Because aluminum is considered by many to be cheap and easy to work with, it’s easy to fall into the trap of thinking any machining setup will work. However, some of the “easiest” materials to machine end up yielding the lowest profit margins at the end of the job, according to Tungaloy’s Frazier.

This avoids collisions, allows for easier programming and ensures demanding and highly precise geometric forms, such as those found on special inserts, can be machined in a single operation. Unlike dedicated insert grinders, the Rollomatic has the flexibility and ability to quickly change over to grinding cylindrical cutting tools within minutes; something that is not possible on dedicated machinery.

Angle of inclination between the face of the cutting tool and the workpiece. If the face of the tool lies in a plane through the axis of the workpiece, the tool is said to have a neutral, or zero, rake. If the inclination of the tool face makes the cutting edge more acute than when the rake angle is zero, the rake is positive. If the inclination of the tool face makes the cutting edge less acute or more blunt than when the rake angle is zero, the rake is negative.

Grooves and spaces in the body of a tool that permit chip removal from, and cutting-fluid application to, the point of cut.

“Usually, coatings are not applied to drills in aluminum applications, as a majority of coatings contain aluminum," he said. Because the majority of coatings contain aluminum as one of their base constituent elements, Frazier said some manufacturers have begun utilizing a titanium-zirconium-nitride coating in aluminum applications. “But the conventional wisdom in this field is to utilize a sharp, high-polished, uncoated carbide drill.”

This bushing adds more thread to the hole and gives the customer an alternative to current fastener methods like weld nuts or threaded inserts. Once the bushing is created, a form tap can create threads, or a self-threading screw can be inserted to complete the job. There are no chips created in either case.

Like all Rollomatic grinding machines, the 630XW comes with a three year parts and labour warranty that is provided at no additional cost, and also free of charge software and software updates for life.

Glendower Cutting Tools, a specialist insert manufacturer, has been located in Leicester since 1972 when Jim Doherty started the business with just a few manual grinding machines. Over the years the company has moved several times and is now located in a modern factory unit in Thurmaston and remains under family ownership with Jim Doherty’s daughter Cynthia Sanders, supported by Glendower’s management team headed up by his grandson Justin Sanders.

“The threshold for aluminum is something like 60,000 sfm, which is enormously fast,” he said. “I’ve seen aluminum run at 24,000 sfm with an uncoated carbide insert, and it didn’t harm the aluminum or the insert. I tell our customers that, within a safe working environment, don’t be afraid to crank it up because I’ve seen that higher speeds in aluminum gets you both better tool life and a better surface finish.”

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Thermal-friction drilling creates a hole and a bushing—but no chips—through the use of heat and pressure. Image courtesy Flowdrill.

However, with production rising to over 40,000 inserts per month it will not be long before the Rollomatic’s automatic part loader is used on larger batches of 1,000 inserts or more. Mr Chattaway states that the sixth axis on the Rollomatic allows him to create special forms that are not possible on machines with less axes. It facilitates one-hit production in a single set-up which saves a lot of time and brings higher accuracies than is possible when grinding special forms on two or three separate machines. The ability to quickly programme and then manufacture small batch work has significantly sped up lead-times through the shopfloor and work in progress on multiple machines.

Ability of a material to be bent, formed or stretched without rupturing. Measured by elongation or reduction of area in a tensile test or by other means.

Self-guided drill for producing deep holes with good accuracy and fine surface finish. Has coolant passages that deliver coolant to the tool/workpiece interface at high pressure.

Evan Jones Thorne, who served as associate editor of Cutting Tool Engineering magazine through February 2017, holds a bachelor’s degree in English and communications from Northern Illinois University. Evan joined Cutting Tool Engineering in October 2013.

Proper chip evacuation involves proper application of coolant, and drilling aluminum is no exception. Pecking is always an option, but many part manufacturers like to avoid withdrawing the drill when possible, which means polished flutes and through-coolant drills are the order of the day.

Fluid that reduces temperature buildup at the tool/workpiece interface during machining. Normally takes the form of a liquid such as soluble or chemical mixtures (semisynthetic, synthetic) but can be pressurized air or other gas. Because of water’s ability to absorb great quantities of heat, it is widely used as a coolant and vehicle for various cutting compounds, with the water-to-compound ratio varying with the machining task. See cutting fluid; semisynthetic cutting fluid; soluble-oil cutting fluid; synthetic cutting fluid.

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Sandvik Coromant’s Hout has observed at least one characteristic unique to aluminum when deep-hole drilling. “When using self-guided drills like gundrills, because of the plasticity of aluminum, the guide path pressure can impact the finish of the hole either positively or negatively, depending on the lubricity of the coolant,” he said. Neat cutting oil typically results in a smooth finish, while a synthetic, water-based fluid might allow some of the aluminum to stick to the guide path, creating a rough, “smeared” finish.

Hardness is a measure of the resistance of a material to surface indentation or abrasion. There is no absolute scale for hardness. In order to express hardness quantitatively, each type of test has its own scale, which defines hardness. Indentation hardness obtained through static methods is measured by Brinell, Rockwell, Vickers and Knoop tests. Hardness without indentation is measured by a dynamic method, known as the Scleroscope test.

“Generally, drills with a high helix angle, polished flutes and 130° to 140° point angle will provide the best chip evacuation and cutting performance,” Frazier said. “However, since aluminum is so soft, drilling operations using the aforementioned geometry tend to present difficulties in maintaining proper hole diameter and sidewall surface finish. If maintaining hole size, finish and hole roundness are the goals, using a straight-flute, through-coolant drill is advantageous.”

Cylindrical tool that cuts internal threads and has flutes to remove chips and carry tapping fluid to the point of cut. Normally used on a drill press or tapping machine but also may be operated manually. See tapping.

Glendower’s philosophy is to have complete in-house control over all manufacturing processes and that extends, for example, to pressing and sintering carbide inserts with its own 12.5 ton insert press and vacuum furnace. Even the dies and punches that are needed are designed and manufactured in-house.

Frazier added built-up edge to the list of primary challenges when drilling aluminum alloys. The aluminum will build up and adhere to the cutting edge and interfere with the formation of new chips from the parent material, which can lead to chip packing, as flutes become clogged. This leads to deposits of aluminum adhering to the drill, promoting even further adhesion and chip packing.

Substances having metallic properties and being composed of two or more chemical elements of which at least one is a metal.

The guide path pressure of a gundrill can impact surface finish, depending on coolant lubricity, due to the inherent plasticity of aluminum. Image courtesy Sandvik Coromant.

Aluminum containing specified quantities of alloying elements added to obtain the necessary mechanical and physical properties. Aluminum alloys are divided into two categories: wrought compositions and casting compositions. Some compositions may contain up to 10 alloying elements, but only one or two are the main alloying elements, such as copper, manganese, silicon, magnesium, zinc or tin.

When drilling, perhaps no variable is as important as the workpiece material. It dictates drill geometry and substrate, tool coating, coolant application, and speeds and feeds.

“Unlike our other bits, it doesn’t require our special lubricant; it can operate with standard machine coolant,” Ray said. “It also countersinks a chamfer into the material, which makes it the only one of our bits that generates a chip.”

On a standard Flowdrill bit, a polygon is ground, consisting of four peaks and four valleys, each referred to as “lobes,” which are what generate the friction and cause the heat. The Aludrill eschews this geometry in favor of more contact with the metal, which creates enough friction in the softer aluminum to generate sufficient heat.

“Chips tend to ‘string out’ because of the softness of the material,” Lynch explained. “The primary way to get around that is through geometry.” AMEC offers an aluminum-specific geometry for its TA product line, which has a high rake angle that effectively forms a chip in gummier, 6061-type materials, he said. A higher rake creates more shear in the cut and forces the material into the impact site on the tool.

“We had a customer who needed to drill 3,000 holes in a plate of aluminum, and if they broke a drill machining one hole, the whole part was scrap,” said John Lombardi, company president. “So they came to us with the problem, and we made a 0.156"-dia. drill with a ½" base about 3" long for the job.” R.I. Carbide used the ZETA coating on the drill, and by running that highly lubricious drill with through-coolant capability at high speeds, the customer was able to successfully complete the part on the first pass.

“Thermal-friction drilling is a process that involves generating heat through friction and pressure,” said Mitch Ray, president of Flowdrill. “We create what we refer to as a bushing in thin-walled material, which extends approximately three to four times the original wall thickness.”

Liquid used to improve workpiece machinability, enhance tool life, flush out chips and machining debris, and cool the workpiece and tool. Three basic types are: straight oils; soluble oils, which emulsify in water; and synthetic fluids, which are water-based chemical solutions having no oil. See coolant; semisynthetic cutting fluid; soluble-oil cutting fluid; synthetic cutting fluid.

Drilling involves generating chips. It’s just a given—after all, the material that’s removed has to go somewhere, right? But while a process that doesn’t generate chips might not sound like drilling to some, St. Louis-based thermal-friction-drilling specialist Flowdrill Inc. offers an alternative to traditional drilling.

While North Americans know it as “aluminum,” most English-speaking countries use the suffix “-ium.” The Canadian Oxford Dictionary lists the spelling as “aluminum,” while the Australian Macquarie Dictionary prefers “aluminium.” The reason?

A South West-based engineering team is aiming to transform the large-format additive manufacturing sector with the launch of its latest product.

At the Polish plant of White, a leading manufacturer of orbital motors and steering solutions, an S110 internal cylindrical grinding machine from Studer has recently been contributing to efficient production.

“If more shops are able to do the work on ‘easy’ materials, there is more competition for those same jobs, inevitably driving down the price of cutting aluminum,” he said. “In this sense, it is important to maximize your speed and efficiency when working with these materials, using updated tooling and advanced concepts, in order to stay competitive.”

Glendower Cutting Tools, which recently celebrated its 50th anniversary, has recently invested in a Rollomatic 630XW 6-axis CNC tool grinding machine that is now busy boosting the production of cutting tool inserts. PES reports.

While known for its relative softness and ductility, misconceptions abound among those who regularly drill aluminum.

Cutting tool material consisting of natural or synthetic diamond crystals bonded together under high pressure at elevated temperatures. PCD is available as a tip brazed to a carbide insert carrier. Used for machining nonferrous alloys and nonmetallic materials at high cutting speeds.

The ultra-efficient synchronous grinding spindle motor provides constant rotation speed and torque regardless of the load on the motor and this, combined with the latest linear motor technology, provides benefits such as an enhanced surface finish.

Today Glendower is exporting inserts to businesses in countries such as Taiwan which, although far from being short of having many local insert manufacturers of its own, prefer to keep coming back to Glendower for the special geometry and high quality of inserts that it can provide. The investment in the Rollomatic grinding machine will further enable Glendower to manufacture inserts that others simply cannot do.

Dave Chattaway, Glendower’s chief engineer, who joined Glendower some 47 years ago, is especially pleased with the introduction of the latest grinding technology in terms of enhanced insert production. He welcomes the ability to programme all special insert geometry from his office; the machine is currently busy producing special inserts in low batches of 10s, 20s and 30s.

Every tool bit diameter has a certain set of parameters, Ray explained. For example, a ¼-20 thread size would require a tool to be run at 2,400 rpm in aluminum or mild steel, require 1.5 hp and have a cycle time of about 3 seconds per hole. The bit contacts the material, and the friction of that contact heats the material while the pressure behind the bit pushes through the material and forms the bushing. There is no external heat source, and Flowdrill bits can be used on any standard CNC machine without any special adapters.

“Glendower is competing head on with anyone globally when it comes to the manufacture of cutting tool inserts as it exports worldwide into other markets itself. There are many considerations that need to be understood when offering grinding solutions for inserts; not only does the software need to be extremely powerful and versatile to cope with the huge variety of forms, but the clamping of inserts can also be challenging.

While offering a vast array of standard inserts and tooling, Glendower also manufactures its own special inserts. From the initial design concept to final product, great attention is paid to manufacturing special inserts to the finest possible qualities.

Hundreds of British manufacturing companies opened their doors in a UK-wide open house today as part of National Manufacturing Day, giving their local communities the chance to see the highly paid careers and jobs on offer in our exciting and diverse sector.

“Especially when you go to longer depths, the issue is always coolant flow for chip evacuation, and that’s not anything unique to aluminum,” noted AMEC’s Lynch. “We prefer not to peck, and I feel that if people have to do any pecking, it’s probably because they’re not forming a good chip. We’ve actually found that the type of cutting fluid is less important than the concentration—the higher the concentration, the better your results, generally speaking.”

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While there are many different aluminum alloys with unique machinability characteristics, Frazier said the most widely drilled aluminum alloys are 6061 and 7075, adding that there are pockets of aerospace and medical work that use specialty alloys exclusively.

Included angle at the point of a twist drill or similar tool; for general-purpose tools, the point angle is typically 118°.

Coalville, Leicestershire-based CMS Cepcor is a leading supplier of aftermarket crusher spares, manganese-steel wear liners and other equipment for the mining, aggregate production and associated industries worldwide.

For grinding Glendower’s inserts, the machine was specified with the optional retractable grinding wheel dressing unit with an in-built Dittel acoustic sensor. The machine is also equipped with a touch probe that determines the exact location of the insert blank after clamping so that the software can grind the tool geometry according to the virtual centreline of the blank which ensures a run-out of just 2µm can easily be achieved.

Microprocessor-based controller dedicated to a machine tool that permits the creation or modification of parts. Programmed numerical control activates the machine’s servos and spindle drives and controls the various machining operations. See DNC, direct numerical control; NC, numerical control.

Using a straight-flute, through-coolant drill is advantageous if maintaining hole size, finish and hole roundness is the goal. Image courtesy Tungaloy.

Use of cutting fluids of only a minute amount—typically at a flow rate of 50 to 500 ml/hr.—which is about three to four orders of magnitude lower than the amount commonly used in flood cooling. The concept addresses the issues of environmental intrusiveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. The minimization of cutting fluid also saves lubricant costs and the cleaning cycle time for workpieces, tooling and machines. Sometimes referred to as “near-dry lubrication” or “microlubrication.”

At the GrindingHub 2024 exhibition, German tool sharpening specialist Vollmer launched its new Filtration System 400 (VFS 400).

One such manufacturer is R.I. Carbide, a tool grinder and machine shop in Smithfield, R.I., that offers its ZETA ZrN coating as an alternative to TiN when extra lubricity is needed.

How high can those cutting speeds be? According to Hout, modern machinery has not yet advanced to the point where the surface speed ceiling for aluminum can be hit.

Running at high cutting speeds while resisting the temptation to overfeed and applying a coolant with high lubricity and moderate-to-low viscosity is the best way to ensure a fine surface finish, Hout said. “You want the oil to move fast.”

At the Polish plant of White, a leading manufacturer of orbital motors and steering solutions, an S110 internal cylindrical grinding machine from Studer has recently been contributing to efficient production.

However, a sharp edge is a weak edge, and many aluminum grades contain high levels of silica—a hard, glass-like particulate in the matrix of the aluminum that can rapidly break down a tool’s edge. “Wear [from silica] can sometimes be combatted with coatings or by switching from carbide to a superabrasive tool material like PCD,” Hout said.

“In 1926, the American Chemical Society officially decided to use aluminum in its publications; American dictionaries typically label the spelling aluminium as ‘chiefly British,’” explained Tungaloy America Inc.’s Elliott Frazier. “The earliest citation given in the Oxford English Dictionary for any word used as a name for this element is alumium, which British chemist and inventor Humphry Davy employed in 1808 for the metal he was trying to isolate electrolytically from the mineral alumina.

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Staff retention has always been very important to Glendower and most of those working there are very long serving and highly skilled employees who are able to master many different processes including pressing, sintering, brazing, milling, lapping, and of course grinding on a variety of 3-axis, 4-axis and now, with the introduction of the Rollomatic, 6-axis CNC tool grinding machines.

Tungaloy’s Frazier always recommends through-coolant. “Higher metal-removal rates require [applying] a lot of coolant, very quickly, to move the chips from the cutting zone, and mrr is typically very high in aluminum.” Flood coolant would require peck cycles, and minimum-quantity lubrication simply doesn’t have the displacement value when holemaking, especially drilling deep holes, he said. “The higher the flow, and higher the pressure, the better.”

The United Grinding Group will exhibit four machines this year from its cylindrical grinding, surface and profile, and tool machining technology groups at BI-MU in Milan, as well as a selection of its Digital Solutions products.

Glendower Cutting Tools, which recently celebrated its 50th anniversary, has recently invested in a Rollomatic 630XW 6-axis CNC tool grinding machine that is now busy boosting the production of cutting tool inserts. PES reports. Glendower Cutting Tools, a specialist insert manufacturer, has been located in Leicester since 1972 when Jim Doherty started the business with just a few manual grinding machines. Over the years the company has moved several times and is now located in a modern factory unit in Thurmaston and remains under family ownership with Jim Doherty’s daughter Cynthia Sanders, supported by Glendower’s management team headed up by his grandson Justin Sanders. While offering a vast array of standard inserts and tooling, Glendower also manufactures its own special inserts. From the initial design concept to final product, great attention is paid to manufacturing special inserts to the finest possible qualities. Glendower’s philosophy is to have complete in-house control over all manufacturing processes and that extends, for example, to pressing and sintering carbide inserts with its own 12.5 ton insert press and vacuum furnace. Even the dies and punches that are needed are designed and manufactured in-house.  Staff retention has always been very important to Glendower and most of those working there are very long serving and highly skilled employees who are able to master many different processes including pressing, sintering, brazing, milling, lapping, and of course grinding on a variety of 3-axis, 4-axis and now, with the introduction of the Rollomatic, 6-axis CNC tool grinding machines. Inserts ground on the Rollomatic 630XW Six axes and single setups Dave Chattaway, Glendower’s chief engineer, who joined Glendower some 47 years ago, is especially pleased with the introduction of the latest grinding technology in terms of enhanced insert production. He welcomes the ability to programme all special insert geometry from his office; the machine is currently busy producing special inserts in low batches of 10s, 20s and 30s. However, with production rising to over 40,000 inserts per month it will not be long before the Rollomatic’s automatic part loader is used on larger batches of 1,000 inserts or more. Mr Chattaway states that the sixth axis on the Rollomatic allows him to create special forms that are not possible on machines with less axes. It facilitates one-hit production in a single set-up which saves a lot of time and brings higher accuracies than is possible when grinding special forms on two or three separate machines. The ability to quickly programme and then manufacture small batch work has significantly sped up lead-times through the shopfloor and work in progress on multiple machines. Today Glendower is exporting inserts to businesses in countries such as Taiwan which, although far from being short of having many local insert manufacturers of its own, prefer to keep coming back to Glendower for the special geometry and high quality of inserts that it can provide. The investment in the Rollomatic grinding machine will further enable Glendower to manufacture inserts that others simply cannot do. The Rollomatic 630XW is designed for grinding many kinds of cutting tools with more complex geometry where its additional sixth A-axis, said to be unique within the industry, provides improved accuracy on ball nose end mills or corner radii with a possibility to incline the grinding wheels by up to 45°. This avoids collisions, allows for easier programming and ensures demanding and highly precise geometric forms, such as those found on special inserts, can be machined in a single operation. Unlike dedicated insert grinders, the Rollomatic has the flexibility and ability to quickly change over to grinding cylindrical cutting tools within minutes; something that is not possible on dedicated machinery. The machine has a general working range of grinding tools from 0.1mm to 20mm in diameter, (3.9mm to 25.4mm inscribed circle (IC) diameter on inserts), has a high-speed multi-pallet pick and place loader with positions for up to 1,360 tools as standard, and, also as standard, a six position grinding wheel changer holding up to 24 wheels. The ultra-efficient synchronous grinding spindle motor provides constant rotation speed and torque regardless of the load on the motor and this, combined with the latest linear motor technology, provides benefits such as an enhanced surface finish. For grinding Glendower’s inserts, the machine was specified with the optional retractable grinding wheel dressing unit with an in-built Dittel acoustic sensor. The machine is also equipped with a touch probe that determines the exact location of the insert blank after clamping so that the software can grind the tool geometry according to the virtual centreline of the blank which ensures a run-out of just 2µm can easily be achieved. Quick change clamping devices for insert manufacture Additional benefits Like all Rollomatic grinding machines, the 630XW comes with a three year parts and labour warranty that is provided at no additional cost, and also free of charge software and software updates for life. Chris Boraston, managing director at Advanced Grinding Solutions, the agent for Rollomatic in the UK and Eire comments: “Cutting tool inserts are not easy to grind. There is an almost infinite number of different and ever more complex forms to deal with. Many have very tight tolerances with ultra small radii and a requirement for fine mirror-like surface finishes. “In the UK you can count the number of dedicated insert manufacturers on one hand and insert grinding is very much a highly specialised field with the majority of UK companies buying these tools in from overseas. “Glendower is competing head on with anyone globally when it comes to the manufacture of cutting tool inserts as it exports worldwide into other markets itself. There are many considerations that need to be understood when offering grinding solutions for inserts; not only does the software need to be extremely powerful and versatile to cope with the huge variety of forms, but the clamping of inserts can also be challenging. “Rollomatic has developed really excellent clamping devices for all types of inserts including beak type jaws for holding dog bone form inserts, a claw clamping device for milling inserts, a flat clamping system for profiled inserts and a cylindrical arbor holder for holding inserts that have a hole in the centre,” he adds. “Glendower needed all of these holding devices and challenged Rollomatic at every level during the test and trial phase when Rollomatic successfully ground a number of different inserts for their approval. We all very much enjoyed the challenge and working with Glendower to help make this investment in the latest grinding technology the success that its being proven to be.” Advanced Grinding Solutionswww.advancedgrindingsolutions.co.uk Glendower Cutting Toolswww.glendower.co.uk

The machine has a general working range of grinding tools from 0.1mm to 20mm in diameter, (3.9mm to 25.4mm inscribed circle (IC) diameter on inserts), has a high-speed multi-pallet pick and place loader with positions for up to 1,360 tools as standard, and, also as standard, a six position grinding wheel changer holding up to 24 wheels.

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“In the UK you can count the number of dedicated insert manufacturers on one hand and insert grinding is very much a highly specialised field with the majority of UK companies buying these tools in from overseas.

“Essentially, the British thought ‘aluminium’ sounded more classical and scientific, so they added the extra letter.”

“Rollomatic has developed really excellent clamping devices for all types of inserts including beak type jaws for holding dog bone form inserts, a claw clamping device for milling inserts, a flat clamping system for profiled inserts and a cylindrical arbor holder for holding inserts that have a hole in the centre,” he adds.

The Rollomatic 630XW is designed for grinding many kinds of cutting tools with more complex geometry where its additional sixth A-axis, said to be unique within the industry, provides improved accuracy on ball nose end mills or corner radii with a possibility to incline the grinding wheels by up to 45°.

Measure of the relative efficiency with which a cutting fluid or lubricant reduces friction between surfaces.

Substance used for grinding, honing, lapping, superfinishing and polishing. Examples include garnet, emery, corundum, silicon carbide, cubic boron nitride and diamond in various grit sizes.

The two main issues when drilling aluminum, explained Chad Lynch, field sales engineer for Allied Machine & Engineering Corp. (AMEC), Dover, Ohio, are chip formation and chip evacuation. “If you approach it without the proper tool geometry, without the proper coating, without the proper coolant, it can very quickly turn into a situation where long, stringy chips are wrapping themselves around the tool.”

“Aluminum is considered by many to be one of the easiest machining materials, but it does present its own unique challenges”—particularly when drilling, explained Elliott Frazier, a product manager at Tungaloy America Inc., Arlington Heights, Ill. “Aluminum is a generally soft, nonferrous, ductile material with low density and naturally high resistance to corrosion. Aluminum is difficult to drill because its ductility and softness causes the material to make constant prolonged contact with the rake face, or cutting edges, of a drill.”

The main difference between drilling aluminum and harder materials, noted Jason Hout, global DHM (deep hole machining) product and application specialist for Sandvik Coromant Co., Fair Lawn, N.J., is that the shear point of aluminum is low enough that it can be sliced by the tool’s cutting edge, as opposed to being pushed out  of the way when machining harder materials. This means an upright, high shear angle with a minimal edge hone is ideal for drilling aluminum.

Cylindrical sleeve, typically made from high-grade tool steel, inserted into a jig fixture to guide cutting tools. There are three main types: renewable, used in liners that in turn are installed in the jig; press-fit, installed directly in the jig for short production runs; and liner (or master), installed permanently in a jig to receive renewable bushing.

At the GrindingHub 2024 exhibition, German tool sharpening specialist Vollmer launched its new Filtration System 400 (VFS 400).

“We’ve got some large applications for the Aludrill," Ray said. "Last year, it was used on the new Ford F150 pickup, making holes in the front aprons of those trucks. They use a self-tapping screw to attach the different wiring lines to the front of the trucks."

Chris Boraston, managing director at Advanced Grinding Solutions, the agent for Rollomatic in the UK and Eire comments: “Cutting tool inserts are not easy to grind. There is an almost infinite number of different and ever more complex forms to deal with. Many have very tight tolerances with ultra small radii and a requirement for fine mirror-like surface finishes.

The United Grinding Group will exhibit four machines this year from its cylindrical grinding, surface and profile, and tool machining technology groups at BI-MU in Milan, as well as a selection of its Digital Solutions products.

When applying a carbide tool, it’s important that it doesn’t have an aluminum-based coating, because the aluminum will tend to stick to the workpiece surface, he added. Common coatings such as Al2O3 or AlTiN, when brought into contact with aluminum under heat and pressure, will not only react with the part, but have abrasive properties that can contribute to BUE. Instead, Hout recommends either titanium diboride or an amorphous diamond film.

1. Permanently damaging a metal by heating to cause either incipient melting or intergranular oxidation. 2. In grinding, getting the workpiece hot enough to cause discoloration or to change the microstructure by tempering or hardening.

If those aren’t available, uncoated carbide with a polished surface provides more-than-adequate performance in most applications, Hout noted. “You want the flutes polished to help material slide out, and if there is a radius within the flute, you don’t want a square edge or a straight wall unless it’s unavoidable [such as when gundrilling].”

“Glendower needed all of these holding devices and challenged Rollomatic at every level during the test and trial phase when Rollomatic successfully ground a number of different inserts for their approval. We all very much enjoyed the challenge and working with Glendower to help make this investment in the latest grinding technology the success that its being proven to be.”

Frazier recommends a micrograin carbide with a hardness from 92 to 93 HRA for low-silicon alloys, but said some aluminum alloys used for forgings or castings contain more than 11 percent silicon and are best approached with drills tipped with PCD or diamond-like carbon.

Added to titanium-carbide tooling to permit machining of hard metals at high speeds. Also used as a tool coating. See coated tools.

1. Permanently damaging a metal by heating to cause either incipient melting or intergranular oxidation. 2. In grinding, getting the workpiece hot enough to cause discoloration or to change the microstructure by tempering or hardening.