The Team met several times a week to brainstorm different methods for crushing pills. Methods deemed test worthy by the team ranged from emulating motions from crushers already on the market to exploring mechanism actions found in household kitchen utensils. Since the MET class of 2011 has required a particle size of .040” or smaller these methods had to be tested and scrutinized carefully. All crushing methods were tested and evaluated at the AMC (Advanced Manufacturing Center) right on campus.
The white board shown above was filled time and time again as new ideas and design improvements were conceive.
An action not commonly seen in market competition involves both linear and axial loading. To evaluate the feasibility of designing for both motions the Team crushed a series of pills by loading them with an arbor press while moving the anvil in a twisting fashion. The image above illustrates the method used.
Before the Team decided against using an external power source, a number of powered crushing methods were evaluated. The hammer drill depicted above proved to be very effective at crushing the pill but this methods size, weight, and sound, were determinedly not feasible to accommodate in the Team’s design.
Very early on in the brainstorming process “rolling” became very popular as a method to pursue. The Team developed a number of unique ways to utilize the rolling action. One avenue that was evaluated involved placing the pills inside a narrow plastic tube. The plastic tube was then loaded from the top and then rolled back in forth between an interface of two flat plates. Much the Team’s surprise the method proved to be difficult and was soon dismissed to more promising ideas.
Shown above, pills are placed on flat crushing anvil and a roller of large diameter was actuated over the top of it. The action of a smooth roller on a smooth anvil wasn’t very effective at grabbing and holding the pills still for the crushing process.
After near all of the Team’s methods were tested the methods that were the most effective got a second look. Shown above, the Team explored rollers of similar diameter but different surface geometry. A piece of welding rod was held over the roller to simulate a ridged interface surface. The sliding issue that was introduced in the first stage of testing was resolved but achieving a fine powder proved to be difficult.
Through creativity and innovative thinking the Team elected to try a roller of similar diameter with a coarse knurled surface. After a series of tests the Team unanimously chose to pursue the roller design. Crushing times in lab tests were short and the powder produced was consistently well within the .040” requirement.
As a group we came to the conclusion it would be better to find a way to mechanize the knurled roller for a couple different reasons. The first reason being that the baggies the pills are crushed in are cheaper, and the second reason being that the motion of the knurled roller is easier to create.