Plastic Working Tribology

Friction Characteristics of Plastic Processing

Plastic processing is the use of mechanical, thermal and chemical processing to form, change, reconstruct and manipulate plastic materials. Thus the friction characteristics of plastic processing are the physical behavior between forming plastic and the tools used in the plastic forming. Plastic Processing is the most common and crucial industrial process in todays consumer-driven society. It is an extremely powerful tool and one of the main reasons for the plastic revolution. This article will cover the main friction characteristics of plastic processing.

Friction plays a significant role in plastic processing as it determines how much of the plastic material is deformed and how deep the plastic deformation is. Friction is a result of the chemical and mechanical interactions between the plastic material and the tools used during the plastic processing. Specifically, when plastic is subjected to forces, material particles interact together and drive away from each other due to plastic deformation and the chemical and mechanical interactions between them. This interaction creates frictional forces acting against plastic deformation.

In terms of the friction force magnitude, plastic materials have a wide range of properties. This range is dependent on the type of plastic and the tools used for plastic forming. The most commonly used friction coefficient for plastic processing is between 0.3 and 0.6. Lower friction coefficient values indicate better plastic forming performance. It is thus important to optimize the friction coefficient used for plastic processing to get a successful end product.

The plastic materials surface thickness also has an impact on the friction characteristics. Generally thicker surfaces provide higher friction facts and result in less deformation. However, it is not always necessary to use thicker surfaces and this is dependent upon the application.

Part geometries of plastic components also impact the friction characteristics. Generally, the more intricate or complex the component geometry is, the higher the amount of friction will be. This is due to the increased complexity of the component surfaces and their interactions with one another.

In addition to these parameters, the temperature and surface treatments also have a strong influence on friction characteristics. Higher temperatures usually result in an increase of friction coefficient. This is due to the increase of fluidity at higher temperatures resulting it greater surface contact between the components. Furthermore, surface treatments such as lubrication, pre-heating and tensioning of the components can also help to reduce the coefficient of friction.

In short, friction characteristics of plastic processing play a very important role in the success of a plastic component. It is thus necessary to choose the right friction coefficient, surface thickness, component geometry, temperature and surface treatments to ensure the best plastic forming performance.

In plastic processing, the primary purpose of friction is to heat workpieces, lubricate process contact surfaces, and reduce the required machine power. To understand the friction mechanism of plastic processing, we must understand the basic principles of friction. The three main types of friction in plastic processing are rolling (or sliding) friction, shear friction, and adhesion friction.

Rolling friction is the force between two surfaces that are in contact with each other and are rolling relative to each other. The coefficient of rolling friction is usually lower than that of sliding friction. The coefficient of rolling friction is dependent on the surface irregularities, the rigidity of the components, and the shape of the contact surface.

Shear friction is a force generated between mating surfaces when they are in contact and subjected to a tangential force. In plastic processing, shear friction occurs when the plastic is cut by a cutting tool. The coefficient of shear friction is highly dependent on the nature of the surface and whether or not a lubricant is being used.

Adhesion friction is the force that occurs between surfaces when one surface is attached to another. In plastic processing, adhesion friction occurs when plastics undergo plastic deformation and extrusion. Adhesion friction is often difficult to predict, as it is highly dependent on the nature of the surface and the degree of plastic deformation.

The coefficient of friction of plastic materials is an important factor in plastic processing. The coefficient of friction is determined by the type of lubricant, the surface finish, the nature of the contact surfaces, the temperature, the degree of plastic deformation, and the type of plastic material. Each of these factors can affect the coefficient of friction and thus, the performance of plastic processing. As such, it is important to understand the fundamentals of plastic processing friction in order to optimize plastic processing operations.