Workholding Slashes Setup Time; Increases Productivity

Production output has increased significantly from the eight vertical machining centers on the shop floor of Adaero Precision Components – a direct result of retrofitting each machine with the Visher & Bolli DockLock Zero-Point system distributed by Kurt Manufacturing Company.

Today's machine tools are very fast in terms of spindle speed, rapid traverse, cutting feedrate, and tool change. Productivity, however, is often restricted because components aren't presented to the cutting spindle quickly enough after the previous batch has been completed. With current trends toward ever-smaller lot sizes, the inability to set up quickly for the next part run impacts profitability.

"At Adaero Precision Components, we shorten spindle down time between part runs using the DockLock Zero-Point workholding system," reports Andy Dickinson, managing director. "This is one of the most cost effective systems on the market. On average, we cut 25% to 30% setup time on our eight 4-axis Chiron and Fanuc machining centers using the DockLock. The savings are huge because some of our runs call for just 10 to 20 parts with three to four part changeovers per day. We save around a half hour for each setup."

The Lean Initiative

Founded in 1988, Adaero Precision serves customers in the aerospace, medical, optical, and laser industries. It has doubled its volume in the last five years and expanded its facilities twice to handle the increased volume. However, increasing competition from Eastern European countries and India threatened to restrict this growth. This led the company in 2005 to investigate lean manufacturing methods, including the DockLock system, as a key tool for developing a lean initiative.

"Our original idea was to install one DockLock system on one machining center and spend some time evaluating it," reports Gary Raymont, works manager at Adaero Precision. "However, in the process of installing the first system, it became abundantly clear that the benefits were going to be so profound that there was no point delaying the installation of DockLock systems on most of our other machining centers as well. New initiatives like this can meet employee resistance, but that wasn't the case with the DockLock systems. Everyone, particularly the machine operators, championed the systems from the start."

Another benefit that Adaero Precision experienced with the DockLock introduction was the reduction in skilled setup time. Using DockLock for most setups, tedious, time-consuming setups are eliminated with a corresponding reduction in skill level required to do the setups.

Improved Profitability

Raymont also cites major improvement on certain small lots that, prior to DockLock, required two hours for setup with only a 25-minute run. "By implementing the DockLock, setup time for these jobs is reduced to one hour, with the removal and replacement of the fixture requiring less than a minute. The overall 50% savings in setup time enormously impacts the profitability on these jobs," Raymont says.

"In addition, the larger the part, the more difficult the setting up process," he explains. "Special fixtures for very large parts are difficult to accurately lock into position, which adds to machine downtime. This is true with angle plates, trunion fixtures, indexing heads, vises, and air chucks – all of which are changed frequently. DockLock solves the large part setup problems with these different holding devices."

Positioning Accuracy

Adaero Precision's machine operators like the DockLock because of its simplicity and ease of use. Top down design makes the fixture handling process effortless. With the DockLock, fixtures and workholding devices are fitted with centering plugs on their undersides. This allows precise and repeatable positioning of these devices to within a few microns in the DockLock receiving plate's collet locks, which are mounted on the machining center bed. If the component to be machined is especially large, a centering plug can be fixed directly into the part itself, allowing convenient five-sided machining. Each fixture or component is accurately located every time to µ0.0002", so the machining cycle can start quickly and the first-off component is usually within tolerance. Little or no scrapped parts are experienced with machining centers equipped with the DockLock system, according to the company.

For Adaero Precision, another advantage of the DockLock system is that jobs can be interchanged freely between the Fanuc and Chiron machining centers without additional setup requirements. There is no loss of production time if a machine goes down or a job needs to be moved to another machine. Similarly, if an incoming rush order requires intervening in a part run, only a small productivity loss results when breaking into a part run to fulfill the rush job.

Precision, Robust Design

The DockLock system operates by precisely integrating a receiving plate onto the machining center bed. A series of locking cylinders are arranged in a grid pattern over the plate, according to customer requirements – which, in the case of Adaero Precision's requirements, primarily involves plates with four locking cylinders (some two-, six- and eight-cylinder plates are also used in various combinations). Each cylinder is located at 250mm centers and generates 1.5 tons of holding pressure (DockLock systems with 3 tons of holding pressure are also available for heavier duty applications.)

For its machining setups, Adaero Precision employs a variety of fixturing devices including Kurt precision vises, angle plates, and indexing heads. Each is fitted with centering plugs that locate in the locking cylinders with µ0.0002" positioning accuracy. Hydraulic pressure locks up and releases these fixturing devices in the exact, desired position instantaneously with the flip of a switch.

"We're extremely pleased with the DockLock system and what it's done for our productivity," Dickinson says. "It is only by adopting lean manufacturing techniques made possible by innovative designs like the DockLock system that UK companies can compete with low-wage manufacturing economies. We calculate that our DockLock systems will pay for themselves in less than two years. As we get better at using them, changeover times continue to decrease. What can be better than that?"

Kurt Manufacturing Company
Minneapolis, MN
kurt.com

Adaero Precision Components
Crediton, Devon, UK
adaero.co.uk