AUTOMATED PIPETTE TIP PACKER v3.0
The automated pipette tip packer saves scientists from performing the tedious activity of packing disposable, plastic pipette tips into trays.
Disposable, plastic pipette tips are used by scientists on pipettors in the collection of biological media. These tips are supplied loose in bags and before they can be used they must be separated, packed into a tray and sterilised. Hand packing these trays is a time consuming task. So for my final year project at the University of Cape Town in 2012 I was challenged with automating the activity by designing and manufacturing a packing machine.
I designed and manufactured sub-systems to perform each of the main functions of the tip packer, and finally assembled the working prototype shown here.
Designing a Solution
Subsystems needed to be designed for the tip seperation, orientation and placement systems. Existing systems were integrated into the design for the tray positioning system (an XY table that moves the tray) and the control system (a microcontroller with input/output ports).
A scientist will place loose tips into the cylindrical hopper for sorting. The hopper base has a slot cut into it. As the hopper rotates tips fall into the slot. The separated tips drop out of the slot and are fed via a chute onto the orientation system.
Two offset rollers are geared to rotate in opposite directions. Tips feed onto the rollers facing in either direction. As the two rollers rotate, and the gap between them increases, the tips’ weight causes them to rotate and hang pointed end down.
When tips reach the end of the rollers they are detected by an infrared sensor. A signal is generated to open the gate and a single tip drops down the tip slide. Another sensor at the base of the slide signals for the gate to close.
Loose tips are feed into the packer which then separates them, orientates them all into the same direction, and finally packs them one-by-one into a tray so that they can then be sterilised.