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Not A Small Challenge: Cutting Tools For Miniature Dental And Medical Parts

Not A Small Challenge: Cutting Tools for Miniature Dental and Medical Parts

Successful development of innovative and dynamic parts in today’s miniature dental and medical components industry presents a formidable and equally dynamic challenge to cutting tool manufacturers. Article by ISCAR.

Successful development of innovative and dynamic parts in today’s miniature dental and medical components industry presents a formidable and equally dynamic challenge to cutting tool manufacturers.

The fast-growing field is driven by enterprising orthopaedic surgeons and dental professionals together with medical screw and implant companies, who work in close cooperation with  computer aided design and manufacturing (CAD/CAM) software developers and dedicated machine and tool manufacturers to transform their inventions into parts that are revolutionizing medical and dental procedures. Each new component demands correspondingly advanced tools and geometries to create the new and complex shapes, and to ensure extreme precision and consistently excellent surfaces.

The materials used for producing medical screws and implants are titanium superalloys, although stainless steel hard materials are used when a special ratio of depth of cut to chip thickness is required. These materials are gummy and cause built-up edge (BUE), which tends to wear down edge sharpness, while the high temperatures generated during chip breaking shorten tool life and damage surface quality.

ISCAR, a manufacturer of cutting tools for metalworking, invested time and resources to develop optimal machining solutions for the medical sector, applying unique geometries, tools, and grades. Utilizing CAD/CAM systems to create custom tool assemblies according to the ISO 13399 standard, ISCAR developed cutting tools for machining miniature medical parts—specifically dental screws and four components for hip joint replacement implants: femoral head, acetabular shell, femoral stem, and bone plate.

Dental Screws

ISCAR provides dedicated cutting tools for each of the main operations involved in machining dental screws. The company developed two options for rough OD (outer dimension) turning. The SwissCut compact tool is designed for Swiss-type automatics and CNC lathes, and enables reduced setup time and easy indexing without having to remove the toolholder from the machine, while the inserts are equipped with chip deflectors designed specifically for machining small parts. The second option features SwissTurn toolholders, with a unique clamping mechanism to optimize insert clamping and replacement on Swiss-type machines, and JETCUT high pressure coolant tools. SwissCut tools are used for the turn threading operation.

CHATTERFREE endmills are utilized for the slot milling stage to maximize stock removal rate, eliminate vibration and reduce cycle time. The unique ground geometry provides excellent surface and tool life, while machining at high material removal rates.

PENTACUT parting and grooving inserts perform the cut-off operations. With five cutting edges and very rigid insert clamping, PENTACUT is a stronger insert for higher machining parameters particularly on soft materials, parting of tubes, small and thin-walled parts.

SwissCut tools are used in the face and OD turning (screw head turning) operation, while the drilling operation is performed by SOLIDDRILL solid carbide drills with 3xD and 5xD drilling depths and right-hand cut. The drills feature coolant holes.

The thread milling operation features SOLIDTHREAD thread mills, whose short three-tooth cutting zone with three flutes and released neck between the cutting zone and the shank enable precise profiles and high performance. The extremely short profile exerts a low force which minimizes tool bending, facilitating parallel and high thread precision for the entire length. The solid carbide SolidMill endmills perform the key head milling operation.

Hip Joint Replacement

Complex operations are involved in machining components for hip joint replacement, which demand high accuracy, pristine surface quality, and absolute reliability. ISCAR provides products for each operation to maximize their precision and efficiency.

Femoral Head

The machining required for a femoral head involves rough turning or rough grooving, semi-finish profile turning, rough drilling, semi-finish milling, semi-finish internal turning, internal grooving (undercut), cut-off, rough turning, and semi-finish turning.

The ISOTURN turning tools may be used for rough turning. The ISO standard tools perform most of the industry’s chip removal in applications ranging from finishing to roughing. Offered in all standard geometries, the trigon (semi-triangular) turning inserts for axial and face turning features six 80° corner cutting edges. For profile machining, ISCAR provides intricate and precise V-LOCK V-shaped special profile grooving inserts for the range of 10–36mm.

SUMOCHAM drilling tools perform the rough drilling operation, offering fast metal removal and economical indexing with no setup time. SUMOCHAM integrates a clamping system that enables improved productivity output rates and a shank designed with twisted nozzles, and a durable and stable body.

The CHATTERFREE 4-flute endmills are utilized for the semi-finish milling operation. CHAMGROOVE internal grooving inserts are applied for semi-finish grooving. The inserts possess extremely small bore diameters starting at just 8mm and incorporate internal coolant.

Semi-finish internal turning is performed by ISOTURN inserts with SWISSTURN toolholders, while the cut-off operation uses DO-GRIP twisted double-sided parting inserts which feature double-ended twisted geometry for no depth of cut limitation.

For rough turning, the SWISSTURN ISO standard insert range with small shank sizes is used. Also available for this operation are standard geometry inserts with precision ground cutting-edges and small radii for manufacturing small and thin parts. The semi-finish turning operation is performed by using CUT-GRIP inserts.

Acetabular Shell

Machining of the acetabular shell component consists of rough internal turning, finish profile milling, shouldering, upper and bottom chamfering, drilling, thread milling, external rough turning, and external grooving operations.

HELI-GRIP double-ended inserts are used for the rough internal turning operation, as the twisted design allows them to groove deeper than the insert length. Internal finish milling is performed by SolidMill 3-flute, 30 deg helix short solid carbide ball nose endmills. SolidMill endmills with 4 flutes, 38° helix perform the finish shouldering operations, as well as the special-shaped endmill which performs the upper and bottom chamfering operations that follow the drilling stage. The SOLIDDRILL solid carbide drills are used for the drilling operation.

Thread milling is performed by SolidMill solid carbide internal threading endmills, which integrate coolant holes for ISO thread profiles. ISO standard inserts with SwissTurn toolholders are used for rough turning, and external grooving is performed with CUT-GRIP precision inserts.

SolidMill endmills with four flutes, 38° helix and SolidMill three flute, 30° helix short solid carbide ball nose endmills perform the final milling operations.

Femoral Stem

Machining the femoral stem involves slotting, spot milling, drilling, chamfer milling, turning, face and profile milling operations.

MULTI-MASTER endmills with indexable solid carbide heads in the diameter range of 12.7–25mm are used for the slotting operation. Spot milling is performed by means of SolidMill endmills with four flutes, 38° helix and variable pitch for chatter dampening with 3xD relieved necks. The drilling operation uses SOLIDDRILL solid carbide drills, while chamfer milling is performed using MULTI-MASTER endmills with indexable solid carbide heads. ISO standard geometry inserts with precision ground cutting edges are used with SWISSTURN toolholders for the turning operation.

SolidMill three-flute, 30 deg helix short solid carbide ball nose endmills are employed for the profile milling operation, and SolidMill endmills with four flutes, 38 deg helix and variable pitch for chatter dampening with 3xD relieved necks are utilized for face milling.

Bone Plate

The machining required to manufacture a bone plate involves rough and finish milling, shouldering, drilling, and mill threading. For rough milling, the FINISHRED endmill geometries allow the tool to perform roughing and finishing operations at the same time. The result is the ability to apply roughing machining conditions, while obtaining excellent surface finish. MULTI-MASTER interchangeable solid carbide tapered heads are applied to the finish milling operation, whereby the curved surfaces can be machined by tilting the tool and applying a large corner radius at small cutting depths. Shouldering is performed with CHATTERFREE endmills, which enable high material removal rates, eliminate vibration, and reduce cycle time.

For the final milling stage, MULTI-MASTER four flute, 30 deg helix short solid carbide ball nose endmills in the 5–25mm range are employed, while SOLIDDRILL solid carbide drills are used to ensure stable and accurate drilling. SOLIDTHREAD 55 deg or 60 deg profile solid carbide taper thread mills are used for the mill threading operation.

Grades

Grades specifically designed for machining applications on stainless steel and super alloys such as IC900, IC907, IC806, IC908, IC328, and IC928 are ideal for milling and turning titanium and nickel-based alloys, such as Nitinol, commonly found in medical components. These grades are available for ISCAR standard tools with specially designed positive and sharp edged chipformers.

It is no small challenge to manufacture miniature parts for dental and medical devices but ISCAR has succeeded in developing highly effective cutting tools for this field that adhere to the stringent standards of quality and precision essential for medical industry applications.

 

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Round Tool Concepts: Indexable, Solid Or Both

Round Tool Concepts: Indexable, Solid or Both

Indexable or solid—which round tool concept is better? As in many subjects of technology, there is no absolute answer to this question. However, a definite answer does exist if the advantages and disadvantages of both concepts are considered according to specific conditions.

An assembled tool carrying removable indexable inserts, a concept that has become common in industry since the 1960’s, requires cutting capabilities only from one of its components—the insert. The cutter body acts as a holder for inserts of a specific shape produced from different hard-to-machine tool materials (for example, various cemented carbide grades, cubic boron nitride or CBN, cermet, etc.), while the body itself is made mainly from steel.

The inserts can differ in their chip forming surface, to generate the necessary cutting geometry. Clamping the insert, which features the geometry and material suitable for cutting the workpiece, in the body results in an optimal cutting tool for the workpiece. The insert possesses several cutting edges. If one edge is worn, it is simply replaced by indexing the insert by means of rotation or reversing. The indexable principle ensures cost-beneficial utilisation of the tool material.

The insert is formed by powder metallurgy technology to produce the unique shape of the chip forming surfaces, whereas obtaining this shape by other technology methods is extremely difficult or even impossible, and an exceptionally strong cutting edge capable of standing up to heavy loading.

At the same time, an indexable round tool has definite disadvantages. Firstly, accuracy is lower compared with a solid cutter. Secondly, the tool diameter cannot be relatively small (for example, less than 8–10mm). Reducing the diameter leads to diminishing the size of all assembly components, including the insert and its clamping elements (usually a screw), which have a natural dimensional barrier. In addition, the insert cutting edge is strong but not as sharp as that of a solid tool. For machining soft materials, like copper, commercially pure titanium or aluminium, which require a sharp edge, additional edge grinding needs to be performed.

The main advantage of a ground solid round tool is its high precision: in average one quality grade higher than that of an indexable cutter. A solid tool cannot be indexed but it is suitable for regrinding.

Ceramic endmill.

Ceramic endmill.

Like an indexable cutter, a solid tool also has dimensional limitations that relate to the tool cost. As opposed to the indexable concept, the solid tool cannot be relatively large in diameter; usually the diameter of the solid tool does not exceed 25mm or 1in in overall length. This type of tool demands significantly more tool material and it takes more time to manufacture such a tool by grinding. These constraints lead to a substantially higher tool cost. By contrast to the indexable tool, the cutting edge of the solid tool is sharper but less strong.

The machined surface dimensions may dictate which concept should be applied to an operation. For example, for drilling a hole of 3mm in diameter, a solid drill will be used. Aside from this dimensional aspect, the following principles characterise correct tool selection.

For heavy cuts (usually rough or semi rough), featuring significant cutting force and power consumption, an indexable tool is the preferred solution. If an operation features light cuts and demands high accuracy and surface finish, a solid tool is required.

Drill with exchangeable carbide head (tool shown in centre).

Drill with exchangeable carbide head (tool shown in centre).

The past few years have seen a dramatic change in this logical—and traditional—concept. The search for new solutions to improve productivity, combined with advances in machine tool engineering, has engendered efficient cutting strategies and appropriate machines. A significant number of modern machines have less power but far higher speed drives and advanced computer numerical control units for high speed machining, performed by a small-diameter tool moving at optimal trajectory for constant tool loading. This step, together with progress in regrinding and recoating technologies, represented a second wind for solid tool use by opening up new options in rough machining. Advances in tool materials have increased the hardness level of machine workpieces. Today, for example, solid carbide endmills, operated by high speed milling technique, are capable of successfully cutting hard steel up to HRC 65.

Tool manufacturers recognised the advantages of combining both solid and indexable concepts into a single design to meet the latest developments. ISCAR’s popular MULTI-MASTER and CHAMDRILL round tool families are representative of this beneficial combination. Both lines feature tools with exchangeable cutting heads made from solid carbide. In the MULTI-MASTER tool range, which was introduced in 2001, a cutting head can be mounted in different bodies, and a body can carry different heads. This “indexable solid” principle enables over 40,000 possible tool configurations.

So, which concept is better? The industry requires both types of cutting tool, depending on technology processes. The ratio of indexable tools to solid and “indexable solid” tools in today’s market is estimated at 1:1, which indicates how cutting tool development is progressing in both directions. But technology advances and improvements in processing will make tool requirements—whether solid or indexable round tools—more and more demanding.

 

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Adapting Cutting Tools To Changing Trends

Adapting Cutting Tools To Changing Trends

In an interview with Asia Pacific Metalworking Equipment News, Jacob Harpaz, ISCAR CEO, IMC President and Chairman of the Board, discusses the current trends in the metalworking tool industry, and how the company is helping their customers address their manufacturing challenges.

Jacob Harpaz

APMEN: Could you provide us with an overview of the trends that are shaping the metalworking tool industry?

Jacob Harpaz: Developments such as electric vehicles and powertrains in large volumes, additive manufacturing and cyber connectivity will mean significant changes in the style of machining and the materials being used. Workpieces will be produced more commonly at near net shapes for final machining and finishing.

By 2030 there will be big changes in the automotive sector. The major OEMs are moving away from the internal combustion engine which will mean much less metal removal will be required. There will be wider use of composite materials and the introduction of 3D printing will also mean less metal removal. At ISCAR we are preparing for these changes. Cutting tools will have to adapt to remove less metal but at much faster speeds and feeds.

Industry 4.0’s impact will not just come through sophisticated new technology such as sensors, process monitoring and acquiring machining data, but in the integration of factories and the supply and distribution of consumables used in manufacturing and products leaving the factory.

APMEN: How has ISCAR kept up with these trends?

Harpaz: ISCAR’s motto of “Machining Intelligently” represents the ongoing process of developing new products for increased productivity.  Our aim is to provide our customers with the latest technology to bring down costs.  ISCAR’s strategic philosophy is ongoing R&D that drives our business growth. As soon as we introduce to the market our newest tooling families, another team from the R&D division focuses on designing tools that will compete with these latest tools

ISCAR recently launched its “LOGIQ” cutting tools campaign featuring highly advanced cutting tool solutions for productive, high quality and efficient manufacturing in all sectors.

APMEN: What are the top three challenges that your customers are facing?

Harpaz: First, machining logically and intelligently is closely connected to today’s smart factories and the current cyber age. The cyber revolution is here, and Asian shops should quickly embrace what Industry 4.0 really means. They need to move beyond seeing Industry 4.0 as just a slogan, and this will take open-mindedness.

Next, companies need to maximise efficiency to stay ahead. They should be developing methods to collect, analyse and leverage data and utilising appropriate tools to cut faster or reduce setup, as well as implementing inventory systems that reinforce the aim of 24/7 machining. ISCAR’s “LOGIQ” product range helps to realise these goals.

Third, the ISO 13999 standard affects CAM procedures on production floors all over the world. Producing metal parts productively and profitably requires many technological changes to ensure that the process is followed correctly. To address this challenge, customers need online data such as the information that appears in ISCAR’s electronic catalog, which features assembly options.

APMEN: How are you helping them address these challenges?

Harpaz: ISCAR embraces a business culture that nurtures, strengthens and maintains strong ties with our customers. We aim to improve profitability and productivity for large and small manufacturers alike, facing every challenge as an opportunity to expand our range of solutions through focused R&D, production excellence, and close cooperation with customers to ensure the right product for their needs.

ISCAR introduced a milling tool assemblies option in E-CAT, its comprehensive electronic catalog. This new option represents a highly valuable instrument for the preliminary process in selecting tools at the design and planning stages of machining. Cutting tool data can be gathered accurately and used to create twin representations of the tools. Creating a digital twin representation of a tool assembly based on ISO 13399 facilitates the accurate communication of tool information between software systems. The assemblies are accessible in both 2D and 3D files, and the files can be downloaded directly from E-CAT on the ISCAR website.

Integrating this new function into the user’s CAM software can prevent errors on the shop floor during machining, while the ability to plan multiple tool assemblies saves time and costs in the planning process.

While we always provide the latest technology to machine the part, the productivity advantage of this technology only matters if you have the tool at the right place at the right time.

APMEN: How do you position ISCAR in the metalworking tools market in Asia?

Harpaz: The Asian market is important and presents its own challenges and opportunities; ISCAR welcomes every challenge as an opportunity for continued research and development of effective cutting solutions that match market developments and requirements.

Our commitment to combining innovation with reliability and cost consciousness, together with our wide market knowledge and penetration and a uniquely strong – and global – corporate culture, enables us to stay at the forefront of the industry and to provide our Asian customers with optimal, cost-effective solutions to their needs.

 

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Iscar Expands Modular Exchangeable Drilling Heads Lineup For Large Diameter Deep Drilling

Iscar Expands Modular Exchangeable Drilling Heads Lineup For Large Diameter Deep Drilling

Iscar has expanded its large diameter drilling options with the new MODUDRILL line, which features two different types of exchangeable heads: one for 33-36mm drilling and the other for 37-40mm drilling.

The MD-BODY modular body measures 400mm, is produced from high-strength steel for durability, and features a small core with central coolant hole for efficient chip evacuation. Its new patented connection withstands high torque, and its high flute helix with polished surface provides a smooth and easy chip evacuation for chips of all sizes

Carrying HFP-IQ CHAMIQDRILL solid carbide head, the MD-DFN modular head from Iscar features a robust structure with concave cutting edge design to enable drilling at high feed rates and provide IT8-IT9 hole tolerance. Its unique pocket design enables many drilling head indexes. Its special axial stopper prevents the drilling head from being extracted during retraction, while its large radial head stoppers provide high resistance to cutting forces, enabling very high cutting conditions.

The MD-DR-DH modular head carries standard SOMX indexable inserts with four cutting edges, providing an economical solution for low- to medium-feed machining.

 

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Iscar Expands Range Of Solid Carbide Milling Heads For The Aerospace Industry

Iscar Expands Range Of Solid Carbide Milling Heads For The Aerospace Industry

Iscar is expanding its MULTI-MASTER solid carbide milling heads for the aerospace industry with new interchangeable models featuring a 100° point angle. The solid carbide milling heads are suitable for chamfering, countersinking, and spot drilling applications.

The new interchangeable heads are available in four diametre sizes: 9.525mm, 12.7mm, 15.875mm, and 19.05mm. They are designed mainly for countersink holes for head cap screws according to ISO 5856, DIN EN 4072, IS 15437 standards; and for rivets according to MIL-STD-40007. The heads can also be applied for machining countersink holes for general-use 100 deg flat countersunk head machine screws, in accordance with ANSI B18.6.3-1972 standard. Most aircraft countersunk screws require a 100° angle countersink.

 

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Solid Ceramic Endmills For Machining Nickel-Based Superalloys

Solid Ceramic Endmills For Machining Nickel-Based Superalloys

Following the steady increase in the processing of nickel-based high temperature superalloys (HTSA) such as various grades of Inconel, Incoloy, and Haynes, amongst others, in the aerospace industry, and the demand to decrease production costs, ISCAR has launched solid ceramic endmills that enable increasing the cutting speed by up to 50 times when compared to carbide tools, drastically saving machining hours and reducing production costs.

Available in two configurations—E3, with three flutes for shouldering applications, and E7, with seven flutes, feed mill style for rough applications—the new endmills can also be successfully applied to productive roughing of cast iron and graphite.

The solid ceramic endmills are produced from two ceramic grades: IS6, designed specifically for machining HTSA, and IS35, intended for cutting mainly cast iron and graphite. They are available in 6mm to 20mm diametres.

 

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Tools For Large Part Manufacturing

Tools For Large Part Manufacturing

In principle, machining large parts involves the same cutting action and chip formation process as for small or mid-size parts. However, large dimensions demand a specific approach to machining, and manufacturers need to plan technological processes and choose more effective cutting tools in order to produce heavy parts that take up a great deal of space. Article by Andrei Petrilin, Technical Manager, ISCAR.

Transporting a part inside a shop floor, mounting the part in a machine tool and clamping it properly, and machine setup are major challenges. Workholding massive and large parts is not an easy task, and often requires non-standard solutions. Machining large parts involves removing a lot of material that may cause significant deformations due to unrelieved stresses. Another factor, which leads to dimensional problems, is thermal expansion caused by heat generation during cutting: the large sizes make it much more sensitive comparing with “normal-in-size” workpieces. The necessity to remove a significant material stock requires appropriate chip evacuation to prevent the chip re-cutting, which negatively affects the applied cutting tools.

The key for overcoming the difficulties lies in technology, based on effective process planning and utilizing the most suitable machine tools, optimal workholding, and minimal part relocation. Single setup machining represents an absolute ideal for machining a large part, and producers from fields such as  power generation, aerospace , railway,  die and mold making, and heavy industry make every effort to approach this ideal. And cutting tools play a meaningful role towards reaching the target.

A distinct feature of these industries is their substantial consumption of large heavy-duty tools, mostly indexable, intended for productive removal of large quantities of material, especially in rough and semi-rough machining operations.

Large part manufacturers expect the same from cutting tools as any other producer using metal cutting technologies: excellent performance, good tool life, and high reliability.  The latter two are especially essential because the large sizes lead to increased machining time, but replacing a worn tool in the middle of a pass and unpredictable breakage of the tool during cutting are totally unacceptable. In order to maximally meet the requirements of large part manufacturers, cutting tool producers provide various solutions, based on both standard and special designs.  As a leading company in the cutting tool industry, ISCAR’s years of accumulated knowhow and experience have proved to be advantageous in developing efficient solutions to these challenges.

Figure 1

Heavy-Duty Facing

It is hard to machine a large part without face milling operations. Rough and fine machining of free and bounded planes and preparing datum surfaces require various indexable face mills. ISCAR’s standard face mills possess nominal diameters up to 315 mm (12″), while special tailor-made tools might feature higher values. The inserts are mounted in face mills and vary in cutting geometry as they are intended for machining different groups of material. Significant removal of machining stock by milling is primarily an issue for the production of large parts from steel and cast iron and, slightly less, from titanium and aluminum.

ISCAR’s line of standard face mills includes many tool families for large part manufacturing. HELITANG T465 features cutters with a 65° cutting edge angle and carrying tangentially clamped inserts. The robust design enables productive machining with a depth of cut up to 19 mm (.750″). The HELIDO 890 family features 89° face mills with lay-down square double-sided inserts (Fig. 1). These efficient mills, which are truly indispensable in milling a plane near the shoulder, offer an important economic advantage: the square inserts provide eight indexable cutting edges for depth of cut up to 9 mm (.354″).

Extended Flute, Extended Effect

Indexable extended flute “long-edge” cutters are considered as winning tools for productive rough milling. In manufacturing large parts, they excel in machining deep shoulders and cavities. Extended flute cutters are also utilised in “edging” – milling wide straight edges, an operation which is common for various processes from machining slabs and ingots to primary contouring.

Figure 2

ISCAR’s line of indexable extended flute cutters varies in design configuration, integrating a shank- and arbour-type mounting method and a radial or tangential insert clamping principle. These tools work in hard cutting conditions and experience significant mechanical and thermal loading. Intensive material removal requires the appropriate volume of a tool chip gullet to ensure effective chip evacuation. The situation can be dramatically improved by applying ISCAR’s extended flute cutters carrying inserts with chip splitting geometry to divide a wide chip into small segments. As a result, cutting forces are reduced, vibrations are stabilized, and thermal problems are eased.

Although 90° tools are the most commonly used cutters, machining large parts also requires rough milling of inclined and 3D surfaces, for which ISCAR provides a family of tapered extended flute cutters with 22.5°- 75°cutting edge angles. In some cases, particularly in die and mold making, combined rough and shoulder milling is needed. The DROPMILL 3 extended flute ball nose mills were designed specifically for such applications.

Producing large-size aerospace components from hard-to-machine titanium alloys is an extremely metal-intensive process with a significant buy-to-fly ratio. The eventual weight of a part may be only 10%, or even less, of the original weight of a workpiece. The XQUAD extended flute cutter family, one of ISCAR’s newest products, is intended for high-efficiency milling of deep cavities and wide edges in titanium parts. These tools (Fig. 2) are suitable for machining with high pressure coolant supply, which significantly increases productivity and improves tool life. The tools have already proved themselves: for example, component producers have achieved a 700-1000 cm³/min (43-61 in³/min) metal removal rate (MRR) by using an 80 mm (3”) diameter XQUAD cutter.

In railway engineering, combine mills are used to ensure simultaneous machining on several areas of the part. These mills incorporate an extended cutting edge, formed by a set of successively mounted indexable inserts.

Figure 3

Productive fast runner

High efficiency machining by indexable extended flute cutters and large-diameter face mills can be likened to the work of a heavy excavator digging sand with a big bucket. The full sand bucket, operated by a powerful engine, slowly moves a large volume of waste material. At the same time, there is an alternative method for efficient excavating. Imagine a more compact track trencher with a rapidly moving digging chain. Each link of the chain removes a small volume of sand but does it fast. In metal cutting, this trencher is a high feed mill, which machines at shallow depths of cut but with a feed per tooth that is far higher than the usual rates – millimetres as opposed to tenths of millimetres.

Fast feed mills are applied mainly to rough machining of plane faces, cavities and 3D surfaces (Fig. 3). These tools are more typical in manufacturing large parts from steel and cast iron, although high feed milling (HFM) titanium and high temperature alloys is not uncommon today.

ISCAR has a wide choice of fast feed mill families, intended for cutting various materials in different applications. The “world” of ISCAR’s HFM cutters encompasses tool families in diameter ranges of up to 160 mm (6.3″) that can meet the requirements of the most demanding customer.

High feed milling requires machine tools with high-speed feed drive. Large part manufacturers often have heavy, powerful but slow machines that are not suitable for high feed face milling. For these customers, ISCAR developed moderate feed (MF) cutters.  Compared with fast feed mills, moderate feed cutters feature a higher cutting edge angle; they move slower but machine at higher depths and need more power to make them suitable for applying to heavy machines.

Large parts are often made from difficult-to-cut materials such as hard and high wear-resistant steel or cast iron. The welded part structure and the process of repairing worn parts by spraying fillers or soldering, add materials that are not easy-to-machine either. High speed milling (HSM) resolves these issues. Originally applied in die and mold making, high speed milling was developed as a productive method of milling hard steel that led to decreasing a part relocation, lessening setup, minimizing manual finish and polish, and, as a result, reducing cycle time. High speed milling features a small-in-diameter tool that rotates at high speed and mills material at shallow, light cuts.

The most suitable HSM tool is a solid carbide endmill and ISCAR’s MULTI-MASTER family of assembled endmills, which carry cemented carbide exchangeable heads, also represents a viable option. ISCAR’s line of solid carbide endmills offers various multi-flute tools in diameters of up to 20 mm (.750″), intended for high speed milling materials with hardness up to HRC 70. Decreasing machining allowances due to the production of more accurate workpieces for large parts, for example by using precise casting or molding, opens up new opportunities for high speed milling.

Figure 4

Exchangeable Heads Change The Dynamics

In many cases, manufacturing large parts is small-volume and even individual. In this context, minimizing machine tool downtime has critical importance. Intelligent process planning to considerably reduce setup time can help solve this issue. Each time a worn cutter is replaced, additional measuring and CNC program corrections are required, which increases downtime.

ISCAR’s families of rotating assembled tools with exchangeable heads – MULTI-MASTER mills and SUMOCHAM drills (Fig. 4) – enable substantial decreases in downtime. Face contact between a head and a tool body ensures that the head overhang is within strict tolerance limits, resulting in high dimensional repeatability of the assembly. Replacing a worn head does not require additional setup operations or removal of the tool from a machine.

Figure 5

U-Turn With Turn Milling

Turn milling, which is the method of cutting a rotating workpiece by a face milling cutter, is a good option for machining heavy rotary parts. In turning, the cutting speed is a function of rotating velocity. If the main drive of a machine tool does not allow rotation of large masses with the required velocity, due to limitations of its working characteristics, then the cutting speed is far from the optimal range and turning performance will be low. Turn milling offers an effective solution to the above difficulties. When turning large eccentric parts like crankshafts, off-centre masses of the parts cause unbalanced forces that adversely affect performance. Turn milling features low rotary velocity of a part, which prevents this negative effect (Fig. 5).

The majority of ISCAR’s indexable face-milling cutters are suitable for turn milling. The success of their application depends on cutter positioning with respect to the machined part, choosing optimal geometry of inserts,  and cutting data calculation. ISCAR’s specialists in the field studied turn-milling kinematics and developed an appropriate methodology for defining these parameters.

Reliable Performance

Machining large parts is a time-consuming process, during which the tools cut material for a long period, and this means that tool reliability, stability, and predictable wear are high priority issues. A sudden tool failure may seriously damage the part and even cause its rejection. A cutting tool manufacturer has a limited choice of instruments for improving reliability, including advanced tool design, progressive cutting material,  and technological development. Effective utilization of these instruments is the key to successful large part machining and ISCAR’s recently-introduced range of new tools and carbide grades provides that key.

 

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New Demands, New Solutions

New Demands, New Solutions

New tool holding products mirror modern metalworking demands. Article by Andrei Petrilin, Technical Manager, Rotating Tools, ISCAR.

In general, tool holding (tooling) equipment has not undergone any fundamental changes for a long time. Although there have been some notable advances such as the introduction of quick-change tooling in the 1970’s and the appearance of modular systems using polygon taper coupling and systems based on  HSK adaptation for high rotational speed in the 1990’s, tooling development seems to fit quite firmly into the “if it ain’t broke don’t fix it” category.

Toolholders act as an interface between cutting tool and machine, and they should both ensure proper clamping of the cutting tool and also be suitable for mounting in the fitted spindle or tool changer magazine of a machine tool. The metalworking industry has compulsory standards to strictly specify the matching surfaces for both these purposes. These standards define a wide range of existing tooling systems to meet different manufacturer requirements: simple holders for manual tool changing for conventional machines with hand control, precise high-grade-balanced adaptors for high-speed machining centres. This variety of tool holding arrangements provides the manufacturer with multifold options for effective tool holding, depending on production targets and available machinery. This is mainly why tool holders reached a certain level of excellence that did not require groundbreaking changes.

Today, modern tooling is evolving along with metalworking industry developments in the world of Industry 4.0 and its impact on state-of the-art manufacturing and new technological horizons. Manufacturing digitisation also plays an important part in the development of new tooling features.

Advances in high speed machining (HSM) exemplify the cause and effect of these changes. Implementation of new technologies in this important field has necessitated a new level of tool balancing to ensure tool holder performance and reliability in a significantly expanded range of rotational speeds, with the objective of improving strength, rigidity, accuracy and other technical parameters of the traditionally designed tool holders. High-efficiency milling of difficult-to-cut aerospace materials, like titanium alloys, have increased demands for durable tool holders working in hard conditions.

The effect of these developments can be observed by noting ISCAR’s introduction of a range of tool holding solutions. As one of the largest cutting tool manufacturers in the world, ISCAR is recognised as a strong supporter of constant product innovation.

Today the company offers a rich choice of arbors, holders, adaptors, blocks, thermal and power chucks etc. for effective tool clamping. Following industry demands, performance parameters for these parts have been tightened up significantly. For example, SHRINKIN thermal shrink chucks with HSK 100 shanks now feature G2.5 balance quality and a residual unbalance of less than 1.0 g/mm (.00139 oz/in) at 20,000 rpm, MAXIN 32 power chucks ensure clamping torque up to 1,760 N/m (1,300 lbf/ft), and FINEFIT radial and angular alignment tool holders for high speed reamers maintain radial and axial runout adjustment to 0.001 mm (.00004 in).

Clamping And Cooling

ISCAR recently launched a series of new tooling families that provide an effective pinpointed coolant supply. In many cases, like machining titanium or exotic high temperature superalloys (HTSA), which are common for the aerospace industry, cooling is a critical factor of success.

X-STREAM SHRINKIN is a family of thermal shrink chucks with coolant jet channels along the shank bore. The family utilises a patented design for holding tools with shank, made from cemented carbide, steel or high-speed steel (HSS). The new chucks combine the advantages of high-precision heat shrink clamping with coolant flow, directed to cutting edges. X-STREAM SHRINKIN has already shown excellent performance in milling aerospace parts, particularly titanium blades and blisks (bladed discs), and especially in high speed milling. In machining deep cavities, the efficient cooling provided by the new chucks substantially improves chip evacuation and diminishes chip re-cutting.

Turning

In turning, ISCAR has developed a new concept for high pressure coolant (HPC) supply for VDI DIN 69880 quick-change adaptation systems, intended for turning machine tools. The JETCUT concept is based on bottom-fed HPC channels and provides coolant supply internally through the tool and externally through the flange. The resulting cooling effect significantly improves performance in turning, grooving and parting applications.

A wet coolant can act as an excellent tool in a radically different field: increasing the rotational speed of a tool. ISCAR’s SPINJET family of coolant-driven high speed compact spindles for small diameter tools is a type of “booster” for upgrading existing machines to high speed performers . The SPINJET spindles are recommended for tools up to 7 mm (.275 in) in diameter, however the optimal diameter range is 0.5-4 mm (.020-.157 in). The “booster” demonstrates a highly impressive output: depending on pressure and coolant flow rate, the spindles maintain a rotational speed of up to 55,000 rpm. The versatile SPINJET products have been successfully integrated in tooling solutions for milling, drilling, thread milling, engraving, chamfering, deburring and even fine radial grinding.

Reaming

In reaming, floating chucks are used in high-precision hole making to correct any misalignment between the central axes of a reamer and a hole. Precise alignment is essential for optimal performance and hole accuracy. To this end, ISCAR added a new design of GFIS floating chucks for high speed reamers to the ER COLLET chuck family. The new chuck is unlike any other floating system in the market, due to the integration of a unique technology that ensures the system remains completely rigid until it reaches a steady state of reaming.

Matrix

The Industry 4.0 concept of data-driven smart manufacturing has had a direct impact on the entire chain of production, including the seemingly conservative field of tool holding. In a smart factory, production systems perform under the conditions of real-time mutual information exchange. ISCAR’s modern tool holders incorporate holes for RFID (radio-frequency identification) chips, which can be mounted according to customer request.  ISCAR’s MATRIX intelligent computerized tool storage unit reads the RFID chips and receives all necessary identification data from the tool holder.

These selected examples characterize the development of tool holding products. Despite a “conservative reputation”, the latest tool holding product innovations both reflect and reinforce the trends of metalworking today and beyond.

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Reasons Why Indexable Tools Will Challenge Solid Carbide For Small Diameters

Reasons Why Indexable Tools Will Challenge Solid Carbide For Small Diameters

Rotating one-piece solid carbide tools traditionally dominate the market for diameter ranges of up to 20 mm (.75”) and indexable tool manufacturers have not yet succeeded in penetrating this solid stronghold. Several important factors contribute to the historical perception of solid carbide as a better bet for tooling reliability. 

SOLID carbide tool accuracy compares favorably with that of indexable tools, particularly for small-diameter endmills and for tools with diameters beyond the range. However, the role of reduced accuracy for tools of small diameter (for example, a milling cutter’s radial run-out) increases in significance as a factor affecting tool life.

An indexable tool is made up of a tool body, replaceable inserts, and mechanical parts such as clamping screws or wedges, which secure the inserts in the body. Decreasing the tool diameter necessitates reducing dimensions of the assembly components. Reducing the size of the securing elements leads to weakening their strength and the tool becomes unable to withstand cutting loads under normal machining data. This seriously limits the tool application and further decrements may cause degradation of the entire assembly structure.

The prices of small rotating tools are also often high compared to the assembled concept, which adds to the perceived limitations of indexable tools in the small diameter range.

The Indexable Option

Indexable tools possess several distinct advantages that makes applying these tools within the above range very attractive in the eyes of the customer. In many cases, especially in rough machining, changing a worn cutting edge by simple indexing provides more economic benefits as compared with having to replace a whole life-expired solid tool with a new tool. In addition, there is no need to use up time and resources on regrinding and recoating worn-out one-piece cutters.

Tool manufacturers have made significant progress in developing reliable designs that could be commercially viable against the solid carbide concept. Work in this direction has already shown results, and assembled mills and drills with interchangeable cutting heads are proving to be a realistic alternative to solid carbide tools.

Competitive Performance

 The introduction of tools with replaceable solid carbide cutting heads signifies a change in focus. ISCAR provides two examples of this concept with the ISCAR MULTI-MASTER milling line and the CHAMDRILL line in drilling.

Performance and accuracy characteristics have positioned the new tools to be functionally competitive with solid carbide designs. Versatility of these lines, where a head can be mounted in different bodies and vice versa, where a single body can carry different heads, facilitates various assembly combinations and contributes to reducing the number of items in a tool stock.

Another important design approach which is the “no set-up time”, characterises these lines, as a worn-out head does not require spending time on set up and can be replaced while the tool is still clamped in the machine tool spindle. This cuts cycle time and, consequently, reduces production costs. In contrast, replacing a worn-out solid carbide mill or drill inevitably leads to a new set-up procedure.

In addition, the concept ensures sustainable use of cemented carbide with all the associated advantages. The principle of “indexable” carbide tools has distinct merits and features strongly in tool design within the diameter range that is under discussion. The minimal diameter of MULTI-MASTER milling heads is 5 mm and that of SUMOCHAM drilling heads is 6 mm, while the MULTI-MASTER combined countersink heads for center drilling feature a minimal 1 mm diameter.

The LOGIQ Factor

 ISCAR has recently introduced a new range of small-size indexable rotating tools under its new LOGIQ line campaign. The company proposes several families of cutters with a nominal diameter of up to 20 mm. A brief look at some of these families can provide a clearer understanding as to whether the new tools will be able to breach the solid stronghold wall.

The new families of indexable milling cutters within the diameter range of 8-16 mm attract the most interest. They have several common features: the cutters carry triangular-shape inserts with three cutting edges and the mechanical part that secures the inserts is represented by a screw. These families are intended for milling square shoulder or fast feed (high feed) milling. But it is here that the similarity ends, and the difference begins. While the design of the HELI3MILL and MICRO3FEED families for tool diameter 10-16 mm is committed to the classical principle of insert securing, by clamping screw through the central hole of an insert, the NANMILL and NAN3FEED families for tool diameter 8-10 mm have adopted another concept.

Within such a small diameter range, the central clamping screw, as noted previously, does not provide an acceptable solution. According to the new concept, the screw is located above the insert, and the screw head plays the role of a wedge. This approach provides reliable and rigid clamping, and ensures a durable homogeneous insert structure with no hole. Allowing for the insert indexing to be quick and simple.

It is predicted that these new families will be particularly effective in manufacturing compact parts and in machining small-in-size cavities, pockets and small parts utilised in industrial sectors such as die and mold making, as well as in producing miniature components.

Small Change, Large Impact

 A 1 mm change in size: is this a lot or a little? For indexable tools in the small diameter range, it does make a noticeable difference. ISCAR’s new SUMOCHAM 5 mm diameter drilling head represents an important step ahead in expanding the application fields of indexable drills.

Within the small diameter range, indexable tools can offer precision and performance advantages that position them competitively against the more traditional solid carbide tools.  Indexable tools are beginning to shear their way into metalworking practices and the industry is taking note.

Article contributed by ISCAR.

The Right Grade Creates The Right Tool: Selecting Tool Materials

The Right Grade Creates The Right Tool: Selecting Tool Materials

Cutting tools have different design configurations. Some of them are assembled comprising a body with replaceable cutting elements (indexable inserts, for example), another is wholly produced from solid material. Functionally, a cutting tool may be divided into a cutting part that is involved in cutting, and a mounting part, which is necessary for mounting the tool in a holder or a machine spindle.

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