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For over 75 years, New England Castings, Inc., has manufactured wood stoves for home use. In recent years, with increasing energy prices, George Mathison, president of New England Castings, has seen sales triple. This dramatic increase in sales has made it even more difficult for George to maintain quality in all of the wood stoves and related products. Unlike other companies manufacturing wood stoves, New England Castings is only in the business of making stoves and stove-related products. Their major products are the Warmglo I, the Warmglo II, the Warmglo III, and the Warmglo IV. The Warmglo I is the smallest wood stove, with a heat output of 30,000 BTUs, while the Warmglo IV is the largest with a heat output of 60,000 BTUs. In addition, New England Castings, Inc., produces a large array of products that have been designed to be used with one of their four stoves. These products include warming shelves, surface thermometers, stovepipes, adapters, stove gloves, trivets, mittenracks, andirons, chimneys, and heat shields. New England Castings also publishes a newsletter and several paperback books on stove installation, stove operation, stove maintenance, and wood sources and cutting. It was George's belief that their wide assortment of products was a major contributor to the sales increases.

The Warmglo III outsold all of the other stoves by a wide margin. The heat output and available accessories were ideal for the typical home. The Warmglo also had a number of outstanding features that made it one of the most attractive and heat efficient stoves on the market. Each Warmglo had a thermostatically controlled primary air intake valve that allowed the sieve to adjust itself automatically to produce the correct heat output for varying weather conditions. A secondary air opening was used to increase the heat output in case of very cold weather. The internal stove parts produced a horizontal flame path for more efficient burning, and the output gases were forced to take an S-shaped path through the stove. The S-shaped path allowed more complete combustion of the gases and better heat transfer from the fire and gases through the cast iron to the area to be heated. These features, along with the accessories, resulted in expanding sales and prompted George to build a new factory to manufacture Warmglo III stoves. An overview diagram of the factory is shown in Figure 1.

FIGURE 1
Overview of Factory

The new foundry used the latest equipment, including a new Disamatic that helped in manufacturing stove parts. Regardless of new equipment or procedures, casting operations have remained basically unchanged for hundreds of years. To begin with, a wooden pattern is made for every cast iron piece in the stove. The wooden pattern is an exact duplication of the cast iron piece that is to be manufactured. New England Castings has all of its patterns made by Precision Patterns, Inc., and these patterns are stored in the pattern shop and maintenance room. Then, a specially formulated sand is molted around the wooden pattern. There can be two or more sand molds for each pattern. Mixing the sand and making the molds is done in the molding room. When the wooden pattern is removed, the resulting sand molds form a negative image of the desired casting. Next the molds are transported to the casting room, where molten iron is poured into the molds and allowed to cool. When the iron has solidified, the molds are moved into the cleaning, grinding, and preparation room. The molds are dumped into large vibrators that shake most of the sand from the casting. The rough castings are then subjected to both sandblasting to remove the rest of the sand and grinding to finish some of the surfaces of the castings. The castings are then painted with a special heat-resistant paint, assembled into workable stoves, and inspected for manufacturing defects that may have gone undetected thus far. Finally the finished stoves are moved to storage and shipping where they are packaged and shipped to the appropriate locations.

At present, the pattern shop and the maintenance department are located in the same room. One large counter is used by both maintenance personnel to get tools and parts, and by sand molders that need various patterns for the molding operation. Pete Nawler and Bob Bryan, who work behind the counter, are able to service ten people per hour. On the average, four people from maintenance and three people from the molding department arrive at the counter per hour. People from the molding department and from maintenance arrive randomly, and to be served, they form a single line. Pete and Bob have always had a policy of first come, first served. Because of the location of the pattern shop and maintenance department, it takes about three minutes for an individual from the maintenance department to walk to the pattern and maintenance room, and it takes about one minute for an individual to walk from the molding department to the pattern and maintenance room. After observing the operation of the pattern shop and maintenance room for several weeks, George decided to make some changes to the layout of the factory. An overview of` these changes appears in Figure 2. Separating the maintenance shop from the pattern shop had a number of advantages. It would take people from the maintenance department only one minute instead of three to get to the new maintenance department. Using time and motion studies, George was also able to determine that improving the layout of the maintenance department would allow Bob to serve six people from the maintenance department per hour, and improving the layout of the pattern department would allow Bob to serve seven people from the molding shop per hour.

FIGURE 2
Overview of Factory after Changes

DISCUSSION QUESTIONS

1. How much time would the new layout save?
   
   
   
   
2. If maintenance personnel were paid $9.50 per hour, and molding personnel were paid $11.75 per hour, how much could be saved per hour with the new factory layout?
   
   

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