The length of the spinneret of the melt blown die head varies from 300mm, 600mm, 1.2m, 1.6m, or even more than 3m, the pore size is usually 0.1mm ~ 0.3mm, and there are more than 300 to thousands of small holes on each spinneret.

 

At present, the drilling process of spinneret is basically drilling and laser processing. These processing methods may cause burr or rough surface in the small hole. In the continuous flow jet, it may cause blockage, or affect the melt jet flow rate and form crystallization, and the service life is also very low. Therefore, these holes must be polished before the spinneret is used.

 

So, what method is used to polish these micropores? Of course, manual polishing is unrealistic. One hole is polished for 2-3 minutes, and 200 holes? A worker can't throw out a spinneret a day. For porous polishing such as spinneret, the polishing method commonly used at present is abrasive flow grinding.

 

Abrasive flow polishing porous workpiece: use soft abrasive (abrasive particle size is extremely small, abrasive is in semi fluid state), after extrusion, directly enter the inner hole of the workpiece, and then flow out. Such repeated circulation flow plays the role of grinding and polishing. After polishing the spinneret, the inner hole can achieve the mirror effect. Even if it is porous, it is polished at one time. A 600mm spinneret can be polished in only ten minutes. Because there are many small holes on the melt jet wire plate, and the hole diameter is small.

 

Therefore, the polishing of melt jet spinneret must use microporous special fluid grinding equipment and diamond soft abrasive with smaller particle size. Let's look at the process diagram of abrasive fluid polishing of spinneret.

 

At present, there seem to be many factories that can make melt blown die heads in China, which is why ordinary masks can be easily bought. However, there are few N95 masks on the market. This is because there are few companies that can make 0.1-0.15mm aperture melt blown die head. The micropore aperture of other mask meltblown die heads is generally 0.2-0.3mm, which seems to have a small gap, but the processing difficulty and polishing difficulty are very different!