Whether its precision machining in New York City, attaining eco-friendly status, or making about-face decisions during the great recession, Linda Tool defies the norm. Founded in 1952, today the 28-person shop, knitted into the Red Hook section of Brooklyn, is a quiet, inconspicuous building at the curb. But once inside, there is a hum of precision in the making from the packed shop floor’s state-of-the art equipment that ranges from 3, 4 and 5-axis machining centers, to multi-tasking lathes, CMM’s and more, for handling a steady flow of aerospace and defense, industrial, medical, oil and gas and communications work. What’s literally above the shop is even more interesting – the entire rooftop consists of a garden where employees grow vegetables and flowers in engineered soil. Linda Tool strives to have a small carbon footprint. All machines are equipped with mist collectors, an HVAC system with HEPA filtration runs around the clock, the green roof enables heating and cooling energy reductions, and all waste is recycled.
Perhaps the most important element of Linda Tool’s unconventional approach is the production process itself, which starts at the end, not the beginning. “A key facet of the new strategy we deployed in 2008 was to first carefully determine the finished part, and then map out every step throughout the shop that is required to ensure the part meets or exceeds spec,” explained Holmes.“ It begins when we decide to make the part and every step in the process throughout the whole shop is documented, saving time and maximizing quality and throughput. We work in teams, applying a manufacturing process approach.”
The process approach is what led to Linda’s search for a solution to successfully machine 7075 aluminum landing gear forgings. “When a big aerospace opportunity came our way – a horseshoe-shaped planar part with tight pocketed inside corners, we tried to figure out a way to efficiently machine the part by face cutting, swarf milling or using a ball nose end mill,” said Holmes. “We had invested in leading 5-axis technology with a Hermle C22 machining center, the best machine for the part, but we weren’t sure how to attack it. We needed a more practical solution for maximum throughput and efficiency. "We were evaluating the advanced CAM software package called hyperMILL® from OPEN MIND Technologies AG, and focused on the hyperMILL® MAXX Machining features, which was highly recommended, and learned that one of it’s innovative programming features was the ability to dramatically drive increased material removal rates via conical barrel cutters – also known as circle-segment end mills.” OPEN MIND developed the concept of conical barrel cutter machining with tapered tools that also have a large radius ground into the taper. Ultimately, the software combined with the end mills, shaves off up to 90% of the time it takes to machine conventionally with ball nose tools.
The Emuge Circle Segment end mills feature a conical form ground into the cutter blank which is further shaped with an extra large radius. The large radius in contact with the material dramatically reduces the number of stepovers required, because much wider paths can be made in each tool pass, removing more material per tool path on planar surfaces, ruled surfaces and inside pockets.
“We worked closely with Emuge and OPEN MIND to program the part and make test cuts” said Holmes. “We wanted a highly efficient, stable process and it fully worked. We were very pleased.”