Precise peen marking ensures high-performance assembly: high-speed marking is the answer to low volume production of high-performance engines

Modern Applications News, June, 2004

The ability to function as a stand-along, programmable peen-marking system of the Richter UniGrav[TM] by Columbia Marking Tools (Harrison Twp., MI) was the solution The Ford Motor Company needed for critical marking of components for its new 500-hp Ford GT DOHC engine.

The special marking machine, designed and built by Columbia, peen-marks numbers on the cylinder head camshaft bearing caps to correspond with those of the matching cylinder head position. These are critical marks to ensure that quality and proper assembly sequence are maintained. Improper assembly of bearing caps can ultimately cause an engine to seize up.

The machine is built with a heavy-duty, welded, all-steel, free-standing base to which is mounted a steel plate table with a mechanical, 180[degrees] rotating turntable fixture that locates and presents the marking surface of the cylinder heads to the peen marker. The Unigrav peen marker is attached to a gantry framework, bolted to the table. This framework supports the X-Y-Z axis movement and the stylus head of the unit. The marker control unit is also mounted to the machine base. Palm buttons mounted to the top plate surface provide for safe actuation of the marker.

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Automatic Marking

In operation, the aluminum heads are manually loaded onto the rotating fixture plate over locators that fit into holes on the bottom of the cylinder head. The fixture is locked in place, and the marking head is actuated to automatically peen mark the six numbers on the bearing cap exterior surfaces. After marking one side, the cylinder head is rotated and the sequence is performed again on the opposite side. A sensor positioned at the back of the fixture ensures the proper side, and the right numbering sequence of the cylinder head is made. Because the Unigrav unit has programmable Z-axis capability, the variations in the distance configuration of the bearing cap bosses can easily be accommodated, according to a company spokesperson.

For this application, the Unigrav unit is designed for X-axis travel of 500mm and Y-axis travel of 100mm. The machine requires a 1/4-inch NPT shop-air line and 110 VAC power supply.

The peen marking head movement is controlled by an X-Y axis slide arrangement that is driven through precise linear ballscrews that are bellows protected. The versatility of the system design permits the user either a quiet-running, servo motor drive that provides high-speed marking capability up to 10 characters per second with 0.005mm positioning accuracy, or a high-performance stepper motor drive that gives 0.02mm repeatability at five characters per second. The cylinder head marking system marks each cylinder head, on both sides, in 24 seconds.

The UniGrav system comes complete with a keyboard and controller that features user-friendly prompts for navigation thru programming. The controller is not needed for operation after setup.

The standard unit interfaces with existing Windows[R] 95, 98 or NT systems, using the included SIGNUMERIC software. This software allows the user to create the required marking program. Data entered by the keyboard can be viewed and edited on the LCD display before a marking is performed. The text can be fixed or variable; numbering can be sequential; date coding can be set up to be automatic, and character size can vary in 0.1 mm steps. Columbia Marking Tools

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