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Precision Manufacturing for Large Parts

 

Shop grows with advanced technology

     

By Jim Lorincz
Senior Editor 
   

 

"Shops that machine small parts may have the luxury of scrap, but we don't," says Don Covert, president of Covert Manufacturing Inc. (Galion, OH). "Accuracy, speed, and a stable process are vital. Big parts take longer to machine, so you have to maximize the number of parts you finish in a day, without sacrificing quality and with as little scrap as possible."

Covert Manufacturing is proud of its near-zero-percent scrap rate, especially considering that many of the parts it produces are for agricultural machinery and class-eight truck customers, where a scrapped part represents a significant amount of raw material and machining time wasted.

Don Covert has grown his company using the latest advanced technology like this Makino A88e HMC."We produce large parts very quickly," says Covert. "Our customers demand delivery on time and correct. We emphasize efficiency and speed with little to no scrap. Because of this, our customers trust us as a vital part of their manufacturing process, often allowing the parts we produce to go straight to their assembly lines without inspection."

Covert Manufacturing was founded in 1967 as a mold shop that focused on making patterns for foundries. In the company's early years, Covert Manufacturing was a relatively small outfit that operated with only three employees. The company grew quickly though, by meeting many of the industry's needs for precisionmachined products. Covert Manufacturing soon branched out into two separate divisions—CNC Machine and Pattern & Mold. The CNC Machine division of the company started off handling job-shop work, but eventually developed into a production environment.  

The company is located in Galion, a key industrial area 60 miles north of Columbus and 60 miles south of Cleveland. The shop may have its roots in the pattern business, but it has evolved into a $50-million-peryear production machining company that has experienced significant growth. It is the largest industrial employer in Galion, and has received many preferred vendor awards from major companies within the industry.

Covert Manufacturing has been with Makino for the life of their business, purchasing its first machines in the 1970s. There are now more than 100 CNC machines in their facility, including lathes, mills, and CNC grinding machines. In the last decade, Covert began adding Makino A77s, a71s, and then A88E HMCs. The machines are preferred for their flexibility and rigidity, and their ability to handle frequent runs of 10,000–50,000 parts. Today, more than 20 Makino A88E horizontal machining centers are in Covert's shop, along with dozens of other Makinos. In addition, Covert's piston shop has Makino a51 and a81 machines that are making parts for the diesel engine market.

Covert's customers come from a mixture of markets, but their focus is on large heavy-duty, off-highway truck and agricultural customers with parts that exceed the limits of small machining centers. Parts machined at Covert include airbrake systems, transmissions, heavy-duty truck parts, industrial compressors, pumps, agricultural equipment, hydraulic pump components, marine engines, truck trailers, components, spindles, brackets, and outdoor power equipment.

Sixty percent of Covert's business is in machining and production, with 40% in mold and tooling work. The company has a total of 345,000 ft2 (32,051 m2) under one roof, and owns a 45,000 ft2 (4181 m2) piston plant. To keep up with the increasingly heavier workload, Covert Manufacturing now has 300 employees running three shifts.

"Our company has been growing every year," says Covert. "We are up 20% over last year. Our core customers help to fuel our growth, especially the agricultural and heavy-duty truck industries, but central to our growth is continued investment in updating our machinery.

"We've always invested to take advantage of sales opportunities, putting millions into the company each year for new technology and reliable equipment. It's important for us to have equipment that exceeds our customers' quality standards and enables us to make delivery, all while retaining a job-shop mentality. This is why we have repeat opportunities," Covert says.This gray iron intake manifold was machined in three stages on the same fixture using a total of 41 tools on the Makino A88e. The 38 (965-mm) long part was fixtured at a 22&$176; angle in one stage to use the machine capacity more efficiently.

"While we employ the very latest technology, we realize that no matter how advanced our technology might be, it is only as good as the people using it. We are proud of our quality-conscious employees who constantly strive to give customers the best service and products available."   

This is, after all, a family business. Covert founded and grew the business with his wife, Martha Rodella Covert, who was involved in office and accounting functions for many years. Their three daughters and son also joined the company. Daughter Teri Williams has been with Covert Manufacturing for 28 years and is vice-president chief financial officer. Daughter Kym Fox is executive vice president of machining operations, and has been with the company for 26 years. Daughter Donna Morrow is vice president of human resources, and has been with the company for 23 years. Don Covert Jr. is the vice president of sales for the mold solution division, and he has been with Covert Manufacturing for 21 years. All the spouses of the Covert children are also employed with the company, further deepening the family connections. For example, Dennis Williams, son-in-law of Don and a sales representative for Covert, recently played an instrumental role in bringing in the largest machining contract in the company's history.

When it comes to the Covert family business, success is a word that directly correlates with the family itself. The hard work they put into the business, and business decisions that have led to the purchase of the highest-quality machinery, have made for a business that will provide for the family and employees for many years to come.

Covert says that in addition to his family's commitment, the company also employs many other families who are just as passionate about the business. "We have a lot of fathers and sons—second and third generation—working in our shop," says Covert. "Most of our people are long-term employees who have been around an average of 15 years. We have 15 to 18 people who have been working here 30-plus years. That contributes to our success."

"Business today, in my opinion, is getting tougher," says Steve Lamontagne, who has been with Covert for 26 years. "Everyone knows simple component machining is going offshore. One of our strengths is tackling more difficult types of parts. We use Makino machines because of their reliability, accuracy, speed, and uptime in these kinds of applications."

Covert Manufacturing uses the Makino A88Es for most of its large parts. They utilize probing and have been pleased with other features, including the large tool capacity (130 tools), through-spindle coolant, and full-function fourth-axis NC rotary table. This machine was chosen for its heavy rigidity, large tools, and large- part capability. It's used for many mixed engine parts, which can range from 3 to 100 lb (1.4–45 kg) in weight. Covert Manufacturing deals with a wide variety of materials, including cast iron, ductile iron, malleable iron, aluminum and steel forgings, barstock, burnouts, and tubing.

Recently, a Makino A88E was used to machine an intake manifold made of gray iron. The part was machined in three stages on the same fixture, using a total of 41 tools. Due to its 38" (965-mm) length, one stage was fixtured at a 22° angle to better utilize the machine's capacity.

The 1000-psi (6.9 MPa) through-spindle coolant was used for deep-hole drilling, and the part required a 15x L:D drill. Probing was also used to measure the casting's cored location, which is not consistent from part to part. This allowed Covert to minimize manual interruption.

Verifying the datum point on newly fixtured parts was necessary due to inconsistencies sometimes experienced in the castings. The probing system is an automated method that measures and establishes a new datum point, allowing the work-coordinate system to automatically shift using the new point and eliminate the need for a manual check.

Silicon-nitride-inserted face mills were used to run at more than 4000 fpm (1219 m/min) and at feed rates of 125 ipm (3.2 m/min) while holding 0.005" (0.13-mm) flatness. Multiple- diameter boring bars were used to rough and finish valve bores, which had a 0.0005" (0.013-mm) diam tolerance and a 32 Ra or better finish.

"This is exactly the type of part that results in high scrap rates for shops," adds Fox. "Deep holes can wreak havoc if chips aren't cleared properly, tight face milling has to result in a very flat surface, and boring bars for finishing down to a fine finish. That's a recipe for a big, junked part if you don't know what you're doing and don't have the right machine."

The results in Covert's large part manufacturing can be partially attributed to the A88E's ability to use its full workzone. All Makino HMCs are designed to machine accurately to the top of the Y axis without pallet-tip. This accuracy, in combination with the thermal stability of the machine, keeps scrap rates at a minimum and allows for tighter work deadlines.

High-pressure through-spindle coolant of the Makino A88e is effective in machining various offhighway and agricultural engine components."It's not unusual for a customer to approach you with an order of high quantity that is needed in a short time," says Lamontagne. "For this reason, it is very helpful to be working on Makino machines that can help keep our scrap rate extremely low. This ability not only helps us to take in large orders with short time frames, but it also enables us to achieve the desired deadline, all while increasing Covert's bottom line."

"Quality is a given these days," says Covert. "The question is, who can deliver parts on time and still make money? Our investment in reliable, accurate, fast machines, combined with our years of manufacturing experience, allows us to achieve the low scrap rates and turnaround necessary to fulfill these large contracts at a profit," says Covert. "Our customers want bigger parts, larger quantities, and more capabilities from their suppliers."

"We're planning on expanding this location to add more equipment, allowing for continued diversification, meeting this demand and growing with our customers," explains Covert. "But the core of our business is high-volume, large-part production. The fact is, low scrap rates and reliable equipment, combined with our whole family of manufacturing experts, are propelling the growth of Covert Manufacturing."   

 

This article was first published in the March 2009 edition of Manufacturing Engineering magazine.


Published Date : 3/1/2009

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