The Dotson Co.: Simplified Manufacturing & Casting Design.
Dotson Co., Inc., Mankato, Minnesota, has transformed itself several times since its founding in 1876. It expanded to a jack-of-all-trades role in the 1960s and 1970s when it had iron, aluminum, bronze and steel casting capabilities, several product lines and a machine shop. Castings ranged from ounces to more than 8000 lb.
Then, in the 1980s, in a move to increase efficiency and focus on one specialty, it narrowed to gray and ductile iron casting. Following a similar trend in the mid-1990s, Dotson trimmed itself again, focusing its in-house operations on casting design and casting manufacture (from only mold/core making to shakeout).
However, Dotson's trimming of in-house operations hasn't reduced its jack-of-all-trades label, as the 100-employee gray and ductile iron job shop now coordinates finishing, machining, heat treating, painting/plating and other value-added services through outside vendors.
This article explores Dotson's refocusing of its services and how it has led to increased manufacturing efficiency and casting design expertise. On the manufacturing side, capital investments referred to as "$10,000 projects" have allowed the foundry to improve production processes through management-employee cooperation. On the design side, the focus has been converting fabrications to castings and participating in customers' initial casting design to improve the final product. Overall, the foundry has determined that its future success rests on its ability to master these disciplines in-house, while managing all other value-added services with their supplier partners.
The re-focusing by Dotson to core casting manufacturing from core and mold making to shakeout has driven the foundry to increased efficiency through a series of "$10,000 projects."
According to Dotson President Denny Dotson, "In the last 10 years, our focus has been on purchasing and improving equipment to eliminate process variation, reduce costs and improve quality. Many projects have done all three in addition to reducing labor-intensive, physical work." The foundry involves employees in choosing any equipment that costs more than $10,000 to ensure that the money is
well spent and results in the purchase of equipment compatible with current foundry processes.
In 1999, the foundry decided to retool its coreroom operations as a $10,000 project. At the time, Dotson was making three different types of cores: 5% oil sand, 40% shell core and 55% coldbox. However, it wanted to reduce variation to a single method to increase efficiency (70% of castings are cored). The foundry sent the coreroom employees to foundries across the U.S. to research core machines in operation and see what process would be compatible with current production at Dotson. The employees talked to coreroom operators at these foundries and learned the benefits and drawbacks of each system they saw. After selecting a coldbox core system because the capabilities were a good match for customers' requirements, Dotson employees returned to the road to learn more about the operational details of the machines and confirm how many and what size machines would work best. This helped employees reduce the expected learning curve for full production on the first machine from 6 months to 4 weeks.
To maximize the efficiency of the core tooling conversion to an all coldbox format, Jim Headington, a process engineer, put together a team that included pattern shops and the core machine manufacturer. Their discussions lead to several enhancements that keep tooling costs to a minimum while making cores better, cheaper and faster. In fact, one pattern shop embraced the equipment and partnered with
Dotson to create a casting solution that makes a significant impact on the cost for rigging the equipment.
In the end, the $10,000 project team was able to reduce the number of coreroom employees from 12 to 4 and relocate the extra employees to other areas in the foundry that needed help. The resulting coreroom produces 10,000 coldbox cores/day on two coldbox systems (Fig. 1).
Last year, Dotson used a $10,000 project to re-examine its furnace charging system. Previously, the charge system consisted of two people moving scrap in several wheelbarrows to preheating and charge buckets. From there, the scrap entered two induction furnaces to produce 100 tons of iron/day. Determined to eliminate this backbreaking, inefficient labor, the foundry investigated an automated operation and chose to implement a robotic arm to perform the heavy work.
The new furnace charging system consists of a manipulator with a large magnet at the end operated by one person in an air-conditioned booth. The magnet picks up charging material and feeds it into a vibratory weight conveyor. Then the material is dumped into preheating and charging buckets (Fig. 2).
Employees helped fit the new charging system into both the plant operations and the physical layout of the plant. Their input produced a maximized layout that allowed one person to perform the job.
According to Jed Falgren, vice president of engineering at Dotson, employees used to threaten to quit if they were required to work in the charge area. This new system has been such a success that one employee threatened to quit if he wasn't allowed to run the charge system. In addition, the project fulfilled more than its goal of reducing the charging area to one employee. The system's efficiency means that the employee running it also has time to help on the melt deck.
Dotson developed the $10,000 project concept five years ago when it was looking to buy a second green sand mold indexing system. The foundry ran four mold lines that produce molds up to 20 x 24 in. These lines feed two mold indexing systems. However, the problem for Dotson was that these systems couldn't keep up with mold-making capacity. Before purchasing a third indexing system, the foundry turned to its employees.
The operators explained what they liked and didn't like about the first two indexing systems, leading to a switch in the systems' rotation. Changing from counter-clockwise to clockwise provided a better connection to the molding line's pouring cell. In addition, the employees provided ideas for sharing peripheral pieces of equipment by setting up the machines as mirror images of each other. This employee input cut costs and helped make the indexing system more efficient. Also, the maintenance department remained involved concerning how to connect the systems to other plant equipment in the most sensible and efficient way possible.
Depending on employee input also meant that operators were more willing to be tolerant of the installation and inconveniences it involved. The operators had to walk across scaffolding to reach their posts, but didn't complain because they had been included in the process and knew it was in everyone's best interest to finish the installation quickly.
"This project exceeded the molds/hr and tons/hr performance numbers used to justify buying a piece of equipment because of the involvement of the shop floor people," explained Falgren.
With the third system installed, the foundry increased production by 50%.
After castings are molded, they travel through a vibratory conveyor for shakeout. A media drum delivers the castings to a manual gating removal system where employees use a hydraulic wedge to separate the casting from the gating. This wedge comprised several $10,000 projects.
In the early l990s Dotson tried using different types of wedges and even sponsored a senior design project at a local university to create gate removal equipment that worked to their specifications. None of these were successful. Rather than return to previous methods of using a sledgehammer to remove the gating system, the foundry finally chose a wedge. However, this wedge design had drawbacks--each one required its own power pack and used 10,000 psi of hydraulic pressure, a large amount for everyday industrial use.
Dotson decided to design its own hydraulic wedge system and put it through several iterations (more $10,000 projects) to bring it to its present form (Fig. 3). Employees that used the hydraulic wedge were consulted during the design phase and helped make adjustments to the equipment. Dotson's wedge now uses one power pack to power four tools and requires only 2000 psi. The foundry participates in a partnership that sells this wedge to other foundries.
Designs `R' Us
Dotson's relationship with customers extends beyond accepting a job and casting it. The foundry employs top-heavy sales and engineering departments--four internal account managers and five new job start-up team members--to work with customers on casting design and converting weldments and fabrications to cast components.
Dotson began this focus in the late 1970s when the truck industry started converting steel forgings into ductile iron castings in hopes of finding cost/weight savings. This drive by its truck-manufacturing customers sold Dotson on the new business opportunities and casting markets available through conversions.
"We see 2000 patterns/yr, but we see each pattern as a different customer. Every job and the specifications it entails are different," says Falgren.
The foundry's focus means that each job receives design attention. To overcome its customers' lack of knowledge about casting design, Dotson invites them into the engineering department at the beginning of each project--to help them own the design. Phil Patterson, an account manager, says, "I work for my customers as much as I work for Dotson."
Dotson's engineers see projects as their own responsibility to customers, not just as a means to make a profit. This hands-on attitude benefits both the foundry and its customers--the foundry can make changes to improve the casting, and the customer can learn about the process and what it can achieve.
One conversion project that Dotson took on, a ductile iron roller bracket, began as a 9-piece steel weldment. The foundry converted the weldment to a 12 x 12 x 8-in. 27-lb casting in grade 80-55-06 ductile iron using the green sand process (Fig. 4). The conversion saved the customer $15/casting, which, at an annual usage of 8000 components, resulted in annual savings of $120,000.
Dotson also used its engineering team to convert an axle housing for a construction skid-steer loader from a 7-piece steel weldment to a 1-piece ductile iron casting (Fig. 5). The 65-lb casting is made of 80-55-06 grade ductile iron using the green sand process. The design saved the customer $15/casting, resulting in an annual cost savings of $120,000.
"There is more money to be saved in converting to castings than beating up other casting suppliers," says Todd Nelson, vice president of sales.
Beyond the designs delivered by customers, Dotson engineers and sales people work with customers to "cast out costs" by visiting customer plants in search of cost-saving ideas. They will perform walk-throughs of customer facilities, picking up components and demonstrating how they would work better as a casting based on performance and/or on cost savings.
The benefit of Dotson's design efforts can be seen in its customers' bottom line. This year the foundry offered over $1 million in cost reduction to its customers. The goal was to be proactive with its customer base--providing results before they are demanded.
In one recent project, a customer requested a 5% price reduction in casting cost. Dotson responded by showing the customer how to save 13% on the project using tooling and machinery investments that would be paid back in less than one year. Although the customer refused "to spend money to save money," Dotson decided to eat the cost itself and implement the changes, figuring that the investment would pay off in the long run.
Dotson currently is pouring as much iron as it ever has, 5.5 tons/hr, averaging 18 hr/day. Due to the economic slowdown over the past year, it decided not to implement any $10,000 projects in 2001. Instead, it is investing in its employees by maintaining its workforce team, confident that the economy will improve in the coming months. According to Denny Dotson, "This has two great advantages. We have the people today to work on cost reductions which the customers are pushing, and we will have the people to support new casting projects when the economy turns,"
The foundry believes that its $10,000 projects help to keep its plant as up-to-date and efficient as possible. By concentrating on conversion designs, it is looking to expand the casting market and turn new customers onto the benefits casting can provide.
The Dotson Co., Inc.
Metals Cast: Gray, ductile, austempered ductile and carbidic austempered ductile iron.
Mold Process: Green sand (horizontally parted).
Core Process: Coldbox.
Melt Process: Coreless induction.
Size: 110,000 sq ft.
Year Founded: 1876.
2000 Production: 10,000 net tons.
Total Employees: 100.
Plant Officials: Denny Dotson, president; Jean Bye, executive vice president; John Close, vice president of technology; Jed Falgren, vice president of engineering; Todd Nelson, vice president of sales.
Dotson Grows through Diversification, Specialization
Lawrence Mayer and his three sons began their business as a blacksmith shop in Mankato, Minnesota in 1876, and started the foundry in 1894. Their first success was the invention of a trip hammer called the Little Giant, a mechanical blacksmith.
During the early 1900s, the Mayers expanded their product line to include boilers, gasoline and steam engines, road signs, woodworking equipment and tractors. In 1937, the foundry, now named Little Giant after its trip hammer, went bankrupt, and L.J. Fazendin bought up the assets and became the owner. In 1943, Fazendin's son-in-law, Jerry Dotson, joined the company. At this point, the outlook was good--the war ensured demand for trip hammers. The foundry grew from a small captive operation to a large jobbing foundry and was renamed Dotson Co. in 1960.
During the next few years, the foundry grew and expanded into new areas. Aluminum and bronze were first produced in large quantities in the 1950s. In 1967, a ductile iron foundry was built on a new site just north from the original foundry, and in 1976, a steel foundry was started.
Jerry Dotson's son, Dennis, became the president in 1978. As with most foundries, the early 1980s became a time of survival for Dotson Co. When sales dropped by more than 80%, the firm stopped brass, aluminum and steel casting as well as its machine shop. The decision was to focus on iron only. This was followed by new molding and melting investments for casting in the early 1990s.
Since the mid-1990s, the foundry has concentrated on developing relationships with value-added service contractors to expand its success. Dotson now coordinates out-of-house casting cleaning and finishing, as well as machining, heat treating and other value-added services. In 1997, the foundry reached ISO 9001 certification.
Computer Technology Leads the Way
Imagine yourself as a Dotson customer. Arriving at work on a Thursday morning, you think about the casting order you've placed with the foundry. Has it started pouring yet? Is the project still on schedule?
As you pick up the phone to call the foundry, an e-mail from Dotson arrives in your inbox. Your order is on schedule--the castings have been poured and are now being inspected. Question answered. This is only one example of Dotson's commitment to technology.
Customers can choose to receive status emails from Dotson containing as much information as they require on a daily or weekly basis. Soon, customers will be able to access information as needed, rather than waiting for the scheduled e-mail. The only way for customers to be more involved with projects at Dotson is to camp out in the foundry itself.
To make this process work, the 100-employee foundry boasts two "computer geeks." These employees concentrate on transforming communications at and with Dotson to create a paperless workplace.
Currently, 100% of shop floor instructions are given at computers. Each workstation has its own computer that provides special instructions for quality control parameters and process control information. They also track attendance, time on a job and casting defects. The system allows for supervisor and online production monitoring.
Dotson invests $250,000/yr into computers and programs to make its foundry run more effectively and to improve interactions with its customers. The next computer steps will be wireless PDAs, wireless computer connections for forklift operators, live real-time operating and process data, one button plant startup via integrated PLCs and customer access to 100% of their data.
Sky's the Limit Value-Added Services
Many of Dotson's customers have cut back on engineers and purchasers and are searching for expertise in those areas. According to Denny Dotson, these customers want a foundry that will "manage the process of everything having anything to do with castings."
Dotson first began this "full service" approach in the late 1980s while casting austempered ductile iron digger teeth for John Deere backhoes. John Deere pushed them to offer a finished product--not just a raw casting, but also heat treated and painted.
Dotson's value-added offerings have expanded since then to include machining and finishing, painting, heat-treating, assembling components, testing and shipping the finished products directly to the customer's customer. Dotson acts as the coordinator for these value-added services, managing the customer's project details and specifications through various service providers. By combining these services, Dotson can offer the customer a better value for a finished product rather than having the customer purchase all items separately.
According to Jed Falgren, Dotson's attitude regarding value-added services is "whatever customers want, we comply. This is where customers are taking us."
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|Article Type:||Company Profile|
|Date:||Oct 1, 2001|
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