{"id":3638,"date":"2026-09-02T11:34:42","date_gmt":"2026-09-02T03:34:42","guid":{"rendered":"https:\/\/www.c-adtech.com\/?p=3638"},"modified":"2026-09-02T11:34:42","modified_gmt":"2026-09-02T03:34:42","slug":"how-do-i-choose-ceramic-foam-filter-ppi","status":"publish","type":"post","link":"https:\/\/www.c-adtech.com\/pt\/how-do-i-choose-ceramic-foam-filter-ppi\/","title":{"rendered":"Como devo escolher o PPI de um filtro de espuma cer\u00e2mica?"},"content":{"rendered":"

Choosing the correct ceramic foam filter PPI starts with the metal being filtered, the size and type of inclusions that must be removed, alloy cleanliness, pouring temperature, required flow rate, casting weight, filter dimensions, and the foundry process. In practical terms, a lower PPI ceramic foam filter has larger pores and usually provides higher metal-flow capacity with lower blockage risk, while a higher PPI filter has smaller pores and can capture finer inclusions but creates greater resistance to molten-metal flow. There is therefore no universally “best” PPI. We normally select the coarsest pore structure that can consistently achieve the required casting cleanliness, then confirm that choice through flow-capacity calculations and controlled foundry trials. Typical commercial grades include 10, 20, 30, 40, 50 and 60 PPI, although available specifications vary by ceramic composition and manufacturer. For many applications, roughly 10 to 30 PPI is associated with iron and steel filtration, while aluminum-alloy filtration commonly uses approximately 20 to 60 PPI. These ranges are starting points rather than fixed engineering rules.<\/p>\n

At AdTech, we regard PPI selection as a filtration-system decision rather than simply a filter purchasing decision. PPI tells us the nominal number of pores per linear inch, but it does not independently define filtration efficiency, permeability, pore-window size, thermal-shock resistance or metal capacity. Two filters marked “30 PPI” can behave differently because their ceramic chemistry, foam morphology, coating thickness, open porosity, pore-window distribution and manufacturing consistency differ. Engineers and buyers should therefore evaluate PPI together with filter material, filter area, thickness, casting process and measurable quality parameters.<\/p>\n

\"Filtro
Filtro de espuma cer\u00e2mica de alumina Adtech para fundi\u00e7\u00e3o de alum\u00ednio<\/a><\/figcaption><\/figure>\n

O que significa PPI num filtro de espuma cer\u00e2mica?<\/h2>\n

PPI means “pores per inch.” It is a commonly used description of the cellular structure of reticulated ceramic foam.<\/p>\n

Uma espuma de 10 PPI apresenta uma estrutura celular relativamente grossa. A 30 PPI<\/a> O produto apresenta uma estrutura mais fina, enquanto 50 ou 60 PPI correspondem a um grau nominal de poros ainda mais fino. O aumento do PPI reduz, em geral, as dimens\u00f5es caracter\u00edsticas das janelas de poros e aumenta a superf\u00edcie interna dispon\u00edvel para interagir com as inclus\u00f5es.<\/p>\n

Isto parece simples, mas o PPI n\u00e3o deve ser interpretado como uma abertura exata do crivo.<\/p>\n

Os filtros de espuma cer\u00e2mica s\u00e3o estruturas reticuladas tridimensionais, em vez de telas tecidas com aberturas quadradas uniformes. Os poros e as aberturas variam em forma e di\u00e2metro. O metal fundido percorre passagens sinuosas interligadas e, consequentemente, a filtra\u00e7\u00e3o depende de v\u00e1rios mecanismos, em vez de uma simples peneira\u00e7\u00e3o mec\u00e2nica.<\/p>\n

Esta distin\u00e7\u00e3o \u00e9 importante na hora de comparar fornecedores.<\/p>\n

A purchasing specification stating only “30 PPI ceramic foam filter” leaves several important properties undefined. Density, open porosity, permeability, ceramic composition and dimensional tolerances can all affect casting performance.<\/p>\n

Um PPI mais elevado significa um filtro de melhor qualidade?<\/h3>\n

N\u00e3o automaticamente.<\/p>\n

Um PPI mais elevado significa, normalmente, uma estrutura celular nominal mais fina. Isso n\u00e3o significa que todos os processos de fundi\u00e7\u00e3o beneficiem da escolha do valor mais elevado dispon\u00edvel.<\/p>\n

A transi\u00e7\u00e3o para uma estrutura mais refinada pode:<\/p>\n