Since the presence of coolant, which was water in this case, can increase the thermal cracking problem, the team decided to run the application dry to see what would happen. This change doubled tool life yet again to achieve 15 parts per corner, and now the failure mode was simply due to normal abrasive flank wear.

Interrupted cuts can be tough on tools. The pounding tools take during interrupted cutting frequently leads to severe edge wear that cuts short tool life. However, by carefully analyzing the tooling wear pattern and making the appropriate grade and geometry changes, the ravages of interrupted cutting can be overcome.

The flange starts out as a 2.25-in. by 1.5-in. rectangular plate, which is rough-faced down to a hub in the center of the part. The company was taking three passes at 0.100 in. each and a final pass at a depth of cut of 0.050 in. The job was running on a Doosan 240 CNC lathe at 300 sfm and a feedrate of 0.01 ipr.

Imprint Cookie-Manager About Media Subscription cancellation Privacy General Terms and Conditions Help AI-Guidelines

Image

Image

Making its UK debut will be Horn's expanded DS range of solid carbide end mills with a new geometry for HPC (high-performance cutting) milling of high strength steels at elevated material removal rates. It particularly excels in dynamic roughing applications as well as in standard roughing cycles. Different helix angles create an irregular tooth pitch, making operation exceptionally smooth. The end mills are available in diameters from 2 mm to 16 mm as standard, with four or five flutes.

The tools’ optimised face geometry reduces the cutting pressure during linear or circular ramping. Improved chip spaces ensure optimal process reliability during chip formation and removal. The system also demonstrates good performance during finishing. Smooth operation means that high surface quality can be achieved during side milling, for example. HPC milling of high strength steels at fast metal removal rates places significant demands on the tools. New carbide substrates and new tool coating technologies make this process feasible. Horn relies on the ES3P grade, again with a HiPIMS coating.

The result was that Main Manufacturing saved 85 percent in cost as well as reducing machining time by 52 percent. “But even more exciting,” said Main Manufacturing general manager Bob Mackey, “is that we can take what we’ve learned from this experience and apply TM4000 to hundreds, maybe even thousands, of other similar jobs that we run.”

“We initially decided to run the TM4000 using the same parameters as a competitor’s tool,” said Seco’s Miller. “But, to everyone’s surprise, TM4000 performed no better than the competitive insert.”

The main advantage of MF4 is its positive cutting angle, which significantly reduces cutting forces to allow for higher cutting speeds and increased productivity. With the MF4 and the enhanced cutting data, the team was able to triple tool life and complete three parts.

The inserts are available in widths of 0.5 mm, 1 mm, 1.5 mm and 2 mm. For milling circlip grooves, Horn offers the system with cutting widths of 0.8 mm, 0.9 mm, 1.1 mm and 1.3 mm. In the case of the full radius versions, radii of 0.4 mm, 0.6 mm and 0.8 mm are offered. To enable the milling of chamfers, angles of 45, 30 and 15° are available. Regarding the substrates, Horn uses coated grade EG55 for general steel machining and IG35 for machining stainless steels and superalloys.

Reaming is an economical machining process. Compared to boring holes to tight tolerances, it is faster and can significantly reduce cost of production. Until now, reaming tools on the market in these larger sizes have been either special brazed tools or diameter-specific reamers with fixed inserts. With such tools, which tend to be delicate and heavy, replacing worn inserts is a complex process and calibration can be tricky for many users. Horn offers a practical alternative with its exchangeable-head, pre-calibrated DR-Large reaming tools and its customer service department offers quick and simple reconditioning.

This portal is a brand of Vogel Communications Group. You will find our complete range of products and services on www.vogel.com

Horn’s DS system for dynamic HPC milling excels at dynamic roughing as well as during standard roughing cycles. (Source: Horn)

“We went from removing 3.6 to 12.483 cu-in./minute,” Bettinger said. “With our in-cut time reduced by one half, our part output increased from 17 pieces per hour to 54 pieces per hour. The improvements were beyond our expectations.”

“However, this was far from the result that we had anticipated,” Miller said. “We examined the inserts under our magnifying loupe, but couldn’t see any particular failure mode.” Then Miller and Henige decided to take a good hard look under the microscope, which provides 60 times the optical power of the loupe. This closer inspection revealed that there was an edge-chipping problem. The chip flow was eroding the back of the land on the MF4. By the wear pattern, they also noted that a larger nose radius would help increase edge strength. As a result of this analysis, they recommended that Main Manufacturing increase the feedrate to 0.016 ipr using a 0.0468-in. radius. Because they didn’t see any other heat-related problems, they left the cutting speed at 650 sfm.

UK — At Mach 2022, Horn will present a modular system for reaming large diameter holes, an extended range of products for circular interpolation milling of holes down to 8 mm diameter, two new, high-performance coatings as well as an expanded range of solid carbide end mills.

A new, modular system for reaming large diameter holes has been introduced by Horn and will be on show for the first time in the UK at Mach 2022 in Hall 20, stand 340. Offering high precision, flexibility and easy handling, DR-Large reamers have exchangeable cutter heads with multiple solid carbide inserts, resulting in high cutting values, short cycle times and low costs. The interface of the insert seats has been designed to offer precise interchangeability to within a few microns and tool setting is unnecessary when exchanging the cutter head.

At the exhibition, Horn will explain the importance of two new, high-performance coatings, IG6 and SG3, it has introduced for the manufacture of carbide inserts used in turning applications. Despite being less than 0.005 mm thick, such coatings can extend service life by a factor of 10 or more compared to uncoated inserts.

Horn's SG3 coating is designed for machining titanium alloys and superalloys, as well as for hard turning and hard grooving applications. (Source: Horn)

In evidence also at the show for the first time will be Horn's extended range of products for circular interpolation milling of holes down to 8 mm diameter. The triple-edged 304 system offers a versatile, productive solution for internal groove, thread and profile milling as well as finish boring and chamfering. The insert has a cutting diameter of 7.7 mm. In conjunction with various vibration-damping carbide shanks, which feature an internal coolant supply, the tool is more economical and versatile than solid carbide milling cutters for machining smaller diameters.

Image

Horn's SG3 coating is designed for machining titanium alloys and superalloys, as well as for hard turning and hard grooving applications. It can withstand temperatures of up to 1100°C and is designed to deliver high performance when working with materials that are difficult to machine. Now that the advantages of the tool coating have been proven on selected Horn tool systems, the 105 Supermini grooving and boring system products are available from stock.

The substrate and geometry of Horn's 304 circular interpolation milling system can be easily matched to the machining process. (Source: Horn)

Main Manufacturing had been a long time user of tools from Seco Tools. Coincidentally, Seco had recently launched its new TM4000 Duratomic turning grades for stainless steel and was in search of a demanding interrupted-cut application. Seco’s sales and application specialists Joel Henige and Todd Miller asked if they could give the new grade a try. Seco Duratomic coatings rely on an alteration in the crystal structure at the atomic level, and have consistently provided both improved toughness and wear-resistance. In lab tests, the TM4000 construction had shown to improve resistance to crater wear and edge breakdown substantially.

For example, Main Manufacturing in Grand Blanc, Mich. – a family-owned business that produces hydraulic flanges and components – was experiencing short tool life and reduced productivity due to interrrupted cuts when machining high-pressure flanges from 304 stainless steel. “The severe interrupted cut was definitely affecting tool wear,” said Main Manufacturing’s plant supervisor Terry Bettinger. “We were only able to achieve about 1.5 parts per insert due to edge chippage.”

IG6 is a copper-coloured, aluminium-titanium-silicon nitride (AlTiSiN) coating for machining steels in groups P and M with Horn's S224 and S229 grooving systems. In conjunction with an adapted carbide substrate, the coating allows faster material removal rates and significantly extended service life. Standard inserts are available from stock, while for special designs, Horn Greenline orders can be delivered within five working days of the customer signing off on the drawing.

The Horn circular milling system offers users many advantages, including a high level of reproducible quality. It is fast, reliable and achieves good surface finish. During processing, the tool plunges into the material either at an angle or horizontally and is interpolated either in a circle, or helically to produce a thread.

“We were pleased,” said Main Manufacturing’s machinist Craig Bendle. “Productivity doubled relative to our original setup, and tool life jumped to seven parts per corner, which was seven times better than we were getting.”

“We knew that TM4000 was capable of high machining parameters,” said Henige. “So we upped the cutting speed to 650 sfm using the new MF4 chipbreaker, which is designed to provide consistent chip formation and breakage in stainless steel turning and other ISO materials.”

The versatile, interchangeable reaming system is suitable for bore diameters from 140 mm to 200.2 mm. Six cutter heads cover the range of diameters in 10 mm increments, with two sizes of head fitting on each size of reamer shank. Modular construction and an ABS-compatible interface means the tool can be extended to any length, in theory without limit. All reamers are equipped with direct internal coolant supply to each cutting edge.

However, Henige and Miller weren’t done with their analysis. Another pass under the microscope revealed that the failure was now being caused by thermal cracking. “Large differences in temperature between the cutting edge and the insert can cause cracks perpendicular to the cutting edge,” explained Henige. “Interrupted cutting applications such as this one tend to generate high heat when in the cut, causing these temperature fluctuations.”