Kurt supplies automated workholding fixtures

Kurt Manufacturing is in the process of delivering USD250,000 in automated custom workholding fixtures to a tier one automotive manufacturer.

The initial order calls for 10 custom workholding fixtures to be integrated with robot arms into existing automated transfer lines.

A second follow-on order is underway.

The newly equipped transfer lines will precision machine an automotive bearing housing.

The machining consists of two mating pieces produced from 10 x 8 x 5in cast iron and requires a flatness tolerance of 15 micron across the mating surface.

Jeff Lenz, business unit manager of Kurt Engineered Systems, said: 'The need for consistent quality along with increased production levels was the driver behind this order.

'The customer's existing machining fixtures were not capable of clamping the parts without distorting them.

'Problems occurred when the assembly distorted the bearings, causing abnormal operating noise and premature wear.

'These problems were compounded as ramped-up production was planned, requiring faster machining-centre output,' he added.

Kurt designed two clamping fixtures for each machining centre, which were integrated with a robotic arm for automation.

This allows for automated loading of the cast-iron part, machining on all four sides, and automated unloading and stacking of the finish machined parts.

After the part is placed in the fixture by the robot, the fixture's preload feature centres and clamps the part securely.

Pressure and proximities sensors communicate wirelessly with the robot and machining centre so that the entire cycle is made without the need for connecting cables and other devices.

The Kurt fixture design is also said to provide better tool access to parts during machining through the use of a pass-through 'window'.

This allows cutting tools to machine on both sides of the fixtured parts at increased turning speeds, reducing cycle time to 90 seconds.

The accuracy of Kurt's system was said to be a major upgrade over the customer's old workholding devices, which were limited to a 30-micron tolerance.

By comparison, the Kurt fixtures can hold parts flat to under 12 micron while maintaining a 1.67Cpk level.

According to Kurt, production output will also be increased using the automated workholding fixtures.

Presently, 1,800 assemblies are processed per day; with Kurt's systems added to additional transfer lines, 4,500 units are to be manufactured in an eight-hour shift.

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