COF Testing for the Resistance of Materials

 The coefficient of Friction of a material would be the measure of the sliding resistance of a material more than a different material. In the case of thermoplastics the mating component is normally steel. When multiplying the co-efficient of friction by the perpendicular force amongst the two mating sliding faces, this result is definitely the force essential to slide the components across each other.

What Does ‘Coefficient of Friction’ Imply?

Coefficient of friction is really a measure on the level of friction existing in between two surfaces. If you obtain a coefficient of friction, you’re calculating the resistance to motion in the interface of two surfaces of similar or dissimilar materials.

The energy of this friction force depends upon the materials which are pressing against one particular yet another. As an example, a steel bar will slide much more simply on a sheet of ice than on a slab of concrete. In these examples, the steel-on-ice mixture has a considerably decrease coefficient of friction.

The coefficient of friction is a vital property of all materials which run on higher speed manufacturing lines; specifically these in the printing and packaging industry. Coefficient of friction is routinely specified for plastic flow-rapping films.

Why does it matter?

Basically, the coefficient of friction will differ amongst mobile and immobile objects. For probably the most element, objects that aren’t moving usually experience more friction. This can be because it requires far more energy to push them into motion than to maintain them moving.

How Do Friction Coefficient Values Operate?

Coefficient values would be the numbers that express how materials interact. These values normally run from 0-1, but they also can be larger than one particular if the components are in particular sticky.

Basically, if objects possess a coefficient value of zero, there’s no friction. This is not common, nevertheless it is achievable with components which have superfluidity. If materials possess a coefficient worth of 1, it implies the friction force is definitely the same because the normal force. In other words, the force expected to move the object is equal to that object's weight.

Objects also can have a friction worth greater than one. As an example, rubber is often a frequent material which will have a particularly high coefficient of friction. As a common rule, most supplies that are not wet are inclined to fall in the 0.3-0.six range.

Plastics Coefficient of Friction COFTesting

Measuring friction might be crucial aspect for a lot of industries, specifically for plastics and packaging. Friction is usually characterized by static friction, and kinetic friction. Static friction of plastic is present when two objects are in contact but not sliding across each other. Kinetic friction is often a resistance friction that is present during sliding motion involving two objects. The coefficient of friction is dependent on the surface situations of both materials which can be in speak to.

COF testing standards like ASTM D1894 and ISO 8295 cover the testing methods to decide the coefficient of plastic supplies. COF testing requires pulling a weight using a plastic specimen among the weight as well as the ground. The force required to accomplish so is usually measured and also a coefficient of friction is then determined.

 

COF Testing in Industrial Packaging

 

The coefficient of friction (COF) is a significant topic in the world of friction coefficient which is defined as a friction force that oppose shear movements divided by normal style to the surface. People run different (most people demand consistent COF between 0.25 - 0.3 running normally) quick steps to quickly demand higher friction. The importance is in how substrates move through and cross print stations, conveyor belts, to containers, or released from mandrel or loading after processing. Film with a COF value greater than 0.5 is considered not slipping. COF is usually determined for the process provided and adjusted to the printer with ink or varnish as needed.

 

There are two types of COF: static, the style needed to start movement, and kinetic, the style needed to maintain movement. In general, the static COF is more than a greater concern for stacked or palatial items, while Kinetic COF is used for film roll. COF provides a relative indication of friction characteristics and is routinely determined in substrates such as plastic films.

 

Depending on the packaging application, high or low can be desired. When the material traction feed system is used, or if the application calls for an easy-to-hold container where the slippery surface will be difficult to control, high COF will be profitable. Conversely, the condition in which an ingredient is drawn through a forming collar, such as the vertical shape, the contents and seals (VFFS) equipment, low COF is considered profitable. Likewise, if the dry arm is applied through high-speed equipment, low COF is usually the best performing.

 

COF Testing

COF or friction test coefficient is used to determine the friction force between two ingredients. COF tests are carried out on various materials such as plastic and polymers, lubricants, ceramic tiles, etc. After COF testing, the value varies depending on the test material

 

Why is COF needed in packaging?

So what should COF do with an automatic packaging line? Lots. More specifically to form a seal form machine, COF packaging films refer to the 'slip' level that is owned packaging materials while interacting with various engine parts.

 

For seal machines fill vertical shapes in particular, packaging films interact with engine components called pull belts. The pull belt presses the outside of the film, memorizes between belts and the forming tube, helps draw it through the packaging system. To optimize performance, there must be enough friction on the outside of the film to overcome friction inside. In other words, the inside of the film must be 'slippery' enough to be able to slide on the assembly of the forming tube (FTA) when the belt pulls drawing movies through the machine.

 

Factors that influence COF testing

COF can be influenced by a number of factors including anti-block additives, corona treatment, anti-stat, ink, varnish, adhesive. Because laboratory testing cannot simulate each element of each packaging process, the COF should not be considered as an indication of system specific performance. Instead, the means to reproduce friction is proven to be successful in a set of certain conditions.

COF Testing Standards and Measures

COF testing measures the convenience with which two surfaces in contacts can slide through each other where there are two different values ​​related to friction coefficients - static and kinetic. Static friction applies to the style needed to initialize the movement between two surfaces and kinetic friction is resistance to slid after the surface in relative movement.

Because the cleanliness of the substrate is very important to collect reliable data, the right steps must be addressed before testing and being taken to when testing ensures freedom from dirt, oil and other contaminants that can affect test results.

ASTM D1894 is the main COF testing standard and used by many industries whose needs are very varied.

Friction test coefficient

New equipment in our laboratory will help food manufacturers evaluate the characteristics of friction from their food and beverage packaging, which is very relevant to the use and handling of packages.

The friction coefficient (COF), or slip resistance, is a significant problem in the world of packaging and is an important property of all the materials running on high-speed printing and packaging lines. COF is routinely determined in materials such as cartet and plastic film containers. Understanding and controlling COF packaging materials provides the processor and packaging the ability to optimize performance and avoid problems in forming, filling, transporting, and even storing packages.

Cologne containers that show high COF will tend to resist sliding in the load unit, while low coefficients can cause potential problems, with packages slipping from the load. For plastic films, low COF values ​​may be conducive to the speed of fast charging lines, while high coefficients may be the cause of abrasion, blisters and jammed films on the phone.

COF Effects in the Packaging Industry

The packaging film "friction coefficient" (COF) provides a relative indication of friction characteristics. Control the COF provides the processor of the ability to optimize performance and avoid problems in forming, transportation, and storage packages.

In the HFFS system (form horizontal fill and seal), too much friction side sealant film can cause drilling or jamming films when passing the metal plate.

In the VFFS system (Form Vertical Fill and Seal), too much friction from the side of the film sealant can cause poor film feedback on a metal-forming collar, the size of the package is inconsistent, and screaming. In both systems, too much friction can cause lateral slips that lead to bad seals (leakers).

Too a little friction outside can cause the package to slip or fall from the conveyor belt tend. Too much friction outside can slow down the shipping launch package down, or too a little friction outside can produce packages that glide from the stack or palette.

You can see that various applications require different fictional properties. Therefore, the coefficient of friction or COF testing is very important and used for process control to ensure consistent production of packaging types.