Tag Archives | Shot Peening

Shot peening is a cold working process used to produce a compressive residual stress layer and modify mechanical properties of metals. It entails impacting a surface with shot (round metallic, glass, or ceramic particles) with force.

Boeing Saves Money By Using System Integrator to Retrofit Existing Shot Peener Machines

The inconsistency in machinery controls created operation and maintenance inefficiencies at two Boeing plants in the state of Washington. With a control system upgrade, they were able to make the aging machines work like new — or possibly better — at a fraction of the cost of purchasing new machines.

The shot peener machines in Boeing’s Auburn and Frederickson plants were between 20 and 40 years old, and based on different, aging control technologies and hardware. Some machines used hardwired relay logic, while others had older Programmable Logic Controls (PLCs) and Computer Numerical Controls (CNCs). The inconsistency in machinery controls created operation and maintenance inefficiencies. Parts were becoming obsolete, and maintenance was becoming more expensive. Reliability was an issue. Managers knew that an upgrade was in order.

The aging equipment in question, seven shot peener machines, is used to form and contour the wings and also to harden the wing surfaces of 737, 777, and 767 aircraft. The process involves blasting the aluminum part at high speed with metal shot of different sizes depending on the operation. Larger shot diameters (as large as 0.54 inch) are used for forming and smaller diameters (as small as .028 inch) are used for cold working (i.e., surface hardening). The specialized shot peener machines are quite sizable. The Spanwise Peener machine is 3 1/2 stories high — large enough to fit the wing skin of a 747 aircraft. Continue Reading →

Control Upgrades Give Peening Machines a Shot in the Arm

Boeing has learned first-hand how a control-system upgrade can make an old machine work like new, at a fraction of the cost of purchasing a new machine. Case in point: recent refurbishing of four shot-peening machines at the Boeing Fabrication Division plant in Auburn, WA. The Boeing fabrication shop uses spanwise peening machines for contouring wing components, and compression peening machines for cold working. Early in 2011, plant managers decided to upgrade the machines’ controls, which ranged from 20 to 40 years old. Some used relay logic and some were CNC-based. Parts had become obsolete, and maintenance had become overly expensive.

The plant’s managers sought new controls that were more process-oriented, and simple-to-use human-machine interfaces (HMIs) standardized with operator controls used at other Boeing plants. To help with the upgrades, Boeing turned to Concept Systems Inc. Albany, OR, and its engineer Jim Ford, who proposed replacing the old CNCs with Allen-Bradley PLCs. In addition, he recommended Allen-Bradley Panel View terminals to provide the graphics displays. The old DC servos were replaced with smaller AC servomotors and new gearboxes were installed to upgrade the mechanical aspects of the machine. Continue Reading →