Mold Surface Research Articles

Analysis of Flow and Fluctuation Characteristics in Coated Slag Using a 2D Model in the Meniscus Region of Mold

Steel is mainly produced through continuous casting; molten steel flows into the mold from the tundish, where it cools and then enters the secondary cooling zone, ultimately solidifying into a billet. During the continuous casting production process, the quality of the casting billet is mainly related to the lubrication state of the coated slag. In the upper part of the mold, the consumption of liquid protective slag directly affects the friction state of the initial solidified billet shell. Therefore, the flow and fluctuation characteristics of coated slag in the meniscus area are very important. There is limited research on the flow and fluctuation characteristics of coated slag in the meniscus area, and little consideration has been given to the shape of the meniscus. In this work, a two-dimensional numerical model for the flow and fluctuation of coated slag in the meniscus region was established, and the transient flow velocity of protective slag and molten steel at each moment of the vibration cycle was obtained, as well as the fluctuation of the slag/steel interface in the meniscus region. The results show that when the surface mold vibrated upwards, the protective slag in the meniscus area flowed clockwise. When the mold moved downwards, the protective slag in the slag pool generated a counterclockwise flow vortex. When the mold was in a positive slip state, the negative pressure formed by the upward flow of the protective slag on the meniscus and the inertia force of steel liquid pushed the meniscus toward the inner wall of the mold. During negative slip, the flow of coated slag generated positive pressure on the slag/steel interface, pushing the meniscus toward the steel liquid, and at the initial moment of negative slip, the steel liquid overflowed into the slag channel. This model could provide a theoretical basis for the flow control of protective slag.

Regional distribution and diversity of Aspergillus and Penicillium species on Croatian traditional meat products

Various factors, such as weather and production practices (e.g., environmental hygiene, process duration, raw material quality, ripening temperature, and relative humidity), in combination with the intrinsic product properties (e.g., pH, aw, salt content), significantly affect the growth of surface moulds. The aim of this study was to isolate and identify surface moulds retrieved from traditional meat products (TMPs) and correlate these data to the production region and production technology. The surface of 250 TMPs (dry-fermented sausages, n = 108; dry-cured meat products, n = 142) from five Croatian regions were sampled during a two-year period. Dry-fermented sausages had a significantly higher pH and a lower salt concentration when compared to dry-cured meat products. In total, 528 isolates were obtained, comprising 20 Penicillium and 17 Aspergillus species. The species most frequently isolated from the dry-fermented sausages were P. commune (32.4 %), A. proliferans (33 %), and P. solitum (14.8 %), while A. proliferans (52.1 %), P. commune (28.9 %) and P. citrinum (19.7 %) predominated in dry-cured meat products. Aspergillus predominated on the TMPs from southern Croatia, while Penicillium was prevalent on products from the other four regions, possibly due to differences in weather conditions. Seven potentially mycotoxigenic species (A. creber, A. flavus, A. niger, A. westerdijkiae, P. citrinum, P. commune, and P. nordicum) were isolated and identified. Regular monitoring of mould species and their toxigenic metabolites present on traditional meat products is of the utmost importance from the public health perspective, while the results of such a monitoring can prove beneficial for the tailoring of the production technology development.

Visualizing the Invisible: How Digital Images Reveal the Impact of Surface Mold on Airborne Fungal Levels

Visualizing the Invisible: How Digital Images Reveal the Impact of Surface Mold on Airborne Fungal Levels

Microstructure, mechanical properties, and tribological properties of laser assisted cold sprayed CuCrZr coatings: Influences of laser power and laser position

CuCrZr has good conductivity, thermal conductivity and high strength and is widely used in the production of continuous casting mold. In this study, for the first time, high-performance CuCrZr coatings were successfully deposited on the surface of CuCrZr mold by laser assisted cold spray (LACS) method as a preliminary trial to validate LACS a repair technique of worn mold surfaces. This study systematically characterizes the microstructure, microhardness, bonding strength, electrical conductivity, wear performance, and thermal shock performance of CS, concentric LACS and eccentric LACS coatings. The results show that compared to CS, LACS shows great improvements in coating density, bond strength, friction and wear performance, and electrical conductivity, thus exhibiting significant prospects in the repair of mold. In particular, eccentric LACS CuCrZr coatings feature higher bonding strength and deposition efficiency, while concentric LACS coatings have better wear, hardness, and electrical conductivity. The best overall coating performance is achieved at eccentric LACS-4 kW-5.5 mm CuCrZr coating which exhibits a porosity of 0.49 %, a grain size of 1.06 µm, a microhardness of 200 HV0.3, a bond strength of 205 MPa (on CuCrZr substrates), a friction coefficient of 0.48 and a wear rate of 1.55 × 10-5 mm3/N·m (counterbody: GCr15 balls, 15 N load), an electrical conductivity of 63.50 % IACS, and a thermal shock resistance of > 120 cycles under 650 ℃. The mechanisms associated with microstructural formation and mechanical performances of LACS coatings are also analyzed. There was no obvious phase change within the coating, while a heat affected zone is formed at the coating-substrate interface with the formation of CuxZry phases and slight oxides. The grain characteristics of LACS coatings include deformed grains, recovered grains, recrystallized grains. The wear mechanisms of LACS coatings are combined adhesive wear and abrasive wear.

Preparation of ultrastable oil-in-water emulsion as a robust superwettable and sustainable concrete release agent

Release agents are compounds that are applied on the surface of moulds to create a thin film that acts as a barrier to prevent adhesion. Water-based release agents are especially preferred during the formulation due to their eco-friendly nature and less toxicity. In this work, we present a facile fabrication of a novel wax-free oil-in-water (O/W) emulsion-based release agent as a sustainable and efficient commercial product for the proficient removal of concrete from mould. The newly formulated O/W release agent was synergistically stabilized by the combination of Sorbitan monostearate (span-60) and Sodium dodecylbenzene sulfonate (SDBS) from 0.6% to 4.0% surfactant concentrations. The surfactant ratio (1:1) was optimized as best based on the hydrophilic-lipophilic balance (HLB). Firstly, physical parameters such as high/shear speed (12000 rpm), oil/water ratio (60:40), temperature (55 °C), and high/shear time (10 min) were optimized. Afterward, the performance and chemical properties of the O/W release agent were investigated by monitoring surface morphology, density, viscosity, contact angle, droplet size, and pH. The new O/W release agent achieved excellent results during on-site trials on iron mould surfaces indicating the promising potential in the construction industry.

PO118: Surface Mould Brachytherapy for Extramammory Paget's Disease: Workflow and Initial Experience

PO118: Surface Mould Brachytherapy for Extramammory Paget's Disease: Workflow and Initial Experience

PO120: High Dose Rate Brachytherapy for Lip Cancer with Interstitial, Surface, or a Combination of Interstitial and Surface Mold Technique

PO120: High Dose Rate Brachytherapy for Lip Cancer with Interstitial, Surface, or a Combination of Interstitial and Surface Mold Technique

Enhancing Surface Temperature Uniformity in a Liquid Silicone Rubber Injection Mold with Conformal Heating Channels.

To enhance the productivity and quality of optical-grade liquid silicone rubber (LSR) and an optical convex lens simultaneously, uniform vulcanization of the molding material is required. However, little has been reported on the uniform vulcanization of LSR in the heated cavity. This paper presents a conformal heating channel to enhance the temperature uniformity of the mold surface in the LSR injection molding. The curing rate of an optical convex lens was numerically investigated using Moldex3D molding simulation software. Two different sets of soft tooling inserts, injection mold inserts with conventional and conformal heating channels, were fabricated to validate the simulation results. The mold surface temperature uniformity was investigated by both numerical simulation and experiment. In particular, both a thermal camera and thermocouples were employed to measure the mold surface temperature after LSR injecting molding. It was found that the uniformity of the mold surface for LSR injection mold with the conformal heating channel was better. The average temperature of the mold surface could be predicted by the heating oil temperature according to the proposed prediction equation. The experimental results showed that the trend of the average temperature of five sensor modes was consistent with the simulation results. The error rate of the simulation results was about 8.31% based on the experimental result for the LSR injection mold with the conformal heating channel.

RESTORATION OF METAL MOLDS FOR CENTRIFUGAL CASTING OF PIPE FROM HIGH-STRENGTH IRON BY ARC WELDING

Currently, metal molds for casting cast-iron pipes operate under severe temperature and deformation conditions, as a result of which they fail due to wear of their inner surface and the formation of cracks and a mesh of heat in the same place. (Research purpose) The research purpose is studying the possibility of defect-free restorative surfacing of the inner surface of metal molds without preheating in the environment of protective gases. (Materials and methods) All work on the development of the metalform surfacing technology was carried out on samples cut from the original metalforms. The method of arc surfacing in the environment of protective gases was taken as a basis. Various welding wires and protective media were tested for surfacing. Assessment of the surfacing quality for the presence of pores and cracks before and after mechanical treatment was carried out visually, followed by determination of the chemical composition and hardness of the deposited layer. (Results and discussion) Surfacing was carried out on the inner surfaces of the samples without preheating them. Various wires were tested for surfacing: Sv-18XGS, Sv-18XM and Np-30XGSA based on obtaining a composition close to the composition of the base metal in the deposited layer. As a result, Sv-18XMA welding wire with a diameter of 2.0 millimeters was chosen for the restorative surfacing, and a welding mixture was used as a protective medium, ensuring satisfactory formation of the deposited layer without pores and cracks with minimal splashing in the selected modes. Studies were carried out to determine the hardness and chemical composition of the deposited layer and the base metal of metal forms. (Conclusions) Proposed a technology for reducing the surfacing of the inner surface of metal molds without preheating. A comparative analysis of the hardness and chemical composition of the deposited layer and the base metal of the metal forms showed a comparable level of hardness and alloying elements in them, which will ensure the necessary wear and heat resistance of the restored metal forms

Clinical implementation of 3D printed plesiotherapy moulds using free open source software

PurposeFrom May 2021 the European regulation EU2017/745 covers the manufacture of medical devices in healthcare facilities under certain conditions. In this context, the use of 3D printing and free software can be combined to provide a solution to some of the problems for which no commercial product can be found in brachytherapy.What we present here is a procedure for the design, using open source software, and manufacture, with Fused Deposition Modeling technology, of brachytherapy surface moulds. Material and methodsThe procedure starts with a CT scan of the patient treatment area with radiopaque markers. 3D slicer software is then used to delimit the applicator mould that follows the patient's surface. After this, we use the Freecad software to design the channels where we will insert the plastic tubes through which the radiation source will deliver the treatment. We also use the Meshmixer software to make the final delimitation of the applicator edges as well as to find and correct any inconsistency. ResultsMoulds created by means of 3D printing allow us to combine the precise fit to the patient's surface of homemade solutions with the geometric accuracy between catheters of commercial products. This is clearly seen when treating small and irregular surfaces such as the ear pinna. ConclusionManufacture of brachytherapy surface moulds with FDG technology is a good example of customized solutions in healthcare facilities supported by new European legistation. If we add to this the use of free open source software, we are facing an alternative to classics solutions used up to now in superficial brachytherapy.

Ultrasonic-Assisted Electrochemical Nanoimprint Lithography: Forcing Mass Transfer to Enhance the Localized Etching Rate of GaAs.

Electrochemical nanoimprint lithography (ECNL) has emerged as a promising technique for fabricating three-dimensional micro/nano-structures (3D-MNSs) directly on semiconductor wafers. This technique is based on a localized corrosion reaction induced by the contact potential across the metal/semiconductor boundaries. The anodic etching of semiconductor and the cathodic reduction of electron acceptors occur at the metal/semiconductor/electrolyte interface and the Pt mold surface, respectively. However, the etching rate is limited by the mass transfer of species in the ultrathin electrolyte layer between the mold and the workpiece. To overcome this challenge, we introduce the ultrasonics effect into the ECNL process to facilitate the mass exchange between the ultrathin electrolyte layer and the bulk solution, thereby improving the imprinting efficiency. Experimental investigations demonstrate a positive linear relationship between the reciprocal of the area duty ratio of the mold and the imprinting efficiency. Furthermore, the introduction of ultrasonics improves the imprinting efficiency by approximately 80 %, irrespective of the area duty ratio. The enhanced imprinting efficiency enables the fabrication of 3D-MNSs with higher aspect ratios, resulting in a stronger light trapping effect. These results indicate the prospective applications of ECNL in semiconductor functional devices, such as photoelectric detection and photovoltaics.

Basal Cell Carcinoma After High Dose Rate Brachytherapy: Medium-term Dermoscopic Evaluation of Cancer's Response.

Basal cell carcinoma of the facial region remains a challenge for contemporary oncology due to the presence of aesthetic regions and critical organs. Surgery is not always the optimal solution, and high dose rate (HDR) brachytherapy has emerged as an organ-sparing treatment method whose effectiveness has been proven by a growing number of publications. Dermoscopy is a diagnostic tool that bridges clinical and pathological examination of skin lesions. It is routinely used for diagnosis, monitoring of treatment, and post-treatment evaluation; however, the literature lacks data concerning changes in dermoscopic patterns of skin cancers during and after irradiation. Our team conducted a prospective non-randomized trial of 39 patients with high-risk basal cell carcinomas (BCCs), mostly localized within the high-risk zone (H-zone) of the facial region, and who qualified for HDR brachytherapy. HDR contact brachytherapy with custom-made surface molds was introduced, delivering a dose of 45Gy in 9 fractions prescribed to the tumor. Every patient was observed clinically and dermoscopically at three observational points: before treatment, at the end of treatment (3rd week), and 24weeks after the end of therapy. The evolution of clinical and dermoscopic patterns was observed by two independent dermoscopists using current diagnostic criteria. A database of 12,088 photographic observations was evaluated. Univariate logistic regression proved that brachytherapy decreases the number of clinical and dermoscopic patterns typical for basal cell carcinoma, as well as dermoscopic features not related to BCC, presumably due to the formation of scar tissue. In addition, univariate logistic regression with random effects proved a positive correlation between tumor size and presence of various dermoscopic patterns typical for BCC. Dermoscopy is proven to be easy to perform and an adequate monitoring tool for patients with BCCs undergoing HDR brachytherapy.

The potential of RHCM technology in injection molding using a simple convention heating and cooling system

In conventional injection molding, low mold temperatures are used; however, the thermal conditions, which vary during the processing, affect the properties of the injection molded parts and the injection molding process parameters. Due to the rapid cooling of the molten polymer against the mold wall, the flow resistance of the molten polymer increases, and the hydraulic injection pressure is directly affected by this. The rapid cooling of the plastic parts affects the quality of the parts, which can result in surface defects.Using the rapid heat cycle molding (RHCM) approach, a simple convection heating and cooling system was added to a conventional injection molding process to study the potential of RHCM technology. We assessed the influence of the mold temperature on the part's morphological features (namely, the frozen layer) and mechanical properties (namely, the Young's modulus), as well as the hydraulic injection pressure.Using RHCM to heat the molding surface up to 100 °C was found to entirely prevent the formation of a frozen layer, with an expected positive effect on the previously mentioned defects. Note that while the decrease of the frozen layer could have been expected to reduce Young's modulus, this did not happen, which is a very positive outcome related to the specific orientation at which the frozen layer is formed and its morphology. The higher the mold surface temperature, the lower the hydraulic injection pressure, which means less strict structural requirements for the mold. These results highlight the potential of RHCM technology in injection molding, namely as a strategy to mitigate or solve molding defects.

A shape-based introduction of manufacturing processes to undergraduate students

Shape or geometrical form is one of the main reason parts function, and creating shapes is an essential outcome of manufacturing processes. Introductory manufacturing education courses and textbooks explain various manufacturing processes as an eclectic collection without highlighting the common underlying thread involved in shape creation. This traditional approach fails to emphasize that there are some basic tenets in shape formation and that shaping is a unique function of manufacturing processes. It is essential to show the student a broader perspective and outline the common themes underlying the various processes that create shapes without getting lost in the process and materials details. It is argued here that the theme emphasized in introducing manufacturing to a nascent mind is making shapes and the way shape information (stored digitally) is transformed at every stage of the process to rearrange raw materials from their existing shape into a new shape. Whether hand-sculpting to make art forms, making patterns needed to make refractory mold cavities, or making molds for injection molding by machining or making parts directly by additive manufacturing, converting shape information into controlled tool motion paths is the primary way to make shapes. This method is the only direct way to make parts or shape-assist devices, such as patterns and molds, from the digital shape information. Once shape information is stored in a pattern or mold surfaces, the secondary way by shape replication is facilitated. A new structure for an introductory manufacturing course that is shape-based is proposed in this paper, which is expected to infuse better student interest in manufacturing.

Modeling and Analyzing Layup Gaps in the Trajectory Planning for Automated Tape Placement

Composite materials are widely used in the aerospace industry thanks to their lightweight along with high stiffness and strength. Automated tape placement (ATP) is an important automated process used for the fabrication of large composite structures. In ATP, the layup paths of contiguous tapes are not parallel along their lengths due to the complex contour of the mandrel, which eventually introduces gaps or overlaps between the edges of tapes. Overlaps or excessive gaps are highly undesirable as they will weaken the resulting composite member. To date, little research reveals the generation and evolution principles of placement gaps on curved mold surfaces. A better understanding of the principles would help to adjust the layup trajectories to eliminate the deposition errors and ensure the layup quality. In this paper, the evolution law of layup gaps on mold surfaces is presented at first. Then, a placement gap model is established to predict the value of gaps in the trajectory planning stage. The gap model has been validated on a series of mold surfaces. One application of this model is to optimize the placement trajectories for ATP.

Utilization of edible coating based on quince seed mucilage loaded with thyme essential oil: Shelf life, quality, and ACE-inhibitory activity efficiency in Kaşar cheese

Edible coatings offer many advantages in cheese coating for prolonging the shelf life and improving quality properties. Mould spoilage that occurs during ripening is one of the most important issues in Kaşar cheese. The current study focused on the effects of an edible coating solution based on quince seed mucilage (QSM) containing thyme oil (TO) in different ratios, on the surface moulding of Kaşar cheese and evaluated the physicochemical, microbiological, textural, and proteolysis characteristics of Kaşar cheese throughout the 120 days of ripening. Also, the effect of edible coating on the in-vitro Angiotensin-converting enzyme (ACE)-inhibitory activities of pH 4.6-soluble extracts of Kaşar cheeses was investigated. Results showed that the coating of Kaşar cheese with QSM and the increased levels of thyme oil significantly suppress mould growth throughout the ripening. Until 120th days of ripening, counts of yeasts and moulds were lower <2 log cfu g−1 in coated cheese sample with QSM containing 2% TO. Coating with QSM caused an increase in moisture loss compared to vacuum-packed cheeses, however, didn't change the normal ripening conditions such as microbiological, chemical, textural, and proteolysis properties of Kaşar cheese. As the ripening progressed, ACE-inhibitory activity increased in all samples, with the highest inhibition in vacuum-packed and coated cheeses. Overall, it was determined that the QSM coating showed good potential as a coating material for the protection of cheese shelf life and quality as well as for enhancing ACE-inhibitory activity.

Effect of mould surface roughness adjustments to increase the flow path length in the injection moulding process

To increase the flow path length in the mould for thin-walled packaging applications or thick-walled technical components with long flow paths, a mould surface machined by electrical discharge machining is used. By varying the process parameters, the moulding compound and the roughness of the surface, the influence of the mould surface structure on the achievable flow path length is investigated. A flow meander mould is used for this purpose. A material dependent, positive influence of the surface roughness on the flow path length can be determined. However, the influence is small compared to other influences such as mould or melt temperature.

Wear Properties of High-Hardness Tool Steel by Directed Energy Deposition Based Additive Manufacturing

Recently, with the increase in the application of UHSS plates in automobiles, the service life of existing molds is being shortened, and directed energy deposited type 3D printing technology is being considered as a way to extend the service life. In this study, in order to improve the service life of cold molds, the wear characteristics of the deposited parts using composition systems were analysed, and the possibility of practical application was estimated through evaluation with shear molds.&lt;/br&gt;Since the high hardness of AM layer can be reached without additional heat treatment, it was expected to improve the service life when applied to the surface of the mold. Through the wear evaluation of the ball-on-disk method, it was confirmed the wear performance improvement of M4, and as a result of the shear mold life evaluation of 1.5 GPa class high-strength automotive steel plate for the M4 deposited, it was found that shear up to 17,000 strokes were possible. When the number of strokes was increased, a fracture layer due to deposition was observed in the cross-section of the mold surface, and it is believed that additional heat treatment research is required to improve the life of the AM mold.

Study of Interfacial Adhesion and Re-Ir Alloy Coating in Chalcogenide Glass Molding.

Precision glass molding (PGM) has become an efficacious technique to fabricate high-precision optics. Chalcogenide (ChG) glass is increasingly used in thermal imaging, night vision, etc., because of its excellent infrared optical properties. Nevertheless, glass-mold interfacial adhesion has emerged as a pivotal issue within the PGM process. The interfacial adhesion during PGM has the potential to significantly undermine the performance of molded optics and reduce the longevity of molds. It is important to investigate interfacial adhesion behaviors in the PGM. In this study, the interfacial adhesion mechanism between ChG glass and the nickel-phosphorus (Ni-P) mold is analyzed using the cylindrical compression test. The effect of ChG glass internal stress on physical adhesion is investigated by finite element method (FEM) simulation. The spherical preform is proven to be capable of reducing the stress concentration and preventing physical adhesion. More importantly, a rhenium-iridium (Re-Ir) alloy coating is deposited on the Ni-P mold surface by ion sputtering to prevent atomic diffusion and resolve the problem of chemical adhesion. Finally, ChG glass microstructures with high accuracy are fabricated using the spherical ChG glass preform and the Re-Ir-coated Ni-P mold by PGM.

Conformal Cooling Channel Design for Improving Temperature Distribution on the Cavity Surface in the Injection Molding Process

Mold heating is an essential process in plastic injection molding. Raising the temperature of the mold before injecting liquefied plastic can ease the mold-filling process. A cooling channel can be used to transport high-temperature fluids for this purpose, such as hot water or oil. This dual purpose is a cost-effective solution for heating the mold because the target temperature is easily achieved using this method. In addition, a conformal cooling channel (CCC) can provide more efficient mold heating than a straight cooling channel. This study used the response surface methodology to determine the optimum CCC shape for heat distribution in a mold, and the simulation results confirmed its optimization. The average temperature of the mold using a CCC was better than that using a straight cooling channel, and the heat zone was uniform across the mold surface.