Increased tool life and greater cost efficiency with Walter Titex DC170 Supreme

By Niraj M Wanikar, Chief Editor, CNCTimes.com, 2015-11-05 12:34:10

It was a spectacular debut: When Feldmann-MAB GmbH applied for the manufacturing contract for rocker arm shafts for a new generation of engines, it was the new DC170 Supreme high-performance drill from Walter that provided the decisive advantage over the competition. The "Ikon of Drilling" landed the contract thanks to its advanced technology and the improvements in cost efficiency this yields.

"Prior to this new project, we always drilled using standard tools. But this time, these were completely new parts for an entirely new engine. We had to drill lengthways through differently sized rocker arm shafts made of very tough steel," explains Mr Udo Achterholt, Managing Director of Feldmann-MAB. This needed to be accurate and quick in equal measure.

"Without external help, we might not have been able to get it right because the positions and position tolerances are incredibly strict." To make things even more difficult, not even the tiniest amount of burr may remain in the drilled hole and the cross holes. The shafts are therefore thermally deburred as well.

Feldmann-MAB GmbH in Velbert is a company that is currently undergoing change and redevelopment, but has a long tradition. 2012 saw Feldmann become Feldmann-MAB (Metallverarbeitung Achterholt & Brögelmann) and it has some 30 employees at present. Nowadays, the company produces precision and CNC turn-milled parts as well as ground parts for plant construction, mechanical engineering, prototype construction, construction of industrial and marine engines and for (commercial) vehicles.

New parts required new solutions

For the upcoming rocker arm shaft project, the Tübingen-based manufacturer of precision tools, Walter AG, introduced the DC170 Supreme at exactly the right time. For Walter Deutschland field service employee Mr Udo Schuster, the situation of Feldmann-MAB is completely typical. Schuster says that "Customers often approach us with interesting requests. They are often not sure how they can carry out machining in an optimum manner. We can generally then assist them with one or more Walter products that are suitable for this precise type of machining."

This is confirmed by Mr Udo Achterholt. The engineer held the expertise of Walter employees in high regard even prior to joining Feldmann-MAB, when he was employed in positions of responsibility in large companies such as Ford and Knipex: "We actually always go directly to Walter with a new part and the demands made on us, and we get to work formulating proposals." When Achterholt took over Feldmann and brought his experience from the automotive industry with him, it was clear that he would get Walter on board. The decisive factor for him is that "The process must be correct in order to manufacture in a way that is cost-effective. Of course other companies also have good tools, but Walter is the best at getting the most from its tools." This now applies to the rocker arm shafts: "They are completely finished when they leave the machine; all we then have to do is subject them to deburring and vibratory finishing."

Accurate, long-lasting and fast

The shafts have to meet extremely high requirements. They are designed for gas engines in stationary generators that will go on to supply hospitals all over the world with electricity, for example. The cost of a station of this kind can quickly add up to around one million euros. This is all the more reason for Udo Achterholt to be pleased that the manufacturer is placing its trust in his relatively small company. "We are supplying the customer with a total of over 50 parts that were all initially sampled for the first time last year."
Mr Oliver Fischer, Head of Process Engineering, goes into detail: "We use Walter tools for all operations on shafts: Tiger tec® Silver indexable inserts for turning, the Proto·maxTM high-performance milling cutter for milling and the X·treme high-performance drill for the rest of the drilled holes." However, the most difficult challenge by far was drilling the long internal hole through high-strength steel heat-treated to 1300 N/mm².

Achterholt explains that "This kind of steel is particularly tough, making it difficult to machine. Nevertheless, the drilled hole must never run off-centre." The DC170 Supreme is at home in this material. Udo Achterholt and Oliver Fischer were impressed by three advantages offered by the new drill: Accuracy, service life and speed. As Fischer explains, "The DC170 Supreme allows us to achieve much higher cutting data than with our standard drills. The DC170 Supreme goes into the material like its butter and we don't ever have to peck in between." For Udo Achterholt, this drilled hole was also a key factor in Feldmann-MAB ultimately being awarded the contract for the shafts.

The bottom line: Much more cost-effective

In this material, a standard drill with a diameter of 5 mm achieves cutting speeds from 50 to 60 m/min and a feed rate of 0.08 mm/rev. According to Oliver Fischer: "We operate the DC170 Supreme at a cutting speed of more than 70 m/min and a feed rate of 0.15 mm/rev, i.e. more than twice as fast." The total time required for drilling the hole is even more impressive, as pecking is no longer necessary: Standard drills require approximately two and a half to three minutes to drill a hole but the Water Titex DC170 Supreme can do this in just 40 seconds.

Udo Achterholt calculates the costs involved in minute detail: "The total cost of ownership is significantly better, and the cost efficiency, the improved accuracy and the time factor are key here. This is why we're happy to pay a little more for the tool." Following this positive experience, all Feldmann-MAB tools are now to be gradually switched over to Walter products. And so that they are always immediately to hand, another major project is already on the horizon: The introduction of a Walter tool dispensing system.

DC170 Supreme – The Ikon of Drilling

The new type of land design is a key factor in the superior properties of the DC170 Supreme from Walter, and heralds a new performance class for drills. A large solid carbide mass in the direction of the cutting force directly behind the cutting edge ensures stability and therefore improved productivity. The drill withstands extreme mechanical loads for inclined exits or cross holes. Even for less demanding drilled holes, this results in significantly increased tool life and improved cost efficiency. The solid carbide mass also effectively dissipates extreme temperatures during drilling. The land design ensures that coolant is circulated significantly more effectively than it is in standard drills: Shallow grooves allow the uninterrupted passage of coolant while preventing hazardous swarf jams at the same time. The special land orientation minimises disruptive vibration. This ensures both operational smoothness and increased process reliability.

The DC170 Supreme drills can be reconditioned up to three times, until only two cooling channels are left remaining. Users who make full use of this now-visible regrinding potential can lower their manufacturing costs.

Product features of the DC170 Supreme at a glance:

• Maximum process reliability thanks to new type of land design

• Radial grooves allow lubricant to pass through and prevent the accumulation of chips

• Increased productivity thanks to 50% longer tool life with 35% higher workpiece values in comparison with conventional solid carbide drills

• Improved component quality thanks to continuous circumferential guidance

• Reduction in production costs thanks to optimum tool use

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