Turning
MAximum precision –
for perfectly meshed gears.
The gear wheels of a printing machine can have diameters of up to 1.20 m. In terms of manufacturing, the partners intend to continue their development work in the future in order to optimise the use of cutting tools.
The challenge lies in maintaining the required accuracy for each and every gear wheel.

Photo: Andreas Knopf and Niklas Kellner from Heidelberger on the gear wheel, Thomas Ament and Volker Gaber from ARNO Werkzeuge.

High-precision turning operations using high-positive indexable inserts from ARNO Werkzeuge deliver the required accuracy. The gear wheels used by the company Heidelberger Druckmaschinen mesh precisely with one another, yet are produced more economically thanks to optimised processes. The new indexable inserts have also increased tool life by up to 100%.

High-quality print products can only be produced with a high-precision printing machine. This begins with the internal fit of the gear wheels. Each printing unit is connected to the next printing unit via the gear wheel, which is optimally adjusted via the gear train. Unless the internal fit is exact to within one-thousandth of a millimetre, the toothing will not mesh correctly with the next gear wheel. Machines containing a larger number of printing units require a correspondingly larger number of gears, making the degree of precision even more important. This has a decisive effect on the quality of the high-gloss magazines with print finishing and high-quality printed packaging that are produced using Heidelberger sheet-offset printing machines. Unless the gears fit exactly into one another, positional deviations of the passing paper sheets will negatively affect the print quality.

Heidelberger Druckmaschinen AG (Heidelberg) manufactures high-precision and reliable digital and offset printing machines. For many years, it has been a major supplier and partner for the global printing industry with several production sites in Germany. The manufacturer has set itself the goal of integrating and automating its entire value-added chain for its customers, the print shops, thereby increasing their competitiveness. Heidelberger has around 11,500 employees worldwide. In Germany, highly automated and versatile high-tech machines in all format classes are manufactured in accordance with customer requirements. Heidelberger also wants to offer the best possible price/performance ratio for its customers. Its employees are encouraged to systematically review the technologies and cost-effectiveness of the components used in production. The goal is to keep workpiece costs as low as possible without affecting quality. In this context, Heidelberger only works with partners who are also constantly pushing forward further developments in this direction – partners such as ARNO Werkzeuge.

Indexable inserts as a cost-cutting tool

Harald Johann, head of work planning for cams, gears and model parts, and Andreas Knopf, technical expert for turning and tools at the company's Wiesloch-Walldorf location near Heidelberg, are responsible for the production of gear wheels for the offset printing presses. As part of an integral review of the existing production process for gear wheels, Heidelberger examined the indexable inserts being used in the turning process in detail. It concluded that these are certainly a cost-reducing factor due to their potential for increased tool life with a corresponding reduction in tool-change and calibration times. As a result of this investigation, Andreas Knopf was looking for an economically attractive alternative to the previously used indexable insert. ARNO Werkzeuge appeared to be a suitable partner – above all due to its expertise and product variety in the field of high-positive indexable inserts, which require only a minimum cutting force due to their particularly large rake angle and sharp execution. Supported by ARNO application technician Thomas Ament, Andreas Knopf attempted to use indexable insert TCGT16T308FN-ALU AL10 to carry out inside turning and finishing of gear wheels made from cast steel. The results were convincing – high-precision workpieces with good surface qualities.

Quality and know-how for tool-life increases of up to 100%

In the shortest possible time frame, the two companies developed an improved and cost-optimised workflow. Andreas Knopf feels the need to mention here that ARNO does not make empty promises. "The results we achieved in the field matched those that had been previously promised. In production, you quickly realise whether someone can actually put the theory into practice." This laid the foundation for further collaboration between Heidelberger and ARNO. A wide range of parts were inspected and new ARNO indexable inserts tested. This necessitated the machining of parts with extremely challenging tolerances. The quality achieved was not only very good, but the new indexable inserts also increased tool lifetimes by up to 100%, even with difficult-to-produce workpieces. "From the beginning, we concentrated on the specific applications. Thanks to our many years of experience, we were confident of one thing right from the start: we can solve these problems!" says Thomas Ament.

The excellent results are mainly due to the excellent surface quality and edge finish of the indexable inserts. These are achieved by ARNO thanks to very strict quality standards during the grinding process. If necessary, the cutting edges of some insert types are edge-honed after grinding to increase their stability. Depending on the application, further increases in tool life and smoother running are achieved. A 100% inspection of all manufactured indexable inserts further underpins the quality standards at ARNO.

Enormous savings with on parts with diameters of up to 1.20m made from 600 kilos of cast iron

Quality and reliability are also important criteria at Heidelberger. With a weight of around 600 kilos, the cast iron gear wheels have a material value of several hundred euros. For this reason alone, particular attention was paid to ensuring process reliability during the testing phase. Although the previously used inserts delivered good process reliability, ARNO Werkzeuge stepped it up a gear. "This really showed us that this tool manufacturer has a lot of experience, takes particular care and applies high quality standards," says Andreas Knopf. The new indexable insert runs without problems: "We are also receiving positive feedback from the workshop about the ARNO insert. For me, it's important that new products are approved by our employees and also prove themselves in actual practice!" From his extensive experience with indexable inserts, he knows that they are prone to damage caused by cavities. This costs additional time and money — a key factor given the lot sizes at Heidelberger, which range from 50 to 500 pieces.

Fast delivery and on-site consulting are standard practice at ARNO

One major advantage of this particular indexable insert is that, as a standard item, it is always in stock at ARNO with only a small minimum order quantity. By contrast, the special inserts that were used previously were subject to relatively large minimum purchase quantities. Punctual delivery, the stocking of enough indexable inserts to be able to react quickly to Heidelberger's requirements, as well as generally shorter delivery times — these were all important additional factors. One month's supply of the indexable inserts can usually be delivered within three days, thanks to precise coordination between the business partners. And thanks to the proximity of ARNO as well as its flat hierarchies and uncomplicated internal structures, it is sometimes even possible to drop off a few extra inserts directly to the customer.

However, Harald Johann emphasises: "Even if we are already good, we want to continue to develop. How can we explore new approaches together with ARNO?" The sheer variety of high-positive indexable inserts they offer creates plenty of room for manoeuvre here. In recent years, ARNO has repeatedly introduced new coatings to the market that successfully meet the requirements for a wide variety of materials and new alloys. "Coatings and cutting-edge alignment are two areas that can still be improved in terms of the end result," explains Volker Gaber, a Sales Engineer at ARNO Werkzeuge who works closely with Heidelberger. "We have our own in-house design and development processes as well as testing machines that are used daily." New indexable inserts must first prove themselves before they are placed on the market or used in customer tests.

Together, the course is being set towards an optimised future

A broad usage range is very important for Harald Johann when it comes to developing the machines. A reduction in complexity is also a major focus. This means using fewer indexable inserts for a wider range of applications. Understandably, he also wants to minimise both the degree of utilisation and downtimes. Furthermore, for both Harald Johann and Andreas Knopf it is fundamentally important to have a partner who works alongside you on the machine on site in the search for optimisation potential. The technical expertise of its internal and field sales staff and application engineers allows ARNO to more than meet these requirements and, in collaboration with Heidelberger, to lay the optimal foundations for the future. Both companies have already demonstrated their ability to master the challenges of process and cost optimisation. Andreas Knopf emphasises the openness of all parties involved in the face of both praise and constructive criticism. Finding solutions remains everyone's focus – which is why the partnership is so successful.

The high-positive TCGT indexable inserts with ALU geometry from ARNO Werkzeuge ensure optimum process reliability when machining cast steel.

Perfect teamwork: Heidelberger and ARNO Werkzeuge find solutions even for difficult-to-manufacture tolerances in the μ-range.

Outstanding
services inclusive

Any questions? Contact your personal ARNO contact person:

Write now Or Call +44 01785 850 072 ARNO (UK) Limited
Unit 9, 10 & 11, Sugnall Business Centre
Sugnall, Eccleshall Staffordshire | ST21 6NF