Wet Blasting Research Articles

Effect of atmospheric plasma treatment and wet blast on adhesion characteristics of carbon fiber reinforced LM-PAEK thermoplastic composites

Surface characteristics of polymeric materials are quite challenging for adhesion especially thermoplastics, requiring specific surface preparation operations before reaching successful bonding. These processes are principally aimed to increase the low surface energy of the material, bonding agent contact area and wetting characteristics to provide proper and strong adhesion. In this study, two different surface treatments with different processing parameters were applied to CF/LM-PAEK thermoplastic composites in order to examine the changes on surface characteristics and adhesion strengths. Apart from desired surface treatments for thermoplastics indicated in previous studies and backgrounds, wet blasting method is used to prepare surfaces before bonding. Separately prepared surfaces, applying wet blasting and atmospheric plasma treatment, were adhered using epoxy-based film adhesive to be subjected to single lap shear testing to examine adhesion strength under tensile loading. According to the results of experimental study, it was observed that both surface treatments increased the adhesion strength of the bonded pre-consolidated CF/LM-PAEK thermoplastic composites compared to specimens having untreated surfaces.Atmospheric plasma treatment increased the surface energy by 18.24% and showed higher strength up to 14.93% compared to the untreated specimens. On the other hand, surprisingly, wet blasted specimens with lower surface energies showed high strength up to 6.48% compared to the untreated specimens. In addition to surface energies and lap shear strengths, roughness measurements and SEM surface evaluations were also issued to enlighten obtained test results accordingly.

Combined post-treatment approach for improving the surface integrity of CVD α-Al2O3 coating and the tool wear resistance

Wet blasting effectively reduces roughness and introduces residual compressive stress on the chemical vapor deposition (CVD) coating surface; however, it possesses some limitations when the roughness exceeds a certain threshold due to the coating thickness reduction caused by wet blasting. In contrast, sprayed abrasives polishing (SAP) further reduces surface roughness but does not significantly alleviate tensile stress. To address these challenges, a composite process that combines wet blasting and SAP is employed for CVD post-treatment. This study aims to compare the effects of this composite process with those of wet-blasting and SAP processes in terms of surface morphology, surface roughness, physical structure, residual stress, adhesive strength between the coating and substrate, and cutting performance. Among different post-treatment methods, the composite process proves to be the most effective, resulting in superior surface roughness and morphology, similar residual compressive stress compared with the wet-blasting process, and strongest adhesive strength between the coating and substrate. This composite process achieves a smoother surface while maintaining the same level of residual compressive stress and preventing further significant thinning of the coating compared with the wet-blasting process. Finally, the composite process successfully enhanced the wear resistance of the CVD-coated inserts as demonstrated by cutting tests.

Surface treatments and substrate-coating interface effects on damage accumulation kinetics in hard-coated WC-Co hardmetals under cyclic multi-axial high-temperature loading

Coated hardmetals are commonly used tool materials for metal cutting applications. For these applications, the substrate- and the coating surface qualities are improved by grinding, polishing, or blasting. The focus of the current work was to study the influence of different combinations of substrate-coating surface processing techniques on the induced damage in Al2O3/TiCN hard-coated WC-12 wt% hardmetal substrates and the depth to which the damage reaches into the substrate. The substrate and coating surfaces were prepared by grinding, polishing, dry blasting, wet blasting, or remaining in the deposited state. Investigations were performed using cyclic indentation with a novel ball-in-cone test method in a vacuum at 700 °C, under conditions that imitate the combined shear-compression loads that occur at the cutting edges of metal cutting tools. Additionally, finite element simulations were performed to characterize the stress state arising during ball-in-cone testing. The kinetics of defect formation and accumulation in the hardmetal substrate as a function of the loading situation during the ball-in-cone test will also be discussed. The defects that formed in the substrate during cyclic loading were studied using scanning electron microscopy in cross-sections prepared by focused ion beam milling. A larger increase in defect frequency was observed for rougher coating surfaces and substrate-coating interfaces than for smoother ones. Furthermore, 6 μm thick coatings exhibited a higher defect frequency after cyclic loading than 15 μm thick coatings. Most of the observed defects were in the nm-size range close to the substrate-coating interfaces and tended to have increased in size after cyclic loading. The ball-in-cone test set-up enables the study of the damage mechanisms in coated hardmetal substrates with different treatments prior to and after deposition under tunable milling-like stress and temperature conditions.

EFFECT OF CUTTING EDGE PREPARATION TECHNOLOGIES ON SURFACE ROUGHNESS, PROCESSING TIME AND K- FACTOR

The geometry of the cutting tool is a crucial factor in its life and performance during the cutting process. In particular, the micro-geometry of the tool, which defines the shape of the cutting edge, has a significant effect on plastic deformation, heat generation, and cutting tool life. This article compares three technologies for removing material from cutting tools: wet blasting, dry blasting, and brushing. The focus was on measuring the processing time for each technology to determine its productivity and processing the cutting edge to a specific value. The surface roughness parameters Ra and Rz on the cutting edge were also measured. The K-factor parameter was monitored for the repeatability of the cutting edge process. The results of the experiment indicate that selecting the appropriate cutting edge technology can positively impact both the productivity and roughness of the tool edge.

Influence of the substrate treatment on the microstructure and properties of chemical vapour deposited Ti(C,N) coatings

The effect of the mechanical treatment on the surface morphology of cemented carbide substrates and on the microstructure and properties of chemical vapour deposited (CVD) Ti(C,N) coatings is described in terms of the functional relationships between the substrate surface roughness, and the grain size, preferred orientation of crystallites, residual stress, indentation hardness and adhesion of the coatings. The substrates were flat fine-grained and coarse-grained cemented carbides inserts that underwent different treatments – wet blasting, grinding or polishing. Although the Ti(C,N) coatings were produced in the same moderate-temperature deposition process, their microstructure characteristics and mechanical properties differed significantly. Microscopic steps and edges present on ‘rough’ substrates facilitated the growth of large V-shaped Ti(C,N) grains with a weak {211} texture. In these samples, the tensile residual stress that is typically produced during the cooling of the CVD samples was reduced. The Ti(C,N) coatings deposited on ‘smooth’ substrates were fine-grained, and possessed a pronounced {211} texture and a better adhesion to the substrate. In these samples, the thermal tensile stress was less reduced than in the samples deposited on ‘rough’ substrates. The indentation hardness of the Ti(C,N) coatings was not affected by the substrate treatment. The physical background of these relationships is explained.

Wetter by Design

The use of wet blasting is making additive manufactured production parts much more widely accessible.

Surface roughness and finishing techniques in selective laser melted GRCop-84 copper for an additive manufactured lower hybrid current drive launcher

Recent advances in selective laser melting (SLM) 3D printing technology allows additive manufacture of lower hybrid current drive (LHCD) RF launchers from a new material, Glenn Research Copper 84 (GRCop-84), a Cr2Nb (8 at. % Cr, 4 at. % Nb) precipitation hardened alloy, in configurations unachievable with conventional machining. Rough surfaces in additive manufactured components are a limiting factor in RF structures. Surface roughness increases RF losses and impedes conditioning by trapping gas and contaminants that induce arcing by evolving from the surface at high power. SLM printed GRCop-84 is post-processed with mass finishing to reduce surface roughness. Wet blasting, vibratory finishing, and chemical etching remove adhered powder grains from SLM printed GRCop-84. Profilometry and scanning electron microscopy were used to quantify resulting surface quality. Chemical etching is examined to remove zinc contamination from wire electrical discharge machining slag prior to vacuum use. Etch rates in SLM printed GRCop-84 are anisotropic, and etch times should be limited to prevent pitting corresponding to the laser hatch pattern. Vibratory mass finishing and mechanical polishing produced surfaces suitable for low RF loss. Use of chemo-mechanical finishing is recommended for the interior of SLM printed structures.

RF losses in selective laser melted GRCop-84 copper waveguide for an additively manufactured lower hybrid current drive launcher

Abstract Recent advances in selective laser melting (SLM) 3D printing technology allow additive manufacture of lower hybrid current drive (LHCD) RF launchers from a new material, Glenn Research Copper 84 (GRCop-84), a Cr2Nb (8 at.% Cr, 4 at.% Nb) precipitation hardened alloy, in configurations unachievable with conventional machining. Rough surfaces in additively manufactured components are a limiting factor that increases RF losses. Surface roughness was found to be the dominant loss mechanism in SLM printed waveguide components. Wet blasting removes adhered powder grains from SLM printed GRCop-84 while vibratory mass finishing smooth’s and flattens waveguide surfaces. Mechanical polishing produced surfaces with low RF loss, however a further mass finishing step is recommended for the interiors of waveguides where polishing is not possible. Power loss in the upcoming LHCD launcher system for DIII-D is used to predict driven current in the plasma.

CNS 表面の作製と潤滑特性

We fabricated contoured nanostripe (CNS) surface consisting of Cr and Cu multilayer films having a contour like grooves by wet blasting. Depth of nanoscale grooves (nanogrooves) on the substrate is 60 to180 nm. The friction tests at a constant load were carried out using an Al ball under a lubricating condition. The CNS substrate having dense nano-grooves showed the lowest wear. The substrate having nano-grooves showed good lubricating properties. Durability of CNS surface probably depended on interfacial strength between films. The friction loop showed that the CNS surface had locally friction reduction properties.

Micro Wet Blasting による材料表面特性の改善

Micro Wet Blasting による材料表面特性の改善

Fatigue life equality of polished and electrical discharge machined WC-Co hard metal achieved solely by wet blasting

WC-Co hard metals are materials widely used in wear applications, metal machining and highly fatigue loaded tools. Shaping tools and components made of hard metals often requires electrical discharge machining (EDM) that is well-known to negatively influence the material's fatigue properties.The current work demonstrates that it is possible to achieve a fatigue limit of electrical discharge machined specimens equal to the one of finely ground and polished reference samples. This is achieved by the application of advanced wire EDM technology combined with a sole surface post-treatment step of abrasive blasting. Stress amplitude-life curves were determined in a four point bending test setup. Depth profiles of residual stress were determined by means of X-ray diffraction for electrical discharge machined samples prior to and after blasting. Surface defect size was documented in metallographic cross sections by scanning electron microscopy. The surface residual stress state was found to be crucially important regarding the observed fatigue behavior. If the applied EMD technology produces cracks shallow enough to allow for their removal by abrasive blasting and compressive residual stress is introduced as deep into the surface as damage reaches, the negative effect of EDM on the fatigue limit is neutralized.

Effect of Corrosion Inhibitor Used in Surface Treatment on the Anticorrosive Performance of an Epoxy Paint System

The mechanism of corrosion is mainly sustained by an electrochemical process, in which anodic and cathodic reactions take place, keeping their kinetics alive by electrons and ions fluxes. Several specific conditions can accelerate corrosion processes. When studying anticorrosive coatings, one of them is the contamination of metallic surface by soluble salts prior to coating, leading to premature failure of the paint system due to corrosion between the metallic surface and the coating. So the surface preparation step prior to coating is a procedure of great importance to the coating anticorrosive performance. The aim of this step is to clean the surface by removing visible and non-visible contaminants. Usually, wet abrasive blasting methods are the most efficient ones to achieve the latter objective, because they may clean the surface, create a surface roughness and also remove the non-visible contaminants, as they use water as a media. On the other hand, evaporation of water after blasting may create flash rust and to avoid this, it is common to use corrosion inhibitors in the water of wet blasting methods. In this paper, the use of sodium tetraborate (borax) as a corrosion inhibitor in wet abrasive blasting is discussed. Electrochemical measurements and mass loss tests show that a borax content of 1% in a saline solution has the best inhibitory action over carbon steel and zinc surfaces, allowing postponing for the painting step some time. However, residual borax left on the surface generated blistering and corrosion under coating, during accelerated corrosion test in a humidity condensation chamber. Electrochemical impedance spectroscopy confirmed that borax accelerated the permeation of water through the coating, downgrading the anticorrosive performance of the paint system.

2G35 ソフトマテリアル相手材に対する表面テクスチャの影響

Micro slurry-jet erosion has been proposed as a precision machining technique for the bearing surfaces against a soft or hydrated material. The micro slurry-jet erosion method is a wet blasting technique which uses alumina particles as the abrasive medium along with compressed air and water to create an ideal surface. The technique will be one of the effective tool to create LOTUS-LEAVES or MOTH-EYES structures, the inspiration for the incredible properties of the new coating comes from nature. The water repellent and self-cleaning abilities resemble those of LOTUS-LEAVES, which use rain for self-cleaning, the surface should be angled at about 150 degrees, causing the water drops to bounce off and take dust along with them. The boost of efficiency comes from an anti-reflective technology that resembles MOTH-EYES in functionality and structure. Thanks to advances in the nano-scaled machining technique, the authors will be able to engineer precisely the nanoscale structures in the future.

表面テクスチャリングが材料表面の親・疎水性に与える影響

Surfaces of lotus leaf and moth eye have fine structures. The structure produces water repellent effect or reflection suppression. The purpose of this study is to reproduce these characteristic to the artificial material surface by using a precision machining method. Micro slurry-jet erosion has been proposed as the precision machining method for a glass or plastic surface. The micro slurry-jet erosion method is a wet blasting technique which used alumina particles as the abrasive medium along with compressed air and water to create the fine structures. The glass surface processed has a hydrophobic character and do not show influence of the light transmission property. These results concluded that the precision machining method was one of the promising method to create the bio-inspired surface on the artificial materials.

人工関節における表面テクスチャリングの効果

The reduction of tissue reactions in an artificial joint composed of an ultra-high molecular weight polyethylene sliding on a Co-Cr-Mo alloy, was investigated. To control the specific wear rate and morphological features of wear debris of the polyethylene, micro slurry-jet erosion was used as a precision machining method for the bearing surface of a Co-Cr-Mo alloy. This method constitutes a type of wet blasting technique, which uses alumina particles as an abrasive medium, along with compressed air and water, to create textured surfaces. Pin-on-disc wear tests, involving multidirectional sliding motion, resulted in a decrease in the polyethylene wear and changes in the morphological features. Primary human peripheral blood mononuclear phagocytes were incubated with the debris, and the wear debris generated on the textured surface changed the secretion of the IL-6 proinflammatory cytokines. We concluded that appropriate surface geometry contributed to prolong the service life of artificial joints.

Textured bearing surface in artificial joints to reduce macrophage activation

Micro slurry-jet erosion has been proposed as a precision machining technique for the bearing surfaces of artificial joints in order to reduce the total amount of polyethylene wear and to enlarge the size of the wear debris. The micro slurry-jet erosion method is a wet blasting technique which uses alumina particles as the abrasive medium along with compressed air and water to create an ideal surface. Pin-on-disc wear tests with multidirectional sliding motion on the textured surface of a alloy counterface for polyethylene resulted in both a reduction of wear as well as enlargement of the polyethylene debris size. In this study, primary human peripheral blood mononuclear phagocytes were incubated with the debris, and it was elucidated that the wear debris generated on the textured surface regulated secretion of the proinflammatory cytokines IL-6 and TNF-α, indicating a reduction in the induced tissue reaction and joint loosening.

J0250102 人工関節軸受部の表面テクスチャが生体反応因子に与える影響

Micro slurry-jet erosion has been proposed as a precision machining technique for the bearing surfaces of artificial joints in order to reduce the total amount of polyethylene wear and to enlarge the size of the wear debris. The micro slurry-jet erosion method is a wet blasting technique which uses alumina particles as an abrasive medium along with compressed air and water to create an ideal surface. From pin-on-disc wear tests with multidirectional sliding motions, the textured surface on a Co-Cr-Mo alloy could change the total amount of wear of polyethylene.

Study on Characteristics of <i>Lactobacillus rhamnosus</i> on Lactic Acid Fermentation with Different Substrates

In order to investigate characteristics of Lactobacillus rhamnosus on lactic acid fermentation using different substrate, in this study, saccharification liquid obtained during wet oxidation blasting of straw were used as substrate, conversion reducing sugar to lactate by Lactobacillus rhamnosus was studied and compared with fermentation using glucose as substrate, The results indicated that Lactobacillus rhamnosus could utilize reducing sugar in saccharification liquid obtained during wet oxidation blasting of straw effectively. The highest efficiency of reducing sugar conversion (92.45%) appeared when concentration of reducing sugar as substrate was 20mg/mL; conversion rate of reducing sugar decreased as increasing of sugar concentration. Fermentation of saccharification liquid obtained during wet oxidation blasting of straw to lactic acid by Lactobacillus rhamnosus had optimal effects in the first 48h of incubation.

Wet blasting as a deburring process for aluminum

Light weight aluminum has shown high applicability in the automobile industry for high fuel efficiency. However, the manufacturing of aluminum is limited by the deburring process owing to the difficulty in employing wet blasting. In this paper, we present experimental and computational studies on the deburring process of wet blasting for aluminum. The process conditions are analyzed to achieve high deburring performance that minimizes the surface damage. Parameters of wet blasting with a significant influence on the deburring process are investigated and a promising deburring technique for aluminum is proposed.

1021 ウェットブラスト法を用いた金属材料の洗浄方法(OS01-4 機械要素とトライボロジー,オーガナイズドセッション 1:「機械要素とトライボロジー」)

1021 ウェットブラスト法を用いた金属材料の洗浄方法(OS01-4 機械要素とトライボロジー,オーガナイズドセッション 1:「機械要素とトライボロジー」)