Manufacturing Processes - Hot & Cold Isostatic Pressing
Isostatic Pressing Processes
There are many different ways in which a product can be manufactured, but most designers probably know only a handful of techniques in any detail.
In Sintering Theory and Practice, leading researcher and materials engineer Randall M. German presents a comprehensive treatment of this subject that will be of great use to manufacturers and scientists alike.
This updated volume is intended as a reference text on the technology of hot and cold isostatic pressing together with applications for development of new materials.
Isostatic pressing is a powder processing process that falls in the category of forming under the general category of manufacturing processes.
There are 2 types of isostatic pressing processes:
- Hot isostatic pressing (HIP), where components are loaded into a furnace and then placed in a pressure vessel so that heat and pressure can be applied simultaneously .
- Cold isostatic pressing (CIP), where powder is sealed in a flexible mould and is then subjected to a uniform hydrostatic pressure without heating.
Hot isostatic pressing (HIP) is used, as indicated, to press and sinter simultaneously in an inert atmosphere (usually using Argon gas). The powder in the hot isostatic pressing process has to be protected from the atmosphere so that oxide films can be avoided. Hot pressing needs the powder to be heated, pressurised and cooled in the protective atmosphere.
Cold isostatic pressing is used to produce green compacts which typically will require further processing stages.
Both processes are expensive from an operating cost perspective but HIP should be considered a very expensive option, the need for a protective environment and the slow cycle time of the process leads to inevitable cost implications. On the positive side there is 100% materials utilisation and the process is reasonably flexible.
The finished products can be produced in solid 3D shapes, mostly utilising metal or ceramic composites, and have relatively low or no porosity. There can be some distortion when producing high aspect ratio components.
One method of producing a finished component using HIP is to fill a formed container with powder, after which the container is evacuated of all gas and is sealed. The container is then placed inside a furnace inside the pressure chamber and the isostatic pressure (utilising an inert gas) and heat is applied.The component using this method takes the shape of the container.
An alternative method is to subject pre-formed components to temperature and pressure as a finishing process that sinters the powder to higher density components.
Note: Isostatic pressure is pressure that is applied from all directions simultaneously.
The process because of the operational costs is normally reserved for the production of high value components that can bear the associated production costs.
Hot Isostatic Pressure Process
Isostatic Pressure Processes - Additional Resources
- Manufacturing Processes and Methods Process
The selection of a manufacturing process is done very much on the basis of a manufacturer choosing the process that best suits his needs. Consideration must be given to a number of factors before deciding on a...
- Materials Selection versus Manufacturing Process
Material selections can determine what manufacturing processes are available, form can determine what materials can be used and manufacturing processes can determine what form can be created. So what you...
- Manufacturing Processes - Vacuum Forming
The vacuum forming process comes under the general manufacturing processes category of forming. The process involves producing components that are formed by heat softening plastic sheet and forcing it against...
- Manufacturing Processes - Blow Moulding
The blow moulding process fits in the general manufacturing processes category of 'forming'. A heat softened hollow plastic blank, sometimes referred to as a 'parison' is clamped between two mould halves. Air...
- Manufacturing Processes - Sheet Metal Forming
The sheet metal forming process comes under the category of forming as a manufacturing process. There are a number of sheet metal forming methods available which all consist of some form of deformation of the...
- Manufacturing Processes - Forging
The metal forging process comes under the category of forming as a manufacturing process. It involves the forming or shaping of bulk metal between dies which mirror the shape of the component or section of a...
- Manufacturing Processes - Extrusion Process
Extrusion fits under the general category of forming in manufacturing processes. The term applies to a variety of processes that involve confining a material in a container and applying a force to push the...
- Manufacturing Processes - Superplastic Forming
Superplastic forming as the name suggests falls in the manufacturing processes category of forming. The process works under closely controlled conditions of temperature and strain rates which allow certain...
- Manfacturing Processes - Rolling And Metal Forming
Metal rolling is manufacturing process that falls under the general category of forming. It facilitates the continuous forming of bulk metal between two rotating roller tools. It is a 2 dimensional process...
- Manufacturing Processes - Pressing and Sintering
Pressing and sintering is a powder processing process that falls in the general category of forming under the manufacturing processes umbrella.The powder is pressed in closed dies to form a green compact that...