Syringebot: Mostly 3D printed chemical synthesis robot

This tech spec was submitted by Dhanalakshmi Vadivel as part of the University Technology Exposure Program.

Problem / Solution

Small to medium-sized laboratories worldwide waste hours of labor manually performing repetitive procedures that could be easily automated. Although commercial laboratory automation technologies are available, they are still difficult to use because of the high cost and inflexibility of their functions. These machines are closed-source, which makes it difficult to do customizations and often requires a specialized operator to execute them.

The Syringebot is an automated liquid handling robot that can be used to perform organic chemistry synthesis. This device can control up to six syringes, a temperature-controlled chemical reactor, and modules for pH and redox electrodes.

Design

The Syringebot comprises a chassis, six syringe units, a valve block for each syringe, motherboard, RC servos board, and a hotplate surface. On the other hand, the CPU comprises Raspberry Pi 3 and power supplies for steeper motors (12V) and RC servos (5V). Additional modules include a pH/electrode surface and a load cell interface.

The Syringebot is a module that handles the movement of disposable syringes for the dosage of reagents. The robot is equipped with two types of Luer Lock syringes: 60 ml and 10 ml. These supports can be easily modified for other syringe sizes. Each syringe installed on the robot has a valve block composed of 2 three-way motorized valves connected in series to direct the flow of reactants and solvents. Stepper motors control the syringes while RC servos control the valves.

The Syringebot can control up to six syringes using a motherboard for 3D printers. It has two end-stop switches. The end-stop switches are exploited using a board with two end-stops (min and max) for each axis. Two additional pins for each syringe. Two additional pins are used for each syringe to control the two three-way valves to direct the liquid flow. The motherboard has two inputs for connecting the thermocouples directly. It is controlled by a microcontroller Raspberry Pi 3 with the control software written in Python. The components are designed using OpenSCAD. This ensures quick readjustment to different hardware components (e.g., syringes with other volumes or different valves/RC servos) as the main design parameters are indicated with variables