January 2008 Edition

CUTTING TOOLS

No Second Chances

Getting it right the first time is the imperative for a mold-making company that beats off-shore competition

"Try and try again" is not a manufacturing philosophy that works at Mar-Lee Mold Co., Leominster, MA. It has to get the job right the first time.

Mar-Lee Mold makes core and cavity molds for high-end, one-off customers. Single-unit jobs require Mar-Lee use the right end mill the first time so it can make molds with minimal hand labor. Like other moldmakers, it is moving toward zero-stock machining, which requires the correct tooling, machine tool, and software to produce cores and cavities without extra stock. The goal is to eliminate manual labor operations such as hand-finishing, polishing, and fitting, while reducing cycle time and improving accuracy and surface finish.

"We don't have room for trial and error, so it's critical that key components of the CNC machining process work together," Mark Lavoie, Mar-Lee purchasing manager, said.

Mar-Lee Mold, one of three Mar-Lee Companies in the Leominster area, was founded in 1972 and employs 32 people at its 20,000 ft² facility.

Leominster was once dubbed Pioneer Plastics City due to the number of factories in the plastics industry within its borders. While plastics work has since slowed in Leominster, it still continues.

Mar-Lee Mold designs and manufactures complex, high-precision injection molds for the plastics industry. Located nearby with a combined employee total of about 48 are Mar-Lee Packaging & Consumer Products, specializing in high-volume, quality products, and Mar-Lee Medical, which manufactures low-volume, complex, high-precision components and sub-assemblies for the medical device, single-use, and bio-absorbable markets.

Long-lasting Reputation

Mar-Lee built its reputation on quality, complex, long-lasting tools in niche markets. About 60 percent of the molds Mar-Lee produces are used by its consumer and medical divisions to develop components and products. Forty percent of Mar-Lee's molds are sent to outside contract manufacturers.

Mar-Lee Mold began operations with an EDM machine. In 1972, a moldmaker that had an EDM machine was considered a pioneer. The company added a CNC milling machine in the early 1980s and turned to high-speed machining circa 1998.

High-speed machining presented opportunities and challenges for mold makers in the late 1990s. Since feeds and speeds were different for high-speed machining versus conventional CNC machining, different end mills were needed. Mar-Lee began its high-speed machining operations on graphite material and then broadened its capabilities to include steel. Milling steel was a challenge.

"We put our first Okuma high-speed machining center on the floor in 1998 with the promise of increased productivity and the potential to broaden our mold-making capabilities," Lavoie said. "However, we needed end mills that would be effective for our high-speed applications."

It was not just a matter of broadening capabilities, it was also a matter of survival.

"For Mar-Lee to remain competitive in a shrinking mold-making market, we needed the best automation to produce high-end, custom products efficiently and profitably. In order to continue manufacturing in the United States, we needed to create efficiencies wherever possible," John Gravelle, Mar-Lee Companies president, said.

About the same time Mar-Lee started using high-speed machining, it invited several end mill manufacturers, including Emuge Corp., West Boylston, MA, to provide tools that would meet the mold-making company's needs. Lavoie said at first he examined and tried a variety of end mills, but none met the company's needs. Then, Emuge came in with a "mystery" kit that contained end mills that met Mar-Lee's needs.

Something Different This Way Comes

"We knew they had something different, something that we needed. We've never seen tools with geometry and coatings like those," Lavoie said. "It was clear they knew their stuff. Only Emuge understood our requirements and had the right solutions. When I consider end mills it is not based just on cost. Longevity and performance of the tools is more important. Ultimately, the proof is in the application – it has to be able to run."

Emuge offers a line of milling tools designed for performance in a range of materials and machining applications. For example, Emuge S-Hard Cut End Mills are capable of hard machining material as hard as 66 R_C. Emuge carbide end mills feature flute geometry, coatings, and designs for specific applications.

Much of Mar-Lee's injection mold involves short runs in hard material on high-speed machines. The Emuge end mills provide 30 to 40 percent more tool life than others Mar-Lee tried.

Time Reducer

"During the process of a cycle, from tool holder to machine to the end mill, there is a notable – up to 50 percent – cycle time reduction using Emuge end mills," Lavoie said.

For example, a high-volume manufacturer of baby wipe containers that shipped 60 million units relied on Mar-Lee to produce an eight-cavity mold for this product with in-mold labeling – IML – which creates company identification in the mold itself so the product manufacturer need not add a label or graphics. Mar-Lee was able to implement the IML process because it had the tooling and automation to perform the operation.

Gravelle said when a company is manufacturing millions of pieces, it must work with suppliers that use dependable automation. High-volume manufacturers cannot afford an interruption in their supply. He said Mar-Lee was able to win the IML job, beating Chinese competition, by producing a quality product at a competitive price.

Lights-out Capabilities

The Emuge end mills helped reduce labor costs by letting one operator tend to three automated work cells, conducting several hours of unattended operation.

"My machine runs all night, working materials with hardnesses of 48 R_C to 56 R_C. By morning the cutter is still good," Scott Hastings, CNC machinist at Mar-Lee, said. "We can't do that with other end mills because we would have to set up four tools and break up the tool program. Retooling wastes time and money."

"When I need to take a few tenths off a mold, an Emuge end mill will do it to tolerance. It consistently removes those tenths without wear."

In one run, Mar-Lee milled four cavities, with the dimensions dead-on consistent.

Using a 6-flute end mill instead of a 4-flute mill, the company achieves molds with a mirror-like finish.

Machinists at Mar-Lee report that Emuge end mills last about twice as long as expected. When a machinist is done using an end mill for a high-speed application, the tool is then used for traditional machining applications, such as on a Bridgeport. Emuge Corp.

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