Gain Resilience ~ CoroMill® Dura Solid Carbide End Mills Help Manufacturers Diversify ~

Querétaro /PRNewswire/ - "Multi-function, production and efficiency are great machining concepts," said American computer programmer and writer Ellen Ullman . "But are they really principles that feed human thought and imagination?" The answer is yes for machine shops, which are diversifying into new product areas to become more resilient but, in doing so, must deal with a broader range of tough materials. Here, Dr. Gaetano Massimo Pittalà, Principal R&D Engineer at Sandvik Coromant's solid rotary tools business unit, explains how its CoroMill solid carbide end mills® Dura can help manufacturers diversify with optimal production and efficiency.

According to McKinsey and Company , "The COVID-19 crisis, the post-pandemic economic effects, and the ongoing conflict in Ukraine have exposed vulnerabilities in today's global supply chains." To gain resilience in these uncertain times, manufacturers are diversifying to survive. For example, a Sandvik Coromant customer in the US has diversified from general engineering into other sectors such as aerospace, defense and medical, to the point where no one customer or industry accounts for more than 25% of its business. total.

In cases like this, diversification means producing new and hitherto unknown parts to close tolerances. But the challenges do not end there. According to another report from McKinsey and Company , "delivering products on time, with good quality and at the lowest cost is no longer enough." The report goes on to say that "organizations now need networks that have the resilience to withstand setbacks and the agility to respond to demanding customers and rapidly changing markets," and they must achieve this with "environmental and social sustainability."

However, diversification also means machining a wider range of difficult-to-machine materials such as aluminium, titanium and Inconel. How can machine shops overcome these challenges and at the same time achieve the goals outlined in the McKinsey and Company report? The answer lies in better tools along with machine tools.

Eliminate vibrations
First, let's take a closer look at the machining challenges. According to an analysis of system parameters for machining tough materials by The International Journal of Advanced Manufacturing Technology , "Chatter is more likely to occur in titanium milling due to self-excited vibrations (i.e., jolt) between the part and the cutting tool”, which also applies to other difficult-to-machine materials such as aluminum or Inconel.

Vibrations during a machining process have several negative consequences. These include degradation of surface finishes on the part, additional wear on cutting edges, and unpredictable cutting tool wear patterns. Vibrations create a negative impact on overall machining safety and can lead to increased energy use and costs, as well as impact part quality.

Naturally, these problems are exacerbated in machine shops that handle different materials as part of a diversification strategy. So what can you do? This was the challenge facing Sandvik Coromant's R&D team: to produce a complete range of solid carbide end mills that can eliminate vibration while being highly versatile in terms of application and materials. The range must be easy to use and outperform competitive tools in terms of productivity and lifespan.

That is why Sandvik Coromant has developed CoroMill ® Dura . The range comprises various solid carbide end mills, including carbide end mills of different lengths, diameters and designs with two, three, four, five and up to seven flutes. In addition, the range features a new Sandvik Coromant patented technology, known as WhisperKut TM , which has been developed to significantly dissipate harmonics while reducing shock and vibration.

WhisperKut TM technology stands out for its asymmetrical variable propeller design. It has long been known that optimizing spline spacing, along with other aspects of end mill design, can greatly reduce vibration and jolt in machining. However, with WhisperKut TM technology , each cutting slot is oriented at a different helix angle relative to all other slots, allowing for good stability and efficiency in removing damaging harmonics. Since each slot is unequally spaced from the others, this reduces constant harmonics that typically occur with conventional end mills.

That's why CoroMill ® Dura solid carbide end mills, equipped with WhisperKut TM technology , are designed to be a unique tooling solution. End mills can be used in all processes required to produce a part, including roughing, finishing, semi-finishing, and ramping. However, it was also necessary to assess whether CoroMill ® Dura could outperform competitive cutters in terms of productivity and tool life.

versatile performance
The performance of CoroMill ® Dura in a side milling operation was then evaluated against a competitive carbide end mill. First, for the machining of a DIN 42CrMo4 ISO P chrome-molybdenum steel part and, second, for the machining of an AISI 304 ISO M stainless steel part.

The DIN 42CrMo4 part had a tensile strength (UTS) of 95 kg/mm ​​2 and a Rockwell hardness (HRC) of 39. The diameter of the tools (D) measured 12.7 millimeters (mm) with a stickout , that is that is, the distance from the tip of the tool to the point where the shank of the tool enters the tool holder, from 33 to 40 mm.

The performance of each tool was evaluated based on the total volume of material (cm 3 ) extracted from the piece. To achieve maximum chip volume (MRR), the tools worked at a cutting speed ( v c ) of 150/60 m/min, a feed per tooth ( f z ) of 0.04 a 0.1mm/tooth; with an axial depth of cut ( a p ) of 1 x D and a radial depth of cut ( a e ) of 0.5 x D. The tools were operated for a maximum of 60 minutes and a coolant was applied.

Different cutting data were used for the AISI 304 piece, which included a v c of 80/40 m/min, an f z of 0.05 mm/tooth, an a p of 1 x D and an a e of 0. 5 x D. Again, the tools were run for a maximum of 60 minutes and coolant was applied.

In the end, in the side milling of the DIN 42CrMo4 part, CoroMill ® Dura delivered more than 25% more performance compared to the competitive solid carbide end mill and more than 20% more performance in the side milling of the DIN 42CrMo4 part. AISI 304. Sandvik Coromant also tested CoroMill ® Dura against a tool from its own previous generation range and found the new tool to be more competitive, more economical and more productive.

Based on these tests, CoroMill ® Dura has proven to be a high performing tool for versatile applications. It is well suited to the needs of machine shops looking to expand into new industry segments, or increase their focus on small batch production. With these more advanced tools, machine shops can, to paraphrase Ellen Ullman , help machine shops gain resilience with maximum production and efficiency while fueling human thought and imagination.

To find out more about the benefits of the CoroMill ® Dura solid carbide end mill , visit the Sandvik Coromant website .

Sandvik Coromant
As part of the global Sandvik industrial engineering group, Sandvik Coromant is at the forefront of manufacturing tools, machining solutions and expertise that drive the industry standards and innovations required for the machining industry today and tomorrow. Training, extensive investment in R&D and strong collaboration with our customers ensure the development of machining technologies that change, lead and direct the future of manufacturing. Sandvik Coromant holds more than 3,100 patents worldwide, has more than 7,900 employees and is present in 150 countries.