Manufacturing of Sintered Filters – All About Sintering

How to manufacture a sintered porous metal fiber filter?

A sintered porous metal fiber filter can be prepared by following steps:

1. A cylindrical mold is placed vertically with its open end facing upward.
2. Liquid and fibers are pushed into the mold. The fibers can be of stainless steel, nickel, thallium, titanium, aluminum, tungsten, copper, metal oxides, or ceramic materials.
3. A pressure differential is created in the mold to expel the liquid. The applied pressure makes it fiber cohesive. The cohesive fiber coheres to form a substantially tube-shaped structure.
4. The extruded tube-shaped structure is removed from the mold and sintered to obtain a porous sintered metal fiber filter element having one end and another end.
5. Finally, densification of both ends of the filter is done.

For more information, refer to this patent.

How to manufacture a sintered metal mesh filter?

A metal mesh filter can be made by the following steps:

1. Metal wires are weaved to make a mesh. The metal wires can be made from iron, copper, nickel, chromium, cobalt, aluminum, titanium, zinc and zirconium or by combining multiple ones of these metal elements.
2. Then the mesh is stacked such that the mesh number increases from one side to another. The layer count in the stack is kept between 2 to 5.
3. The layers are then put in a vacuum furnace for 10-30 hrs and sintered at 900-1500°C.
4. After cooling down, a metal composite layer made of metal powders with a mesh number of 100-600 with a thickness of 0.1-0.5 mm is made by electrostatic spraying.
5. The metal composite layer is sintered together with the multilayer metal mesh at 900-1500°C.
6. After cooling down, a composite filter sheet and tube made of a multilayer metal mesh and metal powders with the multilayer metal mesh as a supporting layer and sintered metal powders as a filtering layer is obtained.

For more information, refer to this patent.

How to make ceramic filters for engine exhausts?

Ceramic filter for a engine exhaust contains a porous segment and a gas channel.

The porous segment is formed by sintering a ceramic-impregnated fiber web sheet under heat. The fiber web sheets are heated in such a way that fibers are burned off and the ceramic material is sintered together to form the continuously porous and gas-permeable filter segment between its two opposing surfaces, also the fiber web sheet are corrugated to form gas channels.

The sintered and corrugated fiber web sheets are superimposed and then rolled to form a monolithic ceramic filter body.

For more information, refer to this patent.

How to make a submicron sintered plastic filter?

A sintered porous plastic filter has a porous membrane attached to a sintered polymeric material.

The membrane can be made of polyvinylidene fluoride (PVDF), nylon, polysulfone, polyethersulfone (PES), polyacrylonitrile and cellulose based material such as cellulose acetate and nitrocellulose membranes. The membrane is made using a phase inversion, a dry evaporation or a thermally induced phase separation method.

The sintered porous polymeric material is made of bicomponent fibers. The filter can have plastic particles as a base. Optionally, elastomeric particles can also be added. Binding agents such as solvents, adhesives and curable prepolymers are added optionally to enhance the mechanical properties.

For more information, refer to this patent.

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