Computational Validation of Injection Molding Tooling by Additive Layer Manufacture to Produce EPDM Exterior Automotive Seals

During the design and development of ethylene propylene diene monomer (EPDM) exterior automotive seals, prototype components can only manufactured through production tooling platforms by either injection molding or extrusion. Consequently, tooling is expensive and has long lead times. This paper investigates whether additive layer manufacture is a viable method for producing tooling used in injection molding of exterior automotive seals in EPDM. Specifically, a novel rapid tooling is a method that combines additive layer manufacture (ALM) with epoxy reinforcement. Computational validation is performed whereby the mechanical properties of the tool are evaluated. The research has concluded that the novel tooling configuration would be suitable for prototyping purposes which would drastically reduce both costly and environmentally detrimental pre-manufacturing processes. This work has laid the foundations to implement rapid tooling technology to the injection molding of prototype EPDM parts

Comparative Assessment of the Laser Induced Plasma Micromachining and the Micro-EDM Processes

Micro-electro-discharge machining (micro-EDM) is a well-established micromanufacturing process and has been at the center of research for the last few decades. However, it has its own limitations. The limitations are primarily due to the requirement of a tool and electric potential between the tool and the workpiece. The laser induced plasma micromachining (LIP-MM) is a novel tool-less multimaterial selective material removal type of micromachining process. In a manner similar to micro-EDM, it also removes material through plasma-matter interaction. However, instead of a tool and electric potential, it uses an ultra-short laser beam to generate plasma within a transparent dielectric media and thus circumvents some of the limitations associated with micro-EDM. The paper presents an experimental investigation on the comparative assessment of the capabilities of the two processes in the machining of microchannels in stainless steel. For comparative assessment of their processing capabilities, microchannels were machined by the two processes at similar pulse energy levels, while other process parameters were maintained at their optimal values for their respective process technology requirements. The comparative assessment was based on the geometric characteristics, material removal rate (MRR), effect of tool wear, and the range of machinable materials

A novel approach to fabricate dye-encapsulated polymeric micro- and nanoparticles by thin film dewetting technique

A new method is reported for fabrication of polymeric micro- and nanoparticles from an intermediate patterned surface originated by dewetting of a polymeric thin film. Poly (d, l-lactide-co-glycolide) or PLGA, a biocompatible polymer is used to develop a thin film over a clean glass substrate which dewets spontaneously in the micro-/nano-patterned surface of size range 50nm to 3.5µm. Since another water-soluble polymer, poly vinyl alcohol (PVA) is coated on the same glass substrate before PLGA thin film formation, developed micro-/nano-patterns are easily extracted in water in the form of micro- and nanoparticle mixture of size range 50nm to 3.0µm. This simplified method is also used to effectively encapsulate a dye molecule, rhodamine B inside the PLGA micro-/nanoparticles. The developed dye-encapsulated nanoparticles, PLGA-rhodamine are separated from the mixture and tested for in-vitro delivery application of external molecules inside human lung cancer cells. For the first time, the use of thin film dewetting technique is reported as a potential route for the synthesis of polymeric micro-/nanoparticles and effective encapsulation of external species therein

Computer aided rapid tooling process selection and manufacturability evaluation for injection mold development

Injection mold development lead time has been reduced presently by over 50% by employing rapid prototyping based tooling methods. Rapid tooling methods however, have certain limitations in terms of mold material, accuracy, surface finish, and mold life. The relevant process knowledge, especially for newer routes, is not very well established, resulting inconsistent or inappropriate rapid tooling (RT) process selection and mold design incompatibility. This paper presents a computer aided rapid tooling process selection and manufacturability evaluation methodology for injection molding, supported by mold cost estimation models and RT process capability database. Rapid tooling process selection is based on process capability mapping in quality function deployment (QFD) against a set of tooling requirements that are prioritized through pairwise comparison using analytical hierarchal process (AHP). The mold manufacturability for the selected RT process is carried out using fuzzy-analytic hierarchy process (fuzzy-AHP) to identify problem features, if any. This is followed by estimating the cost of RT mold and comparing it with a conventional mold, using cost models developed based on the concept of cost drivers and cost modifiers. The entire methodology has been implemented in a software program using Visual C++ in Windows environment and demonstrated on an experimental mold as well as industrial cases. The proposed methodology enables selecting an appropriate rapid tooling process for a given injection mold requirement, and identifying critical features that could be modified to improve manufacturability, thereby achieving better quality and lower cost of molded parts along with shorter lead time.© Elsevie

Pulse Electrocodeposited Ni–WC Composite Coating

In the present work, tungsten carbide (WC) particulate of average size 10 µm were electrocodeposited in the nickel metal matrix, to form metal matrix composite (MMC) coating over the EN8 steel substrate. The electrodeposition of Ni–WC particulate composite coating was carried out using the Watt's bath under the influence of varying current density and duty cycle. It was found that current density of 0.02 A/cm2 was sufficient to start the codeposition kinetics. But, good quality of electrodeposition was obtained at a current density of 0.04 A/cm2. The WC particulate entrapment and distribution of WC particles in Ni matrix according the variation in experimental parameters has been reported. The dense and compact microstructure was obtained at a current density of 0.04 A/cm2 and duty cycle of 30%. Microhardness and corrosion resistance properties of composite coating were also evaluated and reported

Modular design applied to beverage-container injection molds

[[abstract]]This work applies modular design concepts to designating beverage-container injection molds. This study aims to develop a method of controlling costs and time in relation to mold development, and also to improve product design. This investigation comprises two parts: functionality coding, and establishing a standard operation procedure, specifically designed for beverage-container injection mold design and manufacturing. First, the injection mold is divided into several modules, each with a specific function. Each module is further divided into several structural units possessing sub-function or sub-sub-function. Next, dimensions and specifications of each unit are standardized and a compatible interface is constructed linking relevant units. This work employs a cup-shaped beverage container to experimentally assess the performance of the modular design approach. The experimental results indicate that the modular design approach to manufacturing injection molds shortens development time by 36% and reduces costs by 19∼23% compared with the conventional approach. Meanwhile, the information on modularity helps designers in diverse products design. Additionally, the functionality code helps effectively manage and maintain products and mol