Primeturning machining method facilitates competition among manufacturers

From the mid-1930s, three large manufacturers dominated the American automobile market: General Motors, Ford, and DaimlerChrysler. And so it continued for more than 70 years. However, competition among automakers is changing, both in the US and in the world’s top EV markets: Asia-Pacific, followed by Europe.

According to Matthias Hollweg in The Development of Competition in the Automotive Industry (The Development of Competition in the Automotive Industry), a chapter in the book Build to Order: The Road to the 5-Day Car (Make to Order: The Road to the 5-Day Car): During the heyday of Ford’s original series production, competition shifted from cost leadership to variety and choice. [y despus] For diversification through leadership in design, technology, or manufacturing excellence.

This applies to EV markets as well. These markets are emerging as more diverse and competitive than the automobile markets of years past, as large, established companies such as Porsche compete with smaller, globally expanding manufacturers such as Polestar. According to Statista, globally these companies are on par with China; In fact, six of the top ten best-selling plug-in electric vehicles worldwide in 2021 belonged to Chinese brands.

Competitive markets are changing the demand for parts for Original Equipment Manufacturers (OEMs). EVs have fewer, smaller and lighter parts, and have to withstand higher levels of torque from the electric motor. The parts must support higher energy efficiency and increased power density. This, of course, places high demands on parts, which has led to changes in material technology.

Sandvik Coromant estimates that this change will involve a continued increase in the use of high-strength steels, from about 15% of all materials used in car manufacturing in 2010 to 38% by 2030. These new materials, including clean and ultra-clean steels, are made from alloying elements and are able to withstand the above challenges such as increased electric motor torque levels because they contain less metallic impurities.

But how is this related to mechanization? With clean and ultra-clean steels, we see an increase in the plasticity of the material, as the lack of impurities in the steels translates into machining challenges related to breakability and chip removal. These materials have high yield strength, which, in turn, requires high cutting strength during machining and creates high levels of tool wear. Although high-strength, clean, or ultra-clean steels are more difficult to machine, digitization and the increasing integration of computer-aided manufacturing (CAM) into production lines is raising the bar for quality and manufacturing efficiency.

These are the challenges automakers face, and those that don’t update their production processes or traditionalism risk being left behind. But how can manufacturers master the trends? The answer lies in better machine tools, but also in machining hard steels, in a new machining method designed to optimize quality and improve efficiency, cycle time and cost savings.

It is well known that effective chip control contributes to the productivity and reliability of machining processes as well as to the final quality of machined surfaces. Let’s take a closer look at chip control and see how it affects machining productivity and tool wear.

If the insert machine forms the part at an angle close to 90, the chip thickness will be equal to the feed rate (fn); Thus, at the end of 1 millimeter per revolution (mm/rev), the chip thickness will be 1 mm. If we reduce the penetration angle, the smaller it is, the smaller the chip thickness. We can increase fn accordingly. So, for example, if we decrease the penetration angle from 90 to 25 while increasing fn from 0.25 to 0.6 mm/rev, the chip thickness will remain the same. The result is more productive machining with similar levels of chip control.

To achieve this, Sandvik Coromant has created its prime turning method which includes machining with small entry angles to provide very high productivity and long tool life. The method allows customers to turn in all directions and thus can achieve greater efficiency and productivity than traditional turns. Thanks to primeturning, increased productivity and longer tool life are achieved for customers.

However, the process requires specific equipment to take advantage of these benefits. A conventional tool would not allow the same level of chip control, nor a suitable clearance angle, so in practice it would not work. For this reason, Sandvik Coromant has developed the CoroTurn PrimeTurning Tool, the latest development of which is the second generation of CoroTurn Prime Type B inserts. The new generation of tools includes double-sided negative inserts, designed for more cost-effective machining, with a new stronger nose seat design and updated geometry. With these features, the tool can perform high machining speeds (mm/rev) and fn as well as deep cuts (mm) with improved chip control when machining high-strength and other hardenable steels.

This benefits productivity, but what about equipment wear? This tells us about the design of the insert. With a conventional insert, machining with a small entry angle causes most of the heat and load to occur at the corner of the insert, which is also the weakest part of the insert with the least amount of carbide. Instead, each new generation Coroturn Prime Type B insert has four cutting edges instead of two, with stronger corners. With more cutting edges, more machining can be achieved with each insert, while the heat and load are spread over a greater portion of the cutting edge.

The second generation of Coroturn Prime Type B inserts has also been designed to address the problems commonly experienced when using inserts with large axial depths of cut ( Associated Press) and FN. This includes the risk of overloading and the risk of longer chips on the lower Associated Press and FN. In this way, machining operations can be performed at the very end to improve chip control, stability, process safety and tool life. For manufacturers, these higher standards of quality and efficiency can be met by implementing improvements in the machining stage.

The benefits of the primeturning method are further enhanced by digital CoroPlus tool path software. The software is a dedicated online toolpath generator, providing techniques and numerical control (NC) programming code to set appropriate parameters and variables for a particular machining application. When this precise cutting data is used in conjunction with CoroTurn Prime cutting tools, Sandvik Coromant customers achieve small entry angles, efficient edge use and no chip jams.

PrimeTurning also includes CAM software and programming support. For this reason, Sandvik Coromant has established strong partnerships with Mastercam, TopSolid, Siemens NX, CAMWorks and GibbsCAM to ensure that PrimeTurning and CoroPlus Tool Path are included in the most important CAM software packages. Machine shops that do not use CAM software can instead use the above CoroPlus Tool Path digital software to generate NC codes.

On one occasion, a Sandvik Coromant customer from the automotive sector wanted to perform roughing operations on a DIN 48CrMoV6-7 steel part on an EMAG VSC 250 lathe. The customer wanted to achieve high levels of productivity and tool life. their series production, but realized that adjustments to the equipment data would not be sufficient. Therefore, although this was primarily a roughing operation, the application must perform external discrete turning and facing using the primeturning method.

To do this, Sandvik Coromant recommended the second generation of CoroTurn Prime Type B inserts, which were tested against the customer’s existing inserts to assess the performance benefits of the forming tool. Each tool was used with a uniform cutting speed (VC) of 180 m/min and an axial depth of cut ( Associated Press) of 1.5~1.8 mm. However, the second generation Coroturn Prime Type B ran at more than twice the final speed of 0.65 mm/rev compared to 0.3 mm/rev for competing inserts.

Although the life of each insert was approximately the same, 9.58 minutes for the competing insert versus 10 minutes for the new generation Coroturn Prime Type B insert, a significant difference in productivity was observed. The competitor’s tool demonstrated a tool life of just 25 parts with a cutting time of 23 seconds per part. However, the life of a 50-part Sandvik Coromant insert was more than double this figure, as only 12 seconds, about half the time, was spent on each part. The second generation of CoroTurn Prime Type B inserts also feature more predictable edge wear and improved chip control.

Looking ahead, Sandvik Coroment expects its second generation Coroturn Prime Type B insert to yield similar benefits for other automotive customers, including EV manufacturers. By using these inserts within the prime turning method, manufacturers can save time when working with machine-to-machine material, along with the added benefits of increased tool life. With these machine tools and methods, automakers will be able to interpret Hollweg through leadership in design, technology, or manufacturing excellence.