Vending Machine

Background

From humble single-cent beginnings, vending operations in the United States have evolved into a $36.6 billion industry. Canned cold drinks were the industry's top sellers in 1999, posting $15.7 billion in sales and accounting for 42.9% of the industry's gross sales volume. Packaged candy and snacks ranked second, with 19.7% of the industry and $7.2 billion in sales. More than 857,000 coin-operated vending machines were produced and shipped in 1999. More than half (477,102) were refrigerated units vending canned and bottled soft drinks.

Vending accounts for a significant portion of the sales and profits of beverage bottlers and snack makers. In 2000, vending machines generated 14% of total foodservice sales in venues such as college campuses, factories, businesses, hospitals, and schools. Bottlers pay colleges, schools, and other institutions millions of dollars for exclusive rights to place vending machines on campuses. Vended soft drink sales may represent only as much as 15% of a bottler's total yearly sales, but that same volume could easily account for half of their annual profits.

History

The first documented vending machine dates from about 215 B.C. , when the mathematician Hero invented a device that accepted bronze coins and dispensed holy water in the temples of Alexandria, Egypt. In A.D. 1076, Chinese inventors developed a coin-operated pencil vendor. Coin-activated tobacco boxes appeared in English taverns during the 1700s.

The United States government began granting patents for coin-operated vendors in 1896. However, it was not until 1888 that vending became a viable market in the United States. In that year, the Adams Gum Company developed gum machines that were placed on elevated train platforms throughout New York City. The machines dispensed a piece of tutti-frutti gum for a single penny.

In 1926, William Rowe invented a cigarette vending machine that started a trend toward higher priced merchandise, including soft drink and nickel-candy machines that evolved throughout the late 1920s and 1930s. Coffee vendors were developed in 1946, and refrigerated sandwich vendors followed in 1950. In 1984, Automatic Products International, Ltd. (APi) introduced a vending machine that ground and brewed fresh coffee beans.

Practically anything that can be vended, has been at one time or another. The first beverage vendor, dated to 1890 in Paris, France, offered beer, wine, and liquor. Items that have been found in vending machines include clothing, flowers, milk, cigars and cigarettes, postage stamps, condoms, cologne, baseball cards, books, live bait for fishermen, comic books, cassettes and CDs, lottery tickets, and cameras and film. Some modern vending machines dispense hot foods such as pizza, popcorn, and even french fries.

Raw Materials

Vending machines are constructed primarily from four major raw materials: galvanized steel, Lexan or other plastic, acrylic powder coatings, and polyurethane insulation.

The bulk of the machine is constructed from galvanized steel ranging from 10 gauge to 22 gauge in thickness. The thicker gauges are used for the outside cabinet, external doors, and internal tank. Thinner gauges are used for internal doors and plates, can stacks, and mechanisms such as coin validators and product trays.

Lexan, a tough polycarbonate plastic, is used in the front panels of the vending machine. Sheets of Lexan in vending machines usually range from 0.13 in (3.18 mm) to 0.25 in (6.35 mm) in thickness. Lexan is very difficult to break, flame retardant, relatively easy to shape, and can be treated to restrict UV rays, light, and heat transmission. Product logos, names, and illustrations are silk-screened on Lexan sheets, which are installed in channels in the doors of the vending machines.

Acrylic powder coatings are colored powders used to "paint" the surfaces of vending machines. The powder is applied in a uniform layer and baked on during the manufacturing process. Acrylic coatings withstand the rigors of weather and abuse better than paints that are applied wet. In addition, acrylic powders more readily meet governmental environmental standards.

Polyurethane foam provides the insulation for the inside of the vending machine. The foam is blown between the outer cabinet and internal tank of the machine, where it cures into a very tough, rigid material. In addition to thermal insulation, the stiff foam adds structural stability to both the cabinet and tank of the machine.

Some manufacturers, such as Dixie-Narco, also make the complicated electronic devices used in vending machines, while others purchase them pre-made and install them as part of the manufacturing process. These components include bill and coin validators, computer control boards, refrigeration units, and lighting.

Design

The basic design of a vending machine begins with the cabinet, the steel outer shell that holds all internal components and which determines the machine's overall size and shape. Inside the cabinet is a steel inner lining called the tank. The tank and the cabinet fit closely together, leaving enough room in-between for a layer of polyurethane foam insulation. In combination, the tank and the foam insulation help keep internal temperatures stable and protect products against temperature extremes outside the cabinet. Although all products and dispensing mechanisms are contained in the cabinet, in the strictest sense, they are actually installed within the tank.

The outer surfaces of the cabinet are coated with an acrylic powder finish that is baked into place. Powder coatings enable the machine to withstand extreme temperatures, salt or sand, abuse by customers, and other conditions requiring high surface durability.

To store and dispense products, can feeder stack columns or feeder trays are installed inside the machine. Each tray is equipped with a large rotating wire spiral that holds the products. Feeder trays slide in and out of the machine for easy maintenance and restocking of merchandise. The feeder stacks and trays also contain the motor controls that physically push the products forward until they are released from the stack and fall to the access area. When a customer selects a product, a rotor turns and advances a single item, dropping cans or bottles one at a time. In the same way, spirals on snack food trays rotate and push products forward until they fall off the tray.

Some vending machines, especially cold drink vendors, have two doors. The internal door seals the inside of the machine and provides additional insulation. The, outer door contains the electronic controls that allow customers to purchase and receive goods. The outer door also includes signage and illustrations, generally silk-screened onto a panel of Lexan that fits into the front panel of the door. Lighting for the front panel is generally installed behind the Lexan panels. The outer door includes heavy-duty hasps, locks, and hinges to deter theft and vandalism.

Electronic components, such as coin and bill validators, test coins and scan dollar bills that have been inserted to ensure that the cash is genuine and in the proper amount. A panel of control buttons lets customers make their selections. These buttons are connected to the motor controls of the feeder stacks and trays, activating the rotors that release products to the bins. Change-makers hold quantities of coins and release the correct change after a selection has been made. More recent machines may also include card validators for accepting debit and credit cards, LCD panels with pricing details and machine status information, and speech chips that give transaction details to customers by voice.

Design changes occur most frequently in the mechanisms for handling and dispensing the vast number of different types of bottles, cans, boxes, bags, and other packages available on the market. When 20 oz (592 ml) plastic soda bottles were first introduced to vending, they tended to jam in the machine. Designers had to re-work the way those bottles were stored in the machine and delivered to the customer. Constant changes in product packaging have ensured that designers must always look for practical and more efficient ways to vend products.

The Manufacturing
Process

The most popular type of vendor in the United States is the cold canned soft drink machine, which vends the traditional 12 oz (355 ml) aluminum can of sodas and soft drinks. The manufacture of a cold can drink vending machine is often accomplished on several automated, concurrently running assembly lines that make all the components simultaneously. Manufacturing processes for vending machines can be as varied as the products dispensed in them.

1. The cabinet is made from a roll or coil of galvanized steel. At the start of the assembly line, the raw steel passes through automated presses that flatten it and cut it into sheets. Cabinets are frequently made of two or more separate pieces.
2. Other presses then punch and notch the sheets. The punching process creates holes in the cabinet for bolts and fasteners, openings for electrical cords, slits for vents, and other necessary openings. Corners and edges of the sheets of steel are notched where necessary to accommodate the fitting of components onto the finished cabinet.
3. Sheets of steel automatically enter and exit heavy-duty air and hydraulic presses. Each press exerts 200-400 tons of force or more. The steel sheets lie flat as the presses crimp the edges, create bends in the metal, and form the steel into the cabinet's basic shape.
4. The seams are secured using resistance welding, also known as spot welding, a process that uses a high-voltage charge through two contacts that melts metal surfaces together.
5. Finally, the cabinet is unloaded from the line and taken to the finishing area to undergo powder finishing and await installation of the tank.
6. While the cabinet is being made, another line forms the tank. The tank is created by a process similar to that used to make the cabinet. Galvanized steel is cut from rolls of raw material and enters the automated line. Openings for bolts, feeder stacks, motors, and other mechanisms are punched in the sheets, and the corners are notched so that the tank will fit inside the cabinet more easily and securely once it is welded.
7. Presses provide any necessary forming and bending, and separate pieces are welded together to create a whole unit.
8. The tank is then taken to the finishing area, where it is fitted to the correct cabinet.
9. Before powder finishing, the cabinet undergoes an eight-stage pre-treatment. First, the cabinet is attached to an overhead conveyor that runs the cabinet 210 ft (64 m) through the pre-treatment system. Nozzles mounted on both sides of the conveyor thoroughly spray the cabinet at each stage, beginning with an alkaline wash to remove heavy surface soil.
10. A second alkaline bath cleans the surface even further.
11. The cabinet is then rinsed, coated with zinc phosphate, and rinsed again.
12. Chromic acid, a sealer, is then applied and the surface is rinsed once more.
13. Finally, the entire surface is thoroughly rinsed with deionized (DI) water. Units then go into the drying oven for approximately 30 minutes to an hour at temperatures ranging from 350°F to 400°F
    A typical vending machine being stocked.
    (177°C to 204°C) to ensure that no moisture is left on the surface.
14. Upon leaving the drying ovens, the cabinet remains on the overhead conveyor system where it begins the powder finishing process. This process "paints" the cabinet in various colors by applying a coating of acrylic powder to the surfaces of the cabinet and baking it into place. Cabinets, tanks, internal mechanisms, and other parts may all be powder finished during the manufacture of a cold can soda vending machine.
15. Cabinets travel along the convey into environmentally controlled powder booths. The booths are constructed of polypropylene, which is believed to attract less excess powder, improving spray efficiency and reducing the need for clean-up. Each booth applies a single color with an array of 18 to 22 spray guns, all of which are designed to move in order to provide better coverage, reach into cavities, and track along with the cabinet. The guns apply an acrylic powder in a uniform 0.0015-0.002 in (1.5-2 mm) thick layer on the cabinet. The positively charged powder adheres easily to the grounded cabinet surface. Oversprayed powder is collected, mixed with virgin powder, and resprayed, resulting in very little waste of coating material. As much as 95% of oversprayed powder can be recovered.
16. When the powder application is finished, coated cabinets exit the booth and go into the cure oven for 20-30 minutes at 370°F (188°C). The powder finish is permanently baked on.
17. Finished cabinets and tanks are then united for the process of foaming, the application of polyurethane foam insulation to the interior of the machine. The tank is fitted into the cabinet, and both are pre-heated to approximately 120-150°F (49-66°C) while awaiting foaming. When the correct temperature is reached, high-pressure foaming fixtures blow the insulation between the cabinet and the tank using carefully metered shots of material. The foam solidifies, providing not only effective insulation but also a degree of additional structural stability to the cabinet and tank. At one time, the resin additives used to create the structure of foam insulation, called blowing agents, contained large amounts of CFCs, or chloroflurocarbons. However, environmental concerns over the use of CFCs led to the use of alternative blowing agents, including halocarbon (HCFC) substitutes and water.
    
18. When foaming is completed, refrigeration units are installed in the bottom of the cabinet. These units are often acquired pre-manufactured and are slid into place, bolted securely, and wired into the cabinet by a single operator on the assembly line.
19. Can feeder stack columns are installed inside the cabinet. These columns are manufactured and finished using steel forming, punching, notching, and welding processes similar to those used to make the cabinet and tank. The process is monitored carefully to make sure the correct size stack is matched to the proper unit.
20. In the final stage of manufacturing, doors are installed on the cabinets. The exterior door units hold most of the highly sophisticated electronics of the cold drink vending machine, including coin and bill validators, selection buttons, control panels, change tubes, signs, and lighting. Interior doors act as additional seals for the inside of the machine. The majority of doors on can vending machines do not have clear windows for displaying products. Instead, the door fronts often contain artwork, logos, and graphics that advertise the machine's contents. However, machines that vend bottles, candy, and snacks often have clear windows made of Lexan or some other tough, break-resistant material.
21. The basic door shell is created and finished in much the same way as cabinets and tanks, with additional punching necessary to accommodate the controls on exterior doors. Components of doors are often assembled as completely as possible in one area rather than on an assembly line. It is essential that the correct door is fitted to the correct cabinet, so door assembly is centralized in order to reduce the possibility of errors in matching doors with units. During manufacture, doors are placed on revolving, indexible carousels that allow operators to turn and move them.
22. All assembly items are placed on the door while it is in this carousel. Operators fit the coin and bill validators, card acceptors, selection buttons, LCD displays, and other external controls in the appropriate spots and attach them with bolts or screws. Selection buttons are wired to the motors of the proper can stacks. Front panels of silk-screened Lexan are installed in channels on the doors. Lighting fixtures are bolted in place and wired into the power supply. Finished doors are carried to the cabinets and automatically attached. The completed can soda vending machine is then ready for quality checking and testing.

Quality Control

Finished machines are tested after assembly. Checks are made to ensure that all electronic components function properly, that the can stacks are fitted correctly, and that cans are dispensed accurately and safely. If problems are found, the machines are sent to stations capable of holding multiple units. A rework technician makes the needed repairs, and the machine is tested again. If problems remain, the unit is rejected and flagged.

Additional tests include refrigeration pull-down testing, in which the interior temperature of the unit is "pulled down" to 30-31°F (−1-−0.5°C). This test ensures that the machine controls and temperature controls are working properly.

Tested units are given a final visual check, then cleaned and wrapped in clear plastic shrink-wrap. Finished vending machines are transported by conveyor to the warehouse where they are packed and readied for shipping to customers.

The Future

In 2000, the Coca-Cola Company announced plans to invest more than $100 million in online "Dial-a-Coke" vending technology from Atlanta's Marconi Online. For vending companies, the technology will improve efficiency, data collection, and maintenance. Machines will employ remote diagnostics to alert staff at headquarters when machines need refilling or servicing. Detailed stock status will be transmitted to centralized locations so that route drivers and technicians will know exactly what products are needed to re-stock their machines before they even begin their routes. Sophisticated data collection will provide more immediate feedback on what products are selling and what items need to be replaced with more popular merchandise. Machines will transmit real-time data on transactions, allowing companies tighter control and more precise data on cash and stock accountability. For customers, the Dial-a-Coke technology will allow cashless purchasing. Consumers will be able to use their cell phones to dial up a particular vending machine to select and pay for soft drinks.

Data can also be transmitted to the machines. Changing prices, for example, usually requires a technician to physically visit a machine to make the changes by hand. Remote vending will allow changes to be made remotely, permitting vendors the flexibility to accommodate conditions such as promotional pricing or lowered prices during non-peak hours to increase overall sales volume. Cashless systems will also reduce theft and vandalism in machines by reducing the amount of cash stored in a vending machine at any given time. APi has already began production on a vending machine that will accept credit or debit cards.

Technological improvements in wireless machine monitoring systems in early 2001 have allowed companies to utilize the Internet as a type of wide-area network for monitoring and maintaining remote vending sites. Handheld computers have also become increasingly popular as a way to capture sales and stock data directly from machines.

Where to Learn More

Periodicals

Babyak, Richard J. "New Era for Insulation (Change is in the Wind for Blowing Agents)." Appliance Manufacturer 41, no. 8 (August 1993): 47-48.
Bailey, Jane M. "Vending Machines Take a Beating." Industrial Finishing 67, no. 4 (April 1991): 36-37.
"Coca-Cola Customers to Buy Vending Machine Drinks Using Marconi's GSM Dial-a-Coke Solution." Wireless Internet 3, no. 5 (May 2001): 7.
Marcus, David L., Leslie Roberts, and Jeffery L. Sheler. "A Hot Idea From Those Cold-Drink Folks." U.S. News and World Report 127, no. 18 (8 November 1999): 10.
Prince, Greg W. "100 Years of Vending Innovation." Beverage World 117, no. 1651 (January 1998): 214-216.
Simpson, David. "A Peak in the Heart of Dixie (Dixie-Narco Inc.'s Use of Powder Coatings)." Appliance 46, no. 8 (August 1989): 56-57.
Somheil, Timothy. "Vending Innovation." Appliance 55, no. 1 (January 1998): 87-89.
Stevens, James R. "The Dixie-Narco Story." Appliance 47, no. 6 (June 1990): 31-4.
Sutej, Joseph M. "Evaluating Low-CFC Foam Insulation." Machine Design 62, no. 10 (24 May 1990): 108-109.

Other

National Automatic Merchandising Association Page. 8 July 2001. < http://www.vending.org >.
Vending Times Web Page. 8 July 2001. < http://vendingtimes.net >.

Jeffrey W. Roberts

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