compartment Plastic Injection molded
13 Screw (operating lever + base) 1 <1 Lever Holds the operating lever to the base Steel Catalog Purchase
14 Lever top washer 1 <1 Lever Top washer in top of lever mechanism Aluminum Catalog Purchase
15 Lever spacer 1 <1 Lever 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 Steel Catalog Purchase
18 Lever metal contacts 2 <1 Base Completes circuit when lever is depressed Aluminum Stamping
19 Large battery contact plate 2 <1 Base Contacts battery(+ and - pole) to circuit Aluminum Stamping
20 Small battery contact plate (+ end) 2 <1 Base Contacts battery(+ pole) to circuit Aluminum Stamping
21 Small battery contact plate (- end) 2 <1 Base Contacts battery(- pole) to circuit Aluminum Stamping
22 Operating lever 1 4 Base User operated lever to activate shuffler Plastic Injection molded
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 Copper and rubber Catalog Purchase
26 Black wires 2 <1 Gear Connected motor to motor Copper and rubber Catalog Purchase
27 *Outside housing assembly 1 252 Housing Contains all sub-assemblies Plastic Injection molded
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 Injection molded
30 Gear box (L-shaped) 2 6 Gear Holds gears Plastic Injection molded
31 Gear box (planar) 2 6 Gear Holds gears Plastic Injection molded
32 Gear shafts 6 <1 Gear Holds and provides axis of rotation for gears Plastic Extrusion and cut
33 Gear 2 <1 Gear Changes torque/rate of rotation from motor output Plastic Catalog Purchase
34 Rubber gripper 2 <1 Gear Provides grip between card and gears Rubber Catalog Purchase
35 Gear 2 <1 Gear Changes torque/rate of rotation from motor output Plastic Catalog Purchase
36 Aggitator gear 2 <1 Gear Vibrates cards to separate cards Plastic Catalog Purchase
37 Gear 2 <1 Gear Changes torque/rate of rotation from motor output Plastic Catalog Purchase
38 Platform 1 2 Card catcher Holds shuffled cards Plastic Injection molded
39 Platform spring attachment 4 <1 Card catcher Attaches card catcher platform to springs Plastic Injection molded
40 Wire leads 2 <1 Motor Connects to power Aluminum Stamping
41 Brushes 2 <1 Motor Completes the circuit while the motor is turning Copper Catalog Purchase
42 Housing, case 1 <1 Motor Protects components Steel Rolling
43 Housing, cap 1 <1 Motor Protects components Plastic Injection molded
44 Magnets 4 <1 Motor Spins core Ferrous magnet Catalog Purchase
45 Core 1 1 Motor Creates rotational motion Steel Catalog Purchase
46 Retaining clip 1 <1 Motor Holds in magnets Steel Catalog Purchase
47 Washer (red) 1 <1 Motor Distribute load from screw Plastic Catalog Purchase
48 Washer (white) 1 <1 Motor Distribute load from screw Plastic Catalog Purchase
49 Shaft ring 1 <1 Motor Tighter tolerance for shaft Brass Catalog Purchase
  • Note: Part 12 was determined to be one injection molded piece after consulting the staff at the CMU Mech E machine shop. Observations were made by cutting a cross section of the base using a band-saw.
  • Note: Part 27 was determined to be an assembly made up of 5 separate injection molded panels. Panels were most likely fused together through ultrasonic welding.

Design For Manufacturing and Assembly [DFMA]

Design For Manufacturing [DFM]

This card shuffler was clearly designed for cheap and effective mass production. The following highlights 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 affecting 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]

The most probable failure modes do not impact the card shuffler's operation. Notably, the cards tend to jam as they travel from the feeder tray to the collection chamber or flip over on their way down the collection chamber. These failures simply inconvenience the end user for a short period of time while they re-shuffle the decks. The cause for both these problems can be attributed to the loose-fitting routing triangle and feed regulator. As cards pass through the shuffler at high speeds, the assembled parts vibrate and cause an inconsistent flow and angle of cards. We believe this design, while prone to malfunction, is a conscious decision made by the designers to reduce the cost of production. Keeping tolerances low and allowing parts to shift around their connection points makes manufacturing cheaper and assembly easier. If a higher end card shuffler is designed, we recommend keeping tighter tolerances to avoid vibrating components in the system. Furthermore, rollers on the feed regulator could also prevent jamming by more effectively allowing cards to pass into the chamber.

The severe mechanical failures of the card shuffler do not pose any threat to the safety of the consumer. However, they permanently disable the shuffler and are heard to predict and detect. The failure with the highest Risk Priority Number (RPN) is the failure of the mechanical switch assembly that closes the system's circuit. The switch assembly is composed of a bent metal contact that is pushed into another contact by the operating lever. The bent metal contact is prone to fatigue and plastic deformation. Despite the high RPN, this failure mode is very unlikely and we would recommend focusing on gearbox failure. The agitator slot exposes the gearbox and allows debris to fall inside the compartment and jam the gears. One solution to this problem is the addition of brushes or rubber flaps at the agitator slot. This would not add noticeable resistance to the agitator but would prevent anything from entering the gearbox.

FMEA table

Note: The values of Severity (Table 14.12 - pg.708), Occurrence (Table 14.13 - pg.708), and Detection (Table 14.14 - pg. 709) of Failures were sourced from Engineering Design (4th Edition) by Dieter and Schmidt.

Item Function Failure Mode Effects of Failure Severity Causes of Failure Occurrence Design Controls Detection RPN Recommended
Feed Regulator Card Jamming Cards jam in feeder tray and do not enter collection chamber 3 Regulator opens to wide, letting too many cards into the gap between the feeder tray and collection chamber 5 Feed regulator range of motion allows for some flexibility in dispensed card quantity by varying feed gap size. 3 45 Rollers on feed regulator.
Gearbox Gears Jam Cards do not get shuffled 4 Debris falls into gearbox from open agitator slot 2 None 1 8 Place brushes at agitator slot entrance to catch debris before it enters the gearbox.
Gearbox Gear Tooth Wear Agitator and feeder do not spin 6 Plastic gears succumb to wear. 1 None 9 54 Use metalic gears or lubricate gearbox.
Cards Card Jamming Sticky Cards 3 Poor card maintanence 6 Flexibility of feed regulator allows multiple cards to enter chamber. Agitator aids in separating stuck cards. 5 90 None
Routing Triangle Card Misplacement Card falls into the collection chamber perpendicular to all other cars. Deck must be reshuffled. 3 Variation of card contact angle with routing triangle leads to inconsistent card stacking in chamber 7 Card platform moves to maintain optimal card landing position. 3 63 More rigidly fix routing triangle.
Electrical Circuit Assembly Continous Closed Circuit Shuffler remains on and does not turn off 6 Plastic deformation of circuit switches due to fatigue. 2 None 10 120 Use switch that doesn't require repeated elastic deformations of metal.
Wires Loosened Connections Motor will not turn on and cards will not be shuffled 6 Improperly soldered wire connections. 3 Visual inspection and potential powered test. 1 18 Test every unit and avoid large bumps when handling.
Springs Springs Break From Mounts Platform in collection chamber is angled 4 Imporperly melted plastic rivet connectors. 3 Visual inspection. 2 24 Test every unit and avoid large bumps when handling.

Design for Environment [DFE]

To evaluate the impact of the card shuffler on the environment, a life-cycle assessment was completed. This shows the highest areas of greenhouse emissions over the life of the product and allows for improvement assessment. All analyses were completed via a model for greenhouse gas (GHG) emissions found at The model was run using purchaser data from 2002, so information regarding GHG emissions accumulated after manufacturing process is included in the estimates. Data was collected for $1M spent in each sector in order to best show the emissions breakdown within the limits of the model. Throughout the process we assume that the sectors selected to represent the card shuffler, cards, and batteries are all representative of their respective products.


The card shuffler itself was deemed to be part of the doll, toy, and game manufacturing sector. Although it is included in only 19.6% of the sector (classified as other electronic toys and games), a large part of the sector is attributed to children’s toys. Many of these will use similar manufacturing processes and materials and should have roughly the same GHG emissions. However, the other part of the sector is made up of doll and stuffed toy production. Since the materials and processes used here are different than the ones used for plastic and electronic toys, we must take this into consideration when looking at the reliability of our GHG emissions estimate. It is difficult to determine which way this will sway the estimate since both areas use a plethora of electricity and different forms of plastics. Therefore we consider this to be a soft estimate of the GHG emissions for this card shuffler.

Breakdown of GHG emissions for $1M spent in the primary battery manufacturing sector.
Breakdown of GHG emissions for $1M spent in the primary battery manufacturing sector.


Throughout the lifetime of the card shuffler, batteries and cards must be used. We break down their GHG emissions separately.

Although a great deal of the coated and laminated paper, packaging paper, and plastics film manufacturing sector is not represented by playing cards (approximately 12.4%), a reserved estimate can be made on the environmental impact from their manufacture. This is because the majority of the products in this sector are coated papers with designations only for different applications. The processes to make these coated materials can be estimated to be about the same, but the materials coating the papers may vary by application. However, even through the reservations, this gives us the best possible estimate for a set of playing cards.

Breakdown of GHG emissions for $1M spendt in the coated and laminated paper, packing paper, and plastics film manufacturing sector.
Breakdown of GHG emissions for $1M spendt in the coated and laminated paper, packing paper, and plastics film manufacturing sector.

A large portion of the primary battery manufacturing sector is taken up by the manufacture of round and prismatic primary battery cells (86.3%). This makes the environmental impact of the batteries used for a card shuffler well represented by the emissions of the whole sector.

Breakdown of GHG emissions for $1M spent in the primary battery manufacturing sector.
Breakdown of GHG emissions for $1M spent in the primary battery manufacturing sector.

Design Implications

The card shuffler GHG emissions are primary from the power generation and supply and truck transportation sectors. When looking to decrease the amount of emissions for our life-cycle, we look to decrease the use of products from these sectors. To do this we will want to decrease the power consumption for each of our processes, either by having more energy efficient processes or by reducing the amount of steps which require power input. For us it is hard to decrease the amount of truck transportation we require, as the product must be shipped and transported to stores and warehouses in order to be sold.

EIO-LCA: Summary

Product Lifetime Emission Analysis
Product Lifetime Emission Analysis
CO2 Tax and Emission Proportions
CO2 Tax and Emission Proportions


From our completed Card Shuffler life cycle emission analysis, we were able to see that the primary source of GHG emissions resulted from the production of the playing cards followed by the production of the batteries. From the summary above, we can see that the $30/tCO2eq tax results in a $0.17 increase in the cost of production and a $1.46 increase in the cost of using the product.

Since 12 complete decks and 24 batteries are required throughout the product's life cycle, we would recommend that that the redesign efforts focus on improving battery life and reducing any chances of card damage (to improve card life). A possible solution could be to utilize motors of greater efficiency and to market the product with sustainably manufactured cards (to reduce the environment impact of their production). Although these changes are likely to result in a rise in the product's manufacturing costs, the overall fall in the GHG emissions and the product use costs borne by the user are likely to offset these costs especially in the event of the $30/tCO2eq tax on carbon dioxide emissions.

Team Members

FMEA Lead: Rodrigo "Dragon" Bergamasco

Wiki Lead: Allen "Kimbo" Kim

DFMA Lead: Alexander "Kozy" Kozhemiakov

DFE Co-Lead: Angela "No-talkie" Nawrocki

DFE Co-Lead: Pranay "Ultra-Soft" Sharma

The dissection and analysis of the product was done primarily in a group setting where all members contributed equally. The remaining sections of the report were completed in smaller groups depending on individual sectional preferences. The final write-up and review was completed as a team exercise.

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