How do engineers clean makeup brushes?

Envie is a makeup brush cleaning device which automatically washes, rinses, and dries multiple makeup brushes in just seven minutes, rather than hours spent laboring over a sink. Developed by a predominantly female team of Purdue University students, Envie was awarded 1st place among all capstone projects in Mechanical Engineering.



“There’s nothing else like it in the market,” said Dina Abdulaal, a graduating senior who was part of the team that created the prototype.  “It’s a high-end solution designed for professionals, like makeup artists and beauty salons.  A full set of makeup brushes consists of 10 to 20 brushes, and most people wash them by hand over a sink, which is very time-consuming and puts a lot of strain on your wrists!  Envie does it all for you, in a fraction of the time.”

The Envie machine consists of a hexagonal chamber, with a clean water tank on one side and a dirty water tank on the other.  The lid contains holders for six makeup brushes.  Once the brushes are loaded and the touchscreen controls activated, the main chamber fills with a small amount of water and cleaning solution. The brushes revolve through the water, as they independently rotate to maximize the cleaning motion.  A second cycle rinses the brushes, and a third dries them -- all without any user intervention.  Tedious hours of work are now accomplished automatically in seven minutes; and instead of a manual process that takes up to 99 gallons of water, Envie uses just 0.25 gallons.

“We’re really proud of the result,” said Abdulaal.  “It may be a prototype, but it’s a high-quality product.”

Know your customer

Senior Design (ME463) is the capstone class of Purdue’s Mechanical Engineering curriculum.  Students team up, and have one semester to create a prototype product, combining the knowledge they’ve gained over the past four years of classes.  And since most engineering students are men, very few cosmetics-related projects have emerged from the senior design class.

To Abdulaal, that presented an opportunity.  “I first thought of this idea when I was cleaning my own makeup brushes,” she said.  “It takes hours, and the drying time is even longer.  And apparently you’re supposed to do this every two weeks!”  She presented the idea to her team of fellow seniors -- Mina Mohsenian, Robbie Williams, Kevin Sanabria, Heya Kaakeh, and Emily Eifert -- many of whom had faced the same frustration.  They decided to create a device to automate the process, and aim it at the professional market.

First, the team surveyed potential customers to determine their needs.  “We did more than 100 surveys,” said Abdulaal, “and we also interviewed people at different beauty schools and salons.  We really wanted to understand our customers.  The most important things they requested were the ability to clean multiple brushes at a time; the washing and drying to happen all in one cycle; and the whole process to take less than an hour.  We eventually accomplished all these criteria in just seven minutes!”

Make it or break it

For the design process, the team tackled each requirement of the prototype individually.  “We spent a lot of time drawing on whiteboards,” said Abdulaal.  “We designed for each function, and then combined everything together.  It was a very collaborative process.”

They also collaborated on constructing the prototype.  They 3D-printed the makeup brush holders, and laser-cut the planetary gears that spun the brushes.  They laser-cut a plywood exterior, and painted it gray so the machine could visually blend in with any salon setting.  They built watertight acrylic tanks, as well as an acrylic tunnel to protect electronic components from water.  They also had to program the electronics for the touchscreen controls.  For the drying process, they purchased on off-the-shelf car heater, and built ductwork to channel the hot air into the washing chamber.

Abdulaal took particular pride in her role as procurement and project management.  “I had never done procurement before,” she said, “so it gave me a great opportunity to learn something new, and help keep us all on track!”

After a few frantic weeks of constructing the prototype, their first test did not go well.  “One of our pumps burnt out, which was pretty scary, as we were coming up to the deadline,” recalls Abdulaal.  “We were able to find another pump somewhere in the building, and fit it to the machine.  But eventually, it worked!”

To validate the cleanliness of the brushes, they used ImageJ, an open-source image processing program designed by the National Institutes of Health to assess scientific images.  They applied different quantities of makeup foundation to the brushes, ran them through Envie, and brushed them onto a sheet of paper.  The whiteness of the resulting photos showed experimentally that the machine had done the cleaning job quicker and better than cleaning by hand.

Award winning

The final step in Senior Design class involves presenting the prototype to a panel of industry judges.  For many students, this process can be just as intimidating as the design or construction phase.  As a predominantly female team, the Envie students had an extra hurdle to overcome.

“I was most nervous about not being able to find common ground with people that don’t have experience with makeup,” explains Abdulaal.  “But as we were presenting to the judges, they would tell us, ‘My daughter used to work at Sephora,’ or ‘My wife does this every weekend.’  So it really excited me that we could find common ground with the judges.”

In fact, the panel of judges were so impressed by Envie, that they unanimously awarded the team 1st place among all senior design projects that year, as part of the Malott Innovation Awards (a competition created by former Siemens CEO Thomas J. Malott to foster an innovation culture at Purdue).  Malott remarked afterwards, “They gave the best presentation I have observed over all of the years that we have had this program.  They defined the need, the size of the market (half of the world’s population!) and the pricing that they felt they could get for the product.  They could have used this presentation successfully with any set of investment bankers in the real world. Their ideas clearly could form the basis for a sound business.”

For Abdulaal, the award validated all the hard work she and her team put into Envie.  “I feel like I got the chance to go through the full cycle of product development,” she said.  “It was very exciting, and it’s definitely going to help me as I go into the working world.”

She also encourages others to think outside the box when it comes to engineering.  “Mechanical Engineering doesn’t just have to be bolts and gears,” she said.  “You can also build a machine like this.  You can do whatever you want with this degree.  If you’re thinking about it, I say go for it!”


Writer: Jared Pike,, 765-496-0374


Learn more about the other projects from the 2019 Malott Innovation Awards!