Fabricating products processing performance

Regardless of the type of controls available, the processor setting up a machine uses a systematic approach based on experience or that should be outlined in the machine and/or control manual. It is a defined area or volume in a processing system s PC pattern. Within this window fabricated products meet performance/cost requirements. Note that a major cause for problems with any process can be that the process operates outside of their required operating window. 

Measuring the barrier properties of polymers is important for several reasons. The effects of formulation or process changes need to be known, new polymers need to be evaluated, data are needed for a new apphcation before a large investment has been made, and fabricated products need to have performance verified. For some apphcations a full range of data is necessary, including P, Z9, and S plus the effects of temperature and humidity. 

There are destructive and nondestructive tests (NDTs) (2). Most important, they are essential for determining the performance of plastic materials to be processed and of the finished fabricated products. Testing refers to the determination by technical means properties and performances. This action, when possible, should involve application of established scientific principles and procedures. It requires specifying what requirements are to be met. There are many different tests (thousands) that can be conducted that relate to practically any material or product requirement. Usually only a few will be applicable to meet your specific application. Examples of these tests will be presented. 

Even though equipment operations have understandable but controllable variables that influence processing, the usual most uncontrollable variable in the process can be the plastic material. The degree of properly compounding or blending by the plastic manufacturer, converter, or in-house by the fabricator is important. Most additives, fillers, and/or reinforcements when not properly compounded will significantly influence processability and fabricated product performances. 

Im) and wider (> 10 cm) foils will not be easy to produce in reasonable quantities and at low cost. Scale-up of the various active positive materials employed in LPBs is a matter of concern, since, particularly with vanadium-based positives, the cell performance appears critically dependent on the reproducibility of the production processes employed to fabricate the active material. 

One of the most often used production procedures for fabricating a high-performance structural laminate is the Autoclave/Vacuum Degassing (AC/VD) laminating process. In this process, individual prepreg plies are laid up in a prescribed orientation to form a laminate. The laminate is laid against a smooth tool surface and covered with successive layers of glass bleeder fabric, Mylar or Teflon sheets, and finally a vacuum... 

The major processing methods that process well over 80wt% of all plastics are extrusion, injection molding, and blow molding. These processes as well as a few others use a plasticator to melt plastics. It is a very important component in a melting process with its usual barrel and screw. If factors such as the proper screw design and/or barrel heat profile are not used correctly fabricated products may not meet or maximize their performance and very important not provide for low cost process. 

The identification of textile fibers is a task frequently performed in a textile laboratory. The need to identify fibers arises in fibers research as well as during fabric production and processing. The identification of an unknown fiber in a yam... 

Thermoplastic polymers, as they come from the chemical manufacturing process, are powders or pellets. To convert them into fabricated products for the market place, they have to be first heated to high temperatures in an internal mixer or screw extruder (Figure 3.5). This procedure permits the incorporation of additives that are essential to the subsequent service performance of the fabricated product. The screw also conveys the molten polymer to the die for the thermoforming process. 

Dow has developed a pultrusion simulation modeling (PSM) service designed to help fabricators achieve higher levels of productivity and reliability. Process variables such as pull speed, part and die temperature, heater output and pulling force can affect the quality of pultruded components. The PSM tool allows fabricators to predict processing performance for specific applications, and is accurate to within 10% of actual performance. The tool has been validated in customer trials and allows the pultrusion process to be optimized quickly. 

Fabricating products involves conversion processes that may be described as an art. Like all arts they have a basis in science and one of the short routes to processing improvement is a study of the relevant sciences (as reviewed throughout this book that range from the different plastic melt behaviors to febricating all size and shape products to meet different performance requirements. 

Understanding and proper appUcations of the many different destructive and NDTs tests can be an endless project. However, they are essential for determining the performance of materials to be processed and of the finished fabricated products. Testing requires specifying what requirements are to be met. 

The nonwoven fabrics are very versatile materials and are being extensively used for gas and liquid filter appUcations, including pharmaceuticals, food and drink, vacuum cleaners, and industrial applications. Within the automotive industry, there are performance considerations, including pollution reduction and bacterial protection combined with lower weight and the environmental impact. These requirements can be fulfilled with the use of a range of versatile nonwoven production processes. 

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