High-speed machining

With advancements in spindle technology, control systems, and cooling techniques, machine tools are becoming faster and more precise.?This?allows for?faster?production rates without sacrificing part quality, particularly in industries like aerospace and automotive. The demand for both?speed?and precision in?machining?has never been higher. We delve into how?high-speed?machining?(HSM) techniques are helping industries with faster production without compromising on quality with the experts.

With technological advancements, the?geometries in the?composition of?aerospace and automotive sectors are getting?intricate.?As a result, the structural complexity of components has grown, driving higher material removal rates. This is directly linked to the increased speed at which these cuts are made.

In recent years, high-speed machining (HSM) has emerged as a game-changing strategy in machining technology. HSM is an innovative approach designed to maximise metal removal rates by employing elevated cutting speeds alongside swift feed rates, all while ensuring the superior quality of the finished components. HSM assists with crafting quick, light and low-pressure cuts.

High-speed machining extends the lifespan of equipment, as both the machine and cutting tool experience considerably less stress. The higher speed and feed rates used in the process allow for rapid material cutting, minimising heat transfer during operation. With this, we reduce shop emissions and shorten the turnaround time. HSM delivers more precise parts in less time while lowering machining costs. It gives shallow depths of cut and small radial depths (low chip thickness) to better the cutting speeds and feed rates to reach higher levels.?This?leads to reduced cutting forces, less heat buildup in the tool and workpiece, fewer burrs, and improved dimensional accuracy.

Sashikumar Menon, Director of?Gratias Solutions, shares that increased productivity without compromising quality is the most important factor. HSM enhances product quality because of its low cutting forces, low depth of cut, and low feet per tooth. This increases the?ease?of cutting, which naturally improves surface quality and cutting position. Vibrations and resistance can affect the surface finish, quality, and precision.

Technological advancements

A high-speed machine is a steady machine. These machines should have high RPMs. Software programming is another cutting tool.?Daniel Raravi, Director – Marketing & Strategic Initiatives, Mastercam India?shares,?“Innovations in machining have emerged through strategies that define how effective a cutting tool can?be based?on its intricate profiles. These strategies encompass software methodologies, machine tool controllers,?and?the physics and navigation of parts. The optimal operating speed, or?“sweet spot,”?for each machine?is determined?by the interplay of these factors. For instance, if I have machine A and die blocks for machines B and C, I cannot use the same set of cutting tools, strategies, or tool path methods across all these machines. If machine A has a spindle speed limitation of 6,000 RPM—common in older tool room machines—newer?ones?can operate between 10,000 to 20,000 RPM. In advanced tool room manufacturing, spindle speeds can reach 20,000 to 40,000 RPM, with feed rates increasing proportionally. This combination of factors ultimately establishes the optimal performance for each machine. For example, if a machine operates at 4,500 RPM, a typical feed rate might be between 2.2?to?2.3 meters per minute, depending on the material?being cut, the diameter of the cutting tool, and the type of operation?being performed. This blend of science and engineering helps balance?these variables, leading to successful high-speed machining outcomes.”

Micro and Nanoscale machining

Micromachining is a specialised area of manufacturing that includes processes such as lens production and the creation of highly detailed components like reflectors used in motorbikes, automotive parts, and small satellite components. This field focuses on manufacturing at the micrometre scale, involving precise processes and intricate details. Micromachining shares similarities with high-speed machining, but as the scale of the parts decreases, the complexity and precision requirements increase. The?materials?used also differ, with micromachining often involving specialised alloys, ceramics, and composites. For example, graphite machining for die moulds, particularly when intricately detailing the mould core or cavity components, can be considered micromachining.

Daniel Raravi shares an example: a?while back, Tyco Electronics reported issues with components that were off by two microns, equivalent to one-quarter the thickness of a human hair. Despite using high-quality machines and maintaining stable operations, the issue stemmed from a mismeasurement of the tool diameter. The company was measuring to two decimal places instead of three, resulting?in a two-micron error in the components. Unfortunately, many manufacturers overlook such critical details in micromachining, leading to rejections and failures due to mis-machining. While the principles of high-speed machining remain relevant, micromachining requires a significantly higher level of diligence and attention to detail to ensure precision and avoid costly mistakes.

Chip Management

Magesh Boopathy, Chief Manager – Training, Tata Indian Institute of Skills?shares,?“In the CTF machine centre, the configuration of the X-Y axis primarily impacts table movements rather than those of the spindle. High-speed machining and increased Material Removal Rate (MRR) can lead to significant chip accumulation. A key challenge is effectively removing these chips; they can hinder achieving a good surface finish if not cleared away properly. Therefore, effective chip management and design must be prioritised. Ideally, the focus should be on spindle movement rather than table movement. DMG Mori, for example, excels in designing machines with an advanced?‘C’?type configuration, where the axis movement is on the spindle side rather than beneath it, keeping the bottom fixed. This design helps minimise chip interference with axis movement. Chips?are expelled?using high-pressure coolant systems.”

Coolant plays a crucial role in chip removal by applying pressure to push chips away. The chip conveyor design and movement must?be tailored?to the?specific material. For instance, machining titanium—a challenging material—may require dual-chip conveyors to manage heat and chip flow. Continuous monitoring is essential to ensure chips?are transported?back to the collection bin, as any failure in chip evacuation can lead to issues with coolant dispersal across the work area.

Additionally, telescopic cover design can influence overall machine performance by protecting components from chips and coolant.?Spindle performance?is a factor in selecting the appropriate bearings, spindle design, and RPM control to enhance operational efficiency.?These design considerations contribute significantly to creating a reliable, high-speed machine with superior surface finishes.

High-speed machining misconception

High-speed machining?is often misunderstood, says Sashikumar Menon, as many people think?it’s?straightforward, but it is not. Synchronisation among different components is crucial. Your cutting tool must be in optimal condition—ideally in perfect working order. Regular maintenance of machines is essential to ensure clear and consistent operations, particularly verifying that all bearings are functioning?properly?to avoid vibration or tool misalignment.

Efficient chip evacuation is vital in high-speed machining. While breaking the chips is part of the process,?it’s?equally important to ensure?they are?cleared away from the cutting edge. Simply breaking the chips is insufficient; if they accumulate between the cutting edge and the workpiece, they can damage the surface finish and affect overall machining quality. Effective chip evacuation systems, such as high-pressure coolant or specialised chip conveyors, are critical for managing this process.

Due to its flammability, machining?magnesium poses significant challenges.?Special precautions must be taken, as water or traditional cutting oils cannot be used because they may exacerbate the fire risk. Dry machining or specialised coolants designed for magnesium are often employed, and cutting parameters must be carefully adapted to minimise heat generation.

A common misconception is that high-speed machining is easy. However, simply having a good machine and a high-quality cutting tool is?not sufficient. All components—including the machine, cutting tool, CAM software, and machining strategies—must work seamlessly together. For example,?strategies?for navigating corners must be carefully defined to avoid excessive tool wear or damage. Every element, from toolpath planning to material properties,?is crucial?in achieving optimal results.

Daniel Raravi says the?biggest barrier to high-speed machining is that many people believe they are experts in the field and assume it is easy.?However, it is not that simple; achieving success requires specialists, subject matter experts, and consultants with extensive knowledge. These professionals can mobilise teams and implement the right processes, which helps organisations achieve their manufacturing goals with lower costs, fewer hassles, and improved success while maintaining equipment.

Metal working fluid formulations

Technologies for micro and macro emulsions have improved significantly.?Natheem Shajahan, National Sales Manager, Molygraph Lubricants, shares that they?utilise a diverse range of products for metalworking fluids to achieve optimal results.?Metalworking fluids contain unique additive packages?sourced?from various countries, with raw material suppliers constantly conducting research and development.?They continually introduce new technologies and products aimed at enhancing bio-stability and flexibility.

Historically, chlorine was commonly used to prevent corrosion; however, its usage has diminished significantly, and now esters are being employed instead. The evolution of technology in metalworking fluids is progressing rapidly. We are currently at a stage where we have developed a comprehensive set of?R&D?capabilities, allowing us to create new products for emerging applications.

For instance, when machining magnesium alloys, which can react with water, we are developing specialised technologies to address this challenge. Magnesium alloys are poised to become prominent in the market, similar to how aluminium alloys like 6061?were widely used. It is important to note that alloys from the 6000 and 7000 series can react negatively with other metals.

High-speed machining evolution

The high-speed machine has been around for quite some time, dating back to around 2000. At that time, machines with high RPMs were not widely available or?popular. Sashikumar Menon shares,?“My first CNC machine operated at 2,000 RPM, whereas?today’s?machines can reach speeds between 20,000 and 60,000 RPM. There are significant opportunities in the market, especially among diamond companies investing in machines with RPMs between 13,000 and 15,000—this is a positive trend.”

The die and mould industry requires machines with higher RPMs to efficiently machine hardened dies. This helps?reduce costs associated with cubic boron nitride (CBN) tools and other materials, ultimately leading to faster production cycles. As a result, more people are shifting towards high RPM machines.

After additive manufacturing, finishing remains the only?indispensable machining process.?Controlled abrasive cutting (CAC) cannot be replaced, and finishing processes demand high-speed machinery to achieve optimal results.

High-speed machining is evolving alongside additive manufacturing, creating new possibilities for efficient and precise production. High-speed machining, a subtractive process, can now integrate additive technologies like Direct Energy Deposition (DED), paving the way for material optimisation. As these technologies become more affordable in the next three years, their adoption is expected to accelerate, especially with advancements in AI and machine learning.

In aerospace manufacturing, where weight reduction and material strength are critical, combining additive processes with high-speed machining enables simultaneous finishing and production. Innovative solutions integrate additive technologies to reduce cycle times and provide complete manufacturing solutions, eliminating the need for separate processes. This synergy marks a significant step forward in manufacturing efficiency and innovation.

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Sashikumar Menon , Director, Gratias Solutions

High-speed machining is a complex process that requires careful consideration of factors such as cutting tools, CAM software, and system design. High-speed machining is?important?for increasing productivity without compromising quality, as it enhances product quality through low cutting forces, depth of cut, and feet per tooth.

Daniel R. , Director – Marketing & Strategic Initiatives, Mastercam India

Innovations in cutting tool strategies have led to the development of intricate profiles, determining?cutting tool?dependability. The speed sweet spot for each machine is determined by?a?combination of factors such as software strategy, machine tool controller, physics, and?part navigation.

Magesh Boopathy , Chief Manager – Training, Tata Indian Institute of Skills

Effective chip management is crucial in high-speed machining, especially with increased material removal rates that result in significant chip accumulation. The focus should be on spindle movement rather than table movement to minimise chip interference during operation.

Natheem Sha , National Sales Manager, Molygraph Lubricants

The?right?coolant is necessary?as it removes and reduces?heat from chips and tool flow, creating a layer between the coolant and the workplace area.?It also leaves an extreme pressure property, working under extreme pressure and providing a surface finish to the workplace.

High-speed?machining| Mastercam India | Molygraph Lubricants | speed |

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