Flex Filter (Coffee Filter) Mask

This mask basically uses an open/twin frame design to trap the filtration media between the frames. In this way, many different types of filtration can be used if available (Fabric, Melt-Blown Polypropylene, or even standard 10 inch Coffee Filters). Additionally, excess filtration media can be trimmed and folded into the mask to act/aid as additional gasket material. It is very easily printed and requires no post-processing or trimming.

NOTE: that this mask is NOT intended to serve as an N95 replacement and has not been designed/tested to meet ANY specific filtration criteria.

Basic Design Criteria:

1. Readily available filtration material: Many of the existing designs require specially shaped or formed filtration material. Some filters are square, some are round. In order for the masks to function, the appropriate material, in the appropriate shape, had to be available. This mask is designed to use standard 10 inch pleated coffee filters which are readily available in large quantities and very cheap to produce and acquire.

2. Easily 3D printable: In order to help the public “maker” community come on line, I wanted a design that was easily printable. Generally, this means a relatively simple design which requires little or no post processing. Many of the masks which are publicly available require plastic supports (for overhangs) to be trimmed away or the mask to be heated, folded, reformed, and glued for fitment. Post-processing is not only time consuming, it also introduces human error. I wanted a design which could simply be removed from the 3D printer and ready to use.

3. Can be printed in a variety of materials: I wanted a design which could be printed with commonly available filament material. Generally, this means PLA, ABS, or PETG. Most “makers” or institutions who have a 3D printer will have several rolls of at least one of these filaments on hand.

4. Can be printed on a variety of 3D printers: Almost any 3D printer will be able to print with PLA, a smaller subset will be able to print with PETG (requiring a heated build surface), and an even smaller subset will be able to print with ABS (heated build surface and enclosed build volume). Additionally, the easier it is to print with a given material (PLA) the higher the success rate for the operator. While ABS is probably the best choice for this application, it is a little trickier to print with and there will be some printers (without an enclosed build area) and operators who may not be up to the task. This design can effectively be printed with whatever material can be used by a given printer and operator.

5. Can be easily sanitized: The filters are completely disposable and the type of material chosen for printing will dictate the means of sanitation for the frames. While ABS can generally be cleaned in a relatively hot dishwasher, PLA and PETG will likely require a hand wash and/or alcohol/chlorine/disinfectant rinse.