„At first we just couldn’t believe it all“

"At first we thought the statements about trebling tool life were the usual exaggerated promises made by many suppliers when they are rooting for new business," says Dirk Dürre, Technical Buyer at Schuhmacher Präzisionsdrehteile GmbH in Spaichingen. It is also due to Armin König, technical advisor at the tool manufacturer from Ostfildern, that things turned out differently in the end, since the predictions were confirmed. Arno Werkzeuge has now been Schuhmacher’s partner for over five years. When Armin König knocked on the customer’s door in 2017, he not had only promises up his sleeve, he could also prove with tests that were convincing. This impressed Dirk Dürre just as much as the knowledge that König showed about the processes.

Valuable process consulting also for experienced turning professionals

In the meantime, more than 100 tools from Arno Werkzeuge are in use. They include drilling tools, turning tools, parting-off tools as well as tool changing systems and holders, in particular AKB indexable insert drills, turning tools, SA parting-off systems and AWL tool holders. Finally, the Tool Management System from Arno Werkzeuge was also a convincing product as it supplies the right tools quickly, safely, project-related and space-saving.

With over 100 years of company history, it only stands to reason that the family-owned company of Schuhmacher Präzisionswerkzeuge GmbH knows a thing or two about turning. The experts for turned parts machine any material from plastic to aluminium through to all types of steel, such as 100 Cr6, 42CrMoV or 1.412. The series range from batch sizes of one unit to several million units per year. The customer base is correspondingly diverse. Well-known OEMs from the automotive industry are on their client list as well as medium-sized companies from the electrical or heating engineering sectors and small companies, for example from the medical engineering sector.

Customers in almost all countries of the world

The company produces parts such as connecting pieces, bearing bolts or distributor pieces as well as entire assemblies such as valve controls, chain tensioners or regulator valves. Drilling, turning, milling and grinding operations are carried out to manufacture all these products. 120 employees work on 56 machines on a production area of 4500 m², mostly in three shifts to ensure that parts are made of high quality and reach the customers all over the world in time. Currently, the parts produced include important transmission components for the electric drives of a well-known model made by a German truck manufacturer. "Both the precision of the required parts and the tolerances are more demanding than for similar parts in combustion engines," Dürre emphasises. The crank for a coffee grinder is in production for barista fans all over the world, "The number of components this entails should not be underestimated. Three machines produce precision cranks around the clock," affirms the engineer. Parts of the vaporiser assembly for shisha water pipes are produced on six machines. The parts are derived from ventilation machines used in the medical engineering sector.

Dürre relies on the three-flute ATS system, especially for parting off small components with small diameters. "We find various uses for it, for example in short, precision parting-off operations." The extremely stable system made of tried and tested substrates and coatings works very efficiently. A countersunk clamping screw ensures a rigid and precise tool clamp on the ground contact surface. The ATS provides a large cutting depth of 6.5 mm compared to its compact dimensions. Part-off widths start at a very narrow 0.8 mm and extend to 6 mm. Speaking of part-off width: Here, Schuhmacher benefits from the fact that one millimetre less width for a product can save no less than seven tonnes of steel per year. "In money terms, that’s over 21,000 euros," Dürre assures us. Since the system is so compact, the ATS system is perfect for shoulder grooving applications or with Swiss auto lathes. Variants with peripheral ground, sharp flutes are ideal for operations with low cutting pressure on thin-walled parts.

Stable clamping and low vibration for best quality

The two-flute SA grooving system with groove widths of 1.5-10 mm is also used in Spaichingen for parting off and grooving operations at cutting depths of up to 140 mm in diameter. Together with many modules, holders and blades, the parting-off tool is always optimised to the application. In addition, Dürre can rely on a wide range of machine-specific flange-mounted holders for many machine brands. He finds it important to be able to choose from six geometries, seven coatings and two solid carbide substrates to obtain the best possible cut on different materials. The SA grooving system is adapted to steel, stainless steel, aluminium or materials that are difficult to machine. It is a tried and tested product and ensures an uninterrupted cut for applications that require optimum chip breaking geometry, thanks to its negative chamfer geometry. “Chips tend to build up and jam in the groove, especially at parting-off,” says Dürre, from Streicher. “This is compensated for by using the right geometry,” says König, reassuringly. It also produces high-quality parting-off surfaces since the system works at low vibration due to its high stability, regardless of feed rate or cutting speed.

When combined with the patented ACS (Arno Cooling System), the is another enormous hike in productivity. Especially the ACS 2 version acts like a booster. In this version, the coolant channel at the insert seat is coupled with a second coolant jet from the bottom, trained onto the tool flank. The coolant channel is a 3D printed variant and has an optimised-flow, triangular shape which supplies coolant across the full width of the insert right through to outermost part of the cutting edge. "This is the main reason why tool life lasts up to three times longer compared to competitor products," explains König.

Dürre is equally positive about the AKB indexable insert drilling system, which allows his team to produce precision bores even on uneven, crowned or inclined surfaces. For turning operations, he swears by the AWL direct mounts with integrated coolant connection. Since it has been in use, the lathe operators on the machines no longer waste time installing complex or space-consuming coolant hoses.

Save costs and gain more machine capacity

But what all sounds like an exaggerated hymn of praise has only been achieved by all the hard work that Arno Werkzeuge has put in. All the test runs, tool consultations and, above all, meticulous post-calculations, have culminated in Arno not only gaining Schuhmacher’s trust but also contributing to massive cost savings. These savings are not only obtained through lower tool costs, they also come from gaining additional machine capacity or possible additional volumes. In one example, there is an additional machine capacity of 47 hours per year or 5,630 additional workpieces. On a single machine, for example, this saves 5,500 euros per year. So it can be well worth it when Arno expert advisors come knocking on the door, even if the promises first sound too good to be true.