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

In-Situ Preheating in Hybrid Layered Manufacturing for Tooling Elements

Solidification cracking of hard materials such as H13 tool steel is one of the major problems in metal based Additive Manufacturing (AM) processes. Hybrid Layered Manufacturing (HLM) is one of the metal based AM process which uses Metal Inert Gas (MIG) cladding for addition and CNC milling for subtraction of material. In this work, an in-situ induction heating based preheating system has been developed to solve the solidification cracking problem. The Tungsten Inert Gas (TIG) and Induction heating methods are compared and it has been found that the induction based preheating system can produce better microstructure and sound products. In the experimental procedure, before deposition of a layer the prebuild layer is preheated up to 350-5000C. Also the effect of in-situ preheating on the microstructure of the deposited layers have been studied using Scanning Electron Microscope (SEM).Mechanical Engineerin

Evaluation on performance of square finned conformal cooling channel (sfccc) fabricated by selective laser melting (slm) on plastic moulded part

In plastic injection moulding (PIM) process, the cooling stage is the most important phase because it significantly affects the productivity and quality of the molded part. Thus, the cooling system need to be emphasized in designing the injection mould system. The application of conformal cooling channels which only can be fabricated by additive manufacturing technology (AM) are proven to increase the injection moulding performance and able to reduce the quality issues. This research introduced the Square Finned Conformal Cooling Channel (SFCCC) in the PIM as a way to enhance the performance of square shape conformal cooling channel (SSCCC) in PIM. The mould insert with SFCCC has been designed, simulated via finite element analysis software, fabricated (by combination of High Speed Machining and Selective Laser Melting (SLM)), and tested using a front panel housing as the injected part for the case study. Eight types of variate SFCCC design (SFCCC 1 to SFCCC 8) employing finned and sub groove concept were analysed via simulation work to determine the best design in terms of shortest cooling time. The results showed that the shortest cooling time recorded by SFCCC 8 was at 7.621 sec, an improvement of 16.44% compared with SSCCC. In terms of cycle time, the SFCCC is able to improve the SSCCC by 8.33% to 10.26%. Meanwhile, in comparison with industrial mould using Milled Groove Conformal Cooling Channel (MGCCC), the SFCCC showed an improvement of 19.60% to 39.36% based on the coolant temperature. The experimental results showed the greatest shrinkage in the X-direction at 0.93% and the smallest shrinkage at 0.6%. For the Y-direction, the greatest shrinkage is 0.97% and the smallest shrinkage is 0.39%. In comparison with the injected part via MGCCC, the SFCCC had a slightly greater overall shrinkage in relation to the shrinkage and warpage at points X and Y direction. Most front panel housing shrinkage and warpage values in the experimental study were smaller than those of the simulative study. However, the experimental results were in line with the simulative results, proving that the SFCCC design had better cycle times and acceptable quality for an industrial mould

Design and fabrication of conformal cooling channels in molds:Review and progress updates

Conformal cooling (CC) channels are a series of cooling channels that are equidistant from the mold cavity surfaces. CC systems show great promise to substitute conventional straight-drilled cooling systems as the former can provide more uniform and efficient cooling effects and thus improve the production quality and efficiency significantly. Although the design and manufacturing of CC systems are getting increasing attention, a comprehensive and systematic classification, comparison, and evaluation are still missing. The design, manufacturing, and applications of CC channels are reviewed and evaluated systematically and comprehensively in this review paper. To achieve a uniform and rapid cooling, some key design parameters of CC channels related to shape, size, and location of the channel have to be calculated and chosen carefully taking into account the cooling performance, mechanical strength, and coolant pressure drop. CC layouts are classified into eight types. The basic type, more complex types, and hybrid straight-drilled-CC molds are suitable for simply-shaped parts, complex-shaped parts, and locally complex parts, respectively. By using CC channels, the cycle time can be reduced up to 70%, and the shape deviations can be improved significantly. Epoxy casting and L-PBF show the best applicability to Al-epoxy molds and metal molds, respectively, because of the high forming flexibility and fidelity. Meanwhile, LPD has an exclusive advantage to fabricate multi-materials molds although it cannot print overhang regions directly. Hybrid L-PBF/CNC milling pointed out the future direction for the fabrication of high dimensional-accuracy CC molds, although there is still a long way to reduce the cost and raise efficiency. CC molds are expected to substitute straight-drilled cooling molds in the future, as it can significantly improve part quality, raise production rate and reduce production cost. In addition to this, the use of CC channels can be expanded to some advanced products that require high-performance self-cooling, such as gas turbine engines, photoinjectors and gears, improving working conditions and extending lifetime

Keberkesanan program latihan industri di kalangan pelajar jurusan Diploma Akauntasi di Politeknik-politeknik Kementerian Pendidikan Malaysia

Kajian ini bertujuan untuk mengkaji keberkesanan program latihan industri politeknik di bidang perakaunan. Selain itu, tahap kesesuaian, kesediaan pelajar dan keberkesanan program latihan industri juga telah ditinjau. Kajian ini dijalankan pada September 2002 dan melibatkan seramai 60 orang pelajar Diploma Akauntasi semester 5 dan 6 iaitu masing-masing 20 orang pelajar daripada Politeknik Seberang Perai (PSP), Politeknik Sultan Abdul Halim Mu'adzam Shah (POLIMAS) dan Politeknik Ungku Omar (PUO). Responden telah menjalani program latihan industri semasa berada di semester keempat. Seorang pegawai Unit Perhubungan dan Latihan Industri Politeknik Johor Bahru dan seorang pensyarah daripada Politeknik Seberang Perai telah ditemubual. Instrumen kajian ini melibatkan soal selidik dan juga temubual. Statistik deskriptif dan inferensi telah digunakan untuk menganalisa maklumat tersebut. Hasil dapatan kajian ini telah menunjukkan bahawa kesesuaian pelajar adalah pada tahap yang memuaskan. Kajian ini juga menunjukkan kesediaan pelajar berada pada tahap memuaskan. Keberkesanan program latihan industri pula berada pada tahap amat memuaskan. Dapatan juga menunjukkan bahawa responden daripada PSP, POLIMAS dan PUO mempunyai kepuasan pada tahap sederhana terhadap kesesuaian dan kesediaan pelajar manakala bagi keberkesanan program latihan industri, responden daripada PSP dan POLIMAS menunjukkan kepuasan yang tinggi manakala responden daripada PUO menunjukkan kepuasan yang sederhana. Selain itu, bukti-bukti menunjukkan faktor kesesuaian adalah penentu yang paling signifikan terhadap keberkesanan program latihan industri berbanding faktor kesediaan pelajar. Dapatan kajian yang terakhir telah menunjukkan bahawa faktor kesesuaian dan kesediaan pelajar menyumbang kepada 18% varians dalam keberkesanan program latihan industri. Di akhir kajian ini, satu instrumen pra-penilaian program latihan industri dalam bentuk senarai semak telah dibangunkan berdasarkan input dapatan kajian untuk kegunaan pelajar-pelajar politeknik

Near net shape manufacturing of metal : a review of approaches and their evolutions

In the last thirty years the concept of manufacturability has been applied to many different processes in numerous industries. This has resulted in the emergence of several different "Design for Manufacturing" methodologies which have in common the aim of reducing productions costs through the application of general manufacturing rules. Near net shape technologies have expanded these concepts, targeting mainly primary shaping process, such as casting or forging. The desired outcomes of manufacturability analysis for near-net-shape (NNS) processes are cost and lead/time reduction through minimization of process steps (in particular cutting and finishing operations) and raw material saving. Product quality improvement, variability reduction and component design functionality enhancement are also achievable through NNS optimization. Process parameters, product design and material selection are the changing variables in a manufacturing chain that interact in complex, non-linear ways. Consequently modeling and simulation play important roles in the investigation of alternative approaches. However defining the manufacturing capability of different processes is also a “moving target” because the various NNS technologies are constantly improving and evolving so there is challenge in accurately reflecting their requirements and capabilities. In the last decade, for example, CAD, CNC technologies and innovation in materials have impacted enormously on the development of NNS technologies. This paper reviews the different methods reported for NNS manufacturability assessment and examines how they can make an impact on cost, quality and process variability in the context of a specific production volume. The discussion identifies a lack of structured approaches, poor connection with process optimization methodologies and a lack of empirical models as gaps in the reported approaches

Alumide tooling for limited production plastic injection moulding

Published ThesisExisting techniques for the production of conventional steel tooling for plastic injection moulding are expensive and time consuming. The result is that many new products often do not advance beyond the prototype stage. This thesis describes an investigation into the possibility of using laser-sintered Alumide® (an aluminium-filled polyamide material) in a novel approach as an alternative process for producing rapid tooling inserts for the injection moulding process. Alumide® material properties and process parameters, such as heat capacity, accuracy and surface roughness, required for injection moulding applications, were examined. To reduce internal stresses during the manufacturing process of Alumide® inserts, which could result in warpage, the inserts need to be shelled. For shelled inserts to withstand the injection pressures occurring during an injection moulding cycle, they need to be backfilled. A suitable backfilling material as well as a suitable wall thickness for the shelled Alumide® inserts was determined. Injection moulding trials conducted with Alumide® inserts showed that conformal cooling channels inside the inserts have an influence on the cooling of the inserts. During the trials, cooling channels underneath the cavities of the Alumide® inserts collapsed due to injection pressures of the molten polymer. To prevent cooling channels from collapsing during an injection moulding cycle, a suitable distance between the cavity surface and a cooling channel was ascertained. To determine the durability of Alumide® inserts for the injection moulding process, a geometrical product was developed and Alumide® inserts were manufactured for injection moulding trials. Two hundred geometrical parts were manufactured from Alumide® inserts using Polypropylene (PP) and Acrylonitrile-Butadiene-Styrene (ABS) with minimal wear on the inserts. Injection moulding trials conducted with Polycarbonate (PC) and Polyamide 6 (PA 6) resulted in significant wear during the first few injection moulding cycles. From these trials, it was concluded that polymer materials with process parameters similar to PP and ABS can be used with Alumide® inserts for the injection moulding process. A limited production run for an electrical enclosure was conducted with Alumide® inserts. Two sets of inserts were manufactured and injection mould trials with PP and ABS were conducted. Two hundred parts were manufactured from each set of inserts using PP and ABS, without significant wear to the inserts. Production with the ABS material was continued and 2500 parts were manufactured from the Alumide® inserts with deformation occurring to the fixed side insert (cavity) and minimal wear to the moving side insert (punch). A manufacturing cost and time comparison between Alumide® inserts, tool steel and aluminium inserts (manufactured through conventional manufacturing techniques), additive manufactured inserts (through the Direct Metal Laser Sintering (DMLS) and PolyJet processes) and parts manufactured directly from additive manufacturing processes (rapid manufacturing), were conducted. From the comparisons, it was evident that Alumide® inserts are the most cost-effective manufacturing process to produce limited run plastic injection moulded parts

Study on defect of aluminium filled epoxy mold insert in injection molding

The purpose of this project is to study the used of composite material as an insert in injection molding process. Epoxy with aluminium filled was used and casted to fabricate the cavity insert of the mold. As with most cast products, machining is necessary due to the fact that cast parts can only be made to near net shape. For that reason, CNC machine was used to machine the casted material into desired shape and dimensions. Plastic flow analysis software has been used to obtain optimum injection machine parameters for production of polypropylene (PP) part. It was evident that slight changes had happen to the insert as the composite material itself tends to fail after a number of injection shots. Finite element analysis (FEA) software was used to simulate the insert displacement or deformation due to the effect of molding temperature experienced by the insert. After 300 successful injections were obtained, the insert was inspected and measured physically. It was found that the insert experienced a slight change uniformly and dimensionally after comparing the data against results of the FEA software

Design and Development of Cellular Structure for Additive Manufacturing

The demand for shorter product development time has resulted in the introduction of a new paradigm called Additive Manufacturing (AM). Due to its significant advantages in terms of cost effective, lesser build time, elimination of expensive tooling, design flexibility AM is finding applications in many diverse fields of the industry today. One of the recent applications of this technology is for fabrication of cellular structures. Cellular structures are designed to have material where it is needed for specific applications. Compared to solid materials, these structures can provide high strength-to-weight ratio, good energy absorption characteristics and good thermal and acoustic insulation properties to aerospace, medical and engineering products. However, due to inclusion of too many design variables, the design process of these structures is a challenge task. Furthermore, polymer additive manufacturing techniques, such as fused deposition modeling (FDM) process which shows the great capability to fabricate these structures, are still facing certain process limitations in terms of support structure requirement for certain category of cellular structures. Therefore, in this research, a computer-aided design (CAD) based method is proposed to design and develop hexagonal honeycomb structure (self-supporting periodic cellular structure) for FDM process. This novel methodology is found to have potential to create honeycomb cellular structures with different volume fractions successfully without any part distortion. Once designing process is complete, mechanical and microstructure properties of these structures are characterized to investigate effect of volume fraction on compressive strength of the part. Volume fraction can be defined as the volume percentage of the solid material inside the cellular structure and it is varied in this thesis by changing the cell size and wall thickness of honeycombs. Compression strength of the honeycomb structure is observed to increase with the increase in the volume fraction and this behavior is compared with an existing Wierzbicki expression, developed for predicting compression properties. Some differences are noticed in between experimentally tested and Wierzbicki model estimated compressive strength. These differences may be attributed to layer by layer deposition strategy and the residual stress inherent to the FDM-manufacturing process. Finally, as a design case study, resin transfer molding (RTM) mold internally filled with honeycomb is designed and tested instead of the regular FDM mold. Results show that our proposed methodology has the ability to generate honeycomb structures efficiently while reducing the expensive build material (Mold) consumption to near about 50%. However, due to complex geometry of the honeycomb pattern the build time increased about 65% compare to solid FDM mould. In this regard, FDM tool-path can be optimized in future, so that overall product cost will be minimized. As per the author’s knowledge, this design methodology will have a greatest contribution towards creating sustainable and green product development. Using this, in future, expensive build material and production time can also be minimized for some hydroforming and injection molding applications