Optimal tooling solutions and technical support enhance thread quality and machining efficiency in alloy steel component production for the wind power industry
The energy industry provides fuel necessary for our daily lives and requires precision machining of large parts and difficult-to-machine materials that can withstand various hostile conditions. OSG offers optimized cutting tool solutions for the most demanding requirements of power generation metal cutting.
Recently, a technology company located in Dalian, Liaoning Province, China, whose name cannot be disclosed due to confidentiality reasons, was seeking for a tapping solution for a wind power speed increase locking plate made of SCM 440 alloy steel with a hardness of 36 to 43 HRC.
Founded in 2009, this company specializes in the production of precision components mainly for the wind power industry. It currently employs approximately 260 staff and has a production space of 320,000-square-meter. This client has been manufacturing wind power locking discs since the company’s founding and has an annual production volume of approximately 2,000 units. Each disc requires the drilling and threading of 36 blind holes at a thread size of M33 x 3.5. The drill hole size is D29.5 mm x 100 mm and the tapping length is 90 mm. The thread tolerance grade required is 6H. The parts are machined using a domestically made machining center (BT50) with external coolant applied.
Wind power locking discs made of SCM 440 alloy steel. Each disc requires the drilling and threading of 36 blind holes at a thread size of M33 x 3.5.
Without professional technical guidance, this customer used a CNC machine for the thread bottom hole and hole chamfering process, followed by a radial drilling machine to complete the threading. Although the processing cost was low, the disadvantages were obvious. The machining process was dispersed, and the workpiece needed to be repeatedly positioned during machining, which affected the accuracy of the final product and overall machining efficiency.
Initially, this customer used a domestic competitor tool for the drilling process and purchased OSG’s A-SFT-DIN (EDP# 10503923) for threading without consulting with OSG’s technical support team. Running the A-SFT-DIN spiral tap at a cutting speed of 10 m/min (100 min-1) and 350 mm/min in feed rate, the tool life was only 54 holes. OSG’s A-SFT-DIN employs a short flute design and has a flute length of 93 mm. It is a multi-purpose tap engineered for work materials with a hardness of less than 30 HRC. Based on these specifications, the A-SFT-DIN is not suitable for this application. Due to the A-SFT-DIN’s short flute geometry, chip evacuation is unstable in large and deep threading. As a result, the threaded part was badly chipped, tool life was short, and the surface roughness of the machined thread was poor. Soon after, the A-SFT-DIN was replaced by a competitor spiral tap, which averaged around 72 holes per tool. Although the competitor tap’s tool life was 1.3 times higher than the A-SFT-DIN, the quality of the machined threads was also poor. When the client sought help from the competitor’s technical support, the service provided was unsatisfactory. In 2020, this client became a direct sales customer of OSG China. Due to this change, the client decided to reach out to OSG China for technical support regarding this application in 2021. Once in contact, sales representative Dong Yu and applications engineer Chong Zhao from the OSG Shanghai office immediately followed up by visiting the customer’s production plant. Upon a detail evaluation of the application, the pair recommended OSG’s Phoenix P3D indexable drill (P3D2950FS32M09 tool body and grade XP9020 XCMT094008ER-DM inserts) for the bottom hole machining as well as the non-standard V-CPM-SFT M33 x 3.5 spiral tap (EDP# T2115526) with a flute length of 123 mm for the subsequent threading process.
The Phoenix PD indexable drill features a unique flute design with high precision finish and integrated chip breaker. It is engineered for efficient and stable hole-making up to 5 x D. A broad insert lineup is available to accommodate various work materials, such as steels, stainless steels, cast irons, aluminum alloys, and non-ferrous metals.
The Phoenix indexable drill series consists of four length sizes – 2D, 3D, 4D and 5D, and is designed for reliable and highly efficient drilling of large holes. The high precision finishing of this series’ flute surface dramatically improves chip ejection to eliminate common deep-hole machining problems such as chip packing, elongation of chips and tool breakage. Its unique flute design features both high rigidity and superb chip evacuation. With an attached breaker to the cutter body, cutting chips can be broken into small pieces. Thanks to the above features, high-feed machining can be achieved to maximize efficiency even under rigorous 5 x D deep-hole drilling. This series offers a broad insert lineup to accommodate a wide range of work materials, such as steels, stainless steels, cast irons, aluminum alloys and non-ferrous metals. All inserts incorporate an economical 4-corner design that can be applied to both the center and peripheral cutting edge and are applicable to every cutter body in the series to simplify tool management.
OSG’s V-CPM-SFT is a custom powder metallurgy high speed steel spiral tap. Its tool geometry is uniquely engineered with superior chip evacuation to prevent cutting chips from getting tangled during machining.
OSG’s V-CPM-SFT is a custom powder metallurgy high speed steel spiral tap. Its tool geometry is uniquely engineered with superior chip evacuation to prevent cutting chips from getting tangled during machining. With the addition of OSG’s original V coating, long tool life and stable performance can be achieved.
The V-CPM-SFT was tested at a cutting speed of 13 m/min (125 min-1) and a feed rate of 437.5 mm/min. Although the V-CPM-SFT had the same tool life as the competitor tap (72 holes), the thread surface quality is significantly better. Moreover, cutting condition has improved by 25 percent and the need for radial drilling has been eliminated, contributing to greater machining efficiency and quality.
Left, hole threaded by OSG’s V-CPM-SFT. Right, hole machined by a competitor tap, which exhibited galling.
With the previous processing method, it used to take approximately 32 minutes to complete a part. By leveraging OSG’s advice, all of the machining processes are consolidated on a CNC machining center. The total processing time required to complete a part decreased to 22 minutes, which is 10 minutes faster. OSG’s proposal helped the customer optimize machining processes, reduced the number of defective products by improving the surface quality of threads, decreased tooling costs, and improved machining efficiency by 30 percent versus the competition.