Category: Gear Cutting Solutions

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: Gear Cutting to the Power of Three

Gear Broaching,  Gear Milling and Gear Skiving – otherwise known as the technology cycles: gearBROACHING, gearMILL and gearSKIVING. Paul Horn GmbH and DMG MORI have launched a campaign covering these three core areas in gear cutting to demonstrate the high performance of the solutions that have been jointly developed through a combination of machine, cycle and tool. A major advantage is that many existing machines can be adapted to the individual processes.

The exclusive DMG MORI technology cycles assist shop floor programming for increasing productivity and safety as well as for expanding machine capability. The advantages are clear: up to 60 percent faster programming, error minimization through conversational programming, new technologies (gear cutting) and the technology know-how stored in the application software.

As far as the tool is concerned, Horn’s standard or customer-specific special tools may be used, depending on the process and application. When skiving internal and external gears, sizes up to module 8 are possible in gear quality up to ≥ 7. Gear milling with standard tools up to module 3 achieves a gear quality of ≥ 5. Gear quality of ≥ 9 can be achieved when gear broaching internal and external gears up to module 4.

To provide practical proof of these results, there will be numerous events and trade fairs in 2022 that will focus on the joint gear cutting processes developed as part of DMQP (DMG MORI Qualified Products). The first event will be the DMG MORI Open House in Pfronten from 9th to 21st May.

For more Info: www.PHorn.de/dmqp

HORN: Gear Skiving Solutions

 

Mastering Processes: Gear Skiving

More than a century ago, Wilhelm von Pittler filed a patent for gear skiving, which in 1910 was a revolutionary idea. However, the process has only found wider application in modern manufacturing since machining centres and universal turning centres with synchronized spindles and process-optimised software have made it possible to use this highly complex technology. Horn’s product portfolio includes a wide range of tools for skiving different gear geometries. Whether external gears, internal gears, spur gears, splines or even special tooth forms, all these tooth profiles can be produced extremely economically with skiving tools.

The system includes tools for highly productive production of internal gears, splines and other internal profiles as well as external gears close to interference contours. The most important advantages of skiving in these applications are the significantly shorter processing times compared to gear shaping, its use on optimised turning/milling centres, turning and gear cutting in one clamping and elimination of undercuts at the end of the tooth. Compared to gear shaping and broaching,  gear skiving offers production efficiencies of almost four to five times shorter cycle times. There is also the possibility of hard machining of gear teeth from solid. The skiving tools are designed for producing medium to large batches. Each tool is individually adapted to the application and the material to be machined, whereby the different tool interfaces are based on the number of teeth and module size.

Especially for internal gears, Horn delivers the advantage of short processing times when skiving larger modules. Large, rigid milling/turning centres are required with the requisite synchronization between workpiece and tool spindle. The larger the module, the more critical is machine rigidity. With a cut distribution between the left and right flanks, this issue can be mitigated by the tool. After gaining experience with small, solid carbide skiving tools, Horn used the know-how to address larger modules as well. Each application is evaluated for feasibility by the company’s engineers before discussions with the user regarding the tool design and recommendations for the process parameters, followed by project implementation.

Tooling System with Solid Carbide or with a Replaceable Heads

The system includes cylindrical or conical tools for modules from 0.5 to 2. The solid carbide monobloc version is available in diameters up to 20 mm and in a slim design. They are used for producing small modules and small components, preferably when a compact shaft is required due to the risk of collision. The cutting materials and coatings matched to the application produce high surface quality on the workpiece. For tool diameters over 20 mm, skiving tools with an interchangeable head system are used. The precise interface allows the cutting head to be easily exchanged within the machine without removing the holder. The carbide holder ensures high rigidity, wear resistance and precision. For larger modules, Horn relies on the use of a tool holder with indexable inserts. Especially with the WSR tool type, Horn offers the option of placing the internal coolant supply in front of or behind the cutting edge. This means that, depending on the application, blind holes, through holes or stepped bores can be machined with the most appropriate cooling.

 

HORN: Gear Teeth Deburring | AMB 2020 Technologieforum

Defined Chamfering Deburrs Gear Teeth in Seconds

Paul Horn GmbH has developed a process for precision deburring of gear teeth that represents a further advance in the world of gear production. Although gear teeth can be deburred relatively easily with brushes and discs, higher levels of precision and quality are being demanded, with the result that there is often no longer any scope for undefined chamfers at the tooth edges. So Horn has developed a technology – together with the associated production process – to enable the production of defined chamfers. It can be used, for example, to create a 45-degree chamfer on both sides of a module 1 gear wheel with 25 teeth in less than five seconds. A turn-mill centre with synchronised axes is required for this production process. However, users do not need any special workholding equipment. The solid carbide tools can be clamped in a standard collet, or in shrink-fit or hydraulic chucks.

The process is particularly suitable for machining gears in high volumes. The milling cutters are special tools and have to be individually designed for each gear tooth. Based on the application, Horn engineers will design the appropriate cutting edge geometry for the module, tip diameter and desired chamfer. Horn supplies the process data required for machining together with the cutter. Tool costs are low and quickly pay for themselves thanks to short machining times. The carbide substrate, tool coating and cutting edge geometry are all specially designed for each gear tooth material. As far as the actual machining process is concerned, the material is irrelevant. Chamfers can be milled into various steels, aluminium and plastics within seconds.

HORN: Bevel Gear Cutting Solutions | AMB 2020 Technologieforum

Cost-effective even for Small Batch Production

Paul Horn GmbH is expanding its range of gear cutting products. Horn’s new tool system for milling bevel gear teeth allows the complete machining of bevel gears on universal turn-mill centres. The system was created in cooperation with machine manufacturer INDEX and means that users no longer need any special machines to manufacture gears of this kind. It also allows all functional surfaces to be produced together with the gear teeth in one clamping. This enables high component precision, short lead-times, a very cost-efficient process and short machining times as a result of controlled machining cycles. With a universal turn-mill centre from INDEX, components with bevel gear teeth can be efficiently and flexibly manufactured, including in small quantities. This also makes the process attractive to small and medium-sized companies that would previously have bought in gears or had them manufactured externally.

For the process, Horn relies on its S276 and S279 double-edged indexable inserts, which are screwed on tangentially. This makes it possible to achieve a stable insert seat, which is particularly important during form milling. The tool does not have to be remeasured after the inserts have been turned around or changed because the inserts are precision-ground on the circumference. The milling body can be equipped to allow for different numbers of teeth and outer diameters when cutting gears. The process of developing the complete system (cycle, tool and clamping) called for a great deal of expertise on the part of both the machine manufacturer and the tool manufacturer. To implement the process, various types of INDEX machine with a “bevel gear hobbing” cycle are required. Horn offers the milling cutter bodies with the HSK-T40 and HSK-T63 interfaces. The profiles of the inserts are module-dependent and precision-ground.