The Great Ear Loop Dilemma
The most common complaint we get (and thankfully we don’t get many) is that the ear loop has come loose and the made in USA face mask you cherish is now useless. You can always try to staple it back together or glue it back on but it isn’t usually worth the effort and can be frustrating to deal with. This seems to be a rampant problem for all mask manufacturers and I want to explore some of the reasons behind it and the things that we do to try to prevent it.
The first place to start is how the ear loops are applied to the mask, which is via ultrasonic welding. While I could write many pages on the topic, the long and short is that waves of energy are sent through a metal “horn” which gets trapped between the horn and a metal roller or hammer. This generates a lot of disruptive energy which essentially scrambles the fibers of polypropylene and polyester together and forces them to integrate. What results is an amalgamation of mask and ear loop material that sticks together without the need for adhesive. This method of integration is commonly used in many different applications to join plastics and is the primary way in which masks are made.
Now that you understand the basics of how they get attached it’s time to explore what goes wrong. The primary issue that occurs is that the integration does not occur in the right amount. Commonly (and in a lot of overseas masks) the ear loop material is too dense for the amount of ultrasonic vibrations being applied to it and it does not bond with the mask enough. This is easy to see by how much of the ear loop is still distinctly visible at the mask attachment point and usually results in them coming off easily if they are moved in the direction of the mask. They will also pop off when too much tension is applied since not enough of the materials are integrated together. The other end of the spectrum is when too much ultrasonic vibration is applied the materials become too integrated. What this results in is a weld that is more brittle and causes the entire welded area to break off from the mask. This issue can also cause the weld mark to be so brittle that it is somewhat sharp and can scratch your face or be uncomfortable to wear. We first encountered this when we switched to a loose weave ear loop and the first batch of masks made could not keep their ear loops on due to the material being so integrated that it had weakened the fibers at the attachment point.
The second major issue that occurs with ear loop attachment is in regards to how well the ear loop is cut. If you are not aware, we run our machines at 80 - 100 masks per minute, meaning the scissors have to cut ear loop material 1000s of times per hour. We know generally how long it takes for them to dull but no system is perfect and sometimes the scissors aren’t cutting through the material cleanly and we don’t catch it right away. What this causes is the end of the ear loops become frayed and when they are applied to the mask the fibers are more spread out making the weld weaker. This will result in the ear loops coming off if too much tension is applied and can ruin a batch of masks if care is not taken. The other problem this causes is the direction of the “tail” of the ear loop when it is getting welded. A less than sharp scissor will make the grabber tear a number of the fibers that weren’t cleanly cut resulting in a deflection of the ear loop back towards the scissors. What this causes is the ear loop to not be properly aligned with the hammer as it comes down on the welder resulting in a partial weld that does not hold the ear loop on adequately.
Many other things can affect the quality of an ear loop weld such as a loose welding hammer, a badly calibrated welder control box, or an inconsistency in the density of the ear loop. Therefore, there are many reasons why it may happen and we do our best to diligently test our masks but occasionally defects will get through. We want you to have a quality product you can be confident in and if for any reason your ear loops are not up to snuff please reach out to us and we are happy to send you a replacement