Principles of Non-Traditional Machining Process

Non-traditional machining, also known as the modern machining method, is a machining method that uses electricity, heat energy, light energy, electrochemical energy, energy, chemical energy, sound energy, and special mechanical energy to remove, deform, change properties, or plate materials. 

In this article, we will learn more about non-traditional machining, its classification, processes, and needs.

Non-Traditional Machining

Traditional machining processes such as turning, drilling, shaping, and milling are difficult to use on extremely hard and brittle materials. Non-traditional machining processes are used when traditional machining processes are not feasible, satisfactory, or cost-effective for the reasons listed below.

• For traditional machining, very hard, fragile materials are difficult to clamp. 
• When the workpiece is overly flexible or thin
• When the shape is extra complex

To meet the extra machining conditions, several types of non-traditional machining processes have been developed. When used correctly, these processes have many advantages over non-traditional machining processes.

This section describes the most common non-traditional machining processes.

Classification of Non-Traditional Machining Process

The majority of non-traditional procedures are categorised according to the type of energy utilised to remove the material, which includes:

• Mechanical Machining: 

The work material is degraded by a high-velocity stream of abrasives for fluid; it is a common form of in this process that permits the removal of surplus material.

Ultrasonic Machining (USM) and Waterjet Machining (WJM) are two examples of single-action, mechanical nontraditional machining processes. 

The machining medium in WJM is fluid and solid grains in USM. The addition of abrasives to the fluid jet improves machining efficiency and is known as abrasive water jet machining. When ice particles are introduced, as in Ice Jet Machining, a similar case occurs.

• Electrical Machining:

In these non-traditional techniques, electrical energy is used to remove the material; the mechanism is the opposite of electroplating. Using ion transfer in an electrolytic cell, electrochemical machining removes the machining allowance using the electrochemical dissolution phase.

• Thermal Machining:

The use of thermal energy is used to shave or cut the workplace. The thermal energy usually provided to a little piece of the work surface is that portion to be removed by fusion or vaporization. The generation of thermal energy necessitates a complete conversion of electrical energy.

During machining, many secondary phenomena occur, such as microcracking, the creation of heat impacted zones, striations, and so on.  Heat could come from plasma, as in EDM and PBM, or photons, as in LBM, electrons in EBM, ions in IBM, and so on.

Chemical Machining:

Most materials are prone to chemical attack by certain acids or others it contains Chemicals selectively remove material from areas of the workpiece in Chemical Machining by other portions of the surface remain protected by a mask the non-traditional processes are mostly classified as per the form of energy used to material removal They are mechanical in nature, with a high-velocity stream eroding the work material.

Chemical milling, photochemical machining, and photochemical blanking are all methods that use a chemical dissolution action to remove the machining allowance using ions in an etchant.

Non-Traditional Machining Processes

• USM (Ultrasonic Machining) Process:

It is one of the sorts of non-traditional machining processes that produce circular and non-circular holes as small as 1mm in diameter.

The tool vibrates at a very high frequency when very high-frequency vibrations are given to it. Impact loads are induced on the abrasive particles by this tool, which is then induced on the workpiece.

• EDM (Electrical Discharge Machining) Process:

The procedure is also known as Spark Machining or Spark Eroding. In this procedure, electrical energy is used to create a Spark between the tool and the workpiece, which is submerged in a dielectric media, allowing the material to be removed from the workpiece’s surface via local melting or vaporization. 

• ECM (Electro Chemical Machining) Process:

This method uses a combination of electrical and chemical energy to remove material from a workpiece’s surface. It operates according to Faraday’s law of electrolysis.

It operates according to Faraday’s law of electrolysis. NaCl (Conducting Electrolyte) is employed as the electrolyte, and the Wear Ratio is infinite (because of no Tool Wear).

• WJM (Water Jet Machining) Process:

Pressure energy is turned into velocity energy or the kinetic energy when very high-pressure water passes through a convergent nozzle.

As a result, the water is ejected from the nozzle at a very high velocity, estimated to be between 200 and 400 metres per second.

The continuous impact load acts on the workpiece when this high-velocity water Jet impinges on it. As a result, highly soft materials will deform and fracture due to plastic deformation.

• Abrasive Water Jet Machining (AWJM)

It is a type of advanced water jet machining that uses abrasives as a medium. The following is a detailed explanation of Abrasive Water Jet Machining.

Abrasive particles dissolve in the water and are ejected at a high velocity from the nozzle.

• EBM (Electron Beam Machining) Process:

When the electron gun is given a very high voltage power supply, it produces very high-velocity electrons in all directions.

All of these high-velocity electrons are gathered and shaped into a beam of electrons with a cross-section area less than 0.05 millimetre square using a magnetic lens or deflector.

• LBM (Laser Beam Machining) Process:

When the laser gun is powered up, it produces extremely high-intensity electromagnetic waves in the form of a laser beam, and when they strike a workpiece, the electromagnetic wave energy is transformed to heat energy by surface phenomena such as radiation heat transfer.

Need of Non-Traditional Machining Process

Steel alloy strength has increased fivefold as a result of ongoing R&D. In the aerospace industry, the need for high strength at high temperatures while remaining lightweight led to the development and use of hard titanium alloys, nimonic alloys, and other HSTR alloys. The ultimate tensile strength has increased by up to 20 times.

The development of cutting tools with hardnesses ranging from 80 to 85 HRC that could not be machined economically using traditional methods led to the development of non-traditional machining methods.

• High-tech industries such as aerospace, nuclear power, wafer fabrication, and automobiles are increasingly using high-strength temperature resistant (HSTR) alloys (with a high strength-to-weight ratio) and other difficult-to-machine materials such as titanium, SST, mnemonics, ceramics, and semiconductors. These alloys can no longer be machined using traditional methods.
• Production and processing of parts with complicated shapes (in HSTR and other difficult to machine alloys) are difficult, time-consuming, and uneconomical using conventional machining methods.
• Innovative geometric design of products and factors made of exotic matter and face finish cannot be economically produced through conventional machining.

The following are some examples of where NTM processes are preferred over traditional machining processes:

• Low Stress Grinding – Electrochemical Grinding is preferred over conventional grinding
• Deep hole with small hole diameter – for example, 1.5 mm hole with l/d = 20 
• Composites Machining

Conclusion

Non-Traditional Machining is a cutting-edge technique for overcoming the drawbacks of traditional machining. Ultrasonic machining, laser beam machining, water jet machining, abrasive water jet machining, and other non-traditional machining technologies are examples.