Primary Filtration & Membrane Support Materials

Our expanded metal foils and polymers improve the performance of filters, particularly in industries where resistance to high temperatures or caustic materials is essential — including semiconductors, chemicals, and pharmaceuticals.

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American filtration & separations society
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Expanded Materials For Superior Filter Designs

Filtration and separation are key criteria for industries that produce semiconductors, process chemicals, and pharmaceuticals, or systems that control gas or liquids. Dexmet custom manufactures MicroGrid® and PFOA-free PolyGrid® materials in a multitude of open area configurations with controlled pore sizes to provide more consistent particle removal, flow rates, and pressure drops for your filtration application. 

Expanded MicroGrid® can be used for either primary filtration applications to protect critical downstream components or as internal cores to support the filtration media. Typically, expanded metals are used for these applications because they require strength and operate at higher pressures.

cartridge filter-1

Expanded PolyGrid® materials are used primarily as membrane support materials on the upstream and downstream of the membrane. Expanded polymers can be used as a primary filter but typically for lower pressure air or gas applications.

Dexmet produces PFOA-Free PolyGrid® expanded Fluoropolymers. PFOA (Perfluorooctanoic Acid), widely used as a polymerization surfactant in making fluoropolymers including PTFE, PFA, and FEP, has fallen under scrutiny by the EPA and FDA for its potential toxicity and widespread presence in the environment and human population. Utilizing Dexmet's fluoropolymers will ensure that your application meets any new EPA or FDA requirements while being safe to the environment.

PolyGrid® High Performance Polymers

Dexmet custom manufactures PolyGrid® high performance materials from fluoropolymers and thermoplastics with controlled pore sizes to provide proper particle removal with more consistent flow rates and pressure drops for your filter application.

Dexmet Expanded High Temperature PEEK material


Excellent membrane support, primarily used for separation and backing materials in pleated filtration designs


Pore size starting at 75 microns (.003”) with base material thickness down to .025 mm (.001”). Widths to 610 mm (24”)

Support Materials For Pleated Membranes

Filters that are designed to remove fine particulate (less than 0.1 mm) frequently employ non-woven filter media that requires mechanical support within the filter body. The support must provide adequate strength while not significantly reducing the flow of the fluid to be filtered.

  • Assured Media Integrity & Pleat Spacing Even Under Dynamic Flow
  • Increased Filter Surface Area for Pleated Designs (Capability to Expand Thinner Materials to Achieve a Reduced Overall Thickness)
  • Materials Laminate for Contraction, Co-Expansion, and Flex with Filter Membranes (Material Compatibility with Membranes)


Common Polymers

Dexmet specializes in offering expanded fluoropolymers and thermoplastic materials that are often difficult to obtain in either extruded or woven product. 

Specialized fluoropolymers include:


High-performance thermoplastics include:

PEEK, Polysulfone

Performance Features:

  • Ultra-thin for better pleat density & Increased surface area
  • Material thickness down to 50 microns (.002")
  • Pore sizes down to 100 microns (.004")
  • 750+ openings/sqcm (4,800+ openings/sqin)

Design Considerations

Filtration Rating:

Particulate passage is controlled by the opening size or “pore” diameter of the media and is designated by a Micron rating. The opening configuration (pore) might be diamond-shaped (expanded), square (woven wire), or round (perforated). Designate the opening according to the particle size required to be separated out of the flow path.


Flow backpressure results from the “percent open area” and the degree of particulate build-up on the media surface. Choose a material that will more than withstand the full pressure drop across a blocked surface area.

Filter Strength:

Ultimate strength is controlled by material selection, thickness, percent open area and pore geometry. Multiple layers of filter material with varied openings can improve flow, purification, and withstand higher backpressure.

PolyGrid Filtration Membrane Support

PolyGrid® Expanded Polymers for Membrane Support

For information on the advantages and characteristics of PolyGrid Filtration Media and Membrane Support materials, download this free data sheet.

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MicroGrid® Filtration Materials

MicroGrid® precision expanded materials used for primary filtration or internal core applications can be manufactured from a variety of metals, thicknesses and opening sizes to ensure strength, particle removal and media compatibility

Expanded PolyGrid for Filters

Primary Filters & Internal Support Cores

Dexmet expanded metals are used in filters as both filter media (for coarse particles) and internal support cores for fine filter media (especially non-woven fabrics). Dexmet can provide a wide variety of metals and geometries to exacting specifications. With so many materials and configurations, Dexmet has the right material to maximize filter efficiency and usable life, while reducing internal corrosion and other failure modes.

Filters (or pre-filters) that are designed to remove large particulates (over 0.5 mm in diameter) must be made to withstand impact stresses as well as fluid pressure. “Open” (expanded, perforated or woven wire) metal foils are frequently used for this function because they can be easily formed for the specific application.

Common Materials

Stainless Steel, Aluminum, Nickel Alloys, & Carbon Steel (FE).

Dexmet has the capability to expand all ductile metals.


  • Economical Option to Alternative Materials
  • Uniform Material: One Piece Homogenous Design (Assures media integrity under dynamic flow conditions)
  • Engineered Pore Sizes to Achieve Flow, Pressure Drop, and Collapse Pressure Requirements


  • Pore Size Starting at 25 Microns (.001”)
  • Base Material Thickness Down to .025mm (.001”)
  • 1300+ Openings/cm²
  • Widths to 1200 mm (48”)

MicroGrid Expanded Metal Foils for Primary Filter Media Support

For information on the advantages and characteristics of MicroGrid® primary filtration media and internal core support materials, download this free data sheet.

Talk to a Dexmet Expert

Let us help you optimize your filtration system design. Contact one of our experts and start the conversation!