Two core parts of mask machine：“Magic board and stick''

The most important material of the medical mask is the melt blown cloth, and the most important part of the melt blown cloth production equipment is the melt blown die head, which can also be called multi row hole melt blown spinneret. Because it looks like a board, we call it the ''magic board''. When the melt passes through the die head spinneret, under the draft of the high temperature air flow, it forms the ultra-fine fiber, which is bonded by the fiber itself and forms the fiber net on the screen curtain, which is often referred to as the melt blown filter Cloth.

Material and specification of melt blown die head:

Material: preferred pre hard wear-resistant mirror mold steel

Specification: 300, 400, 600, 800, 1000, 1300, 1800, 2000, 3000mm, etc.

Technological process: Die roughing → Drilling → Fluid polishing → Assembly

Difficulties in processing of meltblown die head.

• Sus / Suh series stainless steel is superior to common die steel in strength, hardness and corrosion resistance; which is the first choice.

• The programming method adopts G83 peck drilling method to ensure the small hole chip removal.

• It is recommended to use high-speed machine tools for processing. Generally, the processing speed exceeds 20,000 rpm, and the spindle dynamic balance needs to be guaranteed.

• Due to a lot of rapid movement, there are high requirements for the servo performance and mechanical accuracy of the Z axis.

• The smaller the roundness of the tool, the better, and the runout of the tool system is close to 0.

• During the machining process, ensure the reasonable application of cutting fluid, chip removal, cooling, lubrication, and prevent sticking chips.

In addition, in the production process of mask, the most critical part is the welding of mask, which plays a decisive role in the filtering effect and sealing of mask. The key part of the welding is the "magic stick", which is called welding gear die and cutting die. It is mainly used to weld and cut the edge of the mask. The shape of ordinary mask is relatively simple, N95 and kn95 are relatively complex.

Tips: N95 masks are one of the NIOSH certified mask grades in the United States, while KN95 masks are actually the mask grades of our country. In addition, the two are not much different in other respects. The filtration rate of the two for non-oily particulate matter is ≥95%, all have better protection performance.

Common processing problems of gear die and cutting die.

• Overcut, asymmetric size.

• Breakpoint processing after tool break.

• Incorrect CAM programming processing parameters and process settings.

• Incorrect setting of rotation vector direction in post-processing.

• Low processing efficiency.

Solution

• Four axis parameter standardization and four axis PMC action optimization.

• Program restart.

• Reasonable process, simulation and simulation before processing.

• Reasonable post-processing.

• Reasonable cutting path and process plan.