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.

Manufacturers built their formulas into carbide drills, according to Steve Pilger, senior application engineer for threading and holemaking at YG-1 USA, Vernon Hills, Ill. “Let’s say we’re cutting a carbon steel; we have a carbon steel drill that has a fixed geometry, flute and chip removal system, coolant holes of a specific size, and a specific grade of carbide with a nano-thickness, multi-layer coating on it that works best for that specific material. So, it’s not like one drill does all.”

Blandon said manufacturers vary their drills’ flute construction and point geometry to match specific materials.

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.

With longer drills, said Hobbs, predrilling the hole is an unavoidable and necessary process to prevent breaking the longer drill. The process for longer drills also requires special attention to the longer drill entering the hole at slower speeds and feeds, as well as not turning the through-coolant on until the drill is in the hole and ready to drill. At this time, the proper cutting data and coolant can then be applied.

Emuge’s Blandon urged regular maintenance. “Machining center spindles must be properly maintained to reduce or eliminate runout at the drill point,” he said. “If the spindle is dirty or worn, the drill will rotate unevenly. This can lead to uneven loading at the drill point, which can cause chipping on the cutting edges and drill failure. The best holder technology for drilling today is normally a hydraulic chuck or an Emuge FPC mechanical sleeve design,” Blandon stated.

Sandvik Coromant’s Hobbs said inserted core drills such as his company’s CoroDrill 880 and CoroDrill 881 offer the ability to change the geometry and coating grades that help to break chips. By their nature, core drills produce a harmonic vibration that is helpful in breaking chips. These harmonic vibrations are at times not enough, and long or unbroken chips can still occur.

Where it is appropriate to decrease speeds and feeds is with cross-holes, Pilger said. When the drill is approaching the second solid portion, reduce the speed and feed by 50 percent and re-engage the hole. This gives the drill a moment to make a footprint and get engaged. Then crank the speed and feed back up.

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.

Proper drill selection, the geometry built into the drills themselves, applying proper drilling parameters, and a few tips and tricks from the pros can address nagging drilling problems such as drill breakage, unbroken chips, tool runout, poor hole edges, and poor tool life.

Blandon went on to suggest a checklist of possible reasons for problems if the right tool is already on the job. Surface coatings, geometry, and application parameters are on his list, but so are other influential factors.

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.

“The further the drill tip is from the toolholder, the more damage to the drill tip and the greater the effect on hole quality is had by a drill that runs out of round,” Hobbs said.

Walter USA LLC, Waukesha, Wis., has different technologies to combat tool breakage, including newergrades of coatings, including its own TiSiAlCrN/AlTiN coating to resist wear, said Sarang Garud, marketing product manager. Walter offers full coating and point coating on its drills.

“Similar technology exists for aluminum drills as well,” Garud said. “Our DC170 drills have radial margins that help produce excellent finish on the holes. Adding extra ground margins (four instead of two) can also have significant improvement effect on the hole 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.

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.

“For carbon steel, we recommend our carbon steel drill, or our Dream Drill general; for 304 stainless, we recommend the Inox version of our Dream Drill,” he said. “Each one of these drills has the proper geometry and coatings to best deal with those materials and those applications.”

Garud said Walter’s DC170, with its unique combination of radial margins, coolant channels and solid-carbide mass directly behind the cutting edge, helps extend its life by effectively dissipating even extreme temperatures.

“Otherwise, you might hear a chatter, or break a drill, or you’ll see it’s walking,” he said. “What’s happening is you’re getting a mismatch because you’re hitting an uneven surface and you’re trying to minimize that mismatch.”

“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.

To control burrs, reduce the feed by 50 percent until the margins are engaged. Exit burrs are a little trickier but can also be improved by reducing the feed by 50 percent when the drill is 0.5 mm from the exit.

This runout results in one side of the drill cutting more than the other. When this occurs, not only does the drill cut and wear more on that side, but hole quality diminishes as a result of the drill wanting to walk off center and scar the side walls of the hole.

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.

Sandvik Coromant’s Hobbs agreed the method used to hold drills is critical to the performance of the drill and to tool life. How securely a drill is held has a direct effect on hole quality, such as roundness and surface finish, and on tool life. Weaker toolholding methods allow for more runout at the tip of the drill.

“High-performance carbide drills are the best option for high production lot sizes or higher quality hole requirements,” he said. “They are more expensive but typically have flute and point construction designed to curl and snap chips into manageable sizes that can be efficiently evacuated away from the cutting edge.”

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.

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Drill makers also use the geometry of the cutting edge to their advantage. A traditional chip breaker on a high-speed steel drill has a series of small notches ground on the cutting edge, which creates discontinuous chip formations, Blandon said. This, however, is not a practical design for a drill with a carbide substrate due to the brittleness of the material in comparison to high-speed steel.

There is a time when you want to speed up. “In drilling, a very common way to improve your chip is to adjust one of the parameters on your machine,” Pilger said. “So, when you’re having chip issues and you want to get a better chip, you slightly increase the feed in steel [0.008-0.014 ipr or 0.2-0.36 mm/rev].”

“Tool selection will greatly influence tool life,” he said. “High-speed steel drills are a low-cost solution but rarely the best option. High-speed cobalt drills will operate more effectively in elevated temperature applications, but tool life and performance cannot compete with carbide drills. While carbide drills will normally be the best option, many tool geometry and surface treatment options should be considered.”

Paramount, though, is using the right tool. “Drills break for many reasons, ranging from using improper cutting data to just using the wrong drill for the job at hand,” said Martin Hobbs, product specialist for drilling and milling, USA-West, for Sandvik Coromant, Fair Lawn, N.J. “New technologies will help; however, nothing extends tool life more than using the proper tooling setup and application.”

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.

“Some newer carbide HP drills that are designed for deeper hole applications now have reverse web taper where the web is actually smaller in the rear than it is at the point,” he said. “This provides the maximum amount of chip space within the flute.”

The web geometry of a drill is also very important when it comes to chip evacuation, said Blandon. The web or core of the drill should be constant or parallel from the drill point to the rear of the flute. High-speed steel drills typically have an increasing web taper which reduces the flute space towards the shank. This restricts chip flow out of the flute.

But if you want to step it up a little bit, eliminate runout, and hold the drill better, there are a couple of options. One is a shrink fit holder and the other is a collet chuck with hydraulic pressure. These two systems grip much more of the shank. In fact, university studies have shown that holding this way improves the runout by about 50 percent and improves tool life by 20-25 percent.

The method used for holding a drill becomes more critical the longer the drill becomes. Long drills that are 10, 15, 20, 30 and 40 times diameter should never be held in any type of holder that is not absolutely rigid, Hobbs added.

“Horn’s DDM and DDP system are an example of tailoring the drill point to the application,” said Tonne. “The DDM system works well in difficult alloys like titanium and nickel, but may not be the best choice for iron. Consult the drill supplier for the best recommendation.”

“Assuming that the cutting tool is manufactured to the highest quality standards, the tool life should be consistent from one tool to the next when it is used in the same material and application,” Blandon said. “If tool life is inconsistent, then the issue lies with either the consistency of the machined part material, the wear within the machine tool spindle, toolholder rigidity, the piece part fixturing or the coolant application.”

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.

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“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.”

Proper drilling parameters, including speed and feed rates, can make a difference in drill breakage, chip evacuation, hole burrs, and surface finish.

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At times, program interruptions in the feed motion can help break up chips or, in extreme cases, a pecking cycle may solve the problem, said Walter’s Garud.

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.

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.

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.

Manufacturers have taken the guesswork out of many of the processes that shops used to have to figure out for themselves when selecting the right drill for cutting different materials—a carbon steel, for example, versus aluminum or stainless steel.

Pilger at YG-1 has noticed that when customers start using carbide drills, they often look at the speeds and feeds in the catalog, which seem really high, so they reduce the speed. As a result, the drill runs too slow and does not generate enough heat. Then the material adheres to the drill and flakes off, taking off the coating and carbide with it. Eventually, the drill loses size and breaks.

Drill makers also use geometry to make their products material specific, and to aid in chip evacuation, improving surface finish, extending tool life and preventing drill breakage.

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

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.

Higher feed rates are often used to break a chip by making the chip thicker and more prone to break. There are cases where it can be better to increase the surface footage and decrease the feed rate in order to break a chip, Hobbs said.

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°.

“Heat shrink and hydraulic toolholders, such as Sandvik Coromant’s CoroChuck 930, provide the most stable drill holding and when compared to methods such as ER collets, may even double tool life,” he said.

The company’s DDP type tools are most suited for unalloyed steels, cast steel and alloyed steels with a tensile strength of up to 1,000 N/mm2. They, too, have internal cooling, although there is a variant suitable for flood coolant.

A solid-carbide drill, the Dream Drill, has a strong geometry for making a chip in steel. “It’s going to be completely different when you drill that same hole in stainless steel,” Pilger said. “So it has a geometry to give a better chip. It has a little hook design to help get that chip into the flute a little more precisely.”

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.

“Your holder choice is really important when you get into high production environments like the auto industry,” said Pilger. “In most applications our customers typically hold our drills with collet holders with no issues. However, when drilling in high volume with high productivity, ridged holders with stronger gripping forces are needed.”

Horn’s Tonne said in many cases end users use speed and feed parameters that are too low for the drilling system they are using.

“Material-specific geometries play a huge role in reducing exit burr,” said Garud. “For example, Walter-Titex brand Xtreme-CI drills are designed for reducing exit burrs in cast irons.” The drills have an “edge-break” chamfer on the corners of the cutting edges that greatly reduces the burrs, he said.

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Edwin Tonne, training and technical specialist for Horn USA Inc., Franklin, Tenn., said selecting the drill geometry that matches the material and application is critical.

“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.

YG-1 has built drill selection based on the material to be processed into its 3-catalogs. “We say ‘hey, what are you drilling?’” Pilger said. “Are you drilling steel? You pick the steel drill. Are you drilling a stainless steel? You go with our Inox drill.”

Sandvik Coromant’s Hobbs agreed that it’s very important to know what a drill’s proper cutting data range is for the material being drilled. “High feed rates may produce too thick of a chip or even overload the drill’s web, causing the drill to break,” he said. “Low feeds can cause long, stringy and undesirable chips.”

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.

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.

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.

Horn’s DDM drill system is also intended for machining stainless and acid-resistant steels along with the titanium and nickel alloys Tonne mentioned. They’re designed with internal cooling and have new coatings that aid in longer tool life.

“Using a double-margin flute geometry will help improve surface finish,” Blandon said. “The second trailing margin will help burnish the interior surface of the drilled hole during the drilling cycle.”

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Instead of cutting-edge chip breaker grinds, said Blandon, high-performance carbide drills such as the Emuge EF-Series incorporate various flute shapes that roll the material within the flute and cause it to fracture. When operated at the proper speed and feed rates (which influence the chip thickness), these drills eliminate long, stringy chip formations that lead to flute clogging and drill fracturing. The other benefit of a high-performance carbide drill design is that the elimination of long chips allows the drill to operate at a constant feed rate without peck cycles.

For most solid drilling operations, a ballpark thrust (Z) force can be 3,000-4,000 N (674–900 lb/f), and a dull cutting edge can easily double that value. Consult the tool manufacturer for recommended speed parameters and stay within the range given, Tonne advised. For feed, always run more than the width of the edge prep and less than the maximum feed per revolution.

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

“Heat shrink and hydraulic holders hold drills on center better than Weldon or collet chucks can,” he said. “This rigidity helps to prevent the drill from running out of round at the drill tip.”

Picking the right toolholding system and inspecting it periodically to ensure it’s in good working order can extend tool life and help produce better holes.

Marlon Blandon, product manager for thread milling, Emuge Corp., West Boylston, Mass., said shops can leverage the life of their tools by picking correctly.

“In a high production environment, we highly recommend a shrink fit system or a hydraulic chuck for our solid-carbide drills,” Pilger said.

“The cutting speed must be high enough to avoid material build up or built-up edge [BUE],” he added. “When BUE occurs, the drill behaves like a dull tool and thus creates pressures too high for the drill point.”

YG-1’s Pilger pointed out there are several different ways to drill today, and probably where drill breakage is most common is with solid-carbide drills used for certain materials and for certain hole diameters. Shops use them for drilling holes that are fairly accurate, fast and repeatable, given that their diameter ranges fit the diameters offered.

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

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.

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

Tonne advised using a high-performance collet system like Horn’s Fahrion Centro P, which can increase tool life by more than 50 percent due to the extremely tight tolerances of the taper and collet runout.

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.

“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.