Surface Roughness Of Parts Research Articles

Study of Machinability in Drilling Operation of Enset–Sisal Hybrid Polyester Composite

Due to their light weight, low density, high-specificity strength, and ease of fiber surface treatment, natural-fiber-reinforced composites are recognized as the most suitable materials for interior part applications. Moreover, natural fibers are widely accessible and environmentally friendly. The fabricated parts are assembled predominantly by fastening using drilled holes, which makes drilling operations common machining processes for the composite parts. Damage occurs at the entry and exit surfaces of drilled holes. In this study, hand layup procedures are used to create unidirectional and woven forms of 1:1 ratio enset (false banana)/sisal hybrid polyester composites that have been treated with 5% NaOH. The drill operation was performed using a computer numerical control (CNC) drill machine with high-speed steel twist drill. A Taguchi design tool was used to complete the analysis. The experiments were conducted at different levels of drilling speeds: 600, 1200, and 1800 rpm. Feed rates of 0.1, 0.2, and 0.3 mm/rev and drill bit diameters of 6, 9, and 12 mm were used. These were determined to be the study parameters that influenced the delamination factors (Fd) and surface roughness (SR) of the hybrid composite drilled parts. Delamination occurred at the entry and exit surfaces of the drilled holes, and surface roughness occurred at the inner surface of the sectioned drilled hole. The quality of the drilled holes was compared based on the delamination factor and the surface roughness, as analyzed by the 3D optical surface profiles.

Investigation of the effects of speed ratio and transversal overlapping ratio on CVD form roller dressing of corundum wheels and subsequent grinding performance

Grinding operation performance is strongly affected by grinding wheel surface condition. Two of the main indicators of grinding behaviour are the ground part surface roughness and the consumed amount of energy, which are both affected by grinding wheel dressing operation. Researchers have deeply studied and modelled effects of dressing parameters for stationary and rotary dressers for vitreous-bonded corundum wheels, but there is still a lack of scientific knowledge on the effects of disc dressing parameters on grinding performance and on the ground part surface condition due the grater kinematical and dynamical complexity of the rotary dressing process related to the fact that both bodies are rotating. In this paper, a deep analysis of infiltrated CVD disc dressing efficiency for conventional grinding wheels will be presented, considering the influence of the combination of dressing parameters altogether. Specifically, the effects of a wide range of speed ratios (qd) and transversal overlapping ratios (Ud) will be tested, monitoring dressing and grinding indicators such as dressing forces and grinding power, as well as surface finish of the ground part. This work covers the whole range of speed ratios used in the industry, including those below −1.0 and above 1.0, an area that few researchers have dug into before. Furthermore, the impact of integer qnd ratios is explored, which is yet to be studied in the literature. Results show a high dependency of all analysed indicators on both analysed parameters (qd and Ud) and uncover the significance of taking into consideration the rotational speed ratio (qnd). Hence, findings can result in a useful tool for the selection of most suitable dressing parameters when specific surface qualities need to be achieved.

Development and Validation of Empirical Models to Predict Metal Additively Manufactured Part Density and Surface Roughness from Powder Characteristics.

Metal additive manufacturing (AM) processes, viz laser powder bed fusion (L-PBF), are becoming an increasingly popular manufacturing tool for a range of industries. The powder material used in L-PBF is costly, and it is rare for a single batch of powder to be used in a single L-PBF build. The un-melted powder material can be sieved and recycled for further builds, significantly increasing its utilisation. Previous studies conducted by the authors have tracked the effect of both powder recycling and powder rejuvenation processes on the powder characteristics and L-PBF part properties. This paper investigates the use of multiple linear regression to build empirical models to predict the part density and surface roughness of 316L stainless steel parts manufactured using recycled and rejuvenated powder based on the powder characteristics. The developed models built on the understanding of the effect of powder characteristics on the part properties. The developed models were found to be capable of predicting the part density and surface roughness to within ±0.02% and ±0.5 Ra, respectively. The models developed enable L-PBF operators to input powder characteristics and predict the expected part density and surface roughness.

ANN modelling of surface roughness of FDM parts considering the effect of hidden layers, neurons, and process parameters

ABSTRACT Hidden layers perform a vital role in the performance of artificial neural networks (ANNs), especially for serpentine problems where the curtailment of accuracy and time complexity is observed. A higher number of hidden layers and neurons enlarge the order of weights and influence the ANN accuracy. In the present work, an ANN model is developed to predict the surface roughness of fused deposition modelling (FDM) parts considering the effect of the number of neurons, hidden layers, layer height, infill density, nozzle temperature, and print speed. A feedforward back-propagation machine learning algorithm is used to model an ANN. This study finds better prediction accuracy with the ANN architecture having two hidden layers with 150 neurons on each layer (R-squared: 0.875) followed by one hidden layer with 250 neurons (R-squared: 0.83). This study finds a decrease in the surface roughness of FDM parts with the increase in infill density. However, the surface roughness was observed to increase with the layer height, print speed, and nozzle temperature. This study finds a decrease in the surface roughness of FDM parts with the increase in infill density and an increase in the surface roughness with the layer height, print speed, and nozzle temperature.

Comparison of two-step surface treatment on surface roughness and corrosion resistance of TC4 alloy parts prepared by SLM and SEBM

To reduce the surface defects of additive manufacturing forming parts and improve surface quality such as surface roughness and corrosion resistance, a two-step surface treatment technology, namely, pre -polishing combined with micro-arc oxidation (MAO), is employed to treat bulk samples constructed by selective laser melting (SLM) and selective electron beam melting (SEBM), respectively. Effects of surface morphology and coating thickness on surface roughness and corrosion resistance are systematically studied. Results show that the two-step surface treatment weakens the step effect of the original sample surface distinctively. Meanwhile, the MAO coating can improve the corrosion resistance of the original sample significantly. The corrosion current density Icorr of SLM specimen- is reduced from 6.212 × 10−5 A/cm2 to 2.493 × 10−7 A/cm2 (t = 15 min), and the Icorr of SEBM specimen- is reduced from 8.013 × 10−6 A/cm2 to 2.562 × 10−6 A/cm2 (t = 15 min).

Effects of plasma electrolytic polishing on SLM printed microfluidic platform

Additive manufacturing (AM) of metallic parts is gaining momentum in production industries. In view of producing a metal microproduct using AM the issue of high surface roughness is prominent. Plasma electrolytic Polishing (PeP) is a post processing technology that greatly reduces surface roughness of metallic parts. In this paper the effects of PeP of microfluidic platform, printed with selective laser melting (SLM) technology, is presented. The results show that surface roughness of the specimens was severely reduced. Also, some geometrical defects inherent to SLM technology were partly removed. It is shown, that for smaller geometrical microfeatures (sizes of less than 0.5 mm) the effectiveness of PeP is reduced. Through this investigation it can be concluded that PeP is a promising post-processing technology for SLM printed microparts since it significantly improves the overall part quality. However, further improvements of the process chain need to be implemented in order to render the microfluidic platform functional.

Eklemeli İmalatta Üretim Yönünün Parça Üretimine Etkileri

Eklemeli imalat, geleneksel imalat yöntemleri ile üretimi mümkün olmayan ya da çok zor ve maliyetli tasarımların üretimi için son on yılda giderek yaygınlaşmıştır. Eklemeli imalat parçanın üretim yönü doğrultusunda katman katman eklenmesi ile edilir. Parçaların üretiminde kullanılan destek yapılar, eklemeli imalatın bir bileşenidir. Bu yapılar parçanın taban plakasını oluşturmakta, termal deformasyonları azaltmakta ve yüzeylerde oluşabilecek sarkmalara destek sağlamaktadır. Bu nedenle bir parçanın üretim yönü nesnenin kalitesini, maliyetini ve diğer özelliklerini etkilemektedir. Bu çalışmada düz, eğri ve açısal yüzeylerden oluşacak şekilde tasarlanan bir parça üzerinde üretim yönünün parça bütünlüğü, geometrik hassasiyeti ve yüzey pürüzlülüğü üzerine etkileri araştırılmıştır. Bu doğrultuda üretilen numunelerin üst yüzeyinden pürüzlülük ölçümleri yapılmış ve hassas terazi ile destek yapılarının ağırlık üzerine etkileri incelenmiştir. Ayrıca üretilen numunelerin görüntüleri CAD ortamına aktarılarak geometrik doğruluğu araştırılmıştır. Taban plakasının dengeli ve katmanların yeterli sürede soğuması parçanın yüzey kalitesini ve geometrik doğruluğun elde edilmesini sağlamıştır. Taban plakada homojen olmayan termal gerilme ise parçanın nominal ölçüden sapmasını artırmaktadır.

Surface Analysis in Additive Manufacturing Using Image Processing

Fused Deposition Modeling (FDM) is a type of additive manufacturing process where prototypes are developed by depositing layers on previously deposited layer of material. Surface roughness is an important factor in determining quality of produced parts. This work proposes a methodology to calculate the surface roughness of part manufactured using FDM process. The surface roughness values to be measured using conventional stylus instrument and Digital image processing technique. Stylus comes in direct contact with surface so it destroys the surface topography. Image processing is a non-contact method hence it overcomes this problem. A camera and directional lightings will be used to capture images of surface of specimens. These images will be analyzed and processed using various image processing techniques available in MATLAB image processing toolbox. Experimental results will be validated by comparing the results obtained by using image processing technique with conventional stylus system. The system is also proposed to inspect surface irregularities. Key Words: Surface roughness, image processing, MATLAB, FDM.

Research on Rapid Measurement Technology of Roughness Based on Light Scattering

The roughness is an important parameter to evaluate the parts surface quality, so it is very important to measure the surface roughness of high-precision parts. In order to meet the needs of rapid and non-contact measurement of surface roughness, a new method based on optical scattering distribution is proposed in this paper. By analyzing the modulation effect of surface roughness on incident light, the relationship between surface roughness and scattering distribution is established. Based on the analysis of the characteristics of light source, detector and their relative position, the scattered light distribution measurement system is constructed. In the measurement system, the surface roughness is measured by real-time acquisition of scattering distribution. The roughness of different samples is measured by this method and white light interferometer, and the measurement standard deviation is less than 0.15nm. The measurement results show that this method is feasible and effective.

Impact of Process Variables of Acetone Vapor Jet Drilling on Surface Roughness and Circularity of 3D-Printed ABS Parts: Fabrication and Studies on Thermal, Morphological, and Chemical Characterizations.

Ever since the introduction of 3D printing, industries have seen an exponential growth in production and efficiency. Three-dimensional printing is the process of additive manufacturing (AM) in which the conventional method of material removal is challenged. Layer-on-layer deposition is the basic principle of the AM. Additive manufacturing technologies are used to create 3D-printed objects. An object is built in an additive technique by laying down successive layers of material until the object is complete. Each of these layers can be viewed as a cross-section of the item that has been lightly cut. When compared to traditional production methods, 3D printing allows the creation of complicated shapes with less material. In conventional methods, the materials go through several damages due to the tool–workpiece contact creating friction between them and the dissipated heat that damages the material. Overcoming the conventional method of machining with the help of 3D printing is a new advancement in the industries. The process involves using non-conventional methods for the machining of the parts. This research was oriented towards the chemical vapor jet drilling of the acrylonitrile–butadiene–styrene (ABS) materials. ABS materials are highly machinable and can be recycled for further usage. This paper focused on the usage of acetone as the chemical for drilling. The surface roughness and circularity of the drilled hole was taken into account for this research paper. We set up a manual experiment to run tests and get results. A vapor jet machine was designed with acetone as the core for the vapor. Various analyses were also formulated and conducted during experimentations. Surface roughness analysis provided the insight of roughness after the machining with the help of acetone vapor jet spray. SEM and micro-image parameters were also considered for more clear and advanced reports. In this research paper, DSC and FTIR analysis were performed to understand changes in the internal structure and the material properties of the ABS. Moreover, the research aimed to investigate the effect of various inputs processing parameters such as pressure, flow rate, and stand-off distance on the surface roughness and circularity of ABS workpiece material. The Taguchi L9 orthogonal array design was utilized to conduct tests by chemical vapor jet drilling using acetone and to evaluate the performance of the set-up while reducing the influence of interfering factors in order to provide reliable surface finish and circularity results. The results and conclusion of the research paper aimed to determine the most suitable parameters for the non-conventional acetone vapor jet drilling of the ABS material. The theoretical calculations predicted 1.64432 and 0.3289080 values of surface roughness and circularity, respectively. On the other hand, the experimental values were recorded as 1.598 for surface roughness and 0.322 for circularity. Therefore, a negligible error of 0.046 for surface roughness and 0.0031 for circularity, respectively, was noted which validate the statistical equations and the consistency of the combined vapor jet drilling process.

Effect of printing parameters and post-process on surface roughness and dimensional deviation of PLA parts fabricated by extrusion-based 3D printing

Effect of printing parameters and post-process on surface roughness and dimensional deviation of PLA parts fabricated by extrusion-based 3D printing

Wear Analysis of Additively Manufactured Slipper-Retainer in the Axial Piston Pump

Additive manufacturing (AM) of spare parts is going to become more and more common. In the case of hydraulic solutions, there are also some applications of AM technology related to topological optimization, anti-cavitation improvements, etc. An examination of all available research results shows that authors are using specialized tools and machines to properly prepare AM spare parts. The main aim of this paper is to analyze the influence of quick repair of the damaged slipper-retainer from an axial piston pump by using an AM spare part. Hence, it was prepared with a 100-h test campaign of the AM spare part, which covers the time between damage and supply of the new pump. The material of the slipper-retainer has been identified and replaced by another material—available as a powder for AM, with similar properties as the original. The obtained spare part had been subjected to sandblasting only to simulate extremely rough conditions, directly after the AM process and an analysis of the influence of the high surface roughness of AM part on wear measurements. The whole test campaign has been divided into nine stages. After each stage, microscopic measurements of the pump parts’ surface roughness were made. To determine roughness with proper measurements, a microscopical investigation was conducted. The final results revealed that it is possible to replace parts in hydraulic pumps with the use of AM. The whole test campaign caused a significant increase in the surface roughness of the pump’s original parts, which was worked with the AM spare slipper-retainer: (1) from Ra = 0.54 µm to Ra = 3.84 µm in the case of two tested pistons; (2) from Ra = 0.33 µm to Ra = 1.98 µm in the case of the slipper-retainer. Despite significant increases in the surface roughness of the pump’s parts, the whole test campaign has been successfully finished without any damages to the other important parts of the whole hydraulic test rig.

Fixture Length and Primary Stability: An In Vitro Study on Polyurethane Foam

(1) Background: Recently, novel dental implants that are characterized by different levels of surface roughness in the distinct parts of the fixture’s body have been introduced in the market. These surface characteristics could affect the primary stability of the implants. The aim of this in vitro study was to compare the primary stability of short and long implants, characterized by multiscale surface roughness, inserted on polyurethane blocks. The secondary aim was to understand if the implant length could be a crucial factor in the decision-making in immediate or rather than delayed loading protocol in the different bone densities. (2) Methods: A total of 20 cylindrical dental implants with a diameter of 5.0 mm were tested for the lengths 6.0 mm (short implants) versus 13.0 mm (long implants) on two different solid rigid polyurethane blocks (20 and 30 PCF). The primary stability was evaluated by measuring the insertion torque value (ITV), the removal torque (RTV), and the resonance frequency analysis RFA. (3) Results: The values of ITV, RTV, and RFA showed the same trend in all measurements. Long implants showed a significantly higher primary stability on 30 PCF blocks that present mechanical properties similar to high-density bone. On the contrary, no relevant differences were found on 20 PCF blocks, which mimic trabecular bone density. (4) Conclusions: The impact of fixture length on the primary stability of implants with multiscale surface roughness is significant in 30 PCF polyurethane corresponding to higher bone density, but not in lower ones.

ON THE SURFACE ROUGHNESS OF 3D PRINTED PARTS WITH FDM BY A LOW-BUDGET COMMERCIAL PRINTER

As additive manufacturing machines price is decreasing, while, at the same time, the expertise in the relevant field is rising, it is essential to test and evaluate the low-budget machines that are available for commercial use. Whilst low-budget machines are widely utilized for rapid prototyping and experimentation, they are not capable of producing parts with high surface quality and achieve high levels of repeatability due to low quality hardware and not optimized software. Having said that, the main aim of the current study is to experiment with a low budget Fused Deposition Modeling (FDM) 3D-Printer, and evaluate the surface roughness of the printed parts in respect to the angle from the print plate. Polylactic Acid (PLA) was chosen as filament material, while the printed parts surface roughness was measured according to the ISO ASTM 52902-2021 standard. The surface roughness was estimated in terms of the Ra and Rz values, while a statistical analysis was implemented in order some interesting conclusions to be deduced regarding the correlation between part orientation and surface quality.

The effect of shot peening on corrosion performance of anodized laser powder bed fusion manufactured AlSi10Mg

Anodizing is commonly used on aluminium to improve the surface properties of the product for better corrosion resistance and wear resistance. In this research, the anodizing of laser powder bed fusion (LPBF) manufactured AlSi10Mg parts which were subjected to prior shot peening (SP) were investigated. Anodized specimens were analysed using SEM imaging and the corrosion properties were examined considering the effect of residual stress relief heat treatment and the SP process. The results showed that the SP deteriorates the corrosion performance of the material as such, but together with the subsequent anodizing it resulted to the lowest corrosion current of all investigated structures. As the SP can be used to lower the surface roughness of the LPBF parts and to increase fatigue life as well, the results of this work further encourage the use of SP with anodizing.

Multi-feature fusion imaging via machine learning for laser ultrasonic based defect detection in selective laser melting part

Laser ultrasonic (LU) testing is a promising technique that meets the constraints of additive manufacturing (AM) online monitoring, which is vital for the quality control of AM products and the practical application of AM. However, the scattering noise caused by surface roughness of AM parts and the ambient noise can generally result in defect imaging with low resolution. This is not conducive to defect detection. In terms of this problem, a multi-feature fusion imaging methodology is proposed instead of the traditional method containing a single feature, i.e., maximum amplitude within a set window of all A-scans. The most discriminative features in each A-scan are automatically extracted by principal component analysis (PCA). These features are subsequently fused by a trained artificial neural network (ANN) to obtain an evaluated value that determines whether a A-scan is the normal case or defective case (denoted by 0 and 1, respectively). Finally, a C-scan image with high signal to noise ratio (SNR) can be produced by plotting the binary dataset of 0 and 1. LU inspection on a selective laser melting (SLM) component with the pre-induced micro hole defects on the rough surface is performed to validate the effectiveness of the methodology. The defects are distributed in 2 rows and 6 columns where the diameter of one row is 100 μm and the other is 50 μm. It is demonstrated that the proposed methodology can detect and size all micro defects by the obtained high SNR C-scan.

Tool Wear and Milling Characteristics for Hybrid Additive Manufacturing Combining Laser Powder Bed Fusion and In Situ High-Speed Milling.

We report on milling and tool wear characteristics of hybrid additive manufacturing comprising laser powder bed fusion and in situ high-speed milling, a particular process in which the cutter mills inside the powder bed without any cooling lubricant being applicable. Flank wear is found to be the dominant wear characteristic with its temporal evolution over utilization period revealing the typical s-shaped dependence. The flank wear land width is measured by microscopy and correlated to the achievable surface roughness of milled 3D-printed parts, showing that for flank wear levels up to 100 m a superior surface roughness below 3 m is accessible for hybrid additive manufacturing. Further, based on this correlation recommended tool, life scenarios can be deduced. In addition, by optimizing the finishing tool start position and the number of afore-built layers, the milling process is improved with respect to the maximum millable angle for undercut surfaces of 3D-printed parts to 30° for the roughing process and to 40° for the entire machining process including finishing.

Laser surface polishing of Ti-6Al-4V parts manufactured by laser powder bed fusion

Poor surface quality of Additively Manufactured (AM) components, can greatly increase the overall cost and lead time of high-performance components. Examples are medical devices where surfaces may contact the patient's skin and hence need to be smooth and aerospace components with high fatigue strength requirements where surface roughness could reduce fatigue life. The average surface roughness (Ra) of AM parts can reach high levels greater than 50 μm and maximum distance between the high peaks and the low valleys of more than 300 μm. As such, there is a need for fast, cost effective and selective finishing methods of AM produced components targeted at high-performance industries. In this paper Ti-6Al-4V Grade 23 ELI, popular for medical devices and aerospace parts production, was L-PBF processed to manufacture parts which were subsequently treated via laser polishing. Here in this work, CO2 laser polishing was used for the surface modification of the Ti-6Al-4V produced samples. The most significant processing parameters were optimised to achieve approximately an 80% reduction in the average surface roughness and a 90% reduction in the peak-to-valley distance with a processing time of 0.1 s/mm2 and cost of 0.2 €/cm2.

Prediction Method of Tightening Characteristic of the Bolted Joints considering Surface Roughness of Parts

In case of determining tightening specifications of the bolted joints, it is important to understand the relationships between the rotation angles and axial forces in the joint tightening process. Also, it is efficient to predict accurately the relationship. As the prediction method, the simplified calculation formula is shown in JIS B 1083. However, it was shown that there is a margin of error on the relationship between the prediction results and physical test results. And it is thought the reason is that geometrical details of bolted joints and approaches of interface caused by surface roughness of each part are not considered. In this study, the simplified calculation, FEM analyses and experiments are conducted, and those results of the relationships between the rotation angles and axial forces are compared. Influence of the geometrical detail shape and approaches of interface are investigated. Considering both of detail shape and approaches of interface, it is shown the relationships between the rotation angles and axial forces of actual bolted joints are predicted.

Structuring by laser remelting as a method for waviness reduction on additive manufactured parts

The surface roughness of parts manufactured by laser powder bed fusion (LPBF) is often not sufficient for the intended application. Therefore, surface finishing is necessary. Conventional finishing techniques have many disadvantages like accessibility of complex geometries, high time and cost consumption and a negative environmental impact due to the use of abrasives. As a solution laser polishing is investigated. In this study it was found that surface roughness of LPBF parts up to a spatial wavelength of 0.5 mm can be reduced by ∼96% with laser polishing, while waviness can only be reduced by ∼55%. To further reduce waviness, structuring by laser remelting (WaveShape) is investigated. The basic idea is to structure the inverse of the initial structure and thus to “de-structure” the waviness. A structured profile of a laser polished LPBF surface is “de-structured” with a variation of process parameters. The results show the potential of a waviness reduction of 85%.