How N95 masks are made
Respirators are welded rather than sewn, because a needle hole is a way through the mask.
- stations
- 8
- things upstream
- 16
- raw sources
- 7
- steps from the ground
- 5
The short version
An N95 is a stack of nonwovens, with a charged melt-blown filter sandwiched between spunbond layers. Cup styles are pressed between mating mold halves, and folded styles run through ultrasonic welders that fuse layers, cut contours and attach straps without a single needle hole. A bendable nose band and straps complete the seal against the face, and NIOSH approves the finished design.
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Melt-blow the filter web
Melted polypropylene is pushed through a die with many tiny holes while hot air stretches the strands into extremely fine fibers. They land on a belt as a web, which is wound onto rolls. The filter layer usually carries a charge.
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Spin the outer layers
Outer layers are spunbond polypropylene, spun and laid straight into a web in one continuous process. Melt-blown fabric is fine but weak, so tougher spunbond supports it.
Goes in -
Stack the rolls
Roll-fed fabric enters an automated line with the filter between the outer layers. Counts vary: many respirators use three layers, and one German FFP2 design, comparable to an N95, uses four with a moisture-absorbing fleece against the skin.
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Weld the layers
Ultrasonic welders fuse the stack and cut its contours. A needle and thread can leave a path through the mask, and welding avoids that. The embossed marks on a finished respirator are the welds, running around the rim and holding the nose piece.
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Mold or fold the shape
Cup-shaped respirators are formed between male and female mold halves. Many use a stiff shell layer laminated to the filter, while one patent describes a single-layer web stiff enough alone. Flat-fold designs are folded and cut to their finished shape after welding.
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Add the nose band
A soft strip of aluminum or polypropylene runs across the nose. The wearer bends it to the face, which cuts leakage past the welded edge.
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Attach the straps
Welders fix head straps or loops, or punch reinforced holes for elastic bands. On the German line, two of each machine's four welding stations do only this, fixing left and right loops at once in under a quarter of a second.
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Inspect and certify
Finished respirators leave the line for inspection before packing. To carry the N95 name, a design must be approved by NIOSH as filtering at least 95 percent of airborne particles of 0.3 micrometers.
Worth repeating
- N95 means non-resistant to oil, and filtering at least 95 percent of airborne particles of 0.3 micrometers.
- Under US law, nobody may call a respirator N95 unless NIOSH has approved it, since the term is a trademark held by the federal health department.
- A single German respirator maker expected to turn out 3.5 to 4 million FFP2 masks a week once all its new machines were running.
Back to the ground
Follow every input upstream and n95 mask starts as these 7 raw sources.
Keep walking
Sources
- Univent Medical Finds Better Ultrasonic Welds Boost Respirator Quality And Yield, Textile World
- PPE Manufacturing and Welding Solutions, Branson (Emerson)
- US7905973B2, Molded monocomponent monolayer respirator
- N95 respirator
- Nonwoven fabric
Cite this page: "How N95 masks are made." Assembly Line, 2026-11-03. https://assemblyline.org/make/n95-mask