Equipment injection molding

Control feeding devices to the hopper of primary equipment (injection molding, extrusion, etc.) is important to provide products that meet performance requirements at the lowest cost. Equipment manufacturers have increased the feeding accuracy using different devices such as microprocessor blender/mixer controllers. Also materials are being reduced in size with more uniformity to significantly improve uniformity in melt. Processors can use blenders and other devices mounted on hoppers that target for precise and even distribution of materials. 

The term dispersion refers to how well the pigments are wetted out in the plastic matrix (see below), whereas distribution refers to the uniformity of color in the part. Finally, in referring to the parts fabrication process, the term molder is used below to represent any the following pieces of equipment injection molding machine, injection or extrusion blow molding machine, or rotational molding machine. 

Figure 35-14. Tensile strength in blends of poly (styrene) and high-density poly(ethylene) as a function of the poly(styrene) content of the mixtures. The mixtures were made by mixing the granulates with a torpedo-equipped injection molding machine ( 0—0 ) or with the same machine with premixing in a kneader ( — ). (After C. D. Han.)...

Refer to the following subject entries for additional information Screw Configurations, Screw Transfer Molding, Preplasticating Equipment, Injection Molding, and Sheet Extrusion,... 

TPU elastomers are processed on rubber equipment, injection molded, extruded, compression molded, transfer molded, and calendered. In... 

TPU elastomers are processed on rubber equipment, injection molded, extruded, compression molded, transfer molded, and calendered. To be fabricated into products, such as athletic shoe outer soles, the elastomer and ingredients are mixed in conventional rubber equipment (two-roU mills, internal mixers) and compounded. Subsequently, the compound is processed for example, injection molded. ... 

Injection Molding. In iajection mol ding a molten thermoplastic is iajected under high pressure iato a steel mold. After the plastic solidifies, the mold is opeaed and a part ia the shape of the mold cavity is removed. Geaeral descriptioas of the process and related equipment are given ia Refereaces 29—34. 

Nittile mbber is much like SBR in its physical properties. It can be compounded for physical strength and abrasion resistance using traditional fillers such as carbon black, siUca, and reinforcing clays. The primary benefit of the polymer is its oil and solvent resistance. At a medium ACN content of 34% the swell in IRM 903 oil at 70°C is typically 25—30%. Nitrile mbber processes on conventional mbber equipment and can be compression, transfer, or injection molded. It can also be extmded easily. 

Urethanes are processed as mbber-like elastomers, cast systems, or thermoplastic elastomers. The elastomer form is mixed and processed on conventional mbber mills and internal mixers, and can be compression, transfer, or injection molded. The Hquid prepolymers are cast using automatic metered casting machines, and the thermoplastic peUets are processed like aU thermoplastic materials on traditional plastic equipment. The unique property of the urethanes is ultrahigh abrasion resistance in moderately high Shore A (75—95) durometers. In addition, tear, tensUe, and resistance to many oUs is very high. The main deficiencies of the urethanes are their resistance to heat over 100°C and that shear and sliding abrasion tend to make the polymers soft and gummy. 

Injection Molding Machines Glow Molding Con-presion Presses Transfer presses Thermotorming Machines Molds i Die Auxiliary Equipment Liquid Depensing Systems Irrpregnators Plotters... 

In order to judge performance capabilities that exist within the controlled variabilities, there must be a reference to measure performance against. As an example, the injection mold cavity pressure profile is a parameter that is easily influenced by variations in the materials. Related to this parameter are four groups of variables that when put together influences the profile (1) melt viscosity and fill rate, (2) boost time, (3) pack and hold pressures, and (4) recovery of plastica-tor. TTius material variations may be directly related to the cavity pressure variation. Details on EQUIPMENT/PROCESSING VARIABLE are in Chapter 8. 

Plastic products are made by a variety of basic manufacturing processes. As an example a major method such as extrusion has subdivisions that include profile, pipe, tube, film, sheet, coating, post forming, etc. equipment In injection molding there are subdivisions such as coinjection, gas assist, foam, inmold decorating, etc. equipment. There are literally hundreds of processes used with only about the dozen, as reviewed in this chapter, that are principally used (2). 

The typical TP encapsulation process is an insert injection molding or liquid injection molding operation. The insert, a coil, or an integrated circuit, for example, is placed in a mold equipped with either fixed spider type supports or retractable pins or other features to support it when molten TP is injected. 

Sublimation (diffusion) printing is a textile process in which color patterns in dry die crystals are transferred from a release film to the fabric under high heat and pressure. The process has been adapted to plastics. The equipment used is very similar to that used for hot stamping. Under heat and pressure, the dye crystals sublime (go directly to the vapor phase from the solid phase without melting) and the vapor penetrates the plastic product. As a result, the decoration is very durable and wear resistant. It is also cost competitive against other processes such as two-step injection molding or silk screening. 

Husky is a global supplier of injection molding systems to the plastics industry. Husky designs and manufactures injection molding machines—from 60 to 8000 tonnes, robots, hot runners for a variety of applications, molds for PET preforms, and complete preform molding systems. Customers use Husky s equipment to manufacture a wide range of products in the packaging, automotive and technical industries. The company serves customers in over 100 countries from more than 40 service and sales offices around the world. 

Safety device All machines are equipped (or should be equipped) with applicable electrical, hydraulic, and/or mechanical safety devices. Some of them, such as injection molding machines, have all three modes for safety operations. 

Design of injection molding equipment to produce car bumpers made from polymers Designing feedback control systems for bioreactors... 

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