# Report Writing 1

Control of 3D printer nozzle temperature

The hot end of a 3D printer can be seen in the schematic in Figure 1. The nozzle is heated using a heating element, while a thermocouple is used to record the temperature. The hot end uses two cooling fans: the hot end fan and the layer cooling fan, where the blue lines indicate cold air and red lines indicate hot air. A controller is used to maintain the temperature at a constant 200°C.

Figure 1: Schematic of 3D printer hot end

For the system shown in Figure 1, the layer cooling fan suddenly turns on and the thermocouple temperature drops to 190°C.

Part 1: Using a block diagram, sketch out the interactions between the controller, process, and sensor. Define the following:

1. Set point

2. Process variable

3. Control variable

4. Disturbance

5. Error

Part 2:

Figure 2: Schematic showing heating cycle of hot end

(Figure 2 shows a schematic of the thermocouple data as the 3D printer hot end is heated from roomtemperature to 200°C). CHECK ATTACHED FILE FOR FIGURE

As the temperature hits 200°C, it overshoots to 205°C before returning to a relatively steady of 200°C +/- 1°C. The system uses a PID controller, where the values are set at:

• Kp = 21.33

• Ki = 1.13

• Kd =98.22

Questions:

• For the system above, explain why the thermocouple overshoots?

• Sketch the expected temperature time profile (i.e. the graph in Fig. 2) from room temperature to 200°C for the following 3 scenarios:

1. Kp is halved, the other two values are unchanged

2. Ki is doubled, the other two values are unchanged

3. Kd is halved, the other two values are unchanged

• If a full PID controller was not available, which controller would be more suitable for the system described in figure 2: PI or PD. Explain your answer.

Concernant l'employeur :
( 0 commentaires ) Pune, India

Nº du projet : #32238365