The Ultimate Guide to CNC Machining: Materials You Can’t Use

Many industries have benefited from using CNC machining, making manufacturing more convenient with accurate results. Nevertheless, not every material is suitable for this process, even though it is excellent for shaping various materials. Manufacturers must understand which materials are incompatible with CNC machining to enlist them from their processes and avoid costly errors. This article discusses the technical limitations of CNC machining by outlining a few materials that pose some challenges due to their characteristics or behavior during machining. Seasoned professionals and novices alike will find this guide helpful in improving their material selection methods and optimizing production.

What types of materials are challenging for CNC machining?

The materials that are generally known to pose difficulties to CNC machining can be divided into the following categories:

• Hard or Tough: Such materials include hardened steel, titanium, and others, which may cause rapid wear of tools used for cutting and force application.
• Soft & Elastic: Some types of rubber, as well as certain plastics that can get deformed when subjected to cutting forces, can give rise to difficulties in carrying out accurate machining processes.
• Brittle Material: This category of materials includes ceramics such as glass that are prone to crack or chip during any form of mechanical processing, and thus, they need to be handled with care and using appropriate tools.
• Composite Materials: Due to their variable hardness levels, composite materials, such as carbon fiber composites, could place uneven pressure on tool edges and pose a health risk from dust produced during manufacturing.

Effective material selection must be coupled with proper machining strategies to overcome these challenges.

Incredibly soft or flexible materials

Machining soft materials such as rubber or not-so-hard thermoplastics are problematic due to their physical characteristics. Machining this material deforms under cutting forces and may cause a lower dimensional accuracy and complexity. For instance, cryogenic machining is one unique approach when a low temporary temperature is used to cool down the material, thereby increasing its rigidity. At low temperatures, material deformation can be minimized by reducing the cutting surface finish, making it easier to machine than others. Friction can be reduced using sharp cutting tools with lower rake angles and lubrication.

The flexibility also results in more vibration during the machining, which could affect tool life and the quality of the surface finishes. For example, in the case of thermoplastics, it has been illustrated that slower speeds combined with proper clamping setups can help alleviate inaccuracies caused by vibrations. According to industrial practice tips, machining flexible materials requires HSS (high-speed steel) or carbide tools for maximum durability and precise cuts.

For challenging CNC applications, know how a material behaves under working conditions & customize milling parameters accordingly; hence, the final product will meet the high standards demanded from these materials.

Materials with low melting points

Various industries face unique opportunities and challenges when dealing with materials that have low melting points, such as aluminum, tin, lead, and some thermoplastics. These substances typically have melting points below 600 degrees Fahrenheit (316 degrees Celsius); hence, they can be used in low-temperature applications like soldering, casting, and 3D printing. For example, tin has a melting point of about 450 degrees Fahrenheit (232 degrees Celsius), ideal for soldering electronic equipment with significant temperature control.

For proper machining or processing of these materials, it is necessary to consider their thermal properties to avoid deformations caused by heating effects, including warping. Information indicates that sound cooling systems like high-pressure air or liquid coolant can reduce thermal stress and, in turn, increase tool life while enhancing surface finish. Additionally, studies have shown the importance of using sharp cutting tools and low-rpm spindles to minimize heat generated during machining.

The applications of alloys developed from low-melting-point materials have also increased their scope of use. For example, lead-tin alloys are extensively applied in manufacturing solders since they melt predictably and are long-lasting. In addition, advanced thermoplastics with low softening points are commonly used for additive manufacturing, which requires accurate layer-by-layer deposition.”

Industries can, therefore, use these materials rightly and ensure that their applications last, are harmless, and are efficient by knowing their mechanical and thermal properties.

Highly abrasive substances

Highly abrasive materials have significant hardness and abrasiveness, which is why they are necessary for industrial applications such as grinding, cutting, and polishing. These include silicon carbide (SiC), aluminum oxide (Al2O3), cubic boron nitride (CBN), and diamond. These materials have superior wear resistance and can withstand high-stress operations.

To illustrate, industrial diamonds made synthetically are widely used for cutting tools because their hardness is incomparable, as they rate 10 on the Mohs scale. It can be used to make ultra-hard materials like ceramics and metals with high precision. In contrast, aluminum oxide has a particle hardness that varies between 9-9.5 on the Mohs scale, and it is commonly applied to sandpapers and abrasive blasting.

Recent developments have optimized the sizes and structures of abrasive particles, thereby enhancing efficiency and reducing the wear and tear of processing equipment. Studies involving nanostructured abrasives indicate an increase in material removal rate of 15-20% compared with traditional micro-sized counterparts. Besides, industries continue to explore sustainable development issues, such as employing eco-friendly abrasives like recycled glass and garnet, which balance operational efficiency with environmental sustainability.

Understanding the physical characteristics of materials, such as particle size, hardness, and thermal stability, is crucial for choosing an appropriate abrasive for a given application. This will ensure the tools and equipment last longer while minimizing damage and providing the best results.

Why can’t certain materials be used in CNC machining?

Limitations of CNC machine tools

CNC machines, when dealing with particular materials, have limitations. One of the significant factors could be the hardness of any given material; some complex substances, such as some ceramics or hardened steels, can surpass the capacity of ordinary CNC tooling, which may result in heavy wearing and breaking of tools. This is related to another limitation, which is material ductility. These machining problems, for example, poor surface finishes or clogging cutting tools, may arise from highly ductile substances like certain soft metals. Furthermore, during machining, some materials may not conduct heat, leading to thermal deformation or damage to the workpiece. The machine’s accuracy and continual high performance rely heavily on properly selecting compatible materials that will complement the machine’s performance.

Material properties incompatible with machining processes

Excessive Hardness

Some ceramics or excessively hardened steel can be complex to machine and may wear out tooling rapidly.

Low Thermal Conductivity

Poor heat dissipation materials, including titanium alloy, may cause thermal damage due to machining-induced heat buildup.

High Ductility

These are too malleable materials, like pure copper or soft aluminum, which give unsatisfactory finishes and cause tool clogging problems.

Brittleness

The fear is that brittle substances such as glass and specific composites might crack or chip while machining.

Abrasive Properties

Composites reinforced with abrasive substances or some polymer types could quickly dull cutting instruments and reduce machinability.

Identifying these incompatible characteristics is vital for selecting appropriate materials and improving machine performance during operations.

Safety concerns and potential damage to equipment

Machining materials with incompatible properties can pose safety risks. Brittle materials, which shatter under stress, create sharp shards that may injure operators. Moreover, abrasive materials quicken the wearing off of cutting tools, which may fail while in use. This can cause abrupt machine malfunctioning and hazards to safety. Minimizing such risks and ensuring safe operations requires the right material choice, regular equipment maintenance, and protective equipment use.

What are the alternatives for materials that can’t be CNC machined?

3D printing options

For materials that are difficult to machine using CNC techniques, 3D printing stands as a flexible option. Such additive manufacturing technologies like Fused Deposition Modeling (FDM), Stereolithography (SLA), and Selective Laser Sintering (SLS) can process a variety of materials such as thermoplastics and photopolymers, among others, even metals.

One example is FDM printers, which are extensively useful in fabricating prototypes using ABS, PLA, and PETG to ensure cost-effective solutions. Conversely, SLA gives better precision, hence being best for detailed applications commonly done using tough, flexible, and castable resins. SLS is employed extensively in manufacturing strong functional parts from nylon-based powders, making it suitable for end-use applications in aerospace and medical devices.

According to statistics, 3D printing can save up to 70% of material waste compared to subtractive methods of traditional manufacture. Moreover, there have been developments in metal 3D printing, such as Direct Metal Laser Sintering (DMLS), which creates geometries that are complicated by using materials including titanium and aluminum together with stainless steel. These capabilities make 3D printing an interesting choice for small-scale production runs, quick prototyping, and custom designs.

By incorporating different 3D printing techniques with specific advantages for each material, manufacturers can overcome the limitations of CNC machining while maintaining efficiency, functionality, and design flexibility.

Injection molding for plastics

If you ask me, injection molding is a method for producing plastic parts on a large scale that I would vouch for. In this process, liquid plastic is pushed into a specific mold and then cooled down to form the desired shape. Its strength lies in its capacity to make components with intricate geometries at high production rates. What’s more, different thermoplastics can be used, thus ensuring that material properties are adjusted for specific needs.

Casting methods for metals

One of the basics of metalworking is casting, where liquid metal is poured into a mold and solidified to form the desired shape. Different casting techniques use different materials, applications, and tolerances.

Sand Casting

Sand casting is one of the most commonly used for its versatility and cost-effectiveness. This method uses molds made from sand that can be shaped easily for any complex design. It is widely used to fabricate large and heavy parts in such metals as iron, steel, and aluminum. Contemporary sand castings can achieve tolerances to within ±0.02 inch per inch, mostly found on items like engine blocks or farm machinery components.

Die Casting

In die casting, hot liquid metal is squeezed into a reusable steel mold (die) at high pressure to mass produce precision parts. Thereafter, nonferrous alloys are typically machined through computer numerical control processes, especially when dealing with various CNC applications involving aluminum, zinc, or magnesium, among others. Some advanced die-casting technologies can deliver tolerances as low as ±0.005 inch. Therefore, this technique finds extensive application in automotive manufacturing industries and aviation industry consumer electronics due to its capability to produce intricate geometrically accurate parts at various sizes.

Investment Casting

The investment casting method, called lost-wax casting, is best for manufacturing components with intricate details and smooth finishes. A ceramic shell mold is formed around a wax model, melted out to get rid of the latter, and then filled with molten metal. The objective of this method is to achieve an excellent surface finish as well as dimensional tolerances of ±0.004 inches. This technique is widely used in the medical field and aerospace since it is critical in generating such components as surgical tools and turbine blades.

Centrifugal Casting

This approach uses centrifugal force to distribute molten metal within the mold, producing compact parts with limited porosity. It primarily makes tube-like and cylindrical components, e.g., pipes, bushings, or bearings that employ stainless steel and iron. Materials that are produced through the process of centrifugal casting typically have improved mechanical properties alongside their high efficiency.

Continuous Casting

Continuous casting is a process that is made more efficient by which liquid metal becomes solid continuously as it comes out of a mold, producing sheets, rods, or other long shapes used for CNC materials. Steel and aluminum industries widely use it for high output and quality raw material strength. For instance, the latest technologies suggest productivity rates of over 10 meters per minute, thereby boosting large-scale production.

Every casting technique has its own merits and specific production requirements. With the help of progress in materials science, these approaches have evolved further, offering better accuracy, lesser wastage, and improved mechanical performance in metallic parts.

How do material selection factors affect CNC machining capabilities?

Hardness and machinability ratings

While comparing hardness and machinability scores, I look at how the properties of materials affect the efficiency and practicality of CNC machine operations. Harder materials, however, are tougher to cut than softer ones, thus needing special tooling and slower cutting speeds, though they offer excellent durability and wear resistance. That being said, materials with higher machinability ratings can be machined faster and more accurately, resulting in reduced tool wear and shorter production times. The key to successful outcomes in manufacturing is weighing these factors.

Thermal properties and heat resistance

The selection of materials for machining and manufacturing processes is highly dependent on their thermal properties, particularly in the case of high-temperature environments. Aluminum and copper are some examples of materials with a high thermal conductivity rate. In this regard, they would effectively prevent overheating during machining by dissipating heat faster. Despite these advantages, these materials have lower melting points and, therefore, might be limited when subjected to severe heat conditions.

On the other hand, another group of materials is represented by stainless steel or nickel-based alloys, which are known for their outstanding resistance to heat as they possess low thermal conductivity even at elevated temperatures. For example, nickel superalloys can withstand temperatures exceeding 1,000°C without any structural damage, hence best suited for aerospace and turbine applications.

The coefficient of Thermal Expansion (CTE) is another important consideration since there will be considerable dimensional changes amongst materials with high CTE if their temperature fluctuates, hence negatively impacting precision. For instance, titanium alloys with a moderate CTE also exhibit excellent heat resistance, making them stable but thermally efficient.

There should be appropriate heat management while using CNC machines because too much build-up of heat can result in tool wear or workpiece deformation. Manufacturers need to look at such aspects as conductance, the ability to speed up or slow down the movement of electricity through certain conducting substances; expansion capacity meaning the ability to change size; and stability property, indicating how well it resists physical reactions at different temperatures, including those induced by heating so that they obtain optimum performance and durability for both material and tools.

Chemical composition and reactivity

The CNC machinability of any material is significantly influenced by its chemical composition. The elements present in a material straightforwardly determine various properties like hardness, corrosion resistance, and workability, which matter in the selection of common materials for CNC projects. For example, stainless steel possesses a passive chromium oxide layer responsible for preventing corrosion due to iron, chromium (at least 10.5%), nickel, and carbon it contains.

Reactivity also matters, especially when working on metals such as aluminum and magnesium, which are highly prone to oxidation. Aluminum is highly reactive with oxygen, causing the formation of thin protective oxide surfaces, considerably improving its corrosion resistance. On the other hand, despite being lightweight and strong, magnesium is much more reactive than aluminum and can get ignited at high temperatures; thus, strict safety measures must be observed during machining.

Another crucial aspect to consider is the interaction of an alloy’s composition with cutting fluids and tooling materials. For instance, materials containing high sulfur content, such as free-machining steels, reduce friction and wear on tools, enhancing their machinability. In addition, titanium alloys are complex to machine because they possess impressive strength-to-weight ratios and superior heat resistance, yet their compositions usually consist of aluminum and vanadium.

The empirical data supports these observations. For example, aluminum alloys with 4% to 6% nickel content, such as alloy 2618, help strengthen the material for aerospace applications. On the other hand, increased hardness is standard in steel materials with high carbon content; however, this reduces machinability due to the material’s brittleness under stress. Knowing such compositional details allows engineers to choose materials that combine reactivity, machining quality, and performance for accurate CNC machining operations.

Are there any workarounds for machining complex materials?

Special tooling and coatings

Often, the machining of complex materials implies a need for specialized tooling and enhanced coating technologies to optimize the performance and reduce tool wear. Such tools made from carbide or cubic boron nitride (CBN) have good hardness and temperature resistance, which makes them suitable for processing superalloys and hardened steels in CNC lathe operations. Moreover, polycrystalline diamond (PCD) tooling works well for machining non-ferrous materials such as aluminum-lithium alloys since it maintains accuracy and strength at high-speed cutting.

The coatings also play a significant role in improving tool life and efficiency. Titanium aluminum nitride (TiAlN) coatings are examples of improved heat resistance and oxidation stability. They are preferable for fast material removal, such as on high-strength steels or heat-resistant alloys. Advanced research has also developed carbon coatings resembling diamonds that have fewer frictions, thus reducing heat generated while machines work on them during any machining process.

According to industrial applications data, hard coatings like TiAlN can lengthen tool life by as much as 800% for cutting titanium or nickel-based alloys. Again, when these tools are used alongside cooling or minimal oil for lubrication (MQL), stability increases, and heat stress during the process is reduced. Even under challenging materials, these new methods allow better machinability, but quality surface and high accuracy may be upheld.

Advanced cooling techniques

When machining heat-resistant materials, it is essential to employ advanced cooling techniques to improve performance. Improved machining is possible by ensuring that heat is dissipated correctly out of the workpiece to avoid any thermal deformation and maintain its mechanical properties. The following are the most commonly used methods for advanced cooling:

Flood Cooling

This refers to a traditional approach where a large amount of fluid is poured into the cutting area continuously. It can be effective when handling general machining requirements but may result in environmental issues and high coolant consumption.

Minimum Quantity Lubrication (MQL)

By MQL technology, very tiny amounts of coolant are delivered as fine mist in a controlled manner, hence significantly reducing fluid usage. While still maintaining tool life and surface quality, there has been a reduction in cutting temperatures by up to 30% compared with dry machining, according to some studies.

Cryogenic Cooling

This process employs cryogenic fluids such as liquid nitrogen (LN2) or carbon dioxide (CO2), which help reduce cutting temperatures immensely. Cryogenic cooling enhances tool life even up to 90% while enhancing surface integrity on materials like titanium alloys for example.

High-Pressure Cooling (HPC)

HPC is the acronym for high-pressure cooling systems, which direct in the cutting zone coolants at a pressure of more than 80 bars. This method is especially useful for chip removal and temperature reduction in the cutting area, and therefore, it works well with materials such as stainless steel and superalloys.

Internal Coolant Channels

Tools with a built-in coolant delivery system ensure that fluids are applied right on the edge of the cut. The internal cooling enhances machining stability, improving tool performance when drilling deep holes.

Air Cooling

Compressed air becomes a dry option for machined soft materials. When combined with high-speed machining, it facilitates chip evacuation while preventing oil contamination.

Manufacturers can achieve optimized machining efficiency, extended tool life, and improved sustainability across many applications by choosing these cooling techniques correctly.

Hybrid manufacturing approaches

Combining additive and subtractive operations in hybrid manufacturing exploits the best aspects of both techniques. Layer by layer, 3D printing, and other additive methods are employed to develop composite geometries; on the other hand, surfaces are refined with CNC machining, and dimensional accuracy is improved. This method is most effective in manufacturing complex parts, reducing material wastage, and minimizing production time. In most cases, aerospace, medical, and automotive industries use hybrid manufacturing because of its high customization rates for exceptional performance components efficiency.

What are common misconceptions about materials in CNC machining?

Assumptions about material compatibility

All materials are not created equal, and CNC machining is one of the most common misconceptions in all of manufacturing. Every material type, such as metal, plastic, or composites, has unique qualities that affect machinability. For instance, aluminum is favored for its easy cutting properties and thermal attributes while harder materials like titanium require specialized tools and techniques to minimize tool wear. Besides, there aren’t any materials that can be used for each type of machining process; material stiffness, heat resistance, and surface finish requirements must be thoroughly weighed so as to maximize results. It is vital to comprehend these dissimilarities when deciding on a particular application’s suitable material.

Overestimating machine capabilities

However, another common misconception in relation to CNC machining is that people tend to overestimate the capability of a machine by not knowing its limitations. As advanced as modern computer numerical control machines may be, they cannot handle every complex design or material challenge if not properly set-up and tooled especially where multi-materials are involved.

For instance, high-speed milling machines are designed for fast precision applications, but this can be limited due to factors such as vibration control, tool rigidity, and spindle power. Trying to roughen hard materials such as hardened steel or some composites at inappropriate speeds will result in broken tools or inaccurate cuts. According to research findings, machining harder alloys often requires cutting speeds as low as 30-50 Surface Feet per Minute (SFM) and adopting wear-resistant cutting tools such as carbide or ceramic grades.

Alternatively, there are restrictions on possible tolerances with 5-axis CNC machines because of work holding and machine accuracy, although they can handle complex geometries. Generally, CNC accuracy can range from ±0.001″ up to ±0.005″ however, for ultra-high precision requirements, some machines might have reached their limit without calibration adjustments or subsequent operations.

It is essential to understand these boundaries, both technical and operational. For instance, engineering approaches can be customized to suit the CNC system’s specific capabilities and select tools and parameters to optimize performance. At the same time, a machinist minimizes errors or inefficiencies.

Underestimating the importance of material properties

Ignoring the importance of material properties in CNC machining can result in significant difficulties in achieving precision, maintaining tool life, and optimizing workflow efficiency. Every material, whether it is metals, composites, or polymers, has its own features, such as hardness, tensile strength, thermal conductivity, and chemical stability, that directly affect machining performance and outcomes.

For example, titanium or hardened steel are among the metals with high hardness that require lower cutting speeds and more expensive tools like coated carbide or polycrystalline diamond (PCD) to avoid excessive tool wear. According to industry data, it takes cutting speeds between 40-120 meters per minute to machine titanium alloys and increased cutting edge pressures—making heat removal important for machining. Conversely, softer materials such as aluminum enable higher cutting speeds of 600 meters per minute, sometimes reducing cycle time.

Material properties also depend on thermal expansion. For instance, machining aluminum’s high thermal expansion rate requires accurate temperature control to maintain dimensional tolerances. On the other hand, materials like carbon fiber composites demonstrate anisotropy, meaning their machinability can change depending on cutting directions. Understanding their structure is essential to preventing defects such as delaminations.

Furthermore, machinability ratings provide a quantitative perspective on the behavior of materials concerning conventional processing operations. These ratings allow for comparison between other metals and a specific reference metal, such as free-cutting steel, rated 100%. In contrast, low-rated materials like stainless steel alloys (40%-60%) necessitate toolpath strategies and adjustments in cutting parameters.

By thoroughly assessing these and other material characteristics, engineers can anticipate possible challenges, optimize cutting parameters, and maintain alignment with design tolerances. Ignoring this combination of machining practices and materials science may lead to inefficiencies, compromised part qualities, and longer production times.

Frequently Asked Questions (FAQs)

Q: Which materials can’t be used in CNC machining?

A: Despite being versatile, some materials cannot be used in CNC machining due to their properties. These include very soft materials such as rubber or foam, highly poisonous ones like beryllium, and plastics that have low melting temperatures. Even more, the use of brittle materials and those that produce harmful fumes during machining is not advisable for CNC processes.

Q: Can you use PVC on a CNC machine?

A: As a rule of thumb, PVC is not recommended for computer numerical control (CNC) machining. Machining PVC is possible, but when cut at high speeds, it gives out toxic fumes, which pose serious health risks. Moreover, PVC might melt and stick to the cutting tools, which can damage the CNC milling machine or the lathe. That’s why alternative materials are usually preferred instead.

Q: What are the limitations of using polycarbonate in CNC machining?

A: However, polycarbonate’s application is limited when it comes to its use as a material for The first reason is its tendency to melt or deform when exposed to high temperatures resulting from high-speed machining. This will affect the precision and surface finish of machined parts especially if a laser cutter has cut it under numerical control (CNC) technology. Polycarbonate also cracks very easily, causing drilling holes of low quality and milled edges to be prone to cracks. It is important to machine polycarbonate with caution using appropriate cutting parameters so as to achieve good results in terms of quality of surface finish.

Q. Can CNC machining be done with materials that do not withstand high temperatures?

A. Using low melting point materials and those that deteriorate when subjected to high temperatures can be quite tough in CNC machining. Computer numerical control methods can easily make these types of materials melt, lose their shape, or vaporize due to heat generated during cutting processes. With some specialized cooling techniques and very low feed rates, however, specific low-temperature materials can sometimes be machined at acceptable levels; nevertheless, such efforts usually yield poor results and may damage the milling machine and its cutting tools. Normally, it is better to select materials that are able to resist heat produced while machines work on them during production (Bennett et al.).

Q: Are there any non-metallic materials that cannot be used in CNC machining?

A: Yes, a number of non-metallic materials are not appropriate for CNC machining. Several extremely soft materials like rubber or foam get distorted as cutting forces are applied, and some composites that delaminate when machined. Some types of fiberglass or carbon fiber may have hazardous dust or fumes, which sometimes need safety measures taken and might not be good for all CNC machines. When looking for non-metallic materials for CNC projects, always check the material’s properties and what kind of machining is needed because different inputs can significantly change the outcome.

Q: What materials should I choose for my CNC machining project?

A: Choosing materials for CNC machining entails considering several factors associated with the kind of material. These include desired properties of the end part such as toughness, wear resistance, or corrosion resistance; intended application like aerospace, automotive, or prototype; machinability; cost and the capability of your CNC milling machine or lathe. One also needs to consider the required tolerances and whether the material is compatible with post-processing treatments like heat treatment or surface finishing. In order to select the proper material for your particular CNC machining project, you should talk to experienced machinists or material specialists.

Reference Sources

1. RESEARCH PROGRESS TOWARDS MACHINING OF TITANIUM ALLOY BY USING CNC MILLING: A TECHNICAL REVIEW

• Authors: Mithun Kumar, P. S. Rao
• Publication Date: 2024-11-07
• Summary: The article reviews complications of machining titanium alloys that have been known for their high ratio of strength to weight as well as resistance to corrosion. Therefore, it is emphasized that frequent tool wear and the need for specific cutting tools and techniques make titanium alloys hard to machine.
• Methodology: The authors analyze machining variables such as cutting tool geometries, speeds, feed rates, and their effects on machining efficiency and tool life.

2. Title: The Effects of Assumptions in 3D Printing and Conditions in CNC Machining on the Mechanical Parameters of Some PET Material

• Authors: Krawulski P., Dyl T.
• Publication Date: 2023-03-01
• Summary: This paper assesses the mechanical characteristics of PET materials produced via 3D printing and CNC machines. It also investigates the limitations of machining some 3D-printed materials, particularly their strength and structural integrity.
• Methodology: The research aims to produce pieces through both 3D printing and CNC machining, which will be tested mechanically for comparing this way.

3. Title: A Full Analysis of Machining Parameters in the Turning of SS304 Using 0 °C Coolant in a CNC Machine

• Authors: Pravin Patil, P. Karande
• Publication Date: October 25, 2022
• Summary: This research presents an investigation into the machining properties of SS304 steel, which is well known for its strength and work-hardening nature. The author identifies some of the problems faced when machining this material, which include tool wear and the need for an effective coolant.
• Methodology: The authors performed experiments on a CNC lathe by changing parameters for machining performance influenced by coolant temperature.

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