Hot pressing is one of the fabrication techniques in which metals, alloys or ceramics powders are consolidated under simultaneous heat and pressure to form a monolithic component. This forming process is used to reduce the metals porosity and increase the density of many ceramics. It also improves the mechanical properties and workability of powder materials. This process is one of the most important processes used in powder metallurgy.

In this process, a suitable mold (typically steel or graphite) is designed, and the powder materials with desired chemical composition are prepared. Then, the powder is poured into the mold and placed inside the chamber. By applying heat and pressure simultaneously to the mold, the diffusion processes are activated. Depending on the applied pressure and temperature, different phenomena such as particles displacement, plastic deformation or creep can occur at the particles interface; these phenomena all contribute to the consolidation of particles.

In this process, because of applying a relatively uniform pressure in all directions, the final structure is without porosity and the component final properties are isotropic. Due to the application of high pressures (100 to 200 MPa), use of high strength alloys in fabrication of the device chamber is necessary. Furthermore, based on the powder type, the temperature varies from 900 to 1250 oC.

In this process, an induction system is typically used to create heat inside the mold which can increase the temperature up to 1500 oC in a time less than 90 seconds. It is noticeable that in this process all parameters such as pressure, temperature, time, component dimensions and density are controllable. The main parts of a hot pressing machine include vacuum and gas system, hydraulic system, induction heating system, water cooling system, monitoring and control system. The parts manufactured with this method include a wide range of materials. It is also possible to produce components with different dimensions; some of these are large parts used in the oil industry, turbine blades, and small parts used in machining tools and drilling.

Application

Fabrication of dense ceramic, metallic and composite components.

specification

Vacuum Hot pressing machine, supplied by manufacturer, provides the ability to fabricate dense components under high vacuum, temperature and pressure. Furthermore, development of new materials with certain special features such as amorphous phases, reduced materials gap, high strength and even specific changes in materials structure can be done. Details of technical specifications are presented in the following Table.
 


Advantager of using nanotechnology

Hot pressing technique is one of the main processes in manufacturing of ceramic, composite and even powder metallurgy components. In this forming method, by applying simultaneous heat and pressure, fabrication of high density parts is possible. Therefore, by using nanoscale objects, nanocomposite parts with high quality and high strength can be produced.


Manual and maintenance
 

• By closing the chamber door, the induction sensor operates and the vacuum pump turns on for a short time (10 seconds). Then chamber door is locked and system gets ready for operation.
• This device is equipped with a flexible high temperature thermocouple, which is calibrated from 0 to 1700 degrees and operates completely linear. To use this thermocouple, the operator should create a hole with 4 mm diameter inside the graphite mold and put the thermocouple there.
• For emergency situations, an emergency key is located at the right side of the operator. By pressing this button, except for the cooling system, the entire system stops.
• For more details on how to use the device, refer to the device catalog and user guide.

Safety and package
 

• The ambient temperature can change in the range of 4 to 40 °C.
• The ambient moisture and dust level should be normal.
• Device needs a space with an area of at least 30 square meters.
• The device required input power is three-phases, 380 V, 80 A. 
• A standard earth connecting is essential for the device.