Drink cooler
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===Assembly=== | ===Assembly=== | ||
| - | The design was made in a way to ease assembly. A majority of the pieces fit into the external housing in order from bottom to top. In addition, most of the parts are press fit. These parts round | + | The design was made in a way to ease assembly. A majority of the pieces fit into the external housing in order from bottom to top. In addition, most of the parts are press fit. These parts were designed to be round with guides. This allows for easy insertion that will snap into the correct position. These press fits also reduced the requirement for screws, which are tedious and would complicate the assembly. In addition, the water plumbing was joined with a flexible rubber connector. This improved the tolerances of the tubing. |
| + | |||
| + | The only weakness identified was with the choice of fasteners in some cases. There is one connection created using hot glue that joins the water tubing to the inside wall of the external housing. This was likely done to reduce vibrations. However, this one connection requires the use of a completely new tool. Finding a way to eliminate the hot glue connection with either a screw or a press fit would reduce the number of tools required. This would also save time in assembly. The other weakness was that some of the screws were hard to reach. Their insertion points were at the very bottom external housing. Reaching to these locations to screw them in is inefficient. A potential solution is to either replace them with press fits or relocate the screws such that they are in a more accessible position. | ||
Revision as of 17:52, 9 February 2012
Contents |
Executive Summary
Identification of Stakeholders
Product Usage
The device is used for cooling carbonated beverages quickly. It works for a single can or 12 ounce glass bottle, and can cool a beverage down to 33 degrees Fahrenheit in between 2 and 6 minutes, depending on the beverage and container. The device is about the size of a small toaster and runs off of an AC power supply. The majority of the device is taken up by a reservoir chamber with a spinning roller. All electronics, controls, and actuation mechanisms are beneath or behind the reservoir, sealed away from moisture. Cooling is accomplished by forced convection between the beverage and an ice water slurry. Before operation, the device is filled with ice and water, creating a slurry near 33 degrees Fahrenheit. A single motor spins a roller and turns a small turbine. The roller is a long metal shaft which runs the length of the device. It has a plastic coating to prevent corrosion, and has rubber rings at regular intervals along its length. These rubber rings are what contact the beverage container and force it into motion. The roller spins the beverage at a fixed rate for a set time interval. The time interval is set by a simple microcontroller which takes an input from a four-way switch. This switch is changed by mechanical motion of a rotating dial, which is the user control interface. This allows the switching of the device from off to one of three time intervals: 2 minutes, 4 minutes, and 6 minutes. Setting the dial to one of the three time settings turns the device on for that prescribed amount of time. The motor driven turbine is four flanges projecting from a plastic disk, which spins forcing water from the reservoir up a pipe and out a spout at the top of the device. Though the water does not exit under high pressure or velocity, the spinning of the beverage container causes it to move with high relative velocity to the beverage, thus increasing the effects of the forced convection. The reservoir has a clear plastic lid to seal it during the chilling process, and the latch of the lid triggers a limit switch to prevent the device from running while it is open.
Bill of Materials
| Part Number | Sub-Assembly | Part Name | Quantity | Weight (in g) | Function | Manufacturing Process | Material | Image |
|---|---|---|---|---|---|---|---|---|
| Water Spout Assembly |
| |||||||
| 1 | Spout | 1 | 5 | Ejects water that is pumped up | Injection Molding | Plastic |
| |
| 2 | Screw | 2 | < 1 | Fastner | Purchased Part | Steel |
| |
| 3 | Washer | 2 | <1 | - | Molding | Rubber |
| |
| Bottom Assembly |
| |||||||
| 4 | Rubber Rest | 6 | < 1 | Prevents shaking of the overall structure | Molding | Rubber |
| |
| 5 | Screw | 8 | < 1 | Fastner | Purchased Part | Steel |
| |
| 6 | Bottom Cover | 1 | 121 | Covers the lower portion of the machine | Injection Molding | Plastic |
| |
| 7 | Spring | 2 | < 1 | Damps vibration of the machine | Extrusion and Coiling | Steel |
| |
| 8 | Sealant Gel | - | - | Prevents leakage of water | - | - |
| |
| Rotary Bar Assembly |
| |||||||
| 9 | Plastic Bar | 1 | 16 | Rotates cans/bottles once place | Injection Molding | Plastic |
| |
| 10 | Screw | 2 | < 1 | Fastner | Extrusion and Coiling | Steel |
| |
| 11 | Holder | 1 | < 1 | Keeps bar in palce | Injection Molding | Plastic |
| |
| 12 | O rings | 7 | < 1 | Increases friction | Molding | Rubber |
| |
| Circuiting - Electronics |
| |||||||
| 13 | Plastic Timer | 1 | 21 | Varies how long the motor runs | Injection Molding | Plastic |
| |
| 14 | Spring | 1 | < 1 | Extrusion and Coiling | Steel |
| ||
| 15 | Circuit Board | 1 | 43 | Contains the controlling components | Assembled | - |
| |
| 16 | Screw | 1 | < 1 | Fastner | Purchased Part | Steel |
| |
| 17 | Metal Piece | 1 | < 1 |
| ||||
| 18 | Limit Switch | 1 | 7 | Ensures machine does not operate until lid is closed | Assembled | - |
| |
| Lid Assembly |
| |||||||
| 19 | Lid | 1 | 27 | Covers the top of the product | Injection Molding | Plastic |
| |
| 20 | Torsion Spring | 2 | < 1 | Automatically opens lid if not closed | Extrusion and Coiling | Steel |
| |
| 21 | Screw | 2 | < 1 | Fastner | Purchased Part | Steel |
| |
| 22 | Plastic Casing | 2 | < 1 | Forms a casing for the torsional springs | Injection Molding | Plastic |
| |
| 23 | White Plastic Pieces | 2 | 2 | Holds torsional springs in place | Injection Molding | Plastic |
| |
| 24 | Spring | 2 | < 1 | Extrusion and Coiling | Steel |
| ||
| 25 | Button | 1 | < 1 | Clicks when lid is shut | Injection Molding | Plastic |
| |
| Bottom Drain Assembly |
| |||||||
| 26 | Drain | 1 | Water flows from here to the pump | Injection Molding | Plastic |
| ||
| 27 | Drain Cap | 1 | 4 | Prevents ice from entering | Injection Molding | Plastic |
| |
| 28 | Screw | 2 | < 1 | Fastener | Extrusion and Coiling | Steel |
| |
| Housing of the Entire Item |
| |||||||
| 29 | Housing | 1 | 697 | Houses the product | Injection Molding | Plastic |
| |
| Motor Assembly |
| |||||||
| 30 | Motor | 1 | 173 | Pumps water and rotates bar | Purchased Part |
| ||
| 31 | Drain Channel | 1 | 21 | Channels water towards motor | Injection Molding | Plastic |
| |
| 32 | Lower Housing | 1 | 14 | Houses the motor and provides passage for the water | Injection Molding | Plastic |
| |
| 33 | Middle Housing | 1 | 44 | Houses the motor and provides passage for the water | Injection Molding | Plastic |
| |
| 34 | Upper Housing | 1 | 17 | Houses the motor and provides passage for the water | Injection Molding | Plastic |
| |
| 35 | Rubber Tube | 1 | 13 | Connects the Middle Housing to the L-shaped Joint | Molding | Rubber |
| |
| 36 | L-shaped Joint | 1 | 9 | Connects the Rubber Tube to the Drain Channel. | Injection Molding | Plastic |
| |
| 37 | Circular Plate | 1 | 1 | Rotates under Motor | Injection Molding | Plastic |
| |
| 38 | Metal Holder | 2 | 1.5 | Fastens rubber tube | Extrusion and Coiling | Steel |
| |
| 39 | Belt | 1 | < 1 | Transfer rotational motion from motor to the shaft | Molding | Rubber |
| |
| 40 | Bevel Gear | 1 | 8 | Transfers rotational motion to the belt | Injection Molding | Plastic |
| |
| 41 | Screw | 2 | < 1 | Fastener | Purchased Part | Steel |
| |
| 42 | Washer | 2 | < 1 | Purchased Part | Rubber |
| ||
| 43 | Plastic Shaft | 1 | 3 | Injection Molding | Plastic |
| ||
| 44 | Metal Shaft | 1 | 2 | Extrusion | Steel |
|
Design for Manufacturing and Assembly
The competitor's drink cooler was analyzed to determine strengths and weaknesses with their design pertaining to ease of manufacturing and assembly. Overall, competitor product seemed to be well-designed in these two areas. However, there were a few areas that leave room for improvement.
Manufacturing
The biggest success of the competitor drink cooler was the design of the motor. One motor was designed that played a multifunctional role as it powered both the water pump and also the drink rotator. This was critical to the design as it allowed the entire product to be both compact and cheap. We had anticipated having two separate motor for each of those roles. All parts in the design beyond those that would be specific to this product were standardized. The only custom parts were found to be the external housing, rotator bar, motor housing, and water plumbing. Among these the motor housing and rotator bar were designed such that they could also be used across other drink cooler models produced by this same company, increasing scale of production while reducing required equipment. The standardized components used in the design were the screws, springs, motor, pulley, circuit board, and O-rings. This took advantage of the scale of production. In addition, it was designed such that only one drill size was needed and all the holes could be drilled from as few positions as possible.
The only two areas weaknesses were the mechanical control system and the low construction tolerances. The control system featured several parts that had to be fitted together in a precise way. Still, the control system was very sluggish and left room for improvement. A toggle system might be a potential way to improve the design. The tolerances of the entire system were very small. This was necessary because the system needs to be water tight. This is a weakness, but will also be hard to improve on.
Assembly
The design was made in a way to ease assembly. A majority of the pieces fit into the external housing in order from bottom to top. In addition, most of the parts are press fit. These parts were designed to be round with guides. This allows for easy insertion that will snap into the correct position. These press fits also reduced the requirement for screws, which are tedious and would complicate the assembly. In addition, the water plumbing was joined with a flexible rubber connector. This improved the tolerances of the tubing.
The only weakness identified was with the choice of fasteners in some cases. There is one connection created using hot glue that joins the water tubing to the inside wall of the external housing. This was likely done to reduce vibrations. However, this one connection requires the use of a completely new tool. Finding a way to eliminate the hot glue connection with either a screw or a press fit would reduce the number of tools required. This would also save time in assembly. The other weakness was that some of the screws were hard to reach. Their insertion points were at the very bottom external housing. Reaching to these locations to screw them in is inefficient. A potential solution is to either replace them with press fits or relocate the screws such that they are in a more accessible position.
