Superplastic Forming Equipment Information
Superplastic forming equipment produces complex shapes in a high-temperature process which elongates and deforms a metal blank. Superplastic alloys exhibit extremely high ductility at elevated temperatures and can be stretched several times their initial length without breaking. Superplastic forming (SPF) is a multi-step process that uses a hot-forming press and an inert, pressurized gas such as argon. First, a metal blank is loaded in a die between two platens. The press then heats the blank and die to temperatures as high as 1000 degrees Celsius. When the superplastic temperature is achieved, the inert gas inflates the blank to fit the die. This produces a part which conforms to the die’s smallest details. In some cases, superplastic forming is followed by diffusion bonding (SPF-DB), a solid-state joining process that holds pre-machined components under load at elevated temperatures in a protective atmosphere or vacuum. Often, superplastic forming equipment that performs diffusion bonding is used with aerospace applications.
Specifications for superplastic forming equipment describe the press and platens, heating system, gas control system, and hydraulic system. Press specifications include electrical power, maximum tonnage, physical size, maximum daylight opening, mounting style, insulation type, and cooling method. The platens for superplastic forming equipment are usually made of ceramic materials and powered by an electrical heater with multiple zones. Heating system specifications include heating rate, temperature range, and control accuracy. Number of gas lines, inlet pressure, vacuum pressure, forming pressure, and percentage accuracy describe the gas control system. The hydraulic system for superplastic forming equipment has two main parts: the power unit and the ram. Motor speed, pressure, flow, and fluid type are important power unit parameters. Force, stroke, open/close rate and pressing rate describe the ram.
Superplastic forming equipment can be interfaced to host computer and may include a programmable logic controller (PLC), temperature controller, computer numeric control (CNC), and digital display. Data logging is also available. SPF equipment that communicates with a PLC can be networked to other manufacturing systems in order to transmit data such as hydraulic load pressure, gas flow and pressure, and temperature. Typically, the host computer serves as an operate interface terminal. Communication standards for temperature controllers include RS232, a common serial interface.