HORN Mastering Processes: Grooving

When Paul Horn introduced the type 312 indexable insert to the public in 1972, it was a small revolution in the grooving process. Horn was the first manufacturer ever to develop a tool system with a vertically mounted, three edged carbide insert for grooving. Today, the grooving process with indexable inserts is indispensable in modern manufacturing. Radial grooving, parting-off, face grooving and internal grooving to µ-precision are now part of everyday life in the machining industry. Paul Horn’s incentive at the outset was for the technical perfection of his products and the Horn company continues to set similar standards in tool technology for this machining process.

 

The 312 insert is still popular with users today. Horn has not stopped developing and optimizing successful product families. At the same time, Horn has completely integrated the value creation for its entire product range into its own production. The possible applications of the tool have grown considerably after the insert was originally used almost exclusively in the automotive industry. The “312” is intended for external machining and is used, among other things, for producing workpieces in the medical industry, in the manufacture of hydraulic components and for making everyday objects such as jewellery or ballpoint pens. However, it is not only the type 312 insert that has made the precision tool manufacturer known as a specialist for machining between the flanks. Numerous other tool systems followed the idea from 1972, which are now successfully used for grooving worldwide.

Basically, the grooving process involves a narrow cutting edge that penetrates the workpiece in a radial or axial direction. The art of grooving is, among other things, controlling the chip flow. Chip sticking, jamming or long, stringy swarf must be avoided in practice, as they have a negative influence on process reliability and can lead to tool breakage and damaged flanks. Depending on the material to be machined and the type of machining, Horn has developed different chipbreaker geometries that ensure reliable chip formation, control and breakage. Another important point for economical grooving is a sufficient supply of coolant. Where in the past cooling was external with the classic flood coolant, today modern tool carriers are used, mostly with an internal coolant supply. This ensures effective cooling of the shear zone between the tool cutting edge and the workpiece. For parting-off, Horn also offers a type S100 insert, which supplies the contact zone with coolant at high pressure directly through the insert. Tools are exposed to high loads during parting-off. The quality of the carbides used, the quality of the cutting edge and the insert coating also play an important role in reliable and economical parting-off.

Grooving in Practice

A user produces a wide and deep groove in an aerospace component using the trochoidal grooving method. It is very well suited to the production of of deep, wide grooves where high metal removal rate must be generated.The machinists produce the component from 1.4548 (X5CrNiCuNb17-4-4), a steel with high corrosion resistance, strength and toughness. Roughing is carried out using a full radius Grooving insert S229 with a radius of 2 mm. The grooving process is designed as follows: The 30 mm wide and 15 mm deep (incremental) recess is trochoidally roughed using the full radius indexable insert with a cutting speed of vc = 140 m/min at a cutting depth of ap = 1 mm The programmed feed rate is fn = 0.25 mm -1. The finishing allowance is 0.2 mm. Finishing also involves using a cutting insert from the S229 system. The finishing operation is carried out from two sides with a 3 mm wide grooving insert. The corner radius is 0.2 mm. The total production time to complete the groove is less than two minutes.

 

Face Grooving in the Medical Sector

For the production of a thin-walled valve cover made of titanium for a cerebrospinal fluid shunt system, the SuperMini system type 105 is used. On one hand, the customer uses a tool for the face grooves and, on the other, a special tool for finishing the lid fit. For the narrow fit on the lid with a length of 0.5 mm, Horn had to design the SuperMini tool with a corner radius of 0.05 mm. The difficulty in machining titanium always arises from the dissipation of heat as well as the control of chips. For use as an implant, the user has strict criteria regarding the surface quality and the absence of burrs on the component. By optimizing the cutting paths with a CAM system, the experienced colleagues in the machining department were able to double the tool life from 1,000 to 2,000 components.

Although Horn’s tool portfolio has expanded considerably, not only in the area of grooving but for all applications in the field of demanding machining tasks, grooving and thus machining between two flanks is still considered the supreme discipline.

Looking ahead to the AMB 2022 trade fair in Stuttgart and IMTS 2022 in Chicago, Horn is presenting innovations and expansions in the area of grooving.

 

 

HORN Mastering Processes:  All-Rounders for Milling

Horn Circular Milling System with large range of Diameters, Cutting Teeth (Edges) and Cutting Widths.

 Groove Milling, Parting Off and Gear Cutting: these are just three processes that the Horn circular interpolation milling system accomplishes productively. As a true all-rounder, the extensive tool portfolio of this tool system tackles several other milling tasks as well. It can be used from an inside diameter of 8 mm for precise boring, for slot milling of narrow grooves from a width of 0.2 mm or for milling splines. The system has proven to be a problem solver in its numerous standard variants, as well as in special custom shapes for other milling processes.  

The circular milling system from Horn offers the user a number of advantages: it is fast, reliable and achieves good surface finish. The tool, which is interpolated on a helical path, plunges into the material either at an angle or almost horizontally. This makes it possible, for example, to produce threads reproducibly to high quality. Compared to machining with indexable inserts for larger diameters or solid carbide cutters for smaller diameters, circular milling is generally more economical. Circular milling cutters have a wide range of applications. They machine steel, special steels, titanium, aluminium and special alloys. The precision tools are particularly suitable for groove milling, circular interpolation of holes, thread milling, T-slot milling, profile milling and gear cutting. However, they are also effective in special applications such as milling sealing grooves or machining connecting rods.

 

The Horn milling system provides vibration-free cutting even with a long overhang.

Milling of Splines

The production of splines on a drive shaft had the potential for improvement. The shaft, which is 200 mm in diameter, almost 5,000 mm long and weighs around 600 kg, is used in the construction of large engines. The user previously had the teeth machined externally. Horn suggested that the spline teeth be machined using its 635 circular milling system in the same set-up as the turning operation. The special profile of the tool’s six teeth matches the nominal profile of the tooth flanks on the workpiece. The overhang of the tool is long due to the cutting conditions but the vibration-damping solid carbide shank means there are no problems with tool vibration. All Horn tools for circular milling have an internal coolant supply. The precise interface between shank and insert allows micron-accuracy concentricity and run-out of the insert during changeover. Roughing and finishing are done with the same tool. In addition to the significantly faster production time and the elimination of subcontracting out production, the quality of the splines has also increased.

 

Slot milling a with the Horn 606 Circular Milling System

Slot Milling in Micromachining

Another application example is the machining of a valve component. The workpiece has a diameter of 1.6 mm and a length of around 3 mm. To enable the valve to be adjusted, a 0.3 mm wide by 0.5 mm deep slot has to be milled on the face of the component. The user previously machined the slot with a fine HSS saw blade. However, the variable stability of the process offered the potential for improvement. Horn solved this problem with its 606 milling system. The six-edged insert with a cutting width of 0.3 mm provided the user a secure milling process.

Horn has expanded the circular milling system to include tools for producing narrow grooves. The enlargement of the tool system offers the user the possibility to produce narrow grooves less expensively. Horn supplies the tools in cutting widths from 0.25 mm to 1 mm as standard, depending on the diameter. The maximum milling depth tmax is between 1.3 mm and 14 mm, also depending on the tool diameter. Subject to the material to be machined, the cutting inserts are available with different coatings. The solid carbide tool shank, due to its mass, ensures vibration damping during milling. All variants of the tool are equipped with an internal coolant supply.

These are just two application examples of the many possibilities offered by the Horn circular milling system. The flexibility in the design of the cutting edges, the precise interface between the cutting insert and the shank, the numerous diameter variants as well as the different numbers of teeth that may be milled per insert characterize this tool system.

HORN: New FB Geometry for Groove Finishing

New Geometry for Finishing Grooves

Paul Horn GmbH is proud to present the FB geometry, a solution for finishing grooves.  The new geometry has been in response to user requests for even better surface quality on the flanks and at the base of a groove or recess. This geometry has already been in use successfully for some time as a special solution for producing grooves for sealing rings and shaft seals. High surface quality is possible without any problems in the finishing process, even when the conditions are unstable. Horn offers the geometry for a variety of systems for external and internal grooving.

The geometry is available as a standard tool for the 224, 229, S34T, 315 and 64T systems for precision machining of external grooves. For internal machining, it is available for the 105, 108, 111, 114 and 216 systems. Further insert types are available as special tools and can be delivered quickly via the Greenline system, whereby it is possible to deliver up to 50 customized inserts, depending on the design, within five working days after approval of the drawing by the customer.

HORN: Grooving System 32T on Swiss-Type Lathes

Grooving System 32T on Swiss-Type Lathes

HORN has developed the new 32T system for use on Swiss-type lathes and for grooving and parting off on smaller fixed-head lathes. There is no need for clamping elements, which could potentially have a detrimental effect on chip flow. The head of the clamping screw does not introduce interference contours and therefore permits both grooving and parting off directly at the spindle. The precision-sintered grooving insert can be used as a neutral insert and as both a left-hand and a right-hand insert.

 

 

Please contact us for more information on the new 32T System for Swiss-type lathes.

 

HORN: New Cassette Holders for S224 Grooving System

New Axial Cassette System S224

HORN has expanded its range of face grooving products with new cassette variants for the S224 Grooving System.

 

HORN has extended its modular concept so that various types of cartridge can be clamped using a single base holder. The high coolant pressure ensures improved chip removal from the groove. Thanks to the wide range of chipbreaker geometries and substrates available with the S224 double-edged system, the tool system can be easily adapted to the machining task as well as the material to be machined.