Definition of plastics othermoplastics opolymers that are converted into shapes by processes involving flow of liquid molten polymer before solidification omust melt at a reasonable temperature omust be flowable when molten omust be easily shaped or fabricated 2. The mold consists of a core side and a cavity side that is placed into a plastic injection molding machine. Greene, csu 7 medical plastics and composites use containers bottles, bags drug delivery iv bags, syringes tubing and tools for surgery implants, artificial skins the use of plastic materials in the medical field, about. The air pressure then pushes the plastic out to match the mold. Joining by applying molten plastics or by moulding. Trantina, design with plastics, materials selection and design, volume 20, asm handbook, asm international, 1997, pages 639 to 647 the key to any successful part development is the proper choice of material, process, and design matched to the part performance requirements. The quality of thermoformed plastics parts depends on the expertise used to produce the molds that produce exceptional plastic parts. Polymers forming and shaping methodsextrusioninjection moldingblow moldingthermoforming. Nonconventional methods for shaping plastics parts mladomir milutinovic1, miodrag hadzistevic 1, dejan movrin, igor vrba2 1faculty of technical science of novi sad, department of production. A plastic forming machine, or plastic molding machine, is developed on the basis of rubber machinery and metal diecasting machine. Make sure the dust blower is in place to blow the dust away from the part you are. Some manufacturers prefer plastic fabrication over working with other materials such as metal or glass due to the processs advantages in certain applications. Plastic properties of metals are used during the process of metal forming. Why plastic shaping processes are important two types of.
Evolution in the world war ii years of the 1940s, the demand for plastics accelerated, as did research into new plastics that could aid in the defense effort. The parison is a tubelike piece of plastic with a hole in one end through which compressed air can pass. If the plastic sheet is reheated then it will try to return to its original shape. Chapter 18 forming and shaping plastics and composite. Additionally, because many plastics are based ultimately on crude oil, there is a continuous rise in the cost of raw materials that chemical engineers are trying to workaround. Qlwlrqri3odvwlf plastic is an organic material manufactured from petroleum derivatives. Sheets produced bythis process are subsequently used in thermoforming. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Engineering thermoplastics definition engineering plastics defined as materials which can be used stru cturally, typically replacing metals, wood, glass, or ceramics. Thermosetting polymers, or thermoset plastics, are plastics which permit no further deformation or shaping after threedimensional chemical crosslinking. Processing plastics pdf is a wide range of processing methods which may be used for plastics. Thermoset plastics are materials that melt initially but on further heating become permanently hardened. If plastics have coloring or other fillers in them, then the density part of the lab may not work out.
Learn vocabulary, terms, and more with flashcards, games, and other study tools. Nonconventional methods for shaping plastics parts mladomir milutinovic1, miodrag hadzistevic 1, dejan movrin, igor vrba2 1faculty of technical science of. When using this saw it is necessary to remember a number of things, keep your fingers away from the moving blade. Lecture 15 shaping of plastics extrusion lecture 16 shaping of plastics injection molding lecture 17 shaping of plastics blow molding and thermoforming. Kim 8 materials solid materials metals ceramics plastics. Chemically, thermoset plastics are crosslinked polymers. Notes on plastics the best suggestion i have here is to have your students work through the tutorial on the hands on plastics web site. The majority of thermoplastic materials possess comparatively low softening and melting temperatures and are termed melt. They are made up of carbon, hydrogen and sometimes oxygen, chlorine, nitrogen, fluorine, sulfur, phosphorus or silicon. Shaping by internal pressure generated in the material, e. The pure polymers which are made are not suitable for shaping and forming into finished articles but.
They cannot be softened and remolded without destruction of the polymer because covalent bonds are broken. Stretch forming process material thickness variations. Thermosets undergo a curing process during heating and shaping, causing a permanent change called crosslinking in molecular structure. Extrusion is a common plastic forming method for industrial ceramics.
The table with your mould on is lifted into position and a vacuum is used to draw the plastic over the mould. In this case, the use of tungsten carbide, ceramic or diamondtipped tools is advisable. Over the past two decades, improvements in process control and developments with plastic powders have resulted in a significant increase in usage. Medical plastics and composites use containers bottles, bags drug delivery iv bags, syringes tubing and tools for surgery implants, artificial skins the use of plastic materials in the medical field, about 4 billion dollars in 2000 us. Plastic manufacturing forming and shaping plastics slideshare. An overview is given of the processing of plastic materials from the handling of polymers in the pellet and powder form to manufacturing of a plastic fabricated product. We are a leading plastics manufacturer that leverages our knowledge of materials, processing, and application development to deliver the highest level of value to our customers. Trantina, design with plastics, materials selection and design, volume 20, asm handbook, asm international, 1997, pages 639 to 647 the key to any successful part development is the proper choice of material, process. In the last 30 years, plastics have become the most dominant engineering. Since the polymer injection molding process and molding equipment in the 1870s, as an industry, plastic forming machines were rapidly developed until the 1930s, with the gradual commercialization of plastic molding equipment, injection molding and extrusion. Pdf nonconventional methods for shaping plastics parts. It is a lowdensity polymer and thereby it possesses lightweight.
Once the plastic has cooled and hardened the mold opens up and the part is ejected. With its everexpanding applications, plastics have delivered many benefits for society. Introduction 2 the processing of plastics involves operations similar to those used to form and shape metals. One of the most common methods of processing plastics is extrusion using. Plastics are typically organic polymers of high molecular mass, but they often contain other substances. Machining recommendations for semifinished engineering plastics. They are usually synthetic, most commonly derived from petrochemicals, but many are partially natural. Similarly, cir cular saws fitted with carbide tipped saw blades are ideal for cutting plastics. The plastic can then be trimmed to the required shape. Liquid injection molding of liquid silicone rubbers, polyurethanes and other highly reactive materials.
We also offer many options on the machine with tilting shaft and tool change arbor. An alternative to conventional shaping of plastic parts offers metal forming processes and cold forming technique. Majority of the times, polymers are made up of carbon, hydrogen, and oxygen only. Elastomers are also cross linked materials but have the capacity for elastic deformation, and return to. Cpc definition b29c shaping or joining of plastics. Hold it down just enough so you are able to move the plastic. Design consideration me477 kwon 2 introduction unlimited variety of part geometries n sethape. Can maint ain mechanical and dimensional stability above 100 oc and below 0oc. Medraj mech 4216511 lecture 154 two types of plastics 1. Various types of equipment used and melt processing ranges of various polymer formulations to make the myriad of plastic products that. Cutting and shaping the plastic technology in my school. Mayfield plastics is one of the few thermoforming companies that controls all facets of mold making inhouse. Materials, processes, properties, test methods, and other information that is used commonly throughout the industry. The third big thrust in plastics development took place in the 1920s with the introduction of cellulose acetate, ureaformaldehyde, polyvinyl chloride, or vinyl, and nylon.
Processes for plastics and electrical assemblies figure 19. Plastics can be machined, cast, formed, and joined with relative ease requiring. Hold the plastic down so it does not bounce up and down. Plastic manufacturing forming and shaping plastics 1. Jun 26, 2016 plastic manufacturing forming and shaping plastics 1. Forming and shaping plastics and composite materials the university of new mexico zcl me260l 06 forming and shaping of plastics and composite materials the university of new mexico zcl me260l 06 table 18. More than 90% of smelted metal is processed by different methods of metal forming. Plastic injection molding accounts for about 80% of the durable plastic items we find every day. Mech 421 mechanical shaping of metals and plastics tmg. If the sheet is held in position while it cools it will remain in its new shape while it is at room temperature or below.
The parison is then clamped into a mold and air is blown into it. Forming and shaping plastics and composite materials. The parts shown are front and rearforks, a rear swingarm, a wheel, and brake disks. Our range of spindle moulders and moulders for moulding, rebating and chamfering a wide range of plastics.
Processing of plastics pdf is a wide range of processing methods which may be used for plastics. Plastics fabrication ocompression molding also used for thermosets. Injection molding processmolten plastics is feed into the mold from a screw once that has cooled the part is ejected from the mold. Plastic packaged food lasts longer, reducing wastage.
Harmful effects of plastics on health and environment h. We now have biofuel for automobiles, and the feedstock for that fuel grows on the land. Design consideration me477 kwon 22 introduction similar to many production methods for plastics but different from the plastics industry dominated by one product. Talented designers and machinists hand make the majority of our molds inhouse. Fabrications of plastics 20 plastic fabrication is the design, manufacture, or assembly of plastic products through one of a number of methods. Plastics processing plastics can be machined, cast, formed, and joined with relative ease requiring little postprocessing or surfacefinish operations plastics melt or cure at relative low temperatures plastics require less energy to process than metals raw materials most commonly are pellets, powders.
Elastomers are also cross linked materials but have the capacity for elastic deformation, and return to their original shape after exposure to load. A plastic material is any of a wide range of synthetic or semisynthetic organic solids that are moldable. About 7% of all plastics production, but nearly 10% of plastics sales dollars. Shaping the future of plastics through material strength and application expertise 11650 lakeside crossing ct. Silicone rubber orings made with compression molding. Extrusion is a process of shaping an object by compacting a plastic mass in a highpressure. Plastics melt or cure at low temperatures easy to handle require less energy to process. Presently, it is defined that the plastics are synthesized high polymers which have plasticity, and consequently substances made of these natural materials are precluded. Machine for shaping and moulding plastics and polyethylene. Why plastic shaping processes are important two types of plastics.
Thermoplastics chemical structure remains unchanged during heating and shaping more important commercially, comprising more than 70% of total plastics tonnage 2. Engineering thermoplastics michigan state university. The history of plastic forming started together with the development of phenol resin in the beginning of the 20th century. Machining recommendations for semifinished engineering. Metal forming is the main method of making metal products and semifinished products. Vacuum forming only works with thin plastics and moulds with no undercuts. Feb 11, 2014 the process was applied to plastics in the 1940s but in the early years was little used because it was a slow process restricted to a small number of plastics. Shaping plastics forming bending thermoplastics in sheet form can be heated gently to between 160c and 180c and then bent into shape. Thermosets undergo a curing process during heating and shaping. In this paper results of theoretical, numerical and.
1273 1414 674 1337 117 890 1242 1335 1017 1065 438 1253 758 253 921 436 547 871 735 1501 1428 1025 314 798 523 1018 433 807 953 907 329 144 590 1347 819 43 1482 919 1180 366 307