Inspection Detail

Inspection: 300870953 - Ducommun Aerostructures Inc

Inspection Information - Office: Los Angeles District Office

Investigation Summary

At approximately 10:30 a.m. on April 16, 2010, Employee #1 was setting up a shim in a hydraulic stretch press machine. Employee #1 was placing a 5.5 inch by 11 inch metal shim under the hold downs next to a 72 inch wide aluminum sheet that was approximately 10 feet in length. The machine was a Sheridan Gray L 1,000 ton hydraulic hold down brake used for stretching sheets of stainless steel or aluminum to create fuselage skins for airplanes and helicopter blades. It had 14 separate jaw segments that comprised the top die. Each segment had an individual pneumatic control that was operated by a gate valve. When the end of the metal sheet was placed into the machine, the operators manually placed the valves in the closed position for the segments that would not be in use, as determined by the width of the metal sheet. The operators then would place a shim of equivalent thickness as the work piece under the unused segments so as to keep the die level. The operators then manually released the corresponding gate valve to lower the top section onto the shim to hold it in place. The hold down pressure of each segment was reportedly up to 6,000 psi. Two operators placed the shims, one at each end of the machine at both ends of the metal sheet. When all the shims were in place and the hold-downs have been placed over the shims, the employees move away from the brakes and would be in full view of the Control Operator. An alarm would sound and the actual stretching process would begin. The remaining segments were lowered by the main controls and the two press brakes, which were on rails, would then pull the metal sheet to stretch it over a die to create a convex shape. The die was located between the two presses. Employee #1 was injured when he inadvertently placed his left hand on the press, while with his right hand, he manually released the air pressure on a segment to hold down a shim he had placed. Employee #1 did not realize that his fingers were in the path of the lowering segment. Employee #1's fingers were crushed, resulting in multiple fractures and amputations of his left third, fourth and fifth fingers when his hand was caught in the press. Employee #1 immediately closed the valve and reopened the segment to free his left hand.

Keywords: FRACTURE, AMPUTATED, FINGER, AUTOMATIC MACHINE, CRUSHED, HAND, PRESS, UNGUARDED