Mold Surface Research Articles

On the Milling Process Simulation of an Injection Mold Part

The paper presents the 3-phases milling process simulation of a surface of a polystyrene injection mold, by using CATIA software. The cutting regime parameters are computed and are used, together with other data, as inputs for the simulation process. On the basis of milling process simulation, the software generates the manufacturing program for the NC machine tool.

Wind Tunnel Tests of 3D-Printed Variable Camber Morphing Wing

This paper introduces the realization and wind tunnel testing of a novel variable camber wing equipped with compliant morphing trailing edges. Based on the aerodynamic shape and compliant mechanisms that were optimized in advance, a wind tunnel model called mTE4 was developed, in which the rigid leading edge, rigid wing box, and compliant trailing edge were manufactured by 3D printing technology using three different materials. Due to difficulties in the detailed design of a small-scale model, special attention is devoted to the implementation procedure. Additionally, the static and dynamic characteristics of the proposed wind tunnel model were evaluated by ground tests, and the aerodynamic characteristics were evaluated by numerical methods. Then, the aerodynamic performance and the static aeroelastic deformation of the compliant trailing edge were investigated in a low-speed wind tunnel. The load-bearing ability of the proposed compliant morphing trailing edge device was validated and the continuous outer mold surface was found to persist throughout the entire testing period. Notably, a maximum deflection range of 37.9° at the airspeed of 15 m/s was achieved. Additionally, stall mitigation was also achieved by periodically deflecting the morphing trailing edge, enabling a stall angle delay of approximately 1° and 13% increase in post-stall lift coefficient. Finally, the development procedure was validated by comparing the lift between numerical and experimental results.

Effects of anisotropic and isotropic LIPSS on polymer filling flow and wettability of micro injection molded parts

In micro injection molding, the specific cavity surface texture and roughness directly influence the polymer flow and the heat transfer between polymer melt and mold. In this work, two different types of laser-induced periodic surface structures, linear and hexagonal, were generated, and their impact on the flow length in micro injection molding was evaluated.A complete investigation of the surface treatment effect on the polymer flow was carried out, comparing the performance of an untreated cavity surface with surfaces modified by LIPSS. The phenomenon was examined by localizing the weld lines created by the polymer flowing in two parallel channels having different surface treatments. Several cavity inserts were treated by varying the LIPSS process parameters to generate surfaces with different micro- and nanostructures directions and periodicity. Furthermore, the paper addresses the hydrophobicity achieved on the micro molded surfaces replicated from mold inserts with different LIPSS-based surface topography. Mold surfaces with linear and hexagonal LIPSS and the respective molded parts were analyzed by optical profilometry and scanning electron microscopy to characterize the cavity surfaces replication and localize the weld lines on the micro injection molded parts.

Optimization of Process Parameters for the Laser Polishing of Hardened Tool Steel.

In mold making, the mold surface roughness directly affects the surface roughness of the produced part. To achieve surface roughness below 0.8 μm, the cost of surface finish is high and time-consuming. One alternative to the different grinding and polishing steps is laser polishing (LP). This study investigates and models the LP of tool steel (X38CrMoV5-1-DIN 1.2343), typical for the mold industry, having an initial rough surface obtained by electrical discharge machining. The microstructures of the re-melted layer and heat-affected zone due to the LP process were also studied. Four parameters: the laser spot size, velocity, maximum melt pool temperature and overlapping were investigated via a design of experiments (DoE) approach, specifically a factorial design. The responses were line roughness (Ra), surface roughness (Sa), and waviness (Wa). The surface topography was measured before and after the LP process by white light profilometer or confocal microscopy. DoE results showed that the selected factors interact in a complex manner, including the interactions, and depend on the responses. The DoE analysis of the results revealed that the roughness is mainly affected by the velocity, temperature and overlap. Based on a first DoE model, an optimization of the parameters was performed and allowed to find optimum parameters for the LP of the rough samples. The optimum conditions to minimize the roughness are a spot size of 0.9 mm, a velocity of 50 mm/s, a temperature of 2080 °C and an overlap of 90%. By using these parameters, the roughness could be reduced by a factor of almost 8 from 3.8 µm to approximately 0.5 µm. Observations of the microstructure reveal that the re-melted layer consists of columnar grains of residual austenite. This can be explained by the carbon intake of the electro-machined surface that helps stabilize the austenitic phase.

Significant elimination of pore defect and interfacial reaction of sand casted Al–Li alloy castings via a novel inorganic binder coating

Generally, sand casted Al–Li alloy castings have very serious problems in pore defect and interfacial reaction, remarkably weakening the Al–Li alloy castings quality. How to solve these problems is always a challenge. In this paper, a novel inorganic binder coating containing lithium silicate solution binder and silicon carbide powder on the surface of the sand mold was developed to eliminate pore defect and prevent interfacial reaction of the sand casted Al–Li alloy castings. The effective mechanism of the inorganic binder coating on the pore defect and interfacial reaction was discussed. The obtained results showed that the inorganic binder coating formed a thin shell on the surface of the sand mold after pouring, which can effectively prevent the metal-mold interface reaction of the sand casting Al–Li alloy and significantly reduce the porosity defects. Among them, the Al–Li alloy casting prepared using the inorganic binder coating consisting of the lithium silicate binder and silicon carbide powder basically had no pore defects, and the porosity was only 3.73%, which was 66.7% lower than that of the casting prepared by the sand mold without any treatment. Moreover, the interface reaction of the Al–Li alloy and sand mold was fully eliminated, which was attributed to the low overall atomic diffusion rate of the silicon carbide based on molecular dynamics simulation results.

Application Research of Laser Cladding Remanufacturing Technology to Repair Worn Mold

In recent years, with the development of laser technology and the transformation and upgrading of domestic manufacturing industry, the application of laser cladding remanufacturing technology is increasing. Mold as a common equipment of industrial production, its service life directly affects the production cost and efficiency of the enterprise.Wear is a common form of mold failure. In order to restore the performance of the mold and prolong the service life of the mold, The laser cladding remanufacturing technology to repair worn mold is studied in this paper. Firstly, the laser cladding remanufacturing is outlined, and the main technological process of the mold laser cladding remanufacturing is introduced. Then, taking 45 mold steel as an example, based on the analysis of the die material and weldability, the laser cladding material is selected reasonably, the mold is remanufactured by the experimental method, and the metallographic microscope analysis, hardness test and wear test are carried out.The research results show that the average hardness of the worn mold surface is about 55.5HRC after being remanufactured by laser cladding, and the wear resistance is doubled, and a good application effect has been achieved. Therefore, the laser cladding remanufacturing technology has a broad application prospect in repairing worn mold.

Composition controls soft hydrogel surface layer dimensions and contact mechanics.

Hydrogels are soft hydrated polymer networks that are widely used in research and industry due to their favorable properties and similarity to biological tissues. However, it has long been difficult to create a hydrogel emulating the heterogeneous structure of special tissues, such as cartilage. One potential avenue to develop a structural variation in a hydrogel is the "mold effect," which has only recently been discovered to be caused by absorbed oxygen within the mold surface interfering with the polymerization. This induces a dilute gradient-density surface layer with altered properties. However, the precise structure of the gradient-surface layer and its contact response have not yet been characterized. Such knowledge would prove useful for designs of composite hydrogels with altered surface characteristics. To fully characterize the hydrogel gradient-surface layer, we created five hydrogel compositions of varying monomer and cross-linker content to encompass variations in the layer. Then, we used particle exclusion microscopy during indentation and creep experiments to probe the contact response of the gradient layer of each composition. These experiments showed that the dilute structure of the gradient layer follows evolving contact behavior allowing poroelastic squeeze-out at miniscule pressures. Stiffer compositions had thinner gradient layers. This knowledge can potentially be used to create hydrogels with a stiff load-bearing bulk with altered surface characteristics tailored for specific tribological applications.

MSS08 Presentation Time: 4:20 PM: Dermoscopic Evaluation of Basal Cell Carcinomas During and After Brachytherapy

<h3>Introduction Objectives</h3> Basal cell carcinoma(BCC) is the most common malignancy of the Caucasian population. Dermoscopy is a diagnostic method that provides the bridge between clinical and pathological examination. Surface skin High Dose Rate (HDR) brachytherapy is an organ sparing treatment method used for non-surgical candidates in contemporary management of skin cancers. Literature lacks data reporting observations of dermoscopic patterns of non-melanoma skin cancers (NMSC) undergoing HDR brachytherapy. <h3>Materials and Methods</h3> Single center prospective study was conducted. Twenty three patients with high risk BCC's of facial region were treated with contact, 3D planned HDR brachytherapy with 9 fractions of 5Gy, 3 times a week. Custom made polyacrylamide surface moulds were used. Clinical and dermoscopic images were obtained before treatment and before every fraction and 6 months after treatment. 603 macroscopic and dermoscopic photographs were obtained. In every macroscopic picture 12 clinical features typical for BCC's were analyzed Dermoscopic images were searched for 61 dermoscopic neoplastic features and 31 dermoscopic non-neoplastic features. In total database of 21526 observations was analyzed by two independent dermoscopists using current diagnostic criteria. <h3>Results</h3> Univariate logistic regression showed decreasing number of clinical and pathological features with each fraction of brachytherapy. Correlation was more expressed for features typical for BCC. Older patients showed more pronounced response to treatment. After 6 months number of clinical and dermoscopic patterns typical for BCC as well as number of non neoplastic dermoscopic features is reduced, presumably due to formation of scar (Figure 1). <h3>Conclusions</h3> HDR brachytherapy decreases number of clinical and dermoscopic Basal Cell Carcinoma features. Effect is more pronounced in older patients. Medium time observation shows that effect is persistent after 6 months.

MSS10 Presentation Time: 4:30 PM: Clinical and Toxicity Outcomes with HDR Surface Mould Brachytherapy in Skin Cancer: Indian Experience

<h3>Purpose</h3> Surface Mold Brachytherapy (SMBT) is an established treatment modality in skin cancer especially in accessible areas and provides outcomes comparable to surgery. We present our results for the skin tumor treatment with SMBT treated with High-dose rate (HDR) brachytherapy in terms of clinical outcomes and toxicity at our institute. <h3>Materials and Methods</h3> this retrospective analysis among skin cancer patients with skin tumors treated at our institute between January 2020 to July 2021 were assessed and a total of 15 patients were evaluated. The patient and disease characteristics were assessed and patients were treated using HDR- Surface Mold Brachytherapy using Iridium-192. The median dose was 40Gy in 10 fractions. The dosimetric parameters were assessed and patients were followed-up as per the institutional protocol. All patients underwent individualized CT-based planning. Skin toxicity was assessed using Dermatology Life Quality Index (DLQI). <h3>Results</h3> With majority of the patients being male, the median age was 59 years and most common site being the face (8/15; 53.3%). The histopathology included 7 Squamous cell carcinoma, 6 Basal cell carcinoma and a single case of sebaceous cell carcinoma. The median depth of invasion was 4 mm and median catheter to surface distance was 1 mm. The Complete response rate among the 10 definitive cases was 90% and partial response in one case. The treatment was well-tolerated with no Grade 3-5 toxicities. The median V95% and V90% were 95.42% and 97.37% respectively. The mean Coverage Index (C.I), Dose non-uniformity ratio (DNR) and overdose volume index (ODI) were 0.97, 0.36 and 0.04 respectively. After a median follow-up of 6 months, none of the patients had recurrence. On assessment of DLQI, the scores were found to be significant in association with the tumor size and tumor site with scores favoring <2cm and non-exposed area lesions. <h3>Conclusion</h3> Surface mould brachytherapy is a safe and effective treatment modality for skin tumours providing excellent response and cosmetic outcomes. It is well-tolerated and a non-invasive option for elderly patients with comorbidities and lesions in inoperable areas.

A Numerical Study on Increasing the Cavity Temperature in Injection Molds

In the injection molding process, the filling process will be easier and, in most cases, the surface quality will be significantly improved if the mold surface temperature is high. However, as the temperature of the mold plates rises, the cooling process takes longer, the injection molding cycle takes longer, and the cost of production rises. The most important thing is to keep the mold temperature under control, which means heating the mold surface to the required temperature while keeping the injection cycle time to a minimum. In this research, hot air was used as the heat source for raising the cavity temperature to over 200 °C with a heating time of 20 s. At the end of heating process, the temperature was collected at 10 points for comparison. In addition, the temperature distribution was also discussed.

Possibilities of Repairing Functional Surfaces of Molds for Injecting Al Alloys Using Manual GTAW Cladding

The paper presents the results of research that is focused on the renovation of molds for high-pressure aluminum casting. An analysis of the worn molds was carried out after they were removed from the operator. The extent and mechanism of the wear were determined. GTAW (Gas tungsten arc welding) technology was chosen for the renovation of the shaped parts of the molds. The renovation layers were realized with four types of additional materials Cronitex RC 44, UTP A 73 G 3, UTP A 673 and Dievar® TIG. The quality of the coatings was assessed by destructive as well as non-destructive tests. The mixing of the build-up layers with the base material was determined on the basis of structural analyses. The hardness of the cladding was determined by a metallographic analysis of the cross crowns with the Vickers method. The resistance of the cladding was tested by a complete immersion in a melt of AlSi8Cu3 aluminum alloy which was maintained at a temperature of 680 ± 20 °C in a laboratory resistance furnace for 120 and 300 min. The tribological properties of the produced deposits were determined using the ball-on-disc dry method. Based on the experiments that were carried out, it is possible to recommend the additive material UTP A 73 G 3 for the restoration of the functional surfaces of molds for the injection of Al alloys as the patterns that were created by it have shown the best results in terms of their resistance to Al melt, which is the dominant degradation factor limiting the life of the molds.

Immobilization of Active Antibodies at Polymer Melt Surfaces during Injection Molding.

We demonstrate the transfer and immobilization of active antibodies from a low surface- energy mold surface to thermoplastic replica surfaces using injection molding, and we investigate the process at molecular scale. The transfer process is highly efficient, as verified by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) of the mold and replica surfaces. AFM analysis reveals partial nanometer-scale embedding of the protein into the polymer matrix as a possible mechanism of permanent immobilization. Replicas with rabbit anti-mouse IgG immobilized as capture antibody at the hot polymer melt surface during injection molding show similar affinity for their antigen (mouse IgG) in sandwich enzyme-linked immunosorbent assay (ELISA) as capture antibodies deposited by passive adsorption onto a bare thermoplastic replica. The transferred antibodies retain their functionality after incubation in serum-containing cell medium for >1 week. A mold coating time of 10 min prior to injection molding is sufficient for producing highly sensitive ELISA assays, thus enabling the short processing cycle times required for mass production of single-use biodevices relying on active immobilized antibodies.

Investigation the Effect of Different Oils as Separating Medium on Surface Roughness and Hardness of Tissue Surface of Flexible Denture Base

Background: Flexible dentures (thermoplastic material) are ideal alternatives to traditional methyl methacrylate dentures, since they not only give exceptional aesthetics and comfort, but also adapt to the continual movement of partially edentulous patients. During the manufacturing of acrylic denture base material, an effective separating medium must be used to separate the denture cleanly from the plaster to avoid direct contact between the denture base material and the mould surface.&#x0D; Objective: The goal of this study was to investigate the effect of several types of oil (glycerin oil, olive oil, and black castor oil) on the surface roughness and hardness of flexible denture base material compared with cold-mould seal separating medium.

Use of gaseous ozone in soft cheese ripening: Effect on the rind microorganisms and the sensorial quality

The uncontrolled growth of potential spoilage microorganisms in cheese surfaces can deteriorate cheese quality, especially filamentous fungi. This study aimed to evaluate the effect of several gaseous ozone treatments during the ripening of soft cheese on the growth of cheese rind microorganisms at different production scales. On a pilot plant scale, the cheeses were inoculated with potential spoilage microorganisms (Mucor plumbeus, Kluyveromyces marxianus, and Pseudomonas fluorescens), while on an industrial scale, naturally present microorganisms were evaluated. Ozone treatments showed a considerable fungistatic effect on cheese surface molds at both pilot and industrial scale. However, the effect of ozone on yeast growth was only observed at pilot plant scale, while Pseudomonas ssp. was not affected by the ozone concentrations used in this study. The sensory quality of the cheese was also assessed. Cheese typicality was not affected by gaseous ozone. However, the ozonized samples had significantly higher scores than the control samples for rind appearance and color. Hence, ozonation can be considered an alternative approach to control mold growth in soft cheese during ripening and prevent cheese rind discoloration.

Interfacial Surface Properties of Compression Moulded Hydrolysed Polyvinyl Acetate (PVAc) Using Different Release Materials

Understanding the effect surface production has on polymer properties is important in the design of advanced materials. The aim of this study was to determine how the moulding process affected the rate of hydrolysis and the topography, chemistry and physicochemistry of PVAc moulded, hydrolysed surfaces. Three different mould surface materials were used to produce compression moulded PVAc sheets which were treated with aqueous NaOH at a range of concentrations. The Textile moulded sheet demonstrated the best hydrolysis results. The topography of the moulded sheets was transferred to the surfaces and the Kapton release sheet was visually smooth at lower magnification and demonstrated some pitting at higher magnification. The Teflon surface had features transferred from the coated stainless steel at lower magnifications and linear features at higher magnifications and the textile surface had a wrinkled appearance and irregularly spaced peaks. The release sheet used to mould the PVAc surfaces, affected the physicochemical parameters. The Kapton moulded surface demonstrated the most polar attributes and the Teflon surface the most dispersive. It was clear that the selection of the mould material had an influence on surface properties and hydrolysis of moulded PVAc. Such information is important for engineering design in industrial processes.

Production readiness assessment of low cost, multi-material, polymeric 3D printed moulds

Fused Deposition Modelling (FDM) technology allows to choose a large variety of materials and it is widely used by companies and individuals nowadays. The cost effectiveness of rapid prototyping is achievable via FDM, that makes this technology useful for research and innovation. The application of 3D printing to aid production is the most common approach. Moreover, the use of 3D printing in prototypes result in a waste of material since no reuse is considered. In the following manuscript, this technology is applied to mould fabrication by achieving a low surface roughness at a modest cost compared to conventional manufacturing methods. Moreover, the possibility to use a combination of thermoplastic materials is analysed by examination of the CAD model optimized for Additive Manufacturing (AM) from scratch and was verified using metrology tools. Several moulds were finally built and applied to the specific case study of carbon fibre laminated components. This manuscript aims to analyse the manufacturing process by comparing the mould surface geometry before and after the smoothing process. The achieved tolerance between the produced moulds is ±0.05 mm that ensures the repeatability of the process from an industrial point of view; whilst the deviation between CAD and mould is ±0.2 mm. To combine an accurate FDM process together with chemical smoothing proved to be a powerful strategy to produce high quality components that can be inserted in the production process by means of traditional manufacturing techniques. This will aid to reduce the cost of standard manufacturing for low production batches and prototypes of carbon fibre composites.

Optimization of Nozzle Parameters by Investigating the Flow Behavior of Molten Steel in the Mold under a High Casting Speed

A reasonable flow field in the continuous casting mold is beneficial to produce high quality billets, and the design of the nozzle parameters of the mold is key to regulating the flow behavior of molten steel. Through combining the numerical simulation and physical experiments and taking SEN immersion depth and inner diameter as indicators, the flow behavior of molten steel in the mold during high-speed casting of a 160 mm × 160 mm billet was investigated in detail, and the nozzle parameters were optimized. The results demonstrate that, compared with the inner diameter of the nozzle, the immersion depth has a significant influence on the impact depth of molten steel. On the premise of ensuring that the velocity distribution of molten steel on the surface of the mold is uniform and the impact range inside is appropriate, the inlet immersion depth after optimization is 100–120 mm and the inner diameter is 40 mm. The corresponding impact depth is 605–665 mm, and the maximum velocity of molten steel on the mold surface is between 0.04 and 0.045 m/s. Additionally, the results of the physical experiment and numerical simulation reveal that the optimized nozzle parameters can adapt well to the continuous casting process with a high casting speed.

Facile formulation of sustainable and stable oil-in-dispersion emulsion: A release agent with high demoulding efficacy

In the hunt of new sustainable release agents for concrete removal with improved demoulding efficacy, oil-in-dispersion (OD) release agents have appeared as favourable emulsions, since they display augmented performance in contrast to conventional oil-in-water (O/W) emulsions. This work presents a novel and facile methodology for sustainable preparation of OD release agent employing emulsifiers as active components to produce stable emulsion, leading to a superior and easier commercial product formulation. The new type of OD release agent is optimized by varying the composition of two food grade emulsifiers named as span-80 and AEO-3 from 2.4 to 7.4% in the formulation. The stability and performance of new OD release agents are studied comprehensively through various parameters like creaming index, viscosity, density, pH tests, water contact angle, droplet size and shape. After dilution five times with water, the OD based release agent containing 5.4–7.4% mixed emulsifier concentrations demonstrate excellent stability even after six months of storage and performed well in physico-chemical lab testing. Moreover, OD release agents showed good application results during on-field industrial trials on iron mould surfaces. The formulated OD release agents on the mould took only 12–15 min to generate a smooth and uniform film that was demoulded easily by sledgehammering about 3–5 times. Thus, easily prepared and highly stable OD release agent could be revolutionary in construction industry for sustainable and rapid removal of mould concrete with high efficacy.

Improvement of the durability of cement-based material through surface modification with nano-engineered releasing agents

• Modified releasing agent with NS/NT to make nano-engineered releasing agent. • NS and NT increased the contact angle of releasing agent and help their adhesion on mold. • Reduction of the surface porosity (within 2 mm thick). • Nano-engineered releasing agent can achieve durable concrete surface. Aggressive substances can gain access to the inner structure of cement-based materials through the surface, resulting in deterioration of the structure. This work developed an effective way of improving the quality of cement-based materials surface by applying nanoSiO 2 -/nanoTiO 2 -engineered releasing agents (nSRa/nTRa) on the formwork surface. Continued with our previous work, the positive effects of nSRa/nTRa on cement hydration were used to improve the surface quality of the cement-based samples through its spraying on the mold surface. This work firstly characterized the adhesive properties of these agents on mold surface (contact angle and viscosity measurement), and then their effects on the surface microstructure and the durability of cement-based materials such as 1) sulfate resistance, 2) chloride resistance, and 3) freeze–thaw resistance were determined. Results showed that nanoparticle addition increased the contact angle of releasing agents and helped their adhesion to mold. Applying nSRa/nTRa on cement-based samples benefited the reduction of surface porosity (within 2 mm thick) by 14.2 %, 19.4 %, 8.6 %, and 18.9 % in the nS2Ra-, nS4Ra-, nT4Ra- and nT16Ra-engineered samples. After 120 days of sulfate attack, mortar samples cast in Ra-, nS4Ra-, and nT16Ra-coated molds showed reductions in compressive strength loss of 1.57 %, 0.73 %, and 0.23 %. Noticeable reductions in the chloride migration coefficient of 23.9 % and 26.6 % were found in the nS4Ra-/nT16Ra-modified mortar sample, while their relative dynamic modulus elasticity was 6.72 % and 12 % higher than Ra-sample after 200 freeze–thaw cycles. This work proved that nano-engineered releasing agents can effectively improve the durability of the concrete structure.

Step-by-Step Guide to Surface Mold Applicator-Based Brachytherapy in a Case of Early Carcinoma Penis: An Organ-Preserving Approach

Purpose In this report we discuss an individually customized surface mold applicator technique to treat a case of early carcinoma penis. This case report is one of its kind which describes the brachytherapy treatment planning based on orthogonal X-ray technique. Material and methods T1N0 disease with squamous cell carcinoma histology involving the foreskin of penis and abutting the glans penis was treated by surface mold applicator technique. Impression of the organ was taken using alginate. Cast was prepared from the impression using Type 4 gypsum. The acrylic mold-based applicator was fabricated on the cast. The catheters were positioned and fixed on the acrylic mold. The organ is placed in the mold-based applicator and the catheters are reconstructed on two-dimensional imaging. The brachytherapy is delivered by the 18-channel high-dose rate Oncentra brachytherapy using Ir192 source. The dose given was 45 Gy in 15 fractions, twice daily more than 6 hours apart. Results Patient was reviewed after 6 weeks for follow-up and there was complete regression of the ulcer. At present, patient is on follow-up for the last 10 months and is now disease-free. Conclusion With judicious patient selection, surface mold brachytherapy is an attractive alternative to the interstitial brachytherapy. It is comfortable for the patient, is easily repeatable, and is time saving in high work load and limited resource settings. Early results with this technique are promising.