Sliding applications

The frictional properties of plastics are of particular importance to applications in machine products and in sliding applications such as belting and structural units such as sliding doors. The range of friction properties are rather extensive. The relationship between the normal force and the friction force is used to define the coefficient of static friction. 

In situ hybridization (ISH) permits examination of a wide range of materials, ranging from cells and tissues to metaphase spreads of chromosomes affixed to a slide. Hybridization with specific probes can thus be performed directly on the slide, with the hybridized signal viewed under a microscope. Briefly, the steps involved in ISH include pretreatment of the slide, application of the sample, fixing of the sample, hybridization with probe, and visualization of the probe signal. 

Aramid-containing composites are often used in sliding applications. The estimation and predicrion of the tribological properties of such composites is a desirable skill. Despite the increasing use of polymeric composites, the knowledge of their tribological behavior is limited and lacks predictability. 

Abbott-Firestone curves are used in important sliding applications, particularly cylinder... 

Friction characteristics are very important for fibre to fibre interaction in spin technology. Internal lubricants can be used to reduce the friction which can be quite important in slide applications such as medical syringes. 

Obviously, the potential application list is much more extensive. Polymers are used in tribological applications for many of the same reasons as they are used in structural applications. In many instances, polymers will perform a dual function as both a structural and a tribological material. An example of dual functionality is self-lubricated polymers that are injection molded into structural housings for low-speed lightly loaded rotating shafts. Concerns such as weight, cost, and manufacturability are some of the same issues with the use of polymers and polymeric composites for sliding applications as in structural applications. 

Persson B N J 1997 Sliding Friotion—Physioal Prinoiplesand Applications (New York Springer)... 

For many centuries the application of materials for low friction and wear in sliding and rolling contacts primarily involved wood, stone, leather, iron, and copper. Almost all engineering materials have since been employed at one time or another in the continuing search for the best bearing material. Final selection is commonly a judgment based on the most essential material properties, ease of appHcation, and cost. 

Because of the steep pitch required, slides are limited in application. They are most commonly used to bridge the gap between roller-conveyor systems on two floors, because the roller conveyor can take the container off the slide rapidly and ehminate or reduce the chance for collisions. Slides may also be used when containers can be chuted from an upper floor to a manually loaded carrier. The use of several rollers at the feed point is recommended for easy dehveiy to the sloping section. If the drop is short and containers light, a roller cleanout will prevent backup of containers on the slide. The slope of gravity slides is a function of container weight, size, and friction characteristics and should be selected with care to be sure that containers do not move either too swiftly or not at all. Slides usually use flat steel sheet. 

The following is a summary of visual aids (slides, artefacts and demonstrations) that may be found helpful in presenting the material in this book. Material for slides may be found in this book in the further reading at the ends of the chapters and in other readily available sources (indicated by references [1] to [5] and listed at the end of Appendix 2). Where material for slides needs to be found from more specialised publications and reports we have given appropriate references. Copyright permission should, of course, be obtained where applicable. 

Slides Of reflecting telescopes, aeroplanes, space capsules, bicycles (to illustrate applications of stiff but light materials). 

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