Metal Removal Process Through Milling: A Review Of Procedures And Principles

The motivation behind the research

The metal removal process or machining is the most financial option as far as primary manufacturing is concerned. This has been paid for and cutting away and discarding the achievement of ultimate part. Moreover, despite the tooling costs and least setup, the long machining times has been needed and thus it is cost prohibitive for huge quantities. Thus metal removal is used for restricted amount as in fabrication of various prototypes and custom tools. This is for manufacturing procedures. It is also used commonly as a secondary methods. Here minimal material is eradicated and overall cycle time is short (Zaretalab et al. 2018). Moreover, because of huge tolerances and surfaces outcomes, offered by machining, it is utilized for adding and refining various precision features for current part and smoothing a surface for efficient finish.

Metal removal also involves various procedures, where every elements are removed from the part or work-piece. Most common metal removal processes are denoted as the traditional machining. These have been mechanically cutting smaller chips of metals through sharp tools. Besides, non-traditional machining procedures are used as thermal or chemical means to remove materials. The traditional processes are placed into three type of categories. This is abrasive machining, multi-point cutting and single point cutting (Li et al. 2015). Besides, under a given process of various activities that are done. This has been using particular cutting motions and tools. This machining part has been needing various operations done with proper planning sequence for developing intended elements.

Milling is the metal removal method through using rotary cutters for removing materials from work-pieces. This is done through advancing the cutter to work-piece at specific directions. This is held at a specific angle that is relative to the axis of their tool. In this research various metal removal processes through milling are demonstrated. Further, various processes of milling methods are analyzed. Further, the results are analyzed and processes of experimentation with proper time schedule is discussed.

The study aims to review printed materials. This is helpful to gain knowledge and understand primary milling procedures and theories. Besides, this is useful to become aware of latest technologies and functions and features of machine centers. This primary vertical know mill machine is examined, parameters of successful metal removal are recognized. Here applying the technology to milling is explained. Various machine center functions and features are also highlighted. Besides different cutting tools, work-changing and work-holding devices are been also detailed (Khorasani and Yazdi 2017).

At present, various processes are applied where materials are removed with the help of various processes. This helps in obtaining the final part. The milling machines denotes to the tools that are designed for solid materials, woods and metals. Very often there milling machines are automated. These are positioned in different horizontal and vertical orientation for carving out materials in the basis of pre-existing designs (Wan et al. 2017). Here, the designs are commonly CAD directed. There are various milling machines that are also CNC operated through conventionally and manually automated milling devices that are also popular. They are also able to perform, dynamic movement for work piece and tools. They can also undertake different types of multi-axis machining. Due to different variation of application, operation and orientation, the milling machines consists of various functions and numerous principles of operations. As far as tooling is concerned, the milling machine are outfitted with various heads of tools. This is done to accomplish various needs of machining. Here, few tools include ball end mills, fluted mills, rounding mills and cutters. Furthermore, few milling machines have consisted of ends of rotating tools changing the dependences in the required activities. Here, the communications with computer programming with machine are done as there is any change in the tooling.

Conducting of literature review

Various tools used in milling machines are on the basis of intended and material shapes. Due to the fact that materials such as steel and woods consists of various physical characteristics, the tool bits are required to be machine those metals properly. As the machine of milling utilizes any tool bits that are not strong enough for machine steel, the tooling and machines itself also undergoes damages. This is also strong for soft materials damaging the work-pieces (Stephenson and Agapiou 2016). Here, the primary tooling bit over milling machines are known as cutters. It refers to a shaped bar consisting saw teeth. This rotates very fast for cutting down and shaping materials. This is attached to arbors and is known as madel. This includes a shape bar varying in ending, length and size and used to hold the cutters strongly. A saw ending of millings are oriented, sized and shaped in various ways. These teeth are located in various orientations in straight up and down manner. Besides, it is angled in helical orientations and the straight teeth are preferable in operations over denser materials as the helical teeth creates smooth cuts over soft materials (Sun et al. 2016). Further, there are various cutters at these categories. This includes t-clot cutters, angle cutters and dense end cutters. These are subjected to various standard sizes having CAT sizes as the commonly0utilizwed standardizations categories. As mechanical modelling is a vital feature of this process of engineering, the review is concentrated of various diffusion, isotherm and kinetic models.

It is versatile part of machining processes. This removal of metal is dine through relative motions of multi-axis, multi-edge cutter, motions of rotating movements of work-pieces. It is a form of interrupting cutting. Here various repeated cycles of exit and entry motions of those cutting tools has been accomplishing the actual removal of metals with discontinuous generation of chip. Xiao et al. (2016) mentioned that  The milling comprises of variations of machine work-pieces, tooling and machine types that any other type of machining method. These milling machines coming from models of tabletops ate the standard vehicle knee mills. They have been operating in similar principles and parameters of operations. The most vital part of those operating parameters includes various aspects. The cutting speed is included here which is the speed at which tools has engaged with the task. Further, it includes feed rates. This includes where the distance tool edge has been travelling in cuter revolution. Moreover, there is axial depth of cutting. It represents the tools to set below of machined surfaced. Here, radial depth of cut where the quantity of work surface has been engaged by that tool. Moreover, the abilities of milling machines are calculated by spindle taper size, maximum spindle speeds and motor horsepower.

The primary milling machine includes vertical spindle, ram-type “knee” mill. However, it is adapted well for producing milling. This is ideal of making tools and machining prototypes. Moreover, the knee mills are mainly used for various manual operations. However, Zhou et al. (2018) argues that these abilities can also expanded. The knee has been travelling vertically, up and down the columns and supporting table and saddles. Here the saddle has been moving out and in from column, where table has been moving side by side of that columns. Apart from this, the ram, at top of that column has been supporting milling head that contains feed controls, speed, tool heads and motors, spindle and quills. This non-rotating quill has been holding rotating spindles. Here, ram can be removed from both in and out from that columns and is tilted for drilling and angular milling. The cutting of tools are secured in collecting and drilling chucks that are held in that spindle. Here, works are commonly protected to tables through using clamps and bolts through using fixtures and vises that ate bolted to tables. This work table has containing longitudinal “T” slots for facilitating the attachments of those devices. The abilities of knee mills are expanded through using digital readout displays and technologies (Wu and Zhang 2014).

Basic of milling machines

The engineers has used pressed sintered carbide of tungsten. These AMT cutters are available in various metallurgies and shapes. This broad range of cutter has inserted metallurgical and profile choices. This has been enabling higher flexibilities in designing mills. Here cutting structures consists of particular properties of performances (Jozi?, Baji? and Celent 2015). This is applicable to base of various applications and tasks. Thus depending on that applications, milling tools have been including various kinds of AMT cutters for optimizing different aspects of milling operations. These cutters are designed for taking mills to toughest steels. This includes nickel-content materials and high-chromes.

Then there are cutting structures including cutters that has comprised of developed wear rates, cutting edges, and impact resistances that has been resulting in shortened milling time. Next, they are able to withstand abrasive and exotic materials are common to fishing and milling operations, reducing the time and maximizing performances in broad range of deployments as shown by Han et al. (2016). This cutters has been sharping profiles with chip-breaking features for controlling cutting sizes and shapes, enabling efficient cutting removing and management of debris.

The machines of milling are differentiated as per orientation to work-pieces and degree of motions. The first one is knee-type. This a vertical workspace that is been supported by knee. This is an adjustable vertical casting. This knee supports the saddle and adjusted to allow regarding customizable workspaces. Then there are plain horizontal and vertical tools. These with standard work surfaces are oriented horizontally or vertically. This assembly of tooling is affixed on swivel and turrets and is positioned parallel to workspaces. This swivel and turret has been allowing the tools to move freely across work-pieces for enforcing tight kind of tolerances. Then there are universal horizontal machines of millings as per Canakci and Varol (2015). This differ from plain horizontal kinds since this is a table swivel housing. This is helpful to move the table in 45 degrees from the standard horizontal location. This movement of work-piece permits to gain easy angular or helical operations of milling. Then there are ram type and milling machines. This are also universal in many cases. It is helpful to allow tooling for positioning them over higher ranges of spaces as the work pieces. This ram-type machines consist of spindles over movable housings that can move under any set of horizontal plane.  It is a universal ram-type milling machine that involves swivel housing rising the range of cutting movements. Next, there is swivel cutter head which is a ram-type milling system. Several cutters with milling machines are able to rotate from a totally vertical to horizontal position. This workable has been moving and providing the users with liberal degree of orientation and motion. Various swivel cutters has included hand driven and automatic settings and rise in options of operations.

According to Al-Sandooq, Yousif and Jensen (2015) the milling is a primary drilling taking place among various powered processes of metal cutting. It is versatile for basic processes of machining. However since the milling set up comprises of various degrees of freedom. This milling is less accurate regarding or turning irrespective of rigid featuring is deployed. There are also manual machining and is important to fabricate objects that are not symmetric axially. Moreover, there are broad scopes of various milling machines. This ranges from manual light-duty Bridge-ports. Various CNC machines regarding milling are consisted of hundreds of feet longs. For example, Cao, Zhou and Chen (2015)  analyzes that organizations such as Sinotech has been offering exceptionally wide range of secondary procedures applied to metals that are formed in cold or hot processes. Their quality engineers has been finding the availability of processes under metals forming facilities and quality. As the internal secondary process never meet standards of Sinotech, then the process is done under Sinotech-audited and qualified facilities of secondary processing. Karagüzel (2015) mentioned that it has worked, qualified and audited with QS-9000 and various ISO certified secondary procedures that has been facilitating various nations for many years. It is dedicated to control the project on-sites and delivering various parts at lower process with same quality, service and terms as domestic suppliers.

As per Maher, Sadeghi and Moheb (2014) the milling is the process to eradicate metals through feeding tasks against cutters with rotating multipoint. The surface gained by machine tool is greater in quality and more precise and accurate. Here, the metals ate eradicated through faster rates as the cutters het various cutting edges and rotating with high speeds. It is also possible to perform the machine g through mounting more than a single cutter at any instance of time. This table of machine is moved through accuracy of 0.02 mm. It is also helpful as different cutters and precise tools are machined. Various special attachments ate mounted on machines for performing operations done in additional machine tools. However, tyere are various challenges in this section also.

• This cost of milling machine has been high.
• Since the cost of milling cutters are high, investments to procure the tools are more.
• Production cost rises as one carries out operations that are done with specific shape or drilling machine with milling machines.

As the process cycle goes on, various operations are done to work-pieces for yielding intended part shapes. These operations are done with defined kinds of cutters used and oath of cutters for eradicating metals from work-pieces.

The end-milling indicates making peripheral and slot cuts. This is done through step-over distances around work pieces for machine specific elements. This includes complicated surface contour, pockets, slots and profiles according to Machida and Horizoe (2015). Here the depth of the element is machine in a pass and is reached by machining at least axial depth of cutting and creating various passes.

Next, there are end milling activities or pocket millings. The first one is chamfer milling. This makes peripheral cut across edges of work pieces and featuring to develop angles surfaces that are identified as chamfers. This a typical 45 degree angle and is machines on interior or exterior of parts and follows curved and straight paths. Next, there is chamfer milling activities. This face mill machines are flat surfaces of work-pieces for providing smooth finishes. Here the depth of the face is little and is machines in one pass and is reached through machining smaller axial depth of cutting and creating numerous passes. Next Luo, et al. (2015) analyzes that there is face milling tasks. Then there is drilling. This enters the work-pieces in axial manner and cutting hole with diameters that are same as the tool. This task of drilling is able to create blind holes that extends to some depth within the work pieces and through holes extending totally through work pieces. Then there is drilling operations. Here the boring took enter work pieces in axial way and cuts along internal surfaced forming various features. This is single-point tool of cutting and is set to cut the intended diameter through using boring heads that are adjustable. This is totally done as drilling the hole for enlarging diameters and obtaining precise dimensions.  Then Lu et al. (2016) discusses that there is the boring operation. This counter bore tools gets access to work pieces axially and enlarges the highest part of the current hole to the tool’s diameter. The counter boring is done as the drilling is done for space for heading of fasteners. This includes bolts o sitting below the part of the surfaces. This counter boring tools consists of pilot to end for guiding that straight forward to the current hole.

Next there is counter boring activities. The first one is counterstriking. This tool enter the work piece in axial way and extends the top part of the current hole that has a cone-shaped opening. This counterstriking is done as the drilling is done to provide space for the head of fastener like screw and sitting flush with work piece surfaces. Here, the common angles include various degrees as per Komkiene and Baltrenaite (2016).

The milling machines are found over various designs and sizes and has been still possessing similar elements enabling work pieces to be moved in various dimensions that are relative to the tool. These elements includes various factors. The first one is base and column. Here the base of the machine is put in the platform sitting over the ground and supporting machines. This column is attached to the base and connecting to various components. Next there is the table as stated by Hebbar et al. (2016). This work piece is milled to be mounted of platforms known as table. This is “T” shaped along the surface. This work price id secured with fixtures known as vises and is secured with T slots and work pieces clamped to those slots directly. This table provided horizontal paths of work pieces in various X directions through sliding across platforms below that known as saddle. This is the platform supporting table and allowing longitudinal motions. Golik, Komashchenko and Morkun (2015) mentions that this is also able to provide and move in horizontal motion of the work piece in Y direction through sliding in transverse manner as per another platform known a knee. This is the platform supporting table and saddles. Here most of the milling machines known as columns and knee milling machines has been providing vertical motions of that elements of works. This knee can move in vertical manner around the column and moving work pieces in vertical ways as the cutter stays stationary above that. However, under limited bed machine, this knee is fixed and the cutter mover in vertical path for cutting the work piece.

These elements of milling machine are oriented horizontally and vertically. Thus they have developed two different types of milling machines. This horizontal machine utilizes cutters mounted over horizontal shaft, known as arbor, above work pieces. Due to this cause horizontal milling is also known as arbor milling. This is supported over one side by overarm. This is interconnected to the column and other side of the spindle as per Fischer et al. (2015). It is driven through motors and thus rotated those arbors. As milling takes place, the cutter rotates across the horizontal axis and side of that cutter eradicates materials from worm pieces. This vertical milling machines has been orienting the cutters in vertical way. This cutter is safe within element known as collet. This is attached over vertically oriented spindles. It is situated within the milling head known as column. These activities are done over vertical milling machines eradicating materials through sides and bottom of the cutter.

Apart from this, the milling machines are categorized to various kinds of controls that are utilized. This manual milling machine needs operations of controlling the motion of cutter. This take place as the milling activities goes on. This operator has been adjusting position of cutters through hand cracks moving knee, saddle and tables. Thee milling machines are able o be controlled through computers. This is case they are denoted as CMC or Computer Numerical Control with milling machines. According to Zou et al. (2016) these CNC milling machines has been moving work pieces and various cutters in the basis of commands that are been preprogrammed and offering huge precision. These programs are documented to NC-codes and G-codes. Here, the CNC milling machines are also contain another axis of motions apart from X-YZ motions. Here the various angles of milling machines also gets changed helping various complicated shaped to be milled.

This is needed for milling as the sharp cutters rotating across the spindles. Here, the cutters are cylindrical tools having sharp teeth spaced across exterior. These spaces has been taking place between flutes and allowing material chips for moving apart from elements of works. Thee teeth is straight across the side of cutters. However, they are been arranged commonly in helix. This helix angles has been loading the teeth through distributing the forces. Moreover, Prucek discusses that (2015) there are various teeth over cutter varies. Then there are huge number of teeth providing better finishing of surfaces. These cutters are used for various operations of milling that are mostly diverse. This has been permitting forming of various elements. These cutters has been differing highly in length, diameter and shaping the cut that is formed. This has been differing on the basis of orientations. This is irrespective of the fact that they are used vertically and horizontally. This cutter has been utilized under horizontal milling machine that has the teeth extended across the complete length of that tool. This interior of the tools has been hollowing such that it is counted to the arbor.

This is the primary form that there are still various kinds of cutters used in horizontal milling. This also includes plane or helical form relived and staggered tooth and double angle mills. In this research the Taguchi method is selected. Under the domain of metal removal, the parametric optimizations, central themes are used for Taguchi method. Besides, there is a rise in interest of optimizations as competitive tools towards sustained manufacturing. Besides, Machida and Horizoe (2015)writes that  it is also proved that the problem gained through developed results of optimizations are addressed in urgent way. This is under the perception of rising harsh environment of business. The partnering of Taguchi Method and simplex algorithms has promised developed results of optimizations resulting and pursued benefits of metal removing processes across the world. Studies if optimizations to create and deploy methods for predicting optimal value parameters in mind are the factors such as costs, lead times and productions rates. This also include an energy effective problem. 

Various metal manufacturing processes:

Casting processes	These processes of meal casting has involved pouring molten metals to mold cavities. Here solid metals has been talking shape of cavity. Further, Javanbakht, Alavi and Zilouei (2014) discusses that they are distinguished to two parts on the basis of type of mold. There are expendable mold castings where molds are destroyed for removing their parts. Then there are permanent mold casting where molds gets fabricated out of ductile materials is used repeatedly. Next, there is powder metallurgy where metal powders are compacted to intended shapes and heated for causing particles of bonding to rigid masses.
Deformation processes	These deformation processes has included metal forming and processes of metalworking sheets. They have used plastic deformations that have resulted to use tools that are applicable to stresses for the piece that exceeds yields of stress of metals. Here, Farha (2015) highlights that there are two kinds of processes of deformations. The first one is bulk processes. This is characterized through huge deformation and changes in shape. This by fact includes surface areas to volume rations that is relatively small. This bulk processes has included bar drawing, wires, extrusions, forging and rolling. Then there is sheet metalworking processes is performed on coils, strips and metal sheets having huge area of surfaces for volume ratios. Here, the operations has used punches and dies from work pieces. shearing, drawing and bending are kinds of sheets of metalworking process.
Metal removing processes	The processes has eradicated additional materials from work-pieces foe achieving intended shapes. Then there are machining operations. These are cutting operations through cutting tools that has harder than metal of that product. This has included sawing, broaching, planning, shaping, milling, drilling and turning. Next, there is abrasive machining as per Howarth et al. (2015). Here these materials are eradicated through abrasive particles that forms bonded wheels. Then there is nontraditional processes. Here the methods has used electrochemical energies, chemical erosions, electron beams and lasers. This is used instead of grinding tools and conventional cuttings.
Assembly and joining processes	There are various parts in this assembly and joining process. This is connected semi-permanently and permanently for forming new entities.

This is done through eradicating heavy metals from various streams of wastewaters. The industrial processes are able to release heavy metals to wastewater streams. This results in potential contamination of the current environment. Thus various regulating agencies has needed heavy metal removals originating from wastewaters. This happens before they gets discharged to nature. Various regulatory necessities are to be met on wastewater effluent limits. They have been driving compliances to the goals of environmental stewardships. Moreover, Al-Qodah and Al-Shannag (2017) demonstrates that heavy metals are to be removed over wide range of pH ranges. Then there is usage of chemical solutions in order to particulate various heavy metals like zinc, nickel, mercury, manganese, iron, chromium, copper and lead. Then there is removing of selenium with various advanced kinds of biological treatments.

The ABMet process of SUEZ helps customer ion FGD, mining and various other sectors for emerging strict selenium discharge limits in just one step. This is done with minimal operating costs and attentions of operators. Besides, Ahmed et al. (2017) mentions that ABMet has been removing metals and nitrate including arsenic and mercury. Innovative seed culture with particularly formulated nutrient and design of bio-filter provides time seeding, reliable performances and quick setup.

ABMet for FGD wastewater

This proven solution has been constantly meeting discharge limits in EPA as proposed by ELG for wastewaters of FGD. Then there is effective nitrate removal as per Fischer et al. (2015). Further, there is effective mercury and polishing arsenic. Moreover, there is non-hazardous waste solids that is processed easily through physical and chemical solid systems of handling. Then there is direct discharge instead of post and pretreatments.

ABMet for mining waters

Then there is modular pre-fabricated designing for installation at distant locations. Further, there is direct discharge instead of pre-treatment of post-treatments. Then there is remote process monitoring along with the insight platforms. Next, Habibul, Hu and Sheng (2016) shows that there is only one consumable product. This is all-in-one nutrient product. Then there is low volume solid wastes for hazardous disposal.

This series of operations has been transforming industrial materials coming from raw-material states for finishing various products and parts. The industrial materials are been defined as those that used in manufacturing of hard goods. Then there is less durable machines and tools developed for consumers and industries. It has included unlike the disposal of soft goods like apparel, pharmaceuticals, foodstuffs and chemicals. The manufacturing process cycle has been converting materials to products and parts that have been beginning immediately as raw materials gets extracted from minerals or produced from natural substances and basic chemicals. Then there is metallic raw materials that created in a couple of steps. Firstly, the crude ore is created to rise the concentration of intended metals. It is known beneficiation as shown by Kulikowska et al. (2015). Any typical beneficiation process has involved leaching, flotation, magnetic separation, roasting, crushing. Next, the extra processes like allowing and smelting are used for producing metals that gets fabricated to arts that are assembled to any products.

Lu  et al. (2016) mentions that at the case of ceramic materials, natural clay is the mixture and blends of different silicates for producing raw materials. The plastic resins are created through chemical methods in liquid, putty, powder forms. The synthetic rubbers are created of chemical techniques, produced and natural rubbers in the form of foam, crepe, sheets, slab to fabricate finished parts. Here, processes used for converting raw materials to various finished products has been performing various primary functions. Firstly, they have been forming materials to intended shapes and altering and improving properties of materials. The shaping and forming processes are categorized in various broad types. These are done on materials at liquid states and performed over materials in plastic and solid conditions. This processing of materials in liquid format is referred to as casting as it includes metals, ceramics and glasses. This is known as molding as applied to plastics and nonmetallic materials. Besides, molding processes and casting has included 4 important steps. This includes removal of hardened part from the mold, introducing liquids to molds, creating mold from patterns and creating suitable patterns of that part. The materials present in solid states are been formed to intended shapes. This is done through applying pressure and force. This material that has to be processed is relatively complex and in stable condition. This is in the form of powders, pellets, sheets and bars.

Otherwise this is soft, puttylike and plastic in nature as shown by Machida and Horizoe (2015). Various solid materials are shaped cold and hot. The metal processing in solid state is divided two primary stages. The first one is the raw material in the format of huge billers or ingots that is hot-worked. This is done through rolling, extrusion, forging to smaller shapes and sizes. Secondly, the shapes gets processes to ultimate products and parts through various smaller scale of cold and hot forming processes. As the materials get formed, this can get changed. Here, in material processing, processes are removed that can eradicate portions of body or piece of materials that are achieved through desired shapes. Further, Cao, Zhou and Chen (2015) mentioned that removing process are applicable to various kinds of materials. They are not used widely to different, metallic materials. This can be eradicated from work-pieces through non-mechanical and mechanical issues. Moreover, there are various types of metal-cutting processes. Here machining has included force to cut tools against various materials that are to be shaped. Here, the tool is complicated than the material that has to be cut. This helps in removing various unwanted materials in the format of chips. In this way the elements of machining are the cutting devices. This indicates the positioning and holding of work-pieces and lubricating in nature. Here, four primary non-cutting removal processes are there. This includes chemical milling metals that is removed through etching reactions of various chemical solutions over those metals. This is applicable to metals that is used over glasses and plastics. Then there is electrochemical matching using principles of metal plating as per reverse mode.

This is done instead of being created of plating processes that is eaten away in controlled manners through actions of electrical currents. Further, the electro-discharge grinding and machine has been eroding and cutting metals through high-energy sparks and electrical discharges. Then there is laser machining cuts over refractory and metallic materials having intense beam of lights coming from lasers. Then there is changes of joining, processes of permanently and at many time temporarily, attaching and bonding materials to others as highlighted by Canakci and Varol (2015). Here, the terms used here has included chemical bonding, adhesive, soldering, brazing and welding. At the joining processes, bonds between various pieces of materials are created through applying of assimilation of various types of energy, mechanical, chemical and thermal. This filler and bonding materials, that has been different and same as the materials to be joined and might or might not be utilized. These characteristics of materials can be changes through cold and hot treatments. This is dine through mechanical operations and exposure to various types of radiations. Here, property modifications are brought though changes in microscopic structures of material.

Here, Wu and Zhang (2014) demonstrated that heat-treating has involved temperatures above room temperatures and cold-treating that has included temperatures below room temperature that is involved in category. Here, thermal treatment is the process where temperature of materials is raised or lowered to modify the characteristics of original materials. Maximum of thermal-treating processes are been on the basis of cycles of time-temperatures. This involves three steps. This includes cooling, holding temperature and heating. However, there are thermal treatments that is applicable to most of families of metals. This are most widely used over metals. At last, the processes of completion is employed for changing the material surfaces for securing material against detoriations through deformations, mechanical wears, oxidations, corrosions for providing particular surface characteristics. This includes bearing properties, insulations, electrical conductivities and reflectivity. Al-Sandooq, Yousif and Jensen (2015) analyzed that this is to provide particular surface properties like insulations, electrical conductivity, reflectivity and bearing properties. They have been providing materials with particular decorative impacts. Here, there are two wide teams to finish processes, where coating is done with different materials. This is applicable to surfaces and those where the surfaces of materials that is modified through chemical actions. Here, the initial team involves metallic coating, like porcelain enameling, painting, organic finishing, electroplating.

Milling is referred to as the most versatile among all types of machining processes. Here, removal of metal is done through different relative motions of rotating, multi-axis movements and multi-edge cutters of work pieces. It is a kind of interrupted cutting. Here repeated cycles of various motions of entry and exit of cutting tools are done as per the real metal removal. This also includes discontinuous generation. It consists of different variations in work-piece, tooling and type of movements that any kind of machining methods (Jozi?, Baji? and Celent 2015). Every milling machines from various tabletop models or standard knee mulls or huge CNC machining centers has been operating on similar guidelines and operating parameters. Here most crucial of those parameters are the cutting seeds. This is the speed at which tool engages the work. Then there is feed rates that denotes distance of tool edges in a single cutter rotation. Next is the axial depth of cut where the distance of the tool is been set below machines surfaces. Besides, the radial depth of cut is the quantity of work surface that is been engaged by the tool. Here the abilities of milling machines are calculated through spindle taper size, maximum spindle speeds and motor horsepower (Cao, Zhou and Chen 2015).

Here the Taguchi method is to be conducted. This technique has explored the idea of loss functions of quadratic quality and using statistical performance measurements known as S/N of Signal to Noise ratio.  This denotes to the ratio of signal or mean to noise of standard deviation. Here, the ratio has been depending on quality characteristics of processes and products to be optimized. This optimal setting is the parameter combination that has the largest S/N ratio (Wu and Zhang 2014). On the basis of S/N or signal-to-noise assessments, the S/N or signal-to-noise ratio for every stages of processes parameters are calculated (Jozi?, Baji? and Celent (2015). Higher value of S/N ratio has corresponding to effective performance characteristics irrespective of performance of category. This indicates the process level parameters consists of greatest S/N ratio corresponding to optimum process levels of parameters. At last the confirmatory analysis is done to verify the optimal processing parameters that is obtained from parameter design.

In this research primary data analysis is done through calculating various results obtained from Taguchi’s theory. First of all the cutting parameters are to be selected. Here dimensional accuracy and surface quality are the vital aspects of products in various operations. Various factors has been influencing ultimate surface roughness under CNC milling activities. This theoretical surface roughness has been dependent commonly on various different parameters. This includes too geometries such as run-out errors, tool noise radius and various flank width. The n there are work materials, different cutting conditions and machine-tool rigidity. This includes depth of cutting speeds and feed rates. Apart from this different considerations like material properties, chip formations and chip loads and tool wears. These are the work pieces that are uncontrollable as real machining take place. Further, the presence of vibration chatters of machine tools and issues in surface work materials wear in irregularities and tools of forming chips has contributes to surface damage in practices as the real machining activities take place. However, it must be reminded that it is complicated to consider every factors affecting surface finish.

Then there is the selection of response variables. The experiment must be concentrating on various center line average value of roughness regarding surface quality. However, considerations are not enough for describing the surface quality of multi scale rough surfaces. Here four parameters of roughness are considered. They are center line average roughness, root mean square roughness, kurtosis and main line peak spacing.

Here, the medium leaded brass of UNS C34000 is used. All the specimens of mechanical properties and chemical compositions are in the form of 100 mm*70 mm*25 mm blocks.

Here the cutting tool utilized are the coated carbide tools that are found to do better than the uncoated carbide tools. These tools are also utilized as the mill cutters and flat and that are created through WIDIA or EM-TiAIN. These tools ate also to be coated with the TiAIN coating. Here, for all materials new cutters of similar type of specifications to be used. These details of cutters of end milling includes the following.

Cutter diameter	7 mm
Overall length	105 mm
Fluted length	38 mm
Helix angle	32
Hardness	1560 HV
Density	15 g/cc and
Transverse rupture strength	3600 N/mm square

The techniques of designs of experiments has been allowing to carry analysis and modeling of influence on process variables. These are also known as design factors on response to different variables. Here the depth of study of cut, speed of spindles and feed rates are opted to design factors as the other parameters are through to be consistent over present experimental domain.

Here these design factors and process variables are values over various levels and are limited by the ability for the machine utilized in experimentation and recommended specifications for various work prices and tools of material assimilations. Further, the five levels comprising of equal spacing under the operating range of parameters are selected for every factors. At the current research orthogonal arrays design is taken for analysis. Here the effect of interactions of different process parameters re negligible.

Here, the machines for milling test is are “DYNA V4·5’ CNC end milling” comprising  of machine consisting of control system of “SINUMERIK 802 D” along with a head of vertical milling. Here, this compressed coolant servo-cut is utilized for cutting areas. In order to create milled surfaces, CNC programs for various paths of tools are generated with particular commands.

It is seen that experimental data about various features of bead geometry as per orthogonal array or OA design of experiments are explored. This is to measure utility values of distinct quality attributes through the help of various equations. Here for every surface roughness parameters the LB or Lower-the-Better criterion can be used. Here, for every roughness of the parameters, most of the entries are considered to be of acceptable value. On the other hand, minimum value that is observed here is sees as the desired or best value. The reason is that due to every surface roughness characteristics the LB or Lower-the-Better criteria can be used. Here the main aim is to develop finishing of surface. This indicates that every kinds of values of roughness are lesser as possible.

The common trends in the solution of various multi-objective problems are optimization is the change the multi-objectives initially to equivalent objective function. Through deriving the equivalent objective function, various priority weightages are been assigned to various responses. This is done as per the importance. However, no particular principles are available to assign the weightage of responses. This has been totally depending on the makers of decisions. This can be human judgment or individual perception. This is the reason why the current research has assumed the priority weightage to every reactions. It is seen that as the Taguchi analysis is done once any optimal setting can be predicted. The above Taguchi process has provided the predicted value of S/N ratio of different objective functions at the optimal setting. Experiments on the other hand is done at intended optimal setting. Here the results obtained are assimilated for measuring the overall utility degree and as per the S/N ratio. Next, two of the outcomes are compared. The S/N ratio retrieved experimentally is equal to more than that has been predicted. Since the S/N ratio is maximized, it indicates the least loss in quality.

Milling as a basic process is regarded as the most widely utilized process of metal removal. This is used in industries and milled surfaces that are highly used for mating other parts machinery automotive, machinery, aerospace, die designing and manufacturing sectors. Here the mechanisms beyond this forming of surface roughness is process dependent, complex and dynamic. Hence is the complicated to measure the value with the help of theoretical analysis. Thus the machine operators has been utilizing the trial and error method for setting-up milling machine conditions of cutting. This is to gain the expected roughness of the surface. However, it has been not an empirical and repetitive method that has been much more time consuming. This widespread usage and dynamic nature of milling has raised the necessity to seek systematic approach. This helps in set up milling activities in time.

Moreover this also helps in achieving expected quality of different surface roughness. This prediction of various chatter vibrations that are done between work piece and cutters are vital principle to machine tool users for optimal selection of spindle rotation and depth of cut. This results in most of the chip removal rate instead of having an intended outcome. It is done through various approaches. Here, the method of analytics is done for time varying directional dynamic milling forces of coefficients. This are further expanded in Fourier series and then integrated in width of cut bound through various angles of exit and entry. These contact zone forces are done between work-pieces and cutters as the cuts are analyzed through algorithms of mathematical model. This is derived from various experimental tests with dynamometer situated between machine table and work-piece. Here, the results of algorithm has been depending on physical properties of materials of work-piece and different cutter geometry. Here different modal parameters of machine-work piece-tool system such as residues, damping and frequencies are also experimentally determined. Here, it has been possible to plot those stability lobes for the dynamic system. Here, the curves are related to spindle speeds having axial depth of cutting, separating stable and unstable sectors. It has been permitting the selecting of various parameters of cutting that has resulted most of the productivities. Furthermore, the current experiments has been facing milling tests that are done in knee-type machines. This is done through five inserts cutters. Thus the outcomes has highlighted suitable agreements taking place between chatter prediction and tests of experiments.

On the other hand, principles of Taguchi methods are aided to select optimal process and product parameters. It has been facilitating objectives of Taguchi off like quality controls that is regarded to be an efficient approach to develop high quality products at low costs. The above study has stressed and made it clear that the underpinning conceptual frameworks of methods regarding process robustness and quality improvements. Here, the primary aim of the research is to develop designs hat are robust and comprising of uncontrollable elements and achieving intended target values with minimum variability. These performance measures like signal to noise ratio are also utilized. Here, costs are the fundamental considerations for present day Taguchi method. This includes the concept to gain the best possible designing at the least possible cost. Here, the role of Taguchi to create and implement ideas of quality engineering are vital and constant to be pivotal in various types of quality developments. Here the study has shown a systematic approach to carry out the industrial experiments for manufacturing industry and service industries in the basis of Taguchi’s process of optimization. Deploying Taguchi method of optimization is helpful to decrease the product and process variation. This also minimizes the impacts to use comparatively small quantity of experimental runs and minimizing the expenses to gain the most effective quality of products.

The following experimentation through Taguchi method is illustrated hereafter.

Task Name	Duration	Start	Finish	Predecessors
CNC milling	31 wks	Mon 6/10/19	Fri 1/10/20
Finding control parameter: feed rates, spindle feed, depth of cut	70 wks	Mon 1/13/20	Fri 5/14/21	1
Taguchi designing through 3 Levels of controlled parameters	32 wks	Sun 6/26/22	Fri 2/17/23	2
Experimental techniques	40 wks	Mon 2/20/23	Fri 11/24/23	3
Analyzing outcomes	35 wks	Mon 11/27/23	Fri 7/26/24	4
Finding of material removal rates	36 wks	Mon 7/29/24	Fri 4/4/25	5
Determining roughness of surface	30 wks	Mon 4/7/25	Fri 10/31/25	6

Conclusion: 

Here the studies that are reported has focused on center line average roughness value of service quality. Moreover, it is also seen that considering the core line average roughness has not be sufficient to demonstrate the quality of surface. The above roughness parameters described such a kurtosis, mean line peak spacing is to be taken care off and must be included in the study. This research has considered aforesaid numerous surface roughness properties regarding minimization or optimization to be done simultaneously regarding various roughness characteristics under experimental domains. Hence various conclusions can be drawn from the outcomes of the analysis and experiments of experimental data. This is done in connection with different types of multi-response optimizations in milling activities. Thus the utility based method of Taguchi is seen to be fruitful to evaluate optimum settings of parameters. Moreover, confirmatory tests are validated to parametric setting that is found though utility based proves of Taguchi. This method is suggested for constant improvement in quality and off-line control of quality of products and processes.

References:

Abbas, A., Al-Amer, A.M., Laoui, T., Al-Marri, M.J., Nasser, M.S., Khraisheh, M. and Atieh, M.A., 2016. Heavy metal removal from aqueous solution by advanced carbon nanotubes: critical review of adsorption applications. Separation and Purification Technology, 157, pp.141-161.

Abdelhadi, S.O., Dosoretz, C.G., Rytwo, G., Gerchman, Y. and Azaizeh, H., 2017. Production of biochar from olive mill solid waste for heavy metal removal. Bioresource technology, 244, pp.759-767.

Abdel-Halim, E.S. and Al-Hoqbani, A.A., 2015. Utilization of poly (acrylic acid)/cellulose graft copolymer for dye and heavy metal removal. BioResources, 10(2), pp.3112-3130.

Adeleye, A.S., Conway, J.R., Garner, K., Huang, Y., Su, Y. and Keller, A.A., 2016. Engineered nanomaterials for water treatment and remediation: costs, benefits, and applicability. Chemical Engineering Journal, 286, pp.640-662.

Ahmed, M.B., Zhou, J.L., Ngo, H.H., Guo, W., Thomaidis, N.S. and Xu, J., 2017. Progress in the biological and chemical treatment technologies for emerging contaminant removal from wastewater: a critical review. Journal of hazardous materials, 323, pp.274-298.

Ali, R.M., Hamad, H.A., Hussein, M.M. and Malash, G.F., 2016. Potential of using green adsorbent of heavy metal removal from aqueous solutions: adsorption kinetics, isotherm, thermodynamic, mechanism and economic analysis. Ecological Engineering, 91, pp.317-332.

Al-Qodah, Z. and Al-Shannag, M., 2017. Heavy metal ions removal from wastewater using electrocoagulation processes: a comprehensive review. Separation Science and Technology, 52(17), pp.2649-2676.

Al-Sandooq, J.M., Yousif, B.F. and Jensen, T.A., 2015. Influence of metal coating on sorghum milling process subjected to three body abrasion. International Journal of Precision Technology, 5(1), pp.27-43.

Bilgin, M.S., Erdem, A., Dilber, E. and Ersoy, ?., 2016. Comparison of fracture resistance between cast, CAD/CAM milling, and direct metal laser sintering metal post systems. Journal of prosthodontic research, 60(1), pp.23-28.

Canakci, A. and Varol, T., 2015. A novel method for the production of metal powders without conventional atomization process. Journal of Cleaner Production, 99, pp.312-319.

Cao, H., Zhou, K. and Chen, X., 2015. Chatter identification in end milling process based on EEMD and nonlinear dimensionless indicators. International Journal of Machine Tools and Manufacture, 92, pp.52-59.

Elouear, Z., Bouhamed, F. and Bouzid, J., 2014. Evaluation of different amendments to stabilize cadmium, zinc, and copper in a contaminated soil: Influence on metal leaching and phytoavailability. Soil and Sediment Contamination: An International Journal, 23(6), pp.628-640.

Eranna, G., 2016. Metal oxide nanostructures as gas sensing devices. CRC Press.

Fischer, K., Agostinelli, M., Allen, C., Bahr, D., Bost, M., Charvat, P., Chikarmane, V., Fu, Q., Ganpule, C., Haran, M. and Heckscher, M., 2015. Low-k interconnect stack with multi-layer air gap and tri-metal-insulator-metal capacitors for 14nm high volume manufacturing. polymer, 14000(6000), pp.1-3.

Glukhov, V., Turichin, G., Klimova-Korsmik, O.G., Zemlyakov, E. and Babkin, K., 2016. Quality management of metal products prepared by high-speed direct laser deposition technology. In Key Engineering Materials (Vol. 684, pp. 461-467). Trans Tech Publications.

Golik, V., Komashchenko, V. and Morkun, V., 2015. Innovative technologies of metal extraction from the ore processing mill tailings and their integrated use. Metallurgical and Mining Industry, 7(3), p.49.

Habibul, N., Hu, Y. and Sheng, G.P., 2016. Microbial fuel cell driving electrokinetic remediation of toxic metal contaminated soils. Journal of hazardous materials, 318, pp.9-14.

Han, S., Kim, H., Kim, Y.W., Kim, Y.J., Kim, S., Park, I.Y. and Kim, S.W., 2016. High-harmonic generation by field enhanced femtosecond pulses in metal-sapphire nanostructure. Nature communications, 7, p.13105.

Hebbar, R.S., Isloor, A.M., Ananda, K. and Ismail, A.F., 2016. Fabrication of polydopamine functionalized halloysite nanotube/polyetherimide membranes for heavy metal removal. Journal of Materials Chemistry A, 4(3), pp.764-774.

Hebbar, R.S., Isloor, A.M., Ananda, K. and Ismail, A.F., 2016. Fabrication of polydopamine functionalized halloysite nanotube/polyetherimide membranes for heavy metal removal. Journal of Materials Chemistry A, 4(3), pp.764-774.

Howarth, A.J., Katz, M.J., Wang, T.C., Platero-Prats, A.E., Chapman, K.W., Hupp, J.T. and Farha, O.K., 2015. High efficiency adsorption and removal of selenate and selenite from water using metal–organic frameworks. Journal of the American Chemical Society, 137(23), pp.7488-7494.

Inyang, M.I., Gao, B., Yao, Y., Xue, Y., Zimmerman, A., Mosa, A., Pullammanappallil, P., Ok, Y.S. and Cao, X., 2016. A review of biochar as a low-cost adsorbent for aqueous heavy metal removal. Critical Reviews in Environmental Science and Technology, 46(4), pp.406-433.

Javanbakht, V., Alavi, S.A. and Zilouei, H., 2014. Mechanisms of heavy metal removal using microorganisms as biosorbent. Water Science and Technology, 69(9), pp.1775-1787.

Javanbakht, V., Alavi, S.A. and Zilouei, H., 2014. Mechanisms of heavy metal removal using microorganisms as biosorbent. Water Science and Technology, 69(9), pp.1775-1787.

Jozi?, S., Baji?, D. and Celent, L., 2015. Application of compressed cold air cooling: achieving multiple performance characteristics in end milling process. Journal of cleaner production, 100, pp.325-332.

Kannan, T.T.M., Ramanathan, R., Thirumavalavan, T., Vignesh, G. and Vinoth, M., 2018. STUDY OF MACHINING TIME IN END MILLING PROCESS ON H-13 DIE STEEL. parameters, 2(3).

Karagüzel, U., Uysal, E., Budak, E. and Bakkal, M., 2015. Analytical modeling of turn-milling process geometry, kinematics and mechanics. International Journal of Machine Tools and Manufacture, 91, pp.24-33.

Karagüzel, U., Uysal, E., Budak, E. and Bakkal, M., 2015. Analytical modeling of turn-milling process geometry, kinematics and mechanics. International Journal of Machine Tools and Manufacture, 91, pp.24-33.

Khorasani, A. and Yazdi, M.R.S., 2017. Development of a dynamic surface roughness monitoring system based on artificial neural networks (ANN) in milling operation. The International Journal of Advanced Manufacturing Technology, 93(1-4), pp.141-151.

Komkiene, J. and Baltrenaite, E., 2016. Biochar as adsorbent for removal of heavy metal ions [Cadmium (II), Copper (II), Lead (II), Zinc (II)] from aqueous phase. International Journal of Environmental Science and Technology, 13(2), pp.471-482.

Kulikowska, D., Gusiatin, Z.M., Bu?kowska, K. and Kierklo, K., 2015. Humic substances from sewage sludge compost as washing agent effectively remove Cu and Cd from soil. Chemosphere, 136, pp.42-49.

Lee, C.G., Lee, S., Park, J.A., Park, C., Lee, S.J., Kim, S.B., An, B., Yun, S.T., Lee, S.H. and Choi, J.W., 2017. Removal of copper, nickel and chromium mixtures from metal plating soil by adsorption with modified carbon foam. Chemosphere, 166, pp.203-211.

Lee, K.H., Yeo, I.S., Wu, B.M., Yang, J.H., Han, J.S., Kim, S.H., Yi, Y.J. and Kwon, T.K., 2015. Effects of computer-aided manufacturing technology on precision of clinical metal-free restorations. BioMed research international, 2015.

Li, J., Yang, X., Ren, C., Chen, G. and Wang, Y., 2015. Multiobjective optimization of cutting parameters in Ti-6Al-4V milling process using nondominated sorting genetic algorithm-II. The International Journal of Advanced Manufacturing Technology, 76(5-8), pp.941-953.

Li, S., Wang, W., Liang, F. and Zhang, W.X., 2017. Heavy metal removal using nanoscale zero-valent iron (nZVI): theory and application. Journal of hazardous materials, 322, pp.163-171.

Li, S., Wang, W., Liang, F. and Zhang, W.X., 2017. Heavy metal removal using nanoscale zero-valent iron (nZVI): theory and application. Journal of hazardous materials, 322, pp.163-171.

Li, Y.J., Hu, P.J., Zhao, J. and Dong, C.X., 2015. Remediation of cadmium-and lead-contaminated agricultural soil by composite washing with chlorides and citric acid. Environmental Science and Pollution Research, 22(7), pp.5563-5571.

Lu, L., Li, J., Feng, Z., Kwok, H.S. and Wong, M., 2016. Elevated-metal–metal-oxide thin-film transistor: Technology and characteristics. IEEE Electron Device Letters, 37(6), pp.728-730.

Luo, F., Chen, J.L., Dang, L.L., Zhou, W.N., Lin, H.L., Li, J.Q., Liu, S.J. and Luo, M.B., 2015. High-performance Hg 2+ removal from ultra-low-concentration aqueous solution using both acylamide-and hydroxyl-functionalized metal–organic framework. Journal of Materials Chemistry A, 3(18), pp.9616-9620.

Luo, F., Chen, J.L., Dang, L.L., Zhou, W.N., Lin, H.L., Li, J.Q., Liu, S.J. and Luo, M.B., 2015. High-performance Hg 2+ removal from ultra-low-concentration aqueous solution using both acylamide-and hydroxyl-functionalized metal–organic framework. Journal of Materials Chemistry A, 3(18), pp.9616-9620.

Luo, X., Zeng, J., Liu, S. and Zhang, L., 2015. An effective and recyclable adsorbent for the removal of heavy metal ions from aqueous system: magnetic chitosan/cellulose microspheres. Bioresource technology, 194, pp.403-406.

Luo, X., Zeng, J., Liu, S. and Zhang, L., 2015. An effective and recyclable adsorbent for the removal of heavy metal ions from aqueous system: magnetic chitosan/cellulose microspheres. Bioresource technology, 194, pp.403-406.

Machida, H. and Horizoe, H., 2015. High efficiency metal removal from hexane-extracted algae oil using super and subcritical propane. Energy Conversion and Management, 95, pp.90-93.

Machida, H. and Horizoe, H., 2015. High efficiency metal removal from hexane-extracted algae oil using super and subcritical propane. Energy Conversion and Management, 95, pp.90-93.

Maher, A., Sadeghi, M. and Moheb, A., 2014. Heavy metal elimination from drinking water using nanofiltration membrane technology and process optimization using response surface methodology. Desalination, 352, pp.166-173.

Prucek, R., Tucek, J., Kolar?ík, J., Hus?kova?, I., Filip, J., Varma, R.S., Sharma, V.K. and Zbor?il, R., 2015. Ferrate (VI)-prompted removal of metals in aqueous media: mechanistic delineation of enhanced efficiency via metal entrenchment in magnetic oxides. Environmental science & technology, 49(4), pp.2319-2327.

Stephenson, D.A. and Agapiou, J.S., 2016. Metal cutting theory and practice. CRC press.

Sun, Y., Zheng, G., Seh, Z.W., Liu, N., Wang, S., Sun, J., Lee, H.R. and Cui, Y., 2016. Graphite-encapsulated Li-metal hybrid anodes for high-capacity Li batteries. Chem, 1(2), pp.287-297.

Tien, H.N. and Hur, S.H., 2015. Synthesis of highly durable sulfur doped graphite nanoplatelet electrocatalyst by a fast and simple wet ball milling process. Materials Letters, 161, pp.399-403.

Vilela, D., Parmar, J., Zeng, Y., Zhao, Y. and Sa?nchez, S., 2016. Graphene-based microbots for toxic heavy metal removal and recovery from water. Nano letters, 16(4), pp.2860-2866.

Wan, M., Feng, J., Ma, Y.C. and Zhang, W.H., 2017. Identification of milling process damping using operational modal analysis. International Journal of Machine Tools and Manufacture, 122, pp.120-131.

Wang, B., Lv, X.L., Feng, D., Xie, L.H., Zhang, J., Li, M., Xie, Y., Li, J.R. and Zhou, H.C., 2016. Highly stable Zr (IV)-based metal–organic frameworks for the detection and removal of antibiotics and organic explosives in water. Journal of the American Chemical Society, 138(19), pp.6204-6216.

Wiedenmann, R. and Zaeh, M.F., 2015. Laser-assisted milling—Process modeling and experimental validation. CIRP Journal of Manufacturing Science and Technology, 8, pp.70-77.

Wu, H.B. and Zhang, S.J., 2014. 3D FEM simulation of milling process for titanium alloy Ti6Al4V. The International Journal of Advanced Manufacturing Technology, 71(5-8), pp.1319-1326.

Xiao, Z., Huang, X., Xu, L., Yan, D., Huo, J. and Wang, S., 2016. Edge-selectively phosphorus-doped few-layer graphene as an efficient metal-free electrocatalyst for the oxygen evolution reaction. Chemical Communications, 52(88), pp.13008-13011.

Zaretalab, A., Haghighi, H.S., Mansour, S. and Sajadieh, M.S., 2018. A mathematical model for the joint optimization of machining conditions and tool replacement policy with stochastic tool life in the milling process. The International Journal of Advanced Manufacturing Technology, pp.1-21.

Zhang, Z.Y., Zhang, F.S. and Yao, T., 2017. An environmentally friendly ball milling process for recovery of valuable metals from E-waste scraps. Waste Management, 68, pp.490-497.

Zhou, W., Qiu, Q., Zhou, F., Chu, X., Ling, W. and Yu, W., 2018. Multi-blade milling process of Cu-based microchannel for laminated heat exchanger. The International Journal of Advanced Manufacturing Technology, 95(5-8), pp.2973-2987.

Zhu, W.P., Gao, J., Sun, S.P., Zhang, S. and Chung, T.S., 2015. Poly (amidoamine) dendrimer (PAMAM) grafted on thin film composite (TFC) nanofiltration (NF) hollow fiber membranes for heavy metal removal. Journal of Membrane Science, 487, pp.117-126.

Zou, Y., Wang, X., Khan, A., Wang, P., Liu, Y., Alsaedi, A., Hayat, T. and Wang, X., 2016. Environmental remediation and application of nanoscale zero-valent iron and its composites for the removal of heavy metal ions: a review. Environmental science & technology, 50(14), pp.7290-7304.