1000 Masks per day.
Today we finally reached our milestone of cutting 1000 mask kits in a single day. This would not have been possible without the support of the community and local businesses. We received over 700 yards of fabric in donations, enough to keep us running for another few weeks. Thank you for your support! We would not be able to keep going without you.
In this post we describe our production process, in hopes that it will inspire others to help produce face masks. There are a lot of laser cutters in maker spaces and universities, that can be rallied to the cause.
We produce several mask designs, and most can be found in the mask patterns section. When starting with a new design you will likely encounter a PDF document meant to be printed and used as a template for manual cutting. By loading the PDF in inkscape you will be able to pull the design while maintaining the pattern scale.
Next create a document which matches your laser cutter work area. If the fabric you are cutting is narrower then the laser table, create a document based on the fabric instead. Keep in mind that fabric is quite hard to work with, so leave yourself 0.5 inch margin on each side to help deal with misalignment. We heard from folks that do this for a living that 80% occupancy is common with fabric patterns. Luckily, mask patterns pieces are quite small, so they are easy to arrange. Another thing to remember is that most masks apart from the pleated ones require two pieces of fabric that are mirror images of each other. Depending on how many layers of fabric your laser cutter can handle you may need to have the same number of mirrored pieces.
Once you fill your document, you will end up with something that looks like this:
Before you start the next step you need to make sure your laser bed is level. This is likely the largest work that has been processed on your machine. In our case our working area is 46x34 inches, and we had to work very hard to make sure we got consistent focus across the entire laser table. You will also need to figure out how many layers you can cut in a single run. We were surprised to find that even though we had no problem cutting 0.5 inch acrylic plate, we had a hard time making it through more then 12 layers of woven cotton at a time. Finally, cotton is extremely flammable, take every safety precaution and never leave your cutter unattended in the middle of a job.
First, make sure your fabric is 100 percent cotton. We were fooled by one of the rolls until it entered the cutter, the smell quickly gave the material composition away. A quick test is burning a sample of material with a lighter and checking for the smell of burned plastic. Make sure you do that outside. You may want to wash your fabric prior to laser cutting. While woven cotton does not shrink a whole lot, some rolls have protective waxes that are meant to come off during the first wash.
Once your fabric is ready to cut, place it on a large flat surface. If you are an optical engineer, please look away because we found this optical table is awesome for processing fabric. We promise we will clean all the lint off of it once the pandemic is over. Marking the desired length with a piece of tape (or in our case a 1/4 20 bolt) helps guide your cuts and makes cutting a lot more manageable.
Once you cut the desired number of sheets, its time to stack the fabric. This is a lot harder then it looks, but an iron set to hot will make short work of unruly wrinkles. Some fabric is much nicer to work with then others, but if you are patient and precise in this step, it will make the rest of the process a lot easier. We found that we can cut and stack 10 layers of fabric in the time that it takes the laser cutter to finish the previous batch. The name of the game here is efficiency, every minute that the laser cutter is idle translated into about 5 masks we did not produce. If your fabric has a pattern, try alternating the sides of the fabric you are placing down. Your sewers will thank you, since two pieces they pull off will be mirror images of each other.
Next, comes the most difficult part, transferring the fabric stack to the cutting table. Unlike materials we are used to processing, fabric has a mind of its own. Just getting it transported from the prep station to the laser cutter requires meticulous coordination. Bring a friend.
Laser Cutting the Fabric.
Once the fabric stack is on the table, you need to figure out a way to secure it. We found that the little magnets that hold the iMac screen in place are perfect for the job. If you start with the magnet in the middle of the table and run in to the edge, you can get rig of the wrinkles incurred in transport. We also tried to pull out the cutting table between jobs, but it was too time consuming. Whatever you do, try to keep the fabric as flat as possible.
We found that 2 passes at 80% power and 80% speed gave us consistent results. Our laser is on a larger size for a university maker space, so make sure you test to figure out the best configuration. To make matters worse, no two rolls of fabric we processed were the same, and some required a third pass to finish off the bottom layers. With 10 layers of fabric we were able to produce 90 mask kits in about 15 minutes, which translated into 11 runs to achieve the 1000 masks. Once the fabric is cut stack the cut shapes making sure to keep track of the different pieces. In the case of the Fu mask all pieces are identical, and if you layered your fabric correctly each stack of cut pieces will have interleaved mirror patterns.
Assembling Kits and Sterilization.
There are a few ways to approach this. Due to the asymptomatic nature of COVID-19 you can never be sure if you are sick, so its important to treat yourself as infected. We have been bagging our kits in zip-locks and placing them into a laboratory oven for 30 minutes at 70C. Once the kits leave the oven we treat the contents as sterile, making sure that the next person who opens them is the sewing volunteer. It is likely possible to wash the fabric as well.
Stay safe and happy cutting!
-Your friends at AlohaMask