Aircraft housing assembly machined from bar with the Hwacheon HT-200
Matt Petersen, Vice President - Chief Customer Officer, G&Z
G&Z Industries, Inc., Wheeling, IL, was founded in 1958 in Chicago, IL. Today, the 40-man machine shop specializes in high-precision aerospace and military work, offering value-added services for its prime defense contractors and commercial customers.
"Many parts that we manufacture are shipped on a `dock-to-stock' program," said Matt Petersen, Vice President - Chief Customer Officer, G&Z. "By removing costly receiving and/or in-process inspections, the customer saves time and money with every delivery. In order to do that, we need machines that we can rely on to produce high-quality parts in minimum time."
G&Z operates in a 20,000 sq. ft. facility with 23 CNC machines, mostly mills. The entire manufacturing area is equipped with a closed loop temperature and humidity controlled climate environment to ensure product quality.
To help it handle some significant aerospace turning work, G&Z in 2014 purchased a Hwacheon Hi-TECH 200A MC CNC lathe. The machine features an 8" chuck with a maximum cutting diameter of more than 12". Hwacheon HT-200 lathes are designed for heightened turning center performance and feature a large work capacity and enhanced spindle horsepower.
"We needed more capacity plus live tooling to help us handle the work more efficiently with fewer set-ups," said Petersen. "Previously we had to take this job to the milling department for secondary work, which led to long production cycles for this part.
"We have had a lot of success with the two older Hwacheon turning machines we have - low maintenance cost, strongly built and they always hold tolerance. We reached out again to Hwacheon because we knew the machine would perform reliably over the long term."
G&Z ordered a Hwacheon HT 200 with a C-axis, which it put to good use recently on a two-piece aluminum housing used in the Boeing 787. The C-axis turn-mill option allows for a milling operation after turning. The C-axis uses a high-performance gearbox unit with a 5 HP servomotor with minimum feed increment of 0.001°.
To ensure that the base machine has the best possible foundation, the uni-body bed material is high quality, Meehanite process cast iron, which has shock absorbing characteristics to withstand the forces of heavy-duty machining and the stability to handle fine work precisely.
The precision-ground 5,000 RPM, 15 HP spindle is supported by a rigid headstock with grease-sealed, double-row cylindrical bearings, and angular-contact bearings at the front and double-row cylindrical bearings at the rear, thus keeping heat generation to a minimum. Spindle power is provided by a brushless, variable-speed AC motor, which is both energy efficient and maintenance free.
A versatile drum-type tool turret is servo indexed in just 0.15 seconds and hydraulically clamped, permitting quick and precise cutting-light- or heavy-duty. The quick indexing speed and bi-directional tool selection, by the shortest path, minimizes non-cutting time. A quick indexing servo-type 10-station turret features indexing time of just 0.15 seconds. Rapid feed (X/Z) is 1,200 IPM.
Two inserts and five live tools are used to produce the two parts of the 787 housing assembly, which start out as 12' aluminum bars. The bar is sawed into pieces that can then be chucked. "The center of the workpiece is machined away to leave a thin wall turned to within 0.002 in. We hold the turned part with plugs and sleeves to keep the wall from moving during machining," Petersen said. "We follow the turning operations with a short milling pass on one of the parts with the C-axis.
"The rigidity of the Hwacheon machine allowed us to run faster feeds and speeds on these parts and opened the door to a tooling upgrade resulting in fewer set-ups-one less set-up per part," he continued. "With this new capability we went from a 64 minute cycle time to 28 minutes on the main piece and on the cover from 45 minutes to 20 minutes, despite one operator intervention to insert the plug and sleeve."
The bottom line? "What used to take us 10 weeks to do a 650-part lot size, we can now do in four weeks. With this process, we easily keep up with the variability in demand for the parts," Petersen said. The Hwacheon HT 200 typically usually runs full time-two shifts-week in and week out.
"Previously we had run the parts on a 5-axis multitasking machine, which was more capability than this part required and which actually complicated the process without reducing cycle times," Petersen said.
A fully capable CNC shop, G&Z utilizes sophisticated, high-tech, state-of-the-art solid model software for generating both CNC machine codes and CMM inspection programs. G&Z capabilities include designing castings, brazed components and assemblies that satisfy engineering requirements that provide its customers significant cost saving.
For more information contact:
G & Z Industries, Inc.
541 Chaddick Drive
Wheeling, IL 60090
847-215-2300
www.gzind.com
Hwacheon Machinery America
555 Bond St.
Lincolnshire, IL 60069
847-573-0100
www.hwacheon.com