Heating principle of electric heating wire for EPS cutting line

On the EPS cutting line, the heating principle of the electric heating wire is achieved by passing an electric current through a conductive metal wire (usually a nickel-chromium alloy wire). When the current passes through this metal wire, the metal wire will heat up due to the effect of resistance. This heat energy is then transferred to the EPS foam material, causing it to melt and form the desired cutting shape. The following are some key points of the working of the electric heating wire on the EPS cutting line:

1. **Heating principle**: The electric heating wire generates heat through the thermal effect of the current. When the current passes through a conductive metal wire with a certain resistance, the metal wire will heat up due to the resistance. This heat is enough to melt the EPS foam material, thereby achieving cutting.

2. **Temperature control**: During the EPS cutting process, it is crucial to control the temperature of the heating wire. The temperature must be high enough to melt the EPS material, but not too high to damage the material or affect the cutting quality. Some advanced EPS cutting lines use transformers and constant current and constant voltage regulators to detect the breakage of the heating wire, ensuring safety and quick replacement.

3. **Thermoelectric mechanical model**: A novel thermoelectric mechanical model has been proposed to simulate the hot wire cutting process of EPS foam. The model predicts wire temperature, voltage, and stress during the EPS foam cutting process. The model predicts process parameters such as temperature, slit width, longitudinal stress, and displacement by solving three semi-coupled nonlinear differential equations (heat diffusion equation, electric diffusion equation, and static equilibrium equation).

4. **Experimental study**: In the modeling of EPS cutting, it is a challenge to describe the time-varying slit width as a function of other cutting process parameters. Due to the complexity of the heat transfer processes involved, including conductive, convective, and radiative heat transfer, as well as the melting and evaporation of EPS, there is currently no modeling tool that can deeply study this process.

5. **Effect of cutting angle**: The experiment also studied the case of hot wire cutting of EPS at a certain angle to the horizontal direction. The experiment aims to investigate whether gravity has an effect on the slit width. The results show that the slit width is affected by the cutting angle, and the change in slit width shows a specific trend for the two wire diameters used at a given constant cutting speed.

6. **Parameter Optimization**: Through experiments and modeling, it was found that process parameters such as temperature, energy generated by electrical heating, voltage distribution in the wire, stress, strain and kerf width are crucial to understanding the behavior of the cutting tool and its impact on material removal.

Through the application of these principles and models, EPS cutting wires can efficiently and safely cut foam materials to create precise geometries to meet the needs of rapid prototyping and manufacturing.