Rigid Glasweve® Filters for Permanent Mould, Sand-Casting Improvement

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Foundries are finding they can save an average of 15 percent per filter when switching from a ceramic foam option to Pyrotek's innovative new filter design used in permanent mould and sand-casting processes.

Importantly, they don't sacrifice casting quality when they make the switch. In fact, casting quality can improve.

Aluminium foundries around the world have long trusted Pyrotek to develop innovative ways to improve their melting and casting processes and overall operational efficiency. For foundries that perform permanent mould casting and sand-casting processes today, the latest innovation from Pyrotek is the new patented Rigid Glasweve® (RGW) filtering technology.

RGWSPM1"While ceramic foam filters (CFF) have been a traditional filtration solution for sand and permanent mold casters, there are many difficulties associated with the product," says Jay Fritzke, Foundry Technical Manager for Pyrotek. "Problems like ceramic inclusions in the melt, CFF sticking to degassing rotors, furnace side walls, and floors, and reduced metal value for recycling can all be avoided with Rigid Glasweve."

RGW—for permanent mould casting and sand-casting processes—eliminates the difficulties foundries find with remelting gating, scrap from too much flow variation, the costs of separating filter pockets from gating, and eliminating ceramic inclusions from CFF snow from entering the casting. All are significant challenges presented by CFF. Pyrotek's RGW was engineered to address these challenges, along with others.

Remelt Gating Problem Free

RemeltingGating2Remelting gating efficiently within an existing recycle stream can save casting operations tens of thousands of dollars, and possibly more. Additionally, while several steps are required to remelt CFF gating, gating with RGW, by contrast, can simply be charged into the furnace without contaminating the metal.

RGW filters are less dense than molten aluminium, so they float to the top of the melt during remelting and don’t stick to the furnace walls or degassing rotors. They can be easily skimmed off the top of the melt with the dross.

"Our goal is to maximize our customers’ metal quality and improve their process," says Fritzke. "RGW filters simplify the remelting process."

Eliminate Snow, Reduce Scrap

RGW doesn’t contain any ceramic components, which break off of CFF filters and cause ceramic inclusions, also known as "snow," to enter the casting. In ScrapDiagram1machined castings, Pyrotek has found ceramic snow from CFF filters has resulted in foundries needing to scrap up to 0.7 percent of their castings.

Better Reliability and Repeatability

RGW eliminates the flow-rate variability that CFF can generate that leads to the production of mis-run and cold-shut casting scrap.


"Pouring time standard deviation can be reduced by up to 75 percent," says Fritzke. "This is giving our customers a much more consistent, reliable flow rate."

Along with greater pouring consistency, RGW can match current pouring flow rates foundries use with CFF.


Other process benefits foundries are seeing by replacing CFF with RGW include:

  • Far less floor space for storage - 1 pallet RGW versus 8 pallets CFF
  • Better filter fit and less metal bypass
  • Global expertise and technical support, including metal-quality testing
  • Proactive support including local sales engineer, stocking and services 

"We set out to develop for our customers a filter technology that would perfectly fit our customers' existing mould equipment, match their desired flow characteristics, and have automated placement capability, all while solving the process issues associated with CFF," says Andrew Carlson, Pyrotek Product Manager. "It's great to see aluminium foundries around the world benefitting from this innovative Pyrotek-invented product."

Posted in Article, Feature, New Product, Product Spotlight.

Tags: Aluminium, Filtration, Foundry.