Learning Lessons from Large Parts

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By Ed Robertson

The problem
Improve machining tolerances on large parts and maintain competitive edge.

The solution
Investment in new equipment: boring mill, traveling column mill and laser tracking inspection technology.

Big parts require big investments

Whether you’re talking cell phones or Mini Coopers, miniaturizing components while increasing impact and performance is a major trend in modern times. By comparison, stand back and take a good look at that aircraft on your next business trip or watch a stamping press and its tooling churn out side panels for a new F-150, and you realize large parts continue playing large roles in our lives.

Precision Boring Co., a contract manufacturer located in Clinton Township, MI, has large parts in its DNA. Established in 1937 on Detroit’s east side with a single Swiss SIP jig borer, Precision Boring and its sister company Manor Industries now occupy a 35,000 sq ft facility in Detroit’s northern suburbs and serve a diverse customer base of packaging, aerospace, automation, and automotive supplier companies as well as providing replacement parts for stamping presses.

Jerry Decker, who with his brother Rich form the third generation of brothers owning the business, describes the history of the company as ensuring that large tool and die components were mated together accurately. “In one way, we stay true to our roots by staying relevant to the customer, providing accurate, precision parts and assemblies,” he says. “Back then, we may have been lower on the food chain, basically processing what the customer wanted. Today, we interact much more with customer engineering staffs, seeking higher-precision large parts and ensuring tolerances can be held and the part actually machined. We qualify customers as carefully as customers qualify vendors.”

One of the biggest differences in machining large parts today is the ability to check the part more accurately, says sales manager Harry Smith, a 17-year veteran of the company. “Back then, you had to trust the machine, the setup, the fixturing, and the operator to hold tolerances,” he says. “We still use bore gauges and gauge blocks to check in-process work, but the laser tracker helps us step it up and provide that additional peace of mind for the customer.”

Smith relates a recent example of a customer requiring a machine base to be flat within 0.10 mm (0.004 in.) across 7.92 m (26 ft). “Modern equipment is the difference between being able to accurately check the part in process or doing it by feel as you go,” he says. 

Stamping out a business niche
Precision Boring has kept its customer base diverse by design, serving a wide range of customers across southern Ontario and the US Midwest. The company shares its large-capacity resources with a sister company Manor Industries that specializes in replacement parts for stamping presses. “If a company has a stamping press that came from GM, Ford, Fisher Body, Chrysler, or a major automotive stamping plant in Canada or the US, there’s a good chance that press has Manor parts on it,” says Neal Hamel, engineering manager at Manor. 

The service is a valuable one, because many large stamping-press manufacturers are no longer in business while many of their presses continue a long working life. 

In 2011, the company purchased a 3500 mm x 2000 mm Fermat WFT CNC
boring mill with tool changer and CNC rotary table, seen here.

Parts the company makes are gears, shafts, clutch and brake parts and housings, including castings and weldments that need replacing. But it’s a segment the company must keep a close eye on because such orders are usually one-offs with little room for mistakes.

Manor has a huge advantage making press parts since it always makes a fully dimensioned print of the part before manufacturing, often from a sample part commonly known as reverse engineering. Manor has reverse-engineered parts for more than 55 years and sees repeat orders for parts made decades ago. The wealth of information contained in these prints in its engineering library is another resource the company has to reverse-engineer with confidence beyond the normal techniques, such as measuring the existing part, obtaining specs on any mating parts and determining best fit. This often leads to more economical solutions on how best to fix the part or make a new one.

 “Many of our customers are now keeping track of how long replacement parts last.” Hamel says. “Our goal is for the new Manor part to outperform the worn part it’s replacing. When reverse engineering parts I have the advantage of seeing what areas of the part has failed or worn out; this gives me the opportunity to improve on the original design and materials. You have to understand the whole assembly, some parts are made to be “sacrificial”, so you don’t want to over-improve a $2,000 part, and cause a $10,000 part to prematurely wear out.” 

Keeping the core; attracting the new
With 40 employees, Precision Boring faces many of the same challenges of contract manufacturers across North America, how to keep its core group of employees while attracting new people to the business. “We cross-train and document our training processes as part of our ISO registration,” Decker replies. “We also keep upgrading our CNC programming, data processing, and quality inspection capabilities with 22 computers on the floor and in our offices compared to one in 1989.”

Decker and Smith also see Precision Boring’s diverse mix of parts manufacturing and upgraded equipment as means of keeping its employee base steady. “We like to call it the chance to combine old-school views with new-school tools,” Smith says. 

Technology investments
Co-owner Jim Decker continues to invest in the company and upgrade equipment to establish and keep a competitive edge. New in 2011 for the company were a 3500 mm x 2000 mm Fermat WFT CNC boring mill with tool changer and CNC rotary table, 3000 mm x 1000 mm swing Powermaster lathe, and Faro Ion Laser Tracker system and Inspection Expert software for first-article print detailing. The company also recently added an 8000 mm x 2500 mm FPT Ronin traveling column floor mill with 1500 mm ram and five axis positioning head. Besides new equipment, the company has invested in refurbishing older machine tools including Springfield vertical spindle grinding machines capable of grinding ODs and IDs on parts up to 1600.2 mm (63 in.) in diameter by 1219.2 mm (48 in.) tall and CNC retrofitting a large-capacity 2032 mm (80 in.) swing VTL. SMT

Ed Robertson, is a contributing editor and manufacturing journalist based in the Detroit, MI, area.

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