PLASTIC DESIGN SOLUTIONS

Atkinson P Bagdatlioglu I BASF UK Ltd. Plastic Design Solutions UK (Institute of Materials BASF AG European Chemical News Montell Polyolefins)... 

As these problems were encountered in the past, it became evident that we did not have at hand the physical or mathematical description of the behavior of materials necessary to produce realistic solutions. Thus, during the past half century, there has been considerable effort expended toward the generation of both experimental data on the static and dynamic mechanical response of materials (steel, plastic, etc.) as well as the formulation of realistic constitutive theories (Appendix A PLASTICS DESIGN TOOLBOX). 

Honeywell Engineered Applications Solutions is a Honeywell business enterprise that teams Engineering Plastics, Specialty Films and Metal Injection Molding technologies to provide a source for engineered solutions. Honeywell s EAS website supplies a range of technical services and solutions information helpful to the plastics designer. 

And if those sources fail to lead to a practical solution, try one or more of the many plastics design consultants for some guidance. The consulting fee will generally be well... 

There is no perfect training curriculum that will teach you how to design with plastics, and how to optimize your dimensional tolerances to get more cost-effective design solutions. With time and experience, you will begin to appreciate the subtle differences between working with metals and working with plastics, what tolerances are appropriate (not just achievable, but useful, functional, and cost-effective). 

Many methods for the conversion of acid copolymers to ionomers have been described by Du Pont (27,28). The chemistry involved is simple when cations such as sodium or potassium are involved, but conditions must be controlled to obtain uniform products. Solutions of sodium hydroxide or methoxide can be fed to the acid copolymer melt, using a high shear device such as a two-roU mill to achieve uniformity. AH volatile by-products are easily removed during the conversion, which is mn at about 150°C. A continuous process has been described, using two extmders, the first designed to plasticate the feed polymer and mix it rapidly with the metal compound, eg, zinc oxide, at 160°C (28). Acetic acid is pumped into the melt to function as an activator. Volatiles are removed in an extraction-extmder which follows the reactor-extmder, and the anhydrous melt emerges through a die-plate as strands which are cut into pellets. 

In practice this relationship is only approximately correct because most plastics are not linearly viscoelastic, nor do they obey completely the power law expressed by equation (2.62). However this does not detract from the considerable value of this simple relationship in expressing the approximate solution to a complex problem. For the purposes of engineering design the expression provides results which are sufficiently accurate for most purposes. In addition. 

In many process design applications like polymerization and plasticization, specific knowledge of the thermodynamics of polymer systems can be very useful. For example, non-ideal solution behavior strongly governs the diffusion phenomena observed for polymer melts and concentrated solutions. Hence, accurate modeling of... 

In order to understand potential problems and solutions of design, it is helpful to consider the relationships of machine capabilities, plastics processing variables, and product performance (Fig. 1-10). A distinction has to be made here between machine conditions and processing variables. For example, machine conditions include the operating temperature and pressure, mold and die temperature, machine output rate, and so on. Processing variables are more specific, such as the melt condition in the mold or die, the flow rate vs. temperature, and so on (Chapter 8). 

Failure can be considered as an actual rupture (stress-rupture) or an excessive creep deformation. Correlation of stress relaxation and creep data has been covered as well as a brief treatment of the equivalent elastic problem. The method of the equivalent elastic problem is of major assistance to designers of plastic products since, by knowing the elastic solution to a problem, the viscoelastic solution can be readily deduced by simply replacing elastic physical constants with viscoelastic constants. 

Solid plastic wall thicknesses for most materials should be targeted to be below 0.2 in. and preferably around 0.125 in. in the interest of avoiding the above pitfalls. In most cases ribbing will provide a satisfactory solution in other cases sandwich structures or reinforced materials may have to be considered. As reviewed elsewhere when presenting the ideal target to meet the best design such as the thinner wall just reviewed, does not mean that a thicker wall can not be processed, etc. The thicker wall can be processed requiring closer process controls (Chapter 8). 

The answers to all questions are not known with certainty, and research toward the solution of such problems will require the combined efforts of the plastic chemist and designer with the physician. It is through the efforts of such multidiscipline groups that surgical repair materials of outstanding longterm utility are produced, studied, evaluated, and made available to the patient. 

The past events in designing plastic products have been nothing short of major worldly achievements. Designers innovations and visionary provides the required high level of sophistication that is applied to problems that exist with solutions that follow. Ahead is a continuation of meeting new challenges with these innovations and idealism that continues to make plastics a dynamic and visionary industry. The statement that we are in the World of Plastics is definitely true. In fact one can say that plastic products has made life easier for all worldwide. 

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