Dry-ice Blasting Research Articles

Efficient and Sustainable Cleaning: A Comparative Analysis of Cryogenic Technology

Dry ice blasting is a technology that has been widely studied and applied in different industrial sectors as an alternative to the use of solvent, water, or abrasive spraying methods. It is a CO2 spraying system capable of balancing efficiency and sustainability with a wide variety of equipment available on the market. This study analyses and compares cryo-cleaning equipment manufactured by pioneering companies in the cryogenic industry. Based on data sheets, safety data sheets, and contact with manufacturers, a quantitative comparative study has been carried out. The aim of this study is to identify those with the best performance, efficiency, and adaptability to operational and environmental requirements. The results reflect the strengths and weaknesses of the equipment in terms of occupational safety and operability. These have been discussed and evaluated, recognising improvements of this technology, which is capable of removing surface layers of different natures without altering the underlying substrate.

Assessing the Feasibility of Removing Graffiti from Railway Vehicles Using Ultra-Freezing Air Projection

Unauthorised graffiti is a challenge in urban environments, affecting railway structures, stations, tracks, and vehicles. Inefficient cleaning methods increase the costs and downtime of railcars, limiting passenger transport. In turn, they are harmful to the operator’s health and the environment, due to the VOCs they release. This study focuses on the feasibility of dry-ice blasting, replacing carbon dioxide with ambient air as an innovative and sustainable solution to remove graffiti from rail vehicles. Experimental tests have been carried out with 13 different aerosols, controlling the temperature (<−80 °C), pressure (up to 3 bar), projection distance (0.5 cm) and exposure times (30″/1′/2′/4′/6′/8′/++). The results showed that ultra-freezing with ambient air preserved the integrity of the support materials and altered the topography, colourimetry and adhesion of the aerosols tested, achieving the total removal of one of the paints. Preliminary results suggest that ultra-freezing with ambient air could be a viable and sustainable solution for graffiti removal on railway structures, transferable to other urban environments.

Accelerated In Situ Inspection of Release Coating and Tool Surface Condition in Composites Manufacturing Using Global Mapping, Sparse Sensing, and Machine Learning

The interfacial adhesion, friction, and resulting tool-part interaction during composites manufacturing contribute to the formation of residual stresses and process-induced deformations (PIDs). Tool-part interaction and PIDs are highly sensitive to processing variabilities, one of which is the aging of the release coating and the surface condition of production tools. Unfortunately, due to a lack of available tool inspection methods, manufacturers often attempt to mitigate the aging of release coating based on know-how, leading to cost-deficient tool preparation schedules, lower end-part quality, and in some cases, higher levels of PIDs. This paper presents an in-situ inspection method to evaluate the physicochemical properties of release coating and the surface condition of large production tools by utilizing global mapping, sparse sensing, and machine learning (ML). ML methods are used in conjunction with multiple automated measurement techniques to quickly identify the condition of release coating or contamination on production tool surfaces in manufacturing environments. Results in this paper demonstrate that during autoclave processing, aerospace-grade release coatings undergo significant chemical changes, but may remain highly abhesive for more than twenty autoclave processing cycles. Using the proposed novel inspection technology, dry ice blasting (DIB) is also demonstrated to be an effective method for non-abrasively removing cured resin contamination and release coating from a tool surface. Overall, this paper demonstrates how the proposed inspection method can be integrated into a manufacturing process for automatic surface inspection of large tools to improve production efficiency and potentially mitigate PIDs in composites manufacturing.

Effect of surface cleaning on seam quality of laser beam welded mixed joints

In this study, different surface cleaning methods were used to remove greases and oils from the surface of the E235 steel tube component of the diamond segmented drill bit before laser beam welding. The mechanical, chemical and electromechanical cleaning methods were selected because they are suitable for removing greases and oils adhering to the surface during tube production. The cleaned samples were successfully welded using the same heat inputs by laser welding. The effect of mechanical processes with sandblasting and dry-ice blasting, chemical processes with isopropyl alcohol, acetone and alkaline acidic liquid, electromechanical process with a laser beam on micro-computer tomography, break-out value and micro-hardness measurement examined. The cleanliness of the surfaces and strength of the laser-welded joint was inferred from the break-out value (BOV), as this is the principal qualification value in mass production. The results were compared to the untreated sample. According to the results obtained in this study, any defects in the seams were analyzed, and no cracks founded by computer tomography. According to a shade of grey diagram, all the pretreated samples had a higher absorption than the untreated sample. While the chemical methods had a significant effect (59–66 %), the mechanical and electromechanical methods had a positive effect (22–48 %) compared to the untreated sample. In addition, the break-out values showed that the mechanical methods had a significantly higher effect (19 %) than the other surface cleaning methods. This test showed different results from the micro-CT scan. The microhardness test showed no difference between the hardnesses of the cleaned and uncleaned samples and no difference in seam thicknesses. The optimal oil removal process discusses in the conclusion part.

DeNOx Characteristics of Commercial SCR Catalyst Regenerated On-Line by Dry Ice Blasting in a Coal-Fired Power Plant

DeNO<i>x</i> Characteristics of Commercial SCR Catalyst Regenerated On-Line by Dry Ice Blasting in a Coal-Fired Power Plant

Assessment of energy consumption, carbon emissions and cost metrics under hybrid MQL-Dry ice blasting system: A novel cleaner production technology for manufacturing sectors

Modern industries are seeking innovative and clean cooling techniques in the machining domain to reduce the cost and environmental impact of manufacturing. To diminish the environmental impact of machining, cryogenic and minimum quantity lubrication (MQL) are recent known cooling/lubrication techniques to determine a perfect alternative to mineral-based emulsion cooling. The cryogenic has superior cooling capabilities and poor lubrication and MQL is vice versa. In this endeavor, a new hybrid MQL-dry ice blasting lubri-cooling technology is proposed in machining as eco-benign technology to investigate sustainability as well as machinability metrics in the milling of AISI-52100. The findings have shown that cutting speed and cooling/lubrication showed the most substantial effect on machinability and sustainability metrics. The experimental findings showed that the cutting speed has more significant effect on specific energy consumption, carbon emission, and machining cost. At highest level of cutting speed (300 m/min), processing time, specific energy consumption, carbon emission and surface roughness was 2.6%, 2.3%, 2.35%, and 22.6% less under hybrid dry ice blasting compared to MQL medium. The shares of the standby time in total energy consumption, carbon emission, and total cost are noticed to be dominant. The hybrid dry ice blasting shared a small fraction of the total cost compared to MQL, and dry ice blasting.

A novel low-pressure hybrid dry ice blasting system for improving the tribological and machining characteristics of AISI-52100 tool steel

Hybrid minimum quantity lubrication and compressed carbon dioxide (MQL + CO2) lubri-coolant can play a crucial role in advancing machinability as well as sustainability. However, it is also the fact that the high-pressure throttling of CO2 produces fog and hinders the low-pressure MQL mist to touch the cutting zone adequately. Therefore, a low-pressure novel hybrid MQL-dry ice blasting lubri-coolant technology is anticipated to improve the machinability by providing the cooling and lubrication simultaneously in milling AISI-52100. This low-pressure hybrid dry ice blasting not only reduces an abundance of smog to reduce the cutting zone visibility, but the dry ice grains also behave as carriers to bring MQL-mist to the cutting zone perfectly. In this proposed study, the surface roughness, residual stresses, cutting temperature, surface hardness, tool wear, and cutting forces are measured by varying the cutting speed (75-300 m/min) and feed per tooth (0.04–0.12 mm/z) under hybrid MQL-dry ice blasting lubri-cooling condition in milling AISI52100 tool steel. The results of this study highlighted that as the cutting speed raised from 100 m/min to 300 m/min, an increase in cutting temperature was 22 % at a constant feed per tooth of 0.08 mm/z. Similarly, the decrease in surface roughness was 42 %, tool life reduced to 57 %, surface hardness increased to 9 %, and across-the-feed surface hardness increased to 58 % by the increase of cutting speed from 75 to 300 m/min and constant feed per tooth of 0.08 mm/z. The proof-of-the-concept study showed the machinability advancement under hybrid lubri-cooling technology due to precise penetration of MQL mist and dry ice grains into the cutting zone in terms of ease in chip evacuation, excellent lubrication, and cutting heat dissipation by sublimation of dry ice.

Influence of dry ice blasting process properties on surface roughness and residual stresses of machined and additive manufactured workpieces

Dry ice blasting has shown the potential to remove metallic burrs after machining processes and support structures after additive manufacturing. During blasting, process parameters need to be chosen depending on the material and the geometric properties of the burr. However, dry ice blasting affects the local material properties on a micro level and improper blasting parameters may lead to changes in the part surface. In this article, correlations and interactions between dry ice blasting parameters and resulting specimen roughness and residual stresses are identified for machined and additive manufactured metallic materials.

Investigating the erosive wear caused by dry-ice blasting in paint stripping process

Dry-ice blasting (DIB) has been widely used in the industry for several applications. However, its erosive effect on surfaces has not been studied deeply. This work aims to study the efficiency of DIB for stripping organic coatings (paints) on steel surfaces and its corresponding erosive damage as generated by different jet angles. In addition, the surface cooling during DIB was analyzed to get a deeper understanding of its influence on erosion wear mechanisms. The results have shown that the stripping efficiency increased with the increase of jet impact angle exhibiting minor evidence of surface damage in form of micro craters. In addition, it was observed that surface cooling could be reduced by increasing the initial temperature of the sample and reducing impact angles (i.e., 30°). Finally, it was found that the erosive wear mechanism of DIB is controlled by the ductile–brittle transition of the surface by undercooling caused by DIB.

Efficacy of mechanical procedures for removal of a lichen and a gypsum black crust from granite

This paper provides preliminary data on the use of three different mechanical procedures to remove the lichen Diploschistes scruposus and a gypsum black crust from an ornamental granite. The methods used were wet sandblasting (Hydrogommage®), dry sandblasting (IBIX®) and dry-ice blasting. In addition, lichens were also removed by scraping with a scalpel. The cleaning efficacy and undesirable effects to granite were evaluated by stereomicroscopy, colour spectrophotometry, Fourier-transform infrared spectroscopy and scanning electron microscopy.The cleaning efficacy of the mechanical methods depended on the deposit being removed: i) for lichen, dry sandblasting and dry ice blasting produced the best results, while for the black gypsum crust, although both dry and wet sandblasting removed the black particulate matter from the crust, gypsum crystals remained on the surface; ii) the dry sandblasting method induced extraction of granite grains with the subsequent appearance of fissures; iii) for the lichen, the wet sandblasting method was totally unsatisfactory and iv) for the gypsum black crust, dry ice blasting failed to remove the black particulate matter from the crust.

Operational parameters impact on the performance of dry-ice blasting nozzle

Carbon dioxide due to its chemical and physical properties can be successfully used in the wide range of surface cleaning an pre-treatment applications. One of the main carbon dioxide cleaning application is the dry-ice blasting, which seems to be a promising method of industrial devices cleaning. In the method the solid carbon dioxide particles supplied by the pressurized dry air are speed up to supersonic velocities in the convergent-divergent nozzle to finally reach the cleaning surface. Then via cooling and sublimation, causing in the rapid volume growth the pollution is crashed and removed with the air flow. Main cleaning mechanisms of dry-ice blasting are described in the paper. The crucial part of the system is the nozzle. The article covers the operational parameters impact on the nozzle performance. The authors present the methodology allowing the dry-ice blasting system assessment and provided the bench tests of the convergent-divergent supersonic nozzle in the field of nozzle’s efficiency, cleaning speed and operational costs. Impact of inlet air pressure, nozzle outlet-surface distance, cleaning angle, surface type and crushing sieve implementation was determined and analysed.

Eco-innovation in the cleaning process: An application of dry ice blasting in automotive painting industry

In the field of the automotive painting industry, the conventional cleaning process uses solvents and high amounts of water to clean different substrates. However, not all solvents are suitable for every type of material, so different types of solvents should be used in order to successfully clean different types of material, as the product under fabrication changes, otherwise, a compromise has to be reached. The current cleaning operation system and respective apparatus occupies a significant area of the industrial facility and uses abundant water. Such use of water requires subsequent drying of the cleaned parts and for residual water treatment, leading to high running costs. In this sense, dry ice blasting appears as an alternative to the current process. This method consists of the projection of solid carbon dioxide particles onto a surface as a means of eliminating stains and contaminants prior to the painting. It is suitable for a wider range of substrates, and the necessary equipment occupies significantly less space when compared with the current process. Thus, there is potential for cost savings. In an industrial painting context, this application is considered new, although its physical principle has been established since the late 1980s. The present study aims to qualitatively evaluate the dry ice blasting process according to the quality standards of an industrial unit. Two types of plastic substrates for automotive parts are tested on-site by using a manual dry ice blasting kit, subject to the normal painting process, and then analyzed according to industrial standards. The results show that the process under study meets all the required quality standards. After being painted, the average number of stains per piece is of the same order of magnitude as the normal production, emphasizing that the average primary stains are lower in the process under study. CO2 emissions and cleaning time is greatly reduced, the cleaning runtime decreased by 96.9% if the dry ice is used as an alternative. The viability of dry ice blasting in the pre-painting of plastic surfaces was demonstrated, and the eco-innovation of the new process discussed.

Effect of impact force for dual-hose dry blasting nozzle geometry for various pressure and distance: an experimental work

Dry ice blasting plays an essential role in today’s cleaning industry, where many industry players have used it after realizing its advantages. The disadvantage of dry ice blasting is relatively small kinetic energy and offer less aggressive clean effect, especially for dual-hose nozzle geometry. This project was mainly to study the impact force of nozzle geometry of dry ice blasting concerning pressure and distance variation. The nozzle geometries with optimum size and shape are fabricated based on a recent literature study. The experimental research on the effect of the impact forces on different pressures and distances has been conducted to validate the simulation study. The result shows that the optimum nozzle design gives better performance than a based model. Besides, the optimum distance for dry ice blasting operation is less than 400 mm for the pressure range of 2 bars to 4 bars. This distance gives the maximum value of the impacted force for dry ice blasting operation in the industry.

Influence of divergent length on the gas-particle flow in dual hose dry ice blasting nozzle geometry

A numerical simulation study was performed to examine the effect of nozzle geometry and divergent length on gas-particle flows in dual hose dry ice blasting. The simultaneous model of mass momentum and energy exchange between two phases was solved iteratively. The phases are solid dry ice particle and compressible air fluid as a working medium. The results were presented in the gas flow field along the nozzle centerline. The results showed that increasing divergent length decreases the gas-particle density along the centerline; and the density development along the nozzle centerline decreased along the length. Eddy viscosity of the nozzle cavity was steady for length of 0.25 m, but increased drastically for higher values. The substantial increase in eddy viscosity after that position is due to the mixing flow between dry ice pellet and compressed gas which is diverging out from the nozzle outlet area. Thus, the mixing flow experienced back pressure from the atmospheric pressure. The particle mass concentration decreased by increasing nozzle centerline coordinates. The pressure increased along the length; however, it dropped at the end due to the reverse pressure. The temperature increased steadily because of conversion of turbulence to internal thermal energy. The characteristics of gas-particle flow in the nozzle cavity provide better understanding of multiphase flow in turbine and jet engine flow analysis.

Numerical Analysis of Dry Ice Blasting Convergent-Divergent Supersonic Nozzle

There are several well-known and widely used industrial cleaning methods in the market today. One of them is dry ice blasting. In this method, moisture-free air is compressed, mixed with solid CO2 particles, and blasted though a nozzle; in the process, the gas expands, propelling its velocity. The high-speed, two-phase flow cleans by supercooling and crushing particles on the surface, causing dry ice sublimation. As the nozzle is a crucial component of the system, the authors conducted a numerical analysis of the geometry of the proposed convergent-divergent nozzle. A mathematical model of the supersonic, two-phase flow was developed and implemented in commercial Computational Fluid Dynamics (CFD) code. Various operating parameters, such as inlet pressure and dry ice mass flow, were taken into consideration.

Correction to: Effect of Dry-Ice Blasting on Structure and Magnetic Properties of Plasma-Sprayed Fe-40Al Coating from Nanostructured Powders

Correction to: Effect of Dry-Ice Blasting on Structure and Magnetic Properties of Plasma-Sprayed Fe-40Al Coating from Nanostructured Powders

Duplex and functionally graded Al@NiCr/8YSZ thermal barrier coatings on aluminum substrates

It is difficult to prepare non-ablative thermal barrier coatings (TBCs) on aluminum alloy owing to the sensitivity to oxygen and low melting temperature of the substrate and great difference of thermal expansion coefficient between the substrate and the coatings. In this work, the cladding-structured Al@NiCr was deposited as interlayer between the aluminum alloy substrate and the 8YSZ topcoat to enhance the bonding strength of TBCs. To avoid the oxidation of the bond coat and the substrate, different cooling systems were attempted. Al@NiCr/8YSZ functionally graded (FG) coatings were also designed and prepared on the aluminum alloy substrate. Microstructure, bonding strength and thermal cycling behavior were investigated and compared with the duplex TBCs. The results showed that selective oxidation of aluminum and chromium occurred for plasma-sprayed Al@NiCr interlayer, similar to traditional NiCrAlY bond coat. The aluminum oxides still wrap around NiCr splats in the coatings. With the application of dry-ice blasting, Al@NiCr interlayer presents more significant decrease in the porosity and the oxides than traditional NiCrAlY as well as more improvement in the bonding strength. Al@NiCr/8YSZ FG coatings have incremental density from ceramic to metal side and uniform layer density. The bonding strength of FG coatings was about twice as higher as that of the duplex ones. Al@NiCr/8YSZ TBCs on the aluminum alloy substrates exhibit an excellent thermal cycling lifetime.

Optimum Design of Nozzle Geometry of Dry Ice Blasting Using CFD for the Reduction of Noise Emission

Dry ice blasting has been used in the modern cleaning industry. However, the primary disadvantage of dry ice blasting is high noise exposure. At a high blasting pressure, the process reaches a harmful noise level of up to 130 dBA. The situation significantly impairs to a human being when the noise emission occurs in an inaudible frequency area. Present safety measures are only based on administrative control by encapsulating the entire system with sound insulation. The main objective of this project is to study the optimum nozzle configuration on the effect of dry ice blasting particle velocity and acoustic noise emission. Different nozzle geometry were simulated several times until optimization is achievable. Three-dimension models are designed using CATIA V5. Then the models are simulated with Ansys Fluent V18.2. The numerical studies have been carried out using density based, standard k- e turbulence and Acoustic Broadband Noise Sources model. Six (6) different nozzle configuration namely divergent length, the angle of particle inlet, convergent diameter, expansion ratio, gas inlet diameter and length ratio are analyzed in term of particle velocity magnitude and acoustic power level. The result shows that the optimum nozzle configuration for divergent length, the angle of particle inlet, convergent diameter, expansion ratio, gas inlet diameter and length ratio are 230 mm, 30 mm, 35 mm, 1.00, 6 mm and 0.80 respectively. This configuration provides minimum lowest acoustic noise emission and maximum particle velocity magnitude.

A Study on the Suitability of Mechanical Soft-Abrasive Blasting Methods to Extract Graffiti Paints on Ornamental Stones

Mechanical methods to extract undesired graffiti paints on ornamental stones are efficient cleaning methods from an economical point of view. However, effort on the optimization of mechanical cleaning procedures to avoid any damage to the substrate is required for large areas. In this study, two ornamental stones with different composition and texture, and which are commonly used in Spain and Portugal were selected: Granite Vilachán and Limestone Lioz. Moreover, the most common surface finishes were selected-disc-cutting and bush-hammering to simulate the stones found in buildings. Two graffiti spray paints were selected: Blue Ultramarine and Silver Chrome. As cleaning methods, three soft-abrasive blasting procedures: Hydrogommage (mixture of air–water–micro grained silicon abrasive), IBIX (mixture of air–micro grained silicon abrasive), and dry-ice procedure (carbon dioxide ice pellets), were tested at pressure below 0.4 MPa. The methodology for evaluating the effectiveness and harmfulness of each cleaning method was based on stereomicroscopy, scanning electron microscopy, color spectrophotometry, and confocal microscopy. As result, IBIX achieved the highest level of graffiti paint extraction although this method increased the surface roughness. Conversely, cleaning based on dry-ice projection did not achieve a satisfactory extraction of the graffiti, mainly of the blue paint. Dry-ice blasting can induce acid environments and IBIX causes dust emission during the projection. Hydrogommage was the most efficient cleaning method amongst the tested procedures, because it induced the lowest roughness change and although the graffiti extraction was not complete, it achieved the highest removal level. Therefore, the most satisfactory cleaning method was that achieving a satisfactory extraction level, minimal modifications of the surface roughness, an economic suitability, an environmental integration, and lower human health risks.

Mechanical pretreatment before electroplating of aluminium alloy AlSi12

Electroplating is a coating process used to increase the durability of workpieces or to change their appearance. To form a high adhesive bonding between the coating and the workpiece, its surface has to meet certain requirements achieved by a comprehensive pretreatment. The conventional pretreatment process chain consists of different steps to increase the roughness and the surface tension of the workpieces. But besides its high costs chemicals are used, which are harmful to the environment and health.The complexity of the pretreatment and coating process chain differs depending on the used workpiece material. Particularly challenging to coat are thereby aluminium-silicon alloys. During the conventional pretreatment of these casting alloys, the Silicon phase enriches on the surface of the workpieces and has to be removed in an additional process step using nitric acid.This study compares alternative mechanical pretreatment processes for AlSi12-workpieces prior to electroplating. The investigated processes are conventional grinding, double face grinding with planetary kinematics, lapping and dry ice blasting. Subsequent to the structuring, the workpieces are cleaned by carbon dioxide snow blasting. The investigation of the different surface structures and its properties, like roughness, surface tension and wetting behaviour, allowed the determination of their impact on the adhesive strength of the coating by empirical modelling.By structuring the surfaces of the workpieces they could be coated by electroplating. Thereby, the chemicals used in the conventional pretreatment are substituted. Especially the creation of surfaces, which could be wetted homogenously, showed a satisfactory adhesive strength of the applied coatings.