Joint effort puts productivity on the table

Sept. 1, 2003
Machine tool builder and worktable company exceed customer expectations.

Machine tool builder and worktable company exceed customer expectations.

By Charles Bates
senior editor

Twelve Kingsbury machining centers for a Tier I and II auto supplier sport special tables developed with Koma Precision.

Besides Koma Precision, Kingsbury worked with other suppliers, such as Siemens and GE Fanuc, to build its twin-spindle, 6-axis vertical machining centers.

Koma Precision units on the Kingsbury machines include two rotary tables on a trunnion and two fixed fixture-mounting surfaces 90° from the rotary tables.

Not just any worktables are on the 12 machining centers Kingsbury built for Hayes Lemmerz International Inc., a Tier I and II auto supplier in Montague, Mich. The machine tool OEM teamed up with Koma Precision, Warehouse Point, Conn., and developed a special twin-table, rotary-trunnion arrangement that further increases the productivity of the twinspindle machines from Kingsbury of Keene, N.H.

What is so special about the Koma units is that they house, in addition to two rotary tables on a trunion, two fixed fixture-mounting surfaces 90° from the rotary tables. These fixed surfaces hold the "A"-load and the rotary tables the "B"-load for a total of four parts.

The A-load fixturing is for partial machining, and the B-load rotary fixturing is for complex angle cutting. Once Hayes' suspension components (measuring about 10 3 10 3 5 in.) are complete and unloaded from B, the ones in A transfer to B, and two new ones load into A — so every cycle produces two complete parts.

Another beneficial aspect of the Koma unit is the result of Kingsbury's requirement to integrate the machining center's table into the Koma unit. "Typically, a rotary unit's base mounts to a machining center's T-slotted table," says Bill Meo, president of Koma. "This new design, which took a cooperative effort between Koma and Kingsbury engineers, increases accuracy and rigidity, while also reducing weight and cost."

The Koma tables rest on Kingsbury twin-spindle, 6-axis vertical machining centers. Although similar in principle to previous models, the new reconfigured versions include upgraded speeds, feeds, toolchange times, and spindles. "In less than 12 months, Kingsbury went from design to shipping product," says Brian Simonds, Kingsbury sales manager of metalcutting products and the program manager for the Hayes project.

Besides Koma, Kingsbury worked with other companies to get the best cycle times from the 12 Hayes machines. Two of those companies were GE Fanuc and Siemens.

According to Kingsbury controls engineers, the machine changes tools 16 times in one cycle. Reducing toolchange times and maintaining aggressive spindle acceleration/ deceleration required a powerful spindle drive-andmotor system.

The goal was to eliminate a full second in acceleration/ deceleration time. This doesn't seem like much, but multiplied by 16 3 translates to a substantial gain.

Everyone gains
Historically considered an expert builder of engineered rotary dial, transfer lines, and turning and machining centers, Kingsbury supplies complete turnkey manufacturing systems — including everything from initial process development to fixturing to final statistical measurement and analysis. The company evaluates a customer's volume requirements, production needs, parameters, and goals. It then decides on the best process, and the equipment involved is either made inhouse or comes from companies Kingsbury works with.

"While Kingsbury is a complete designer, manufacturer, and assembler of metalcutting and assembly systems, there is always a certain vender-content in any project we build," says Brian Simonds of Kingsbury. "That can include controls, ballscrews, and other such components."

Contracting outside suppliers is a project-by-project decision based on what Kingsbury can make itself. "If it's a fixture or critical detail, most likely we'll produce it ourselves. Generally, we try to keep the highaccuracy components in-house and under our own control," says Simonds.

Both Kingsbury and the companies it works with benefit. For instance, Koma Precision gained some good exposure from the Hayes rotary-table project.

"Our customer wasn't familiar with the Koma product," says Simonds, "but through Koma's relationship with Kingsbury and by meeting project specifications, the customer was more than satisfied." Being able to tour the Koma facility and meet with its design engineers also increased the customer's comfort level, he says.

Initially, Kingsbury was to use both a motor and drive from GE Fanuc, along with the company's controls. However, to pick up the 1 sec/toolchange timesavings, GE Fanuc and Siemens together packaged a workable solution that combined Siemens spindle motors and GE Fanuc amplifiers.

The Siemens 460-V IPM4 137 model motors are hollow shaft and liquid cooled. These hollow-shaft motors accommodate the hydraulics for a direct connection to the machines' tool drawbars.

All 12 machines sport GE Fanuc's new 16i MB CNC and HV series spindle-drive systems to handle the 460-V motors. Fanuc's new control has all the options needed for these specially designed machines, say Kingsbury engineers. These include 8-axis capability, a smaller overall package, and faster processing and servo update times. Also, Fanuc motors run the Koma rotary tables, so there are no interface problems with the CNC.