Upon placing the beakers above the magnetic stirrer to test out the stirring mechanism, we realised the space between the bottom of the beakers and the magnets were too close. This resulted in magnets being attracted to some stirrers in certain beakers, impeding the stirring motion. Additionally, this problem was further exacerbated by the fact that the entire base of the beakers were not consistent in height from the magnets. Hence, for those stir bars that managed to stir, the stirring was inconsistent. 

Hence, we printed a new beaker holder where it is slightly elevated to increase the gap between the bottom of the beakers and the magnets. We also improvised by adding additional rectangular holes beside each existing beaker hole to hold the beaker in a more consistent manner so the bases of the beakers are at the same height from the magnets. 

Before and after diagram of the beaker holder

After experimenting with the new beaker holder, all the magnetic stir bars in the 6 beakers managed to stir more consistently. However, it must be noted that the stirring may not be consistent all the time. This is still attributed to the fact that there are minor manufacturing differences in the dimensions of each beaker so there are very minor variations in the position of each beaker from the magnets, which occasionally affects the magnetic field for stirring.