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Due to the wide and ever increasing application of thermoplastics for the transportation and automotive industries, the performance of the under-the-hood plastic parts depend upon optimized design and processing technology and properties of polymer based materials. Nylon (polyamide) based plastics are used widely for automotive cooling fans and various under-the-hood injection molded components. For injection molding of multi-blade cooling fans and various rotating plastic parts the complex of multiple gating injection molding tools were used. Both the design of the various rotating parts (including industrial and automotive cooling fan, and the molding tool design are very important to get optimum flow patterns and to predict the locations and interaction of stress-bearing areas and knit lines (planes or inter-phases)1. The mechanical performance of the injection-molded thermoplastic components depends on the peculiarity of the part and the molding tool design.

Engineering thermoplastics were successfully utilized in the design of injection molded rotating parts such as the impellers, wheels, and cooling fans of commercial air-cooled chillers, and gas and diesel engines. Complex aerodynamic and mechanical performance of impellers and cooling fans are very important for the efficiency of integrated air-movement, climate control and cooling systems of various types of engines of vehicles, cars, heavy-duty tractors and trucks. The transportation and automotive industries have developed a culture of reliability and cost effectiveness, in which high risks and adventures are not encouraged. Due to the wide and ever increasing application of thermoplastics for the transportation and automotive industries, the performance of the under-the-hood parts depend upon optimized design and processing technology and properties of polymer based materials.

A comparative study of the mechanical performance of welded polyamide joints is evaluated. Under optimized welding (linear and orbital vibration, hot plate, transmission laser) conditions, the tensile strength of welded polyamide/nylon (filled and fiber-reinforced) is close or slightly higher (up to 14%) than the tensile strength of the base polymer (non-filled polyamide). In this study, the influence of two important effects (local reinforcement and “memory”) on the mechanical performance of polyamide/nylon welds is analyzed and discussed. The results presented in this study will help plastic part designers, material developers and manufacturers, choose optimized welding conditions for polyamide/nylon parts in a wide range of industrial applications.

The advantages of magnetic implant induction welding (Emabond™)1 technology for various thermoplastics were widely discussed since the mid-eighties in a series of technical articles and reports, and presented to the professional Societies (SAE, SPE, SME, etc). In 1998-2003, we reported to SAE International our technical achievements in optimizing the mechanical performance of welded nylon (6, 66, 6/66, 46, etc.) using frictional (linear and orbital vibration, ultrasonic), contact (hot plate), and non-contact (laser through-transmission) welding technologies. Our recent developments focused on optimization of mechanical performance of induction welded nylon 6, which has reached a new performance level through continuous improvement of magnetic implant induction welding technology, including properties of the formulated magnetic implant material, new equipment, SPC process control, optimized design of joints, etc.

Resent developments were oriented on two high-flow, high-modulus grades fiber-glass reinforced nylon 6 (HMG series) grades for transportation, autos and other industrial applications requiring high stiffness, high strength and high fatigue resistance. These materials combined the following improved technological (injection molding, vibration and hot plate welding, etc.) and mechanical performance properties such as greater dimensional stability, higher short-term (strength and stiffness) and long-term (fatigue and creep with the influence of temperature effects). Both HMG series grades Capron®1 HMG10 and Capron® HMG13 - are for injection molded parts where stiffness, strength, impact resistance, and good surface and improved appearance are preferred. The current and possible applications of these plastics includes auto mirror housing brackets, clutch pedals, clutch master cylinders, ski bindings, steering wheels, levers, auto seat frames, door handles and door lock mechanisms.

Previously we reported to the SAE 2000 basics in selection of various colored and un-colored/natural nylon 6 (polyamide - PA 6) based plastics for laser welding technology. Later we presented to Antec1 2001 and to SAE 2002 our developments of colored in black through-transmissible grades of PA 6 plastics, which were specially tailored for the specifics of the design and laser welding technology. In this current paper, we will try to enhance the understanding of the engineering community regarding the usefulness and applicability of laser welding technology, developed colored thermoplastics, and its increasing use in various automotive and transportation applications.

Previously we reported to SAE 2002 the basic principles in materials selections for the fastening of plastics. In this current paper, we will try to increase the understanding of the automotive community regarding the usefulness and applicability of aluminum made self-tapping screws in the fastening of various thermoplastic components. Utilization of the light alloys for the manufacturing of fasteners for plastic applications allowed us to manage efficiently the stiffness considerations, short- and long-term performance of the assembled plastic components. The results presented in this study will help designers, technologists, thermoplastic and fastener developers and fastener manufacturers, to optimize mechanical performance of assembled automotive components, where self-tapping screws will be used.

In this current paper, we will try to increase the understanding of the engineering community regarding the usefulness and applicability of aluminum made self-tapping screws in fastening of various automotive thermoplastic parts. Utilization of the light alloys for manufacturing of fasteners for plastics applications allowed us to manage the stiffness considerations, short-term (strength) and long-term (life) performance of the assembled plastic parts. The results presented in this study will help designers, technologists, plastics and fasteners developers and manufacturers, to optimize mechanical performance of assembled automotive thermoplastic parts, where self-tapping screws will be used.

Previously we reported to the SAE'99 our findings on selections of nylon (polyamide) based plastics for laser welding (LW) technology. In this current paper, we will try to increase the understanding of the engineering community regarding the usefulness and applicability of an advanced LW technology (and developed thermoplastics), and its increasing use in various automotive applications.

The mechanical performance of injection molded glass-fiber reinforced plastic parts is highly anisotropic and depends strongly on the kinetics (orientation and distribution) of the glass-fiber and the part geometry. Similarly, the bulk and local mechanical performance at the ribs, walls and welds is influenced by these glass-fibers and the specific processing technology (including joining) used, as related to melt-flow and melt-pool formation and glass-fiber re-orientation. The purpose of this study is to show: the effect of short glass-fiber orientation at the pre-welded beads, ribs and wall areas for injection molded and subsequently welded parts the short-term mechanical performance of welded butt-joints that have various geometry and thickness, namely “straight” and “T-type” welds.