Sanding Process Research Articles

Evaluation of surface roughness and frost retardancy of a glass fiber/unsaturated polyester composite

Frost retardant of glass fiber (GF)/unsaturated polyester (UP) composites was evaluated with surface roughness. Glass fiber reinforced composites (GFRCs) were manufactured, using 8 ply fabric type GF mats and UP at 50 vol% volume fraction, using a vacuum assisted resin transfer molding (VARTM). Surfaces of the GFRCs were sanded using different grit sand papers. Static and dynamic contact angle (CA) measurements were performed to determine the hydrophobicity of specimens with different surface roughness. Observation of frost thickness versus time was performed to evaluate frost retardant as a function of surface roughness. An atomic force microscope (AFM) was used to quantify the surface roughness produced by sanding with different grit sand paper. It was found that surface roughness, CA and frost formation thickness were all-dependent on the grit of sand paper used in the sanding process. These behaviors appeared to be interrelated with an optimal sanding grit size of 320 CC.

The simulation of surface topography generation in multi-pass sanding processes through virtual belt and kinetics model

Belt sanding is an effective manner of material processing and widely used to improve the surface roughness and obtain high polishing glossiness. During the belt sanding process, the contact condition exhibits more complexity than grinding due to the flexibility of the belt. For the sanding application where surface glossiness is expected, it always involves multiple sanding as well as polishing passes. This makes the analytical modeling of the surface generation as well as its impact on glossiness formation complicated in this multi-pass operation. In this paper, the surface generation model for multi-pass sanding operation is established through the development of the virtual sanding belt model and the multi-pass kinematics simulation of the sanding process. As for the belt-workpiece contact zone, the 3D Hertz contact model is incorporated into the kinematics simulation to duplicate the real contact condition for multi-pass sanding. Furthermore, the critical surface topography parameters are identified to establish the correlation with belt sanding parameters. Finally, surface topography parameters related with glossiness properties, e.g., surface roughness Sq, surface height distribution kurtosis Ku, surface height distribution skewness Sk, and surface correlation lengths Lx and Ly, are studied for optimal sanding process parameter analysis. The optimal sanding condition for ideal glossiness should be that the rotation speed should be beyond 1200 r/min, and the workpiece feedrate should be below 50 mm/s.

A hydro-mechanical sand erosion model for sand production simulation

Sand production while producing hydrocarbons from a well is a critical issue faced by the oil and gas industry. It is a complex process controlled by several factors, including the mechanical failure of materials around the wellbore and the material erosion due to fluid flow. The coupling between these factors leads to considerable challenges in modeling and predicting sand production. This paper presents a finite element based approach for simulating the realistic sanding process, considering coupling between mechanical failure and hydrodynamic erosion of the rock. A well calibrated sand criterion proposed by Papamichos was implemented to model sand erosion. An adaptive meshing technique was used to track receding of the eroded surfaces and to progressively modify boundary conditions on new surfaces, which are important for capturing the realistic sanding process. Sand production in both open-hole and perforated-casing completions was simulated to illustrate capabilities of presented method. Numerical results show that sand production is controlled primarily by the plastic strain and flow velocity around the wellbore. Other parameters, including drawdown, in-situ stress, and perforation orientation, are shown to have considerable influence on sand production rate and are discussed in this paper.

Research on neural network model of surface roughness in belt sanding process for Pinus koraiensis

At present, researches about surface roughness mainly focus on the measurement methods and the relation between wood surface roughness and adhesion strength as well. It is well known that some sanding parameters are considerably key factors for analyzing the cause of surface roughness. However, only a few research studied the relations among surface roughness, sanding parameters, sanding pressure and wood texture direction. Back-propagation network (BP network) system was applied to simulate and predict the surface roughness value during the sanding process. The aim of this study was to determine the effects of sanding parameters on surface roughness of pinus koraiensis and the relation between sanding pressure and surface roughness, and finally establish the model of surface roughness combined with wood texture characteristic of pinus koraiensis through neural network system. The results showed that All values of surface roughness had a “vacuum belt” when λ = 0° and λ = 45°, but it did not appear when λ = 90° (λ refers to the angle between the feeding direction and the wood grain). The confidence of the fitting surface roughness results was 97% by BP network model and the average error was 5.8%, which can simply and successfully predict surface roughness during sanding process.

Surface quality of the Ficus sp. wood veneers submitted to finishing treatments

The objective of this investigation was to evaluate the roughness, wettability and the surface color of Ficus sp. genus before and after the process of manual sanding and application of a finishing product (stain). The roughness and color were determined before and after the sanding process and after applying the stain using Surftest SJ 400 Mitutoyo and ColorEye XTH spectrophotometer. The wettability was evaluated by measuring the contact angle between the water drop and the surface of the veneers, using a goniometer Krüss DSA30. The roughness of the veneers, subjected to 180, 240, and 320 sandpaper, decreased after the sanding process and remarkably after stain application. The contact angle was over 90° for all treated samples. Regarding the colorimetry, there was a decrease in L* average values after sanding. After applying the stain, there was a change in color of the wood, from grayish-white to yellow-olive.

A method for assessing the wear of sanding abrasive discs differing in the type of grains (SiC, Al2O3(95A))

This paper describes a method for studying the wear of abrasive mesh discs differing in the type of grains employed to sand plaster. The tests were conducted at a specially developed and constructed setup. The investigations involved analysing the influence of the basic input parameters (the size of the abrasive grains covering the disc surface, the force exerted by the plaster sample pressing against the abrasive disc and the no-load speed of the abrasive disc) on the efficiency of the sanding process. The paper also describes the structural details of the experimental setup.

The simulation and experimental study of glossiness formation in belt sanding and polishing processes

Glossiness is an optical index representing the capacity of a surface to reflect light, which is vital criteria for components in need of esthetic appearance. To achieve the stringent glossiness requirement, sanding and polishing for smooth surface generation become the necessary material removal method. However, the intrinsic correlation of surface roughness and glossiness is still not clear. Small roughness value does not always guarantee perfect glossiness, and high surface glossiness does not always require extreme surface roughness perfection. In this paper, the surface topography features and glossiness conditions are analyzed for sanded and polished surfaces. And the surface glossiness is modeled and simulated for surfaces generated with non-Gaussian topography features manufactured by sanding and polishing. Finally, the critical surface topography parameters are identified to establish the correlation with the surface glossiness.

Effects of extractives removal on the performance of clear varnish coatings on boards

In this work, the effects of extractives removal on the performance of used varnishes were studied. The experimental samples were prepared using defect-free alder ( Subcordate alnus) and ironwood ( Zelkova carpinifolia) with moisture content of 12% and were coated with polyester and two-part polyurethane (urethane alkyd) varnishes. Removal of extractive materials followed Tappi Test Methods using hot water and ethanol. Variable parameters were based on the solvent type (extraction method), wood species, and varnish type. Other parameters such as moisture content, sanding process, and dimensions were kept constant. Pull-off adhesion and dynamic absorption tests were used to assess adhesion and performance of the two clear varnish coatings. Sanding process was employed prior to coating, which helped prepare surfaces virtually free of damage. In general, the extractive-free samples had better adhesion strength and wettability compared with the untreated (control) ones. Based on the results of this study, it can be pointed out that all the variable parameters, including the type of wood, varnish, and solvent, had significant effect on the adhesion of varnishes, applied on the wood surface. The difference in wettability between extracted and unextracted samples is due to blocking of the free hydroxyl groups by extractive materials. In addition, it was found that the removal of extractives had the effect of increasing the surface wettability of both species, an important consideration for the varnish coating. The highest adhesion was obtained from polyurethane varnish, applied on ironwood specimens. It seems that the diffuse-porous anatomical structure of ironwood along with its high density of 0.79 g/cm3 could be responsible for its higher adhesion strength than alder species.

Improving the strength of adhesively bonded joints through the introduction of various surface treatments

The aim of this paper is to model an interface adhesion and failure mechanism of single lap joints, subjected to tensile loading, focusing on the effects of various surface treatments, including surface characterization parameters, such as surface roughness and contact angle of adherend surfaces. The applied surface treatments are sandblasting, etching, anodic oxidation and hybrid processes. The influence of surface treatment techniques and conditions on single lap joint strength and interfacial properties is investigated by performing a static tensile test. A numerical approach, which is a cohesive zone model, is implemented using ABAQUS™ and introduced to create a correlation between maximum interface traction and surface processing parameters, such as surface roughness and work of adhesion. As a result of experiments, an etching plus sanding process was found to provide the best single lap joint performance (8726 N), having surface roughness of Ra = 2.93 μm and work of adhesion, Wa = 119.4 mJ/m2. Based on numerical solutions, a correlation between maximum interface traction and type of surface treatment process has been established, taking certain assumptions into consideration.

Wear and Adhesive Failure of Al2O3 Powder Coating Sprayed onto AISI H13 Tool Steel Substrate

In this study, an alumina (Al2O3) ceramic powder was sprayed onto an AISI H13 hot-work tool steel substrate that was subjected to sanding and ultrasonic nanocrystalline surface modification (UNSM) treatment processes. The significance of the UNSM technique on the adhesive failure of the Al2O3 coating and on the hardness of the substrate was investigated. The adhesive failure of the coating sprayed onto sanded and UNSM-treated substrates was investigated by a micro-scratch tester at an incremental load. It was found, based on the obtained results, that the coating sprayed onto the UNSM-treated substrate exhibited a better resistance to adhesive failure in comparison with that of the coating sprayed onto the sanded substrate. Dry friction and wear property of the coatings sprayed onto the sanded and UNSM-treated substrates were assessed by means of a ball-on-disk tribometer against an AISI 52100 steel ball. It was demonstrated that the UNSM technique controllably improved the adhesive failure of the Al2O3 coating, where the critical load was improved by about 31%. Thus, it is expected that the application of the UNSM technique to an AISI H13 tool steel substrate prior to coating may delay the adhesive failure and improve the sticking between the coating and the substrate thanks to the modified and hardened surface.

Mathematical Modelling of Surface Roughness on Tropical Wood Machining Using Response Surface Methodology

Surface roughness is an important indicator to assess the surface processing quality and has a decisive impact on the furniture finishing effects. In this research, the application of response surface methodology (RSM) has been carried out for modelling and analysing of influences in the sanding process on wood materials. Surface roughness parameterRashowed surface characteristics of Tembesu, Jati and Petanang. This study is aimed to observe the effect of feed rate and grit size onRa. The central composite design (CCD) was used as a design of experiment (DOE). There were 8 runs at factorial points and additional 5 replicated runs at the centre point. The sanding process was done using a modified horizontal milling machine. The results are statistically analysed by using Design Expert software. It was found that increasing of feed rate had a positive effect on the roughness value ofRaand greater feed rates increased the surface roughness. On the other hand, grit size influenced negative effect. Larger grit size affected the smoother surface roughness. At the end of this study, it was also revealed that the optimum machining conditions in terms of feed rate and grit size were 17 mm/min and 240 for Tembesu and Jati, while Petanang was 18.63 mm/min and 226.52.

Research on Power Consumption for Sanding Process with Abrasive Brushes to Solid Spruce and MDF Panels

The objective of the experimental research presented in this paper was to analyze the relationship between the cutting power and the roughness parameters characterizing the Spruce wood and MDF panel, brush sanded with two grit sizes, namely P180 and P220. Sets of samples were analyzed for each sanding conditions. The variables of the processing parameters were considered to be the feed speed and the rotation speed. The power consumption was measured using a power monitor device. The roughness was measured on a stylus based detector. The assessment of the quality of the sanded surfaces and the optimum energy was carried out by comparing these parameters, depending on the applied processing parameters.

Wettability of Sanded and Aged Fast-growing Poplar Wood Surfaces: I. Surface Free Energy

The sanding process influences the surface morphology and chemical components of wood, which are two important factors that influence the surface free energy and wettability of wood. The objective of this study was to investigate the roughness of sanded poplar wood and the effects of sanding and aging on the surface free energy using different methods. The roughness parameter (Ra) decreased as the grit number increased, but no change was evident when the grit number increased from 120 to 240. The contact angle of water on the fresh wood samples decreased as the grit number increased. Fresh wood samples were more easily wetted by water than was the aged wood sample, and the contact angles increased as the surface roughness decreased. The surface free energy of sanded, aged wood obtained by the Zisman method may be unsuitable. For the fresh wood samples, the change of surface free energy and its components were not significantly changed when the grit number was higher than 120; for the aged wood samples, the dispersion component appeared to increase slightly as the grit number decreased. The effect of roughness on the acid/base component, acid component, and base component calculated by the vOCG method was unremarkable. The surface free energy of the wood samples (obtained using the liquid parameters provided by Volpe and Siboni (1997)) can effectively balance the relationship between the acid and base components.

Influence of sanding parameters on adhesion recovery in contaminated wheel–rail contact

Adhesion in wheel/rail contact influences performance and safety of railway traffic. Low adhesion brings problems during braking and traction. Sanding is the most common way how to increase adhesion when the poor contact conditions due to a contamination occur. On the other hand, excessive sanding leads to higher wear of wheel and rail. To optimize the sanding process, description of the influence of sanding parameters on the adhesion in the contaminated contact is highly required.In this work a new twin-disc machine in scale 1:3 was developed and addressed to the study of wheel/rail adhesion under different contact conditions. An influence of sanding parameters such as sand quantity, wheel slip and rolling speed was investigated using a real sanding system in the contact contaminated with water, leaves and wheel flange grease.It has been shown that under wet, leaf or grease contamination, quantity of the sand applied during fixed time period has significant effect on adhesion recovery only for low wheel slip and low rolling speed. In the contaminated contact the effect of sanding on adhesion recovery increases with wheel slip and rolling speed.

Effects of plasma treatment and sanding process on surface roughness of wood veneers

An ideal veneer surface is crucial for good panel properties in plywood manufacturing. The aim of this study was to compare plasma treatments and sanding (mechanical) processes with respect to the surface roughness of veneers. Rotary-cut veneers with a thickness of 2 mm from Scots pine (Pinus sylvestris) logs were used as material. After rotary peeling, veneer sheets were dried at 110 °C in a veneer dryer. Veneer sheets were divided into 4 main groups. The surfaces of the control veneer sheets were left untreated. Two different grits of sandpaper, 80 and 180, were used for sanding the surfaces of veneers. Plasma treatment was applied to the last veneer group with 3 different gases (oxygen, nitrogen, and ammonia) and 3 different plasma times (1 min, 5 min, and 15 min). The Mitutoyo Surftest SJ-301 instrument was used to determine surface roughness of samples. Average roughness (Ra), mean peak-to-valley height (Rz), and maximum roughness (Rmax) parameters were measured to evaluate the surface roughness of the samples based on DIN 4768. It was found that the smoothest veneer surfaces were obtained with the sanding processes. Surface roughness values (Rz) of veneer sheets sanded with 180 grit sandpaper were lower than those of veneers sanded with 80 grit sandpaper. Compared with the plasma treatment in terms of surface roughness, plasma-treated veneers had higher Rz values. It was also determined that Rz values were the lowest in the veneers treated with nitrogen plasma. Additionally, the surface roughness values of Scots pine veneers treated with ammonia plasma were a little higher than those of veneer sheets treated with oxygen plasma. The effect of plasma treatment time on surface roughness was not found to be statistically significant.

Experimental analysis of the automated process of sanding aircraft surfaces

AbstractITA and EMBRAER are currently executing the research project Automation of Aircraft Structural Assembly (AASA) whose goal is to implement a robotic cell for automating the riveting process of aeronautical structures. The proposal described herein complements the AASA project, adds other manufacturing processes, namely sanding and polishing of aircraft surfaces. To implement the additional processes AASA project resources and facilities were used (robots and metrology systems) and devices designed and /or acquired to allow sharing of these resources. Among these, an Automatic Tooling Support for AERonautics structures (ATS_AER) was designed and built; also, a robot tool changer with high load capacity was acquired. The outcome of this research project is the evaluation of the feasibility of automating the processes of sanding and polishing metal surfaces in the aircraft manufacture using robots. The operating method adopted for surface treatment employed the ‘U’ type trajectory optimised to be run by a KUKA robot KR 500. The sanding process has been applied to aluminum metal sheet specimen sized 2•18ft2 (0•20m2) and used commercial 600 and 800 sandpaper. The automated sanding process yielded an average value of RA 0•48 ± 0•08 which is 25% more efficient when compared to the traditional, manual process whose average value of RA is 0•75 ± 0•51.

An experimental method for the determination of metal–polymer adhesion

A method is proposed in order to reduce significantly the influence of the coating shear stress and its cohesion failure on the normal adhesion stress of metallic films on polymers. Most methods used so far were not able to avoid the interference of the cohesion failure when the interface was delaminated in order to measure the adhesion strength. Our method has been proved to work and the results are more accurate than the standard pull-off method. The experiments consisted in delaminating copper films deposited by physical vapor deposition on four different kinds of polymeric substrates: polypropylene, polyamide 6, high impact polystyrene and polyethylene terephthalate. The polymer surfaces have also been modified by means of substrate sanding and flaming processes. Optical and scanning electron microscopies were used to study the morphology of both the removed copper film and the polymer surface after pulling-off. Adhesion work was measured by contact angle to determine the necessary energy to pull-off the metal–polymer interface.

Influence of rock failure behaviour on predictions in sand production problems

The mechanical strength of rock in terms of shear or compressive failure has been previously adopted as a criterion for sand production and when used solely has been proven to overestimate the process. On the other hand, ignoring the mechanical strength behaviour of the material increases the tendency for inaccurate estimations of the erosion process. In this work, an equally proportionated inclusion of the mechanical strength and erosion-based criteria in sanding predictions is proposed and assessed by numerical models. Several rock failure models and their influences on the sanding process have been analysed, including models such as the Drucker–Prager (DP), the Drucker–Prager hardening (DP hardening), the Mohr–Coulomb (MC) and the Mohr–Coulomb softening (MC softening). Modelling outcomes show distinct differences in rock response to operating and boundary conditions (e.g. flow rate and drawdown), and predictions of sand production. It was confirmed by modelling results that despite the low magnitude of stresses and strains developed at the well face and perforation regions, post-yield hardening behaviour increases the estimation of the amount and intensity of sand production. Also, incorporating a post-yield softening behaviour increases the magnitude of stresses and strains; however, this effect is observed to have a negligible impact on sand production. The role of void ratio has been recognised as a dominant factor, as its evolution significantly determines the pattern and intensity of sand production. A more cautious selection and rigorous coupling of rock strength models in sand production modelling is therefore essential if accuracy of predictions is to be improved.

Evaluation of two surfacing methods on black spruce wood in relation to gluing performance

Surface quality and gluing performance of black spruce samples prepared by peripheral straight-edge knife planing and sanding were studied. Four wavelengths (1.5, 1.9, 3.1, and 6.5 mm) and four rake angles (15°, 20°, 25°, and 30°) were tested for peripheral planing. Three feed speeds (4, 10.5, and 17 m/min) and three grit size sandpapers (80, 100, and 120) were studied for sanding. The resulting surfaces were glued with an isocyanate adhesive and tested to evaluate their gluing performance (shear strength and percent wood failure). Results revealed that planing with a rake angle of 20° and wavelengths of up to 3.1 mm produced wood surfaces with adequate glueline shear strength. Sanding with 80-grit sandpaper produced the best glueline shear strength, regardless of feed speed. After accelerated aging, the loss of gluing performance was lower for the sanded samples compared with that of planed samples. In general, sanding process produced better wood surfaces for bonding with the adhesive studied.

Estimation and Analysis of Sanding Length in Brush Sanding Specially Shaped Wood Products

Abstract Sanding is an important process in furniture production. Components with unconventional shapes are usually sanded by hand rather than by machine because heavy sanding makes machine sanding more difficult. However, manual sanding is inefficient and costly. Thus, a machine capable of sanding unconventionally shaped surfaces is needed. In this study, we defined the cumulative sanding length L of a brush sander and built a numerical simulation model of L to analyze the problem of heavy sanding during surface brush sanding of specially shaped wood products. Based on our analysis of the motion and sanding process of a sander roller, we propose that the sanding strip should be bent when sanding flat surfaces and straight when sanding bulging surfaces. We also analyzed the effects of specific sanding parameters and the causes of heavy sanding. This research shows the following results: L increases with increasing theoretical contact length, the radius and rotational speed of the sander roller are proportional to L, feed rate is inversely proportional to L, and the L of a bulging point is 7.5 times greater than that of a flat surface. This difference is the main cause of heavy sanding, which is, in turn, mainly caused by different sanding strip patterns used when various parts of the component are sanded. This study provides a theoretical basis for using surface brush sanding for specially shaped wood products.