Extruded and injection moulded virgin PA 6/6 as abrasion resistant material

Polyamide (PA6/6) is often used as a tribological pair in abrasion prevalent applications such as hinges and sliders. PA6/6 is frequently processed by injection moulding and extrusion process. It is known that these processes influence the polymers mechanical behaviour, but their influence on the polymers wear response has not been studied. Hence the present research attempts to study the influence of different manufacturing processes on tribological behaviour for PA6/6. Wear tests were performed on a pin abrading tester (DIN 50322). Abrasion resistance of both extruded and injection moulded PA6/6 were tested at different loads (20 and 35 N). Single-pass (nonoverlapping mode) and multipass testing (overlapping mode) were used to understand the influence of clogging of wear debris. It is evidenced that with increasing load the specific wear rate decreases; moreover, fine abrasives tend to reduce the wear rate. In multipass testing a transfer layer clogged on the counterface that acted as a protective agent and lowers wear rate. Poor mechanical strength of injection moulded polymers is apparently compensated by microstructural response for having a similar wear behaviour between extruded and injection moulded PA 6/6. Hence a proper balance between microstructural and mechanical characteristics is an absolute must in PA 6/6 for better wear performance

Measurement of Nanoparticles Release during Drilling of Polymer Nanocomposites

Nanomaterials are one of the promising technologies of this century. The Project on Emerging Nanotechnologies [1] reports more than 1600 consumer products based on nanotechnology that are currently on the market and advantages link to the reinforcement of polymeric materials using nano-fillers are not to demonstrate anymore. However, the concerns about safety and its consumer perception can slow down the acceptance of nanocomposites. Indeed, during its life-cycle, a nanotechnology-based product can release nano-sized particles exposing workers, consumers and environment and the risk involved in the use and disposal of such particles is not well known. The current legislation concerning chemicals and environment protection doesn’t explicitly cover nanomaterials and changes undergone by nanoparticles during the products’ life cycle. Also, the possible physio-chemical changes that the nanoparticles may undergo during its life cycle are unknown. Industries need a standard method to evaluate nanoparticles release during products’ life cycle in order to improve the knowledge in nanomaterials risk assessment and the legislation, and to inform customers about the safety of nanomaterials and nanoproducts. This work aims to propose a replicable method in order to assess the release of nanoparticles during the machining of nanocomposites in a controlled environment. For this purpose, a new experimental set-up was implemented and issues observed in previous methods (background noise due to uncontrolled ambient environment and the process itself, unrepeatable machining parameters) were solved. A characterisation and validation of the chamber used is presented in this paper. Also, preliminary testing on drilling of polymer-based nanocomposites (Polyamide-6/Glass Fibre reinforced with nano-SiO2) manufactured by extrusion and injection moulding were achieved

Experimental Research Work to Optimize Process Parameters into Electro Chemical Abrasive Flow Machining using Taguchi Methodology

Electrochemical assisted abrasive flow finishing is a newly developed hybrid finishing process which is used to finish the internal parts of work piece having complicated geometry to large extent. In electrochemical assisted abrasive flow machining higher abrasion of the material was detected due to the combine effect of ECM and AFF processes. In Electrochemical aided abrasive flow machining a electrolyte is added to the prepared media .This media consist a kind of polymeric carrier and abrasive particles that are hydrocarbon gel, Al2O3, Silicon based polymer, and NaI Sodium iodide as electrolytic salt. In this experimental research different process parameters such as voltage, abrasive concentration, Number of cycle, molal concentration and diameter of rod were considered at different levels for response characteristic of surface roughness Ra and material removal MR based on Taguchi method using standard L27 orthogonal array OA for the plan of experimentation. To determine the contribution of each parameter analysis of variance was used. Sandeep Singh | Sunil kumar "Experimental Research Work to Optimize Process Parameters into Electro Chemical Abrasive Flow Machining using Taguchi Methodology" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-4 , June 201

The potential of additive manufacturing in the smart factory industrial 4.0: A review

Additive manufacturing (AM) or three-dimensional (3D) printing has introduced a novel production method in design, manufacturing, and distribution to end-users. This technology has provided great freedom in design for creating complex components, highly customizable products, and efficient waste minimization. The last industrial revolution, namely industry 4.0, employs the integration of smart manufacturing systems and developed information technologies. Accordingly, AM plays a principal role in industry 4.0 thanks to numerous benefits, such as time and material saving, rapid prototyping, high efficiency, and decentralized production methods. This review paper is to organize a comprehensive study on AM technology and present the latest achievements and industrial applications. Besides that, this paper investigates the sustainability dimensions of the AM process and the added values in economic, social, and environment sections. Finally, the paper concludes by pointing out the future trend of AM in technology, applications, and materials aspects that have the potential to come up with new ideas for the future of AM explorations

A comparison of processing techniques for producing prototype injection moulding inserts.

This project involves the investigation of processing techniques for producing low-cost moulding inserts used in the particulate injection moulding (PIM) process. Prototype moulds were made from both additive and subtractive processes as well as a combination of the two. The general motivation for this was to reduce the entry cost of users when considering PIM. PIM cavity inserts were first made by conventional machining from a polymer block using the pocket NC desktop mill. PIM cavity inserts were also made by fused filament deposition modelling using the Tiertime UP plus 3D printer. The injection moulding trials manifested in surface finish and part removal defects. The feedstock was a titanium metal blend which is brittle in comparison to commodity polymers. That in combination with the mesoscale features, small cross-sections and complex geometries were considered the main problems. For both processing methods, fixes were identified and made to test the theory. These consisted of a blended approach that saw a combination of both the additive and subtractive processes being used. The parts produced from the three processing methods are investigated and their respective merits and issues are discussed

Nonterrestrial utilization of materials: Automated space manufacturing facility

Four areas related to the nonterrestrial use of materials are included: (1) material resources needed for feedstock in an orbital manufacturing facility, (2) required initial components of a nonterrestrial manufacturing facility, (3) growth and productive capability of such a facility, and (4) automation and robotics requirements of the facility

Thermo-mechanical analysis of additively manufactured hybrid extrusion dies with conformal cooling channels

Profile overheating and surface defects during hot aluminum extrusion can occur when seeking higher productivity rates at increased ram speed velocities. The incorporation of cooling channels in the die-design allows overcoming this process limitation by keeping the profile temperature below the melting point of the alloy used [1]. Selective laser melting (SLM) of conformal cooling channels provides, in contrast to conventional manufacturing techniques, the opportunity to place the cooling circuit inside the mandrel of a porthole-die in a well-defined position to the critical bearing region [2]. In the framework of this study, a preliminary numerical investigation on the extrusion process under the assumption of liquid nitrogen cooling is analysed. The results show, that by combining conformal cooling channels with liquid nitrogen as a cooling media high cooling rates, which are well beyond the state of the art of conventional dies, can be achieved. In a hybrid extrusion die set-up, a part of the mandrel, that is additively manufactured, is either joined [3] or directly selective leaser melted onto the conventionally manufactured parts [4]. For a proper implementation in the extrusion process, material testing of the welded joint are needed. Thus, in the current study, tensile tests performed at room temperature for hybrid specimens, partially consisting of conventionally processed tool steel 1.2343 and partially additively manufactured 1.2709, will be presented. Moreover, four different heat treatment sequences of the hybrid specimens will be discussed. In addition, for each configuration, micro-structural images are taken to investigate failure at the bonding region. Finally, an optimal manufacturing sequence for a hybrid die with the described material combination is proposed

Roughness evolution of previously milled samples along a polishing test

In the present work results about roughness evolution along a polishing operation with corundum disks of size Norton 400 are presented. Hardened steel and hardened stainless steel samples were previously subjected to ball-end milling or side milling with cylindrical tool at different cutting conditions. Roughness height parameters Ra and Rt, as well as parameters related to the Abbott-Firestone curve such as Rk, Rpk, and Rvk, and shape parameters such as Rsk and Rku were studied. It is usually considered that a polishing operation is complete when Ra does not decrease significantly with more polishing time. In the present paper, an alternative method for determining the end of a polishing test is presented. Roughness is measured both in the longitudinal and in the transversal direction with respect to cutting marks, and it is assumed that the polishing operation is finished when longitudinal values equal transversal values, provided that from that moment on roughness values do not decrease significantly. Moreover, it is recommended to measure parameter Rvk in addition to or even instead of Ra, in order to obtain information about the presence of valleys from the previous milling operation.Postprint (author's final draft