Biomachining Process Research Articles

Biologicalisation of surface structuring: Comparative environmental assessment of microbial biomachining vs. chemical etching

In 2015, the United Nations adopted the 2030 Agenda for Sustainable Development in response to growing global concern about climate change, resource scarcity and environmental impacts on ecosystems. This agenda also places high demands on industrial manufacturing systems to promote sustainability. Biologicalisation of manufacturing processes can be a promising approach to contribute to the sustainability goals in industrial production systems. In recent years, biomachining has emerged as a field of research in biologicalisation with potential advantages compared to conventional surface treatment methods of metals, such as chemical etching. Surface structuring of metals plays a crucial role in various industrial applications, such as pre-coating preparation, hierarchical structuring, superhydrophobic surfaces and geometries. To assess the environmental impacts of biomachining, this paper focuses on environmental impacts of utilizing the bacterium Acidithiobacillus ferrooxidans compared to a conventional chemical etching process with cupric chloride solution for surface structuring of a metal specimen. The study examines the environmental impact of both processes, considering all relevant material and energy flows from cradle to gate for multiple environmental impact categories. In doing so, the environmental impacts of each process can be comprehensively evaluated and compared, and hotspots for future improvement of the biomachining process can be identified. On current lab-scale, the results indicate higher impacts for the biomachining process in most categories compared to the chemical etching process, mainly due to the energy demand for pre-cultivation and preparation of the biomachining solution.

Experimental Investigation on Bio-Machining of Nickel, Titanium and Nitinol (Shape Memory Alloys) Using Acidithiobacillus ferrooxidans Microorganisms

Micromachining plays a vital role in the manufacturing industry in producing microcomponents with high sensitivity and fine dimensional tolerances for implant materials in medical applications. Micro-machining can be carried out through various machining processes like physical, chemical and biological processes, although the use of biological machining is limited. In biological machining, microorganisms are used as a source of energy to machine the components, and machining with microorganism brings a lot of advantages in the machining process like the production of components with lower energy resources, low cost, no heat-affected zone and fine dimensional tolerances, which makes it suitable for machining implant materials. In other machining process like conventional and unconventional machining processes, the heat-affected zone, dimensional tolerances and environmental-related problems are the major issues, as these processes generate more heat while machining. This damages the material, which will not be able to be used for certain applications, and this issue can be overcome by bio-machining. In this present work, nickel, titanium and nitinol are manufactured using the powder metallurgy technique. They are manufactured as a 10 mm diameter and 5 mm thick pellet. The fabricated nickel, titanium and nitinol shape memory alloys are machined with Acidithiobacillus ferrooxidans microorganisms to obtain a better material removal rate and surface roughness and to check the bio-machining performance by considering various parameters such as shaking speed, temperature, pH and percentage of ferric content for the future scope of biomedical applications. Considering these parameters, microorganisms play a vital role in the temperature, shaking speed and time of the bio-machining process, and it was observed that a better material removal rate and surface roughness are achieved at a temperature of 30 °C, shaking speed of 140 rpm and machining time of 72 h.

Experimental studies on biomachining process using novel Thiobacillus novellus microorganism — a comparative study

Experimental studies on biomachining process using novel Thiobacillus novellus microorganism — a comparative study

Application of biomachining on copper for a minichannel heat exchanger

Studies have established a random surface roughness found on the surface of copper after immersion in an Acidithiobacillus ferooxidans-containing culture medium during the biomachining process. In this study, a heat exchanger system was built by employing the biomachining process to manufacture the copper-based minichannel parts for the system. This study investigates the effect of the surface roughness of the minichannel obtained from the biomachining process upon the pressure drop and heat transfer of a fluid flowing through the system. These parameters were also compared to another system possessing minichannel parts with a lower surface roughness made by conventional milling. The result shows that the system containing the biomachined minichannels tends to increase the pressure drop and heat transfer rate of the fluid flow compared to the milled example due to the effect of the roughness average (Ra), which consistently occurred with flow rates (Q) of 32 and 64 mL/min. A novel finding revealed in this study is that the biomachining method can contribute to fluidic channel and heat transfer applications, due to its naturally unique surface roughness.

WITHDRAWN: Micro machining in biological perspective – Critical review

• This article discusses the importance of bio machining in modern manufacturing process. • Importance of different micro organism in machining aspect and its capabilities are discussed in details. • Importantly, the available of mechanism equation and modelling is discussed and presented. • The benefits of various parameter on reducing the surface roughness and increasing material removal rate are discussed in detail. Micromachining process is one of the versatile process in making miniature components for different application. Miniaturization is playing a vital role in reducing the size, shape and density of the part. Microfabrication and further machining are the only way to get the desired shape and size. This paper reviews the importance of biological kind of micro machining process in terms of its capability, advantages and future scope in this area are discussed and presented. The article is discussed in the following order, overview of the bio machining process; it summarizes the possibility of bio machining process, subsequent section covers the progress in bio machining, principle mechanism deals with direct and indirect mechanism of material removal. Finally, the scope for the future work is discussed and presented.

Viability of two alternatives for treating waste solutions from the biomachining process

Biotechnology is currently playing an important role in sustainable development, and advances in this field are, in fact, among today’s most cutting-edge scientific contributions. Nevertheless, they are not free from waste generation. This research studies the viability of two alternatives for treating the depleted solutions obtained in the biomachining of copper pieces, paying special attention to the recovery of copper. The precipitation alternative of increasing the pH value required the preliminary oxidation of Fe2+, iron precipitation and filtration, and finally, Cu precipitation (as CuO) and filtration. The recovery was quantitative but time-consuming, and the reagent’s overall cost was 1.69 €/L. The electrorecovery alternative also required the oxidation and precipitation of iron before copper deposition (as Cu0) at a constant voltage. This deposition was also quantitative, but faster than the recovery at a constant current (14 min versus 20 min). The reagent’s cost was 1.54 €/L, and the copper electrodeposition’s energy cost was 3.6 times lower than the cost of the raw metal, which made the electrochemical treatment viable, affordable and sustainable.

Biomachining properties of various metals by microorganisms

Abstract The biomachining properties of five pure metals (Cu, Co, Fe, Sn, and W) and four sintered components made from binary powder mixtures (Cu-Co, Cu-Fe, Cu-Sn, and Cu-W) were synthetically studied under the same conditions. The material removal rate (MRR) in the machining process was recorded. The surface roughness (Sa), topography, and element distribution of the surface were compared before and after machining. The cross-sections of machined surfaces from nine samples were also observed. The electrochemical corrosion resistance of the five pure metals was evaluated by potentiodynamic polarization curves. The experimental results showed that the MRR of all samples presented good linear behavior in the machining process with different slopes. Sa of all samples increased from below 0.1 μm to 0.3–5.4 μm after machining. Material removal mechanisms involved in the biomachining process were also explored. The MRR of pure metals was mainly affected by the electrochemical corrosion resistance of the material. However, the generation of a reaction layer could reduce the MRR for the pure Co. The MRR of sintered components was affected by the reaction processes between the binary powder mixtures in the sintering process. Three material removal mechanisms were proposed for the sintered components corresponding to the different reaction processes.

Profile Characteristics of Biomachined Zinc

Biomachining is one of the alternative methods in micromachining, which is environmentally friendly and have high efficiency (eco-efficient). This method uses bacteria (this research used Acidithiobacillus ferooxidans), which can extract the metal by using oxidation-reduction reactions as a part of its life cycle. This study reports the characterization of the biomachining process using zinc (Zn) materials. Pattern making was done by the visible light maskless photolithography process using DLP (Digital Light Processing) projector, and the characterization was done by varying the biomachining time. Surface profile data and photos of the workpieces were obtained using ‘SURFCOM’ and ‘Dino-Lite’ microscope, respectively. The results of this study show the profile of the surface of biomachined zinc forms a valley shaped like, with the horizontal feed larger than the vertical feed, and for the depth, width, and surface roughness tend to increase, while for the material removal rate and specific material removal rate tend to decrease with the increase of biomachining time.

Development of Empirical Model for Biomachining to Improve Machinability and Surface Roughness of Polycrystalline Copper

The demand for sustainable micro-manufacturing technologies is growing with their increasing application in micro and nanoelectromechanical systems. The micro-manufacturing techniques utilizing physical or chemical energy have adverse effect on environment. Utilization of biological energy could be a benign alternative approach. In the exhaustive list of micro-manufacturing processes, biomachining is the only process that utilizes biological energy by making use of the energy pathway of microorganisms for removing metals. Biomachining has been proven to present numerous advantages such as being environmental friendly, low consumption of energy, and no recast layer/heat affected zone generation. Despite all the advantage, biomachining has not been commercialized because of the common shortcomings reported i.e. a low metal removal rate and increased surface roughness after machining. The aim of this study is to develop an empirical model to optimize and predict machinability and surface roughness of polycrystalline copper in a biomachining process using response surface methodology. The correlation between different processes has been investigated and central composite design (CCD) was employed to develop an empirical model based on the correlation between input variables (process parameters) and output responses (MRR and change in Ra). The optimum values of selected parameters were predicted and verified by performing a series of experiments.

Biomachining: Preservation of Acidithiobacillus ferrooxidans and treatment of the liquid residue

Biomachining has become a promising alternative to micromachining metal pieces, as it is considered more environmentally friendly than their physical and chemical machining counterparts. In this research work, two strategies that contribute to the development of this innovative technology and could promote its industrial implementation were investigated: preservation of biomachining microorganisms (Acidithiobacillus ferrooxidans) for their further use, and making valuable use of the liquid residue obtained following the biomachining process. Regarding the preservation method, freeze-drying, freezing, and drying were tested to preserve biomachining bacteria, and the effect of different cryoprotectants, storage times, and temperatures was studied. Freezing at -80°C in Eppendorf cryovials using betaine as a cryoprotective agent reported the highest bacteria survival rate (40% of cell recovery) among the studied processes. The treatment of the liquid residue in two successive stages led to the precipitation of most of the total dissolved iron and divalent copper (99.9%). The by-products obtained (iron and copper hydroxide) could be reused in several industrial applications, thereby enhancing the environmentally friendly nature of the biomachining process.

PDMS Surface Modification Using Biomachining Method for Biomedical Application

Engineering a cell-friendly material in a form of lab-on-chip is the main goal of this study. The chip was made of polydimethyl siloxane (PDMS) with a surface modification to realize a groovy structure on its surface. This groovy surface was naturally and randomly designed via biomachining process. This measure was aimed to improve the cell attachment on the PDMS surface that always known as hydrophobic surface. The biomachined surface of mold and also products were characterized as surface roughness and wettability. The result shows that the biomachining process were able to be characterized in three classes of roughness on the surface of PDMS.

Inclination Angle Effect on Surface of Copper in Biomachining

Nowadays micro fabrication technology is very varied and being continuously developed. One of them uses bacteria as tools that known as biomachining. Acidithiobacillus ferooxidans is a one of bacteria which can do metal removal as a source of energy. The previous research has proven the ability of Acidithiobacillus ferooxidans for material removal process. In this research, biomachining process was added by angle of inclination parameter to know the effect on copper surface profile and roughness. This method was used to get profile shape result of multi-axis in biomachining. Workpieces were patterned by photolithography method and put in the bacterial culture medium, which was inclined 20° and 30° on inclinator. Profile shape and the surface roughness measurement data were taken by SURFCOM machine. The results of this research showed that by inclining 20° and 30° of biomachining sample produced different profile shapes and surface roughness.

Visible Light Maskless Photolithography for Biomachining Application

Maskless photolithograpy is an alternative method of conventional UV photolithograpy for microfabrication since its advantages of time and cost saving. For this reason, a visible-light based maskless photolithograpy is proposed as a part of biomachining process. Modification of the method is done by replacing light source of UV light to visible light, utilizing commercial DLP projector and changing the material removal process that generally uses echant with biomachining process. The process was done by using the profile generated by computer then displayed through a commercial DLP projector shining speciment test. Focusing lens placed under the projector to draw the focal point and reduces the size of the profile. The best parameter was determined by setring exposure time, developing time, variation profiles, focusing, colors combination and optical aspect. Using a commercial projector maskless photolithography on a negative resist tone successfully performed. The best characteristic was obtained by placing the focusing lens 3X magnification within 3 cm below the projector and 14 cm above speciment test, color combination of black-light blue (R = 0, G = 176, B = 240), with the timing of prebake 1 minute, exposure 7 minutes, postbake 5 minutes, developing 5 minutes produces the smallest profile 166 μm with 13,7 μm deviation. Biomachining process with bacteria Acidithiobacillus ferrooxidans NBRC 14262 on copper was also successfully performed with the smallest profile of 180 μm with 26 μm deviation.

Development of digital lithography masking method with focusing mechanism for fabrication of micro-feature on biomachining process

An alternative method is developed to remove metal from a work piece by combining a digital lithography system with biomachining. The purpose of this system is to obtain extra advantages as compared to conventional micro-fabrication processes currently used in practice. The use of microorganisms as a cutting tool in biomachining can eliminate the use of hazardous chemical materials, and the target surface is not affected by heat as a result of machining. The proposed process has a low material removal rate, but with less energy consumption. The greatest advantage is that the tools used in biomachining can be cultured continuously; i.e., they are renewable. Theoretically, the resolution of biomachining can reach 1 um due to the size of the bacteria. To achieve selective material removal, we combine the biomachining process with a polymer mask generated by a digital lithography (DL) system. In order to minimize errors and noise, the DL system was constructed by choosing robust and commonly available devices for most of the sub-tasks. This construction then can bring projected image onto work piece surface on fully controlled.

Metal based micro-feature fabrication using biomachining process

Graphical abstractDisplay Omitted Highlights Biomachining process that use microorganisms as the tool to remove metal from a workpiece promises environmental advantages. The characteristic and capa...

Metal based micro-feature fabrication using biomachining process

Biomachining processes that use microorganisms as the tool to remove metal from a workpiece may have environmental advantages. These processes, used innovatively, will be an alternative technology for micro machining. The objective of this study is to investigate the feasibility of biomachining processes in fabricating micro-size features on pure copper. This paper presents Acidithiobacillus ferrooxidans-based biomachining processes of pure copper and their performance in producing several complex features.

Profile characteristics of biomachined copper

Biomachining is a machining process that uses microorganisms as the tool to remove metal from a workpiece. This is an alternative micromachining process that may have environmental advantages. This paper presents the biomachining processes of copper using bacteria of Acidithiobacillus ferrooxidans, including bacterial culturing and workpiece preparation, and comparisons of profiles or cross-sectional forms of copper that are developed in the biomachining process for different parameters. To analyze the final result, a scanning electron micrograph and a noncontact 3-D microsurface profiler were used. This research revealed that the profile form of copper was u-shaped, close to a semicircular form. The dimensions of cutting depended on the machining time. The required dimension can be obtained by selecting an appropriate machining time.