Implementation of Innovative Manufacturing Technologies in Foundries for Large-Volume Components

The development of new manufacturing technologies opens up new perspectives for the production of propellers (diameter < 5 m), especially since the use of the established sand casting process as a technology is only partially competitive in today’s market. Therefore, different applications of generative manufacturing methods for the implementation into the production process were investigated. One approach is the mould production using additive manufacturing processes. Investigations showed that especially for large components with high wall thicknesses available systems and processes for sand casting mould production are cost-intensive and conditionally suitable. With our development of a large-format FDM printer, however, the direct production of large-format positive moulds for, for example, yacht propellers up to 4 m in diameter is possible. Due to the comparatively low accuracy requirements for the mould, the focus is on the durability of the drive system and the rigidity of this FDM printer. Equipped with simple linear technology in portal design and cubic design of the frame structure with rigid heated print bed, the aim is to achieve maximum material extrusion via the print head. The production of plastic models not only facilitates handling during the moulding process, but also allows considerable time and cost savings to be made during the running process. A further step in our development is the direct production of the components using WAAM. A possible concept for robot-supported build-up welding for the production of new innovative propeller geometries is presented using the example of a hollow turbine blade for a tidal power plant.

Influence of Sand Casting Waste as Substitutor of Quartz Sand in Mortar

Sand casting waste has the potential to replace quartz sand in mortar manufacture because it contains high silica. This study uses sand casting waste from the steel industry in Gresik, Indonesia to observe how it affects the quality of the mortar. Initial characterization were carried out to determine the properties of the material, including; magnetic test which results are not attracted by magnets, moisture content test with a value of 0.328%, XRD test to determine the crystallinity content which results contain 99.52% Silica Quartz, and XRF test to determine the content of the compound in which results are 81.25% Silica dominant. Then observations were made by making mortar with the replacement of quartz sand by sand casting with variations of 0% wt, 25% wt, 50% wt, and 100% wt and then tested its compressive strength at 3 days, 7 days, and 28 days. Based on the research that has been done, the optimum result using sand casting is at 25% wt with a compressive strength of 251.15 kgf/cm2 at 28 days of age which is higher than the standard.

Optimization of Aluminum Sand Casting process parameters on RSM and ANN methods

Sand casting is one of the best processes to produce a product to satisfy the customer requirements. The prime advantages of choosing the sand casting technique are perfect dimensional geometry, development of pattern is easy, production rate is high, and solidification time is low when compared to other casting techniques. The main purpose of sand casting is to produce a product with better quality in low cost. The properties of the green sand are based on the sand composition and the most important parameters in the preparation of moulding sand are green strength, moisture content and clay content. In this work, the silica oxide is blended in green sand with various compositions for cope box. The various compositions of sand parameters are experimentally investigated by using Response Surface Methodology (RSM). The results of sand parameters are compared with Artificial Neural Network (ANN) analysis. The blending of 9.2% SiO2 with green sand is very suitable for this casting process. The blending of 9.2% SiO2 with green sand is very suitable for this casting process. The effect of SiO2 blending with green sand, the initial raw material is reduced up to 25% of volume without casting defects. The hardness value increased up to 22% and the surface roughness decreased up to 12% by varying the percentage of SiO2 in green sand.

Green strength properties of waterjet abrasive waste as potential composition in green mould by Taguchi and ANOVA approach

The sand casting process still continues today due to the cost-effectiveness of materials and processes. There is a wide variety of castings related to composition and size, but silica sand is widely available from coastal line mining and has a negative impact on the environment. Moreover, waste from waterjet cutting of non-ferrous and ferrous metals is practically unhazardous and may potentially be used in sand casting mould. The aim of this paper is to optimize the proportion of coal dust, water and bentonite added to the silica sand mixture and the waterjet cutting abrasive waste as a new way of handling waste with the potential to be used in sand casting manufacturing. The method used was L9 orthogonal array optimization and the composition was qualitatively measured using a green compression strength test and a green shear strength test. Factors were evaluated using the analysis of variance (ANOVA) to find the the critical factors while confirmation test was conducted for the optimal material proportion. The study concluded that the ideal ratio for silica sand mixture with waterjet abrasive waste is bentonite-12%, coal dust-5%, and water-7% for green compression strength while bentonite-12%, coal dust-6%, water-7% for green shear strength. With proper selection, the incorporation of waterjet abrasive waste into the green sand mixture is promising to potentially be used in green sand mould casting without undermine the quality of mould.

Tensile and Hardness Properties of Cast 6063 Aluminium Rods produced from Sand and Squeeze Casting Moulds

This work presents experimental analysis to determine the effect of sand and squeeze casting methods on the Tensile and Hardness properties of AA6063 Aluminium. Sand and squeeze cast moulds were fabricated and used to produce Aluminium rods. The test samples from cast rods were subjected to Tensile and Hardness tests. The results obtained showed better Tensile and Hardness properties, in the squeeze cast samples that were produced under varied pressure. The hardness of squeeze casting varied from 72.9 to 82.3Hv, while that of sand casting had 70.0Hv. Also, Ultimate Tensile Strength increased with increased pressure in squeeze castings from 178.01 to 194.04MPa and 161.97 in sand castings. Conversely, the mechanical properties of the cast products improved from those of sand casting to squeeze casting. Therefore, squeeze cast products could be used in as-cast condition in engineering applications requiring high quality parts while sand casting may be used in as-cast condition for non- engineering applications or engineering applications requiring less quality parts

Process Characteristics of Water-based Self-curing Coatings for Sand Casting

The rheological and gas evolution characteristics of water-based self-curing coatings for sand casting were analyzed and the influence of coating-thickness and graded coating on self-curing rate of coatings was studied. It can be seen from the test results that: the new water-based self-curing coating has both the characteristics of thixotropic fluid and pseudoplastic fluid, which has moderate thixotropy rate and high brushing index, good brushability and excellent comprehensive balance of flow-levelling and anti-flowability. It can meet the rheological requirements of various coating methods. The self-curing speed of water-based self-curing coating increases in an approximately linear manner with the decrease of its thickness. Thick coating should be best to paint at one time in the premise of ensuring its surface quality. Although the gas evolution volume of the new water-based self-curing coating is approximately equal to that of ordinary water-based baking coatings, but the gas evolution speed of self-curing coatings is almost half as that of the latter, which provides good conditions for preventing gas hole defect of casting.

नेपाली धातुकला विधि र परम्परा [Nepali Metalwork Method and Tradition]

मूर्ति रचना पद्धतिका सन्दर्भमा नेपालमा धातुकलाको निकै लामो र विशिष्ट परम्परा रहिआएको छ ।धातुकलामा ढलाइ (Casting) पद्धति र पाता अर्थात् रिपोसे (Sand casting) पद्धति प्रचलित रहेका छन् । स्यान्ड कास्टिङ (Sand casting) लाई ढलान पद्धतिमा वैकल्पिक विधिका रूपमा लिइन्छ । धातुमूर्ति रचना पद्धतिमा मैन निर्गम पद्धति (Lost wax Process) को अलगै महत्व रहेको छ । प्रस्तुत अध्ययन मैन निर्गम पद्धतिको परम्परामा केन्द्रित रहेको छ । ढलाइ पद्धति साँचामा पग्लेको धातु खन्याई मैनको ‘मानसरा’ मा मधुच्छिष्ट विधानम् भनी उल्लेख गरिएको पाइन्छ । यस पद्धतिलाई फ्रान्सेली भाषामा ‘सेर पर्डु’ (cere-perdue) र अङ्ग्रेजी भाषामा (lost wax process)भनिन्छ । ऐतिहासिकताका दृष्टिले सिन्धुघाटी सभ्यताको मोहेन्जोदारोमा प्राप्त २५०० इस्वी संवत्पूर्वको ‘नर्तकी’ नाम दिइएको धातु मूर्ति सर्वाधिक प्राचीन मानिएको छ । मैन निर्गम पद्धतिबाट गठित तथाखोक्रो दुबै खालका मूर्ति बनाउन सकिन्छ । यो पद्धति भारतका बिभिन्न आदिवासी समुदायमा पनि ‘डोकरा कास्टिङ’ नामले प्रचलित रहेको पाइन्छ । आधुनिक पद्धतिका तुलनामा यो पद्धति कम खर्चिलोभए तापनि परम्परागत पद्धतिमा केही चुनौतीहरू पनि रहेका छन् ।

Comparative Study on Microstructure and Corrosion Resistance of Al-Si Alloy Cast from Sand Mold and Binder Jetting Mold

This investigation is focused on the corrosion evaluation of an as-cast Al-Si alloy, obtained by two different casting methods: traditional sand casting and three-printing casting, using a binder jetted mold. The experimental results are discussed in terms of chemical composition, microstructure, hardness, and corrosion behavior of two different casting parts. The microstructure and composition of the sample before and after the corrosion tests was analyzed using light microscopy (OM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (DRX). The corrosion of the two processed castings was analyzed using anodic polarization (PA) test and electrochemical impedance spectroscopy (EIS) in an aerated solution of 3.5% by weight NaCl, similar to the seawater environment. After the corrosion process, the samples were analyzed by inductively coupled plasma/optical emission spectrometry (ICP/OES); the composition was used to determine the chloride solution after immersion times. The sample processed by binder jetting mold showed higher corrosion resistance with nobler potentials, lower corrosion densities, higher polarization resistance, and more stable passive layers than the sample processed by sand casting. This improvement of corrosion resistance could be related to the presence of coarse silicon particles, which decrease of cathodic/anodic ratio and the number of micro-galvanic couples, and the lower amount of intermetallic β Al-Fe-Si phase observed in cast alloy solidified in binder jetting mold.