Fiberglass cap filter for Low pressure casting gating block sprue

Fiberglass cap-style filter is woven with special high-twist & high-strength alkali-free fiberglass yarn, coated with special resin and produced by carbonizing by special high temperature. 

The maximum temperature resistance can reach 900 ℃.

Widely used in automobile and motorcycle wheels, cylinder pistons, aluminum rods, aluminum materials, aluminum ingots, aluminum plates and precision casting of all types of aluminum alloy casting.

Cap type fiberglass filter mesh is usually a network structure, which is a non-metallic liquid metal purification device with the required mesh opening. Its porosity is higher, the slag collection surface area is larger, and it can reduce the the Reynolds number of the mesh metal surface flowing through the cast filter, then it can make the filler be more stable and reduce the production of secondary oxidation slag in the mold.

The usage of cap type fiberglass filter mesh can:

● Effectively remove liquid metal and non-metallic inclusions, 

● Improve the structure and mechanical properties of castings, 

● Improve the high quality standards of precision castings production and reduce the rate of casting defects. 

● Reduce tool wear during machining and significantly improve efficiency. 

● Reduce porosity in the casting, reduce surface defects and reduce casting and filling lines, significantly increasing the process yield, which is much better than high silicon screen casting filters and cast filter products with straight holes.

For some castings that require high surface quality and good densification, in order to prevent inclusions and improve the internal quality of the castings, it is very necessary to install a cap type fiberglass filter mesh in the gate system. Especially in the field of small and medium-sized castings such as automobiles, high-speed railways, machine tools and hydraulic parts, the purification effect of the cap filter mesh has been widely recognized by most foundry workers.

Purification mechanism of cap type fiberglass filter mesh:

1. Since the cap fiberglass filter mesh is placed at the bottom of the gate of the sprue cup, runner or sand mold, the molten metal injected from the sprue cup into the cavity can stay momentarily while passing through the position. The slag can be the main small-density inclusions floating and separating from the molten metal. These inclusions also produce deep adsorption when they pass through regular or irregular grids. This phenomenon can continue to purify molten metal before the pouring cup is filled.

2. The role of surface filtration: Surface filtration is a common metal liquid purification function of all casting filters. When the molten metal passes through the casting filter, unfloated or floating inclusions with a relatively large surface area, such as molten slag, are captured by the surface of the casting filter. In addition, the captured inclusions will form a finer filter eye with the cast filter continue trapping subsequent inclusions, thus enhancing the filtration effect. However, at the same time of this surface filtration, with the decrease of the pouring temperature and the increase of the viscosity of the molten metal, as well as the extension of the pouring time, the cap filter mesh will be blocked to varying degrees, thus make filtering effect be worse.

So, the cap filter mesh should be replaced with a new one according to actual casting scenario to keep its best filtering effect.

Product performance of cap fiberglass filter mesh:

● The cap fiberglass filter mesh is made of high temperature resistant fiberglass by special process weaving and post-treatment. Products have become serialized, advanced technology, stable quality. Compared with other types of cap type filter, the lower cost, easy to use, does not change the composition of the casting, good slag filtration effect and small air volume have already attracted all clients from the world attention and choose.

● The cap fiberglass filter mesh cost is cheap, easy to use, it can improve the mechanical properties of castings without changing the metal composition, improve the production quality of castings. At the same time, it is resistant to high temperature and ablative properties, and it can operate at temperatures of about 850 degrees.