Since its inception in 1969, Horn has evolved into a leading manufacturer of solid carbide tools and carbide, CBN and PCD indexable insert tooling. Globally, the business employs 1,400 people of which 930 are based at the Tübingen headquarters. In 2016 the company recorded sales of €275 million with annual insert production standing at nine million pieces.
Closer to home, Ringwood, Hampshire-based Horn Cutting Tools Limited is the wholly owned UK subsidiary. Headed up by general manager Mike Green, the company was incorporated in the UK in 2008, having previously traded as Horn UK since 1995.
Horn’s product range is wide-reaching encompassing tooling for grooving, profiling, parting-off, broaching, turning, threading, milling, boring and reaming. As Andreas Vollmer, Horn’s sales manager/board member explains, whilst the split between standard and special tooling – products designed to meet specific customer applications – is pretty much 50/50, it’s the latter that has taken the business into some interesting application areas.
“We have key customers operating in demanding industry sectors such as automotive, aerospace, oil and gas and medical and they inspire us to continuously improve our products, processes and services to meet their requirements,” he says. “In fact, since Paul Horn started the business 48 years ago, we have produced more than 125,000 individual, specific tooling solutions for our customers.”
Accounting for around 60% of its total business, the automotive industry is Horn’s largest market sector by some margin. Unrelenting technical progress means that things advance at a rapid rate and Horn has longstanding direct relationships with a number of automotive OEMs as well customers in the wider ranging supply chain.
Not surprisingly, the solutions developed by Horn for the sector tend to be application-specific and highly customised. A complementary growth area for Horn is the development of tooling solutions for the aluminium wheel industry. This encompasses both cast and forged wheels.
Forward thinking
The recent multi-million Euro investment in the Tübingen site is testament to Horn’s forward thinking plans and commitment to its customers and staff. The company marked the end of 2016 by moving into two new buildings for production and administration – effectively doubling manufacturing capacity. The investment amounted to more than €70 million.
“We are investing in our future,” affirms Horn’s managing director, Lothar Horn. “It will be especially beneficial for our customers as we continue to focus on speed of response to orders, top quality and precision.”
Covering an area of 3,500m2 across six floors, the new administrative building houses not only offices but also seminar rooms for customer and staff training. The new, 20,000m2 production facility – known as Plant No.2 – is located next to the existing factory. Completed and occupied in the summer of 2016, the two-storey structure houses toolholder manufacturing, the tool coating department and logistics.
The new production building has 1,100m2 dedicated to the coating department, twice as much as before. To supplement the nine coating systems it already had in place, Horn has invested in three new stations featuring HiPIMS technology. They are used to manufacture more complex coatings, to generate coloured layers and top coats and to increase coating productivity.
Horn has 75 machining centres, turning machines and other machinery for in-house production of all its toolholders and additional equipment. Automated guided vehicle systems will be introduced to transport materials, production orders and tools around the site, signalling a move towards Industry 4.0. With its capacity tripled, the new logistics centre is able to process customer orders quickly and deliver tools even faster.
But planning for the future doesn’t stop there. During the Technology Days press conference, Andreas Vollmer announced that similar levels of investment are planned for Horn in the US: “This will triple the size of Horn USA and will come to fruition in 2020,” he enthuses.
But plant is nothing without highly trained people so in line with a longstanding tradition of producing home-grown talent, Paul Horn GmbH is currently training 60 apprentices with 15 new apprentices recruited every year on a four year programme.
Technology Days
Horn’s Technology Days are popular and with more than 3,000 people visiting this year, the 2017 event continued the tradition with new technology, eight technical seminars and practical demonstrations from Horn and the 40 partner companies taking part.
The seminars embraced a number of technologies – from titanium machining, turbo and rotary whirling, gear machining, grooving and parting-off, through to micro-machining, milling, coatings, and carbide cutting inserts with sintered precision interfaces.
"We don't see our Technology Days as a promotional event,” Mr Horn adds. “We want to engage with our customers in order to advance technology, innovate and pool our knowledge. This is also why the presentations are application-specific rather than product focused.”
But often technology and products go hand in hand. At Technology Days 2017, Horn showcased a new milling tool, developed initially for machine tool giant DMG Mori, for manufacturing cyclo-palloid gears based on the Klingelnberg design.
The M279 milling system is intended for producing small batches and individual parts. The cut distribution of the 12-insert tool enables a high chip volume to be achieved with a low cutting pressure. A system was required that would save time and be at least 20% faster than existing methods involving the use of solid carbide tools.
A robust tool with indexable inserts was needed for taking full cuts on milling and turning machines, while also being suitable for simultaneous 5-axis milling using DMG Mori gearMILL – a Technology Cycle developed by the machine tool manufacturer that enables cost-efficient gear cutting to be carried out on standard machines with standard tools.
Horn met this challenge with the development of a new concept. Four S279 indexable inserts with 2mm corner radii are screwed into place on the face and eight tangentially secured 409 inserts, all with stable insert seats, produce an ideal combination. The fact that the rows of edges overlap enables the system to achieve high depths of cut.
A crown wheel made from 17CrNiMo6 with module 7.6 was used as a trial workpiece. The Klingelnberg cyclo-palloid gear was produced with vc = 250 m/minute and vf = 650mm/minute with full cutter engagement and the tooth flanks with vf = 2,000mm/minute.
With the development of the M279 milling cutter, Horn is extending its portfolio for the manufacture of gears in the 0.5 to 30 module range. In addition to the DS solid carbide milling cutters and the DG exchangeable head system for finishing tooth flanks, Horn offers solutions for rough machining in the form of the DAH high-feed milling cutter system. What's more, tool solutions for broaching internal and external gear teeth can be brought into play, subject to the application.
Titanium – a challenging material
The challenging subject of machining titanium has been a hot topic in the metalcutting world for several years now. In order to machine titanium materials such as Ti6Al4V, which is in widespread use in the aerospace industry, Horn has developed a portfolio of special tools that are able to overcome the main problems associated with processing titanium thanks to sharp cutting edges, a positive rake angle, a large relief angle and polished cutting edges.
For the specific purpose of machining titanium in the aerospace and medical technology sectors, the company has developed the cutting material grade TSTK for its solid carbide milling cutters, which exhibits good tribological properties, high temperature resistance and low discharge of heat into the substrate – therefore providing a sort of heat shield.
Another important aspect that had to be taken into account in the development of solid carbide end mills was to endow them with different helix angles and a different pitch. This results in a soft, low-noise cut and prevents vibrations. The titanium range from Horn comprises a completely new series of solid carbide milling cutters with diameters from 2mm to 20mm, four or five cutting edges and 2 x D and 3 x D versions.
For titanium, the high feed rate milling cutters of the DAH 25, 37 and 62 system are suitable for large structural parts. For turning applications, Horn recommends the tool solutions it developed for machining stainless steels, which are highly temperature resistant, sharp, available in grades EG3 and HP6, and feature excellent tribological properties. A substantial and targeted supply of coolant is essential for all types of machining.
Horn www.phorn.co.uk
