Advancements in thermoplastic building.Few would argue the advantages of processing thermoplastic materials thermoplastic materials materials used in making casts for broken limbs. Malleable when warmed in hot water or heated with a hairdrier, very quick setting and very strong, e.g. Hexcelite. versus thermoset A polymer-based liquid or powder that becomes solid when heated, placed under pressure, treated with a chemical or via radiation. The curing process creates a chemical bond that, unlike a thermoplastic, prevents the material from being remelted. See thermoplastic. materials. Heat it up, extrude extrude /ex·trude/ (ek-strldbomacd´) 1. to force out, or to occupy a position distal to that normally occupied. 2. in dentistry, to occupy a position occlusal to that normally occupied. it, mold mold, name for certain multicellular organisms of the various classes of the kingdom Fungi, characteristically having bodies composed of a cottony mycelium. The colors of molds are caused by the spores, which are borne on the mycelium. it, shape it, etc., and let it cool. Presto. You have a part. Thermoplastics have been used for some time to mold small rollers, but large rollers presented special problems due to uneven cooling. During the last five years, Remco has worked with thermoplastic A polymer material that turns to liquid when heated and becomes solid when cooled. There are more than 40 types of thermoplastics, including acrylic, polypropylene, polycarbonate and polyethylene. material suppliers and consultants to customize its strip winding system for the application of thermoplastics. Practicality is no longer in question. A whole new class of polymers that have unique properties and improved processing advantages is now being introduced to an industry that has the ability to use them. As we write this article, new and existing applications are being discovered or explored. Thermoplastic urethane urethane (yoor´ithān´), n ethyl carbamate used as an anesthetic agent for laboratory animals, formerly used as a hypnotic in humans. (TPU TPU - Text Processing Utility ) was the most obvious and well known replacement material for the roller roller, common name for brightly colored Old World birds noted for performing somersaults in flight. They include the rollers proper (subfamily Coraciinae) and ground rollers (subfamily Brachypteraciinae industry. For this reason, more attention was focused on TPU as an easier method to produce urethane covered rollers. We now know it is only a small part of the total picture. While thermoplastic urethanes have proven themselves to be viable as a roll covering material, hundreds, if not thousands, of new polymers are now being considered for roll coverings; some for reasons we would least expect, such as high temperature resistance, or toughness and durability. We are talking about materials that can be made to be bullet-proof or strong enough to lift a ship out of the water. We are also talking about materials that can tolerate temperatures above 350[degrees]F and still function as designed. These high performance materials are generally referred to as engineered thermoplastics, and are available in pellet pel·let n. 1. A small pill; a pilule. 2. A small rod-shaped or ovoid mass, as of compressed steroid hormones, intended for subcutaneous implantation in body tissues to provide timed release over an extended period of time. form to be processed through an extruder. The most common questions that have been thoughtfully asked about strip winding thermoplastics are as follows: * How well do they bond to steel and to each other? * Is pre-heating or post-heating the roller ever required for best bonding? * What are the cost comparisons to thermoset materials? * Where can I buy these thermoplastic materials? * Is tape wrapping ever required following strip building? * How long do rollers have to cool before grinding grinding, process by which surface material is removed from an object, usually metal, by the abrasive action of a rotating wheel or a moving belt that contains abrasive grains. ? * What about grinding and polishing? Are coolants required? * What about application? Is it as easy as rubber? Can my present operator master the change? * Can I use my existing rubber stripbuilding machine for thermoplastics? If not, can it be modified? * What other products should I look at if I purchase a thermoplastic building machine? * Can thermoplastic materials be blended to achieve durometer? Properties? Color? * How do I determine processing parameters? Can I strain? * What about storage? How long can I keep thermoplastic materials? Do I need to refrigerate re·frig·er·ate tr.v. re·frig·er·at·ed, re·frig·er·at·ing, re·frig·er·ates 1. To cool or chill (a substance). 2. To preserve (food) by chilling. ? * How do I process scrap material? How can scrap material be added to virgin material? * Do I always need to dry thermoplastic materials before extrusion? How many dryers do I need? How should they be sized? The questions are many, and each one could be a topic for another article or a seminar. Do not assume that answers cannot be provided for any of the above questions. If Remco cannot provide a suitable answer, many consultants and polymer suppliers can. It would be safe to say that most of the questions would have a very positive reply. Progress has been good over the last five years, and tremendous progress has been made. With the help of some of our customers working with their customers, thermoplastic test rolls have been put into service in some of the most demanding applications ever designed for rollers. Almost without exception, they have all performed well; sometimes even better than expected when compared to their thermoset counterpart. This is the best way we have and you have for evaluating total performance. If you have questions similar to the ones in this article, or if you have other questions, contact Remco at www.rollerequipment.com. |
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