Tailored for Success

Custom S-XPF thread forming tap boosts performance and quality in wind power large-diameter application

Jie Zhu | OSG Shanghai

The energy industry is growing, and each day brings a new challenge. Renewable energy in particular, is a major global agenda. Needless to say, parts in this industry are just as big in size and are very expensive. Scraping a part can easily jeopardize the bottom line.

Recently, a renewable energy company located in central China’s Hunan region, whose name cannot be disclosed due to confidentiality reasons, was seeking for an improved threading solution for its production of embedded bushes for a world renowned wind power manufacturer.

Established in 2012, this company specializes in the processing of embedded bushes and ground anchor bolts used in the wind power industry. Currently, this company has more than 10,000 employees and operates in a 30,000-square-meter production facility. Among its product offering, the embedded bushes for wind power blades have occupied more than 80 percent of the global market share, making this company the largest supplier in the global market segment.

This end user has been business partner with the world renowned wind power manufacturer since the company’s founding. Made of 17MuV6, which is a kind of low-alloy steel specified by the client, the annual production of the embedded bushes is estimated at around 500,000 pieces. Each part requires the threading of a through hole at a diameter of M30 and a thread length of 120 mm. The accuracy tolerance must be within 6H. The parts are processed using a CNC lathe machine with a cutting parameter of 100 min-1 in cutting speed and a feed rate of 350 mm/min. Oil for internal cooling is applied at the center of the lathe spindle.

The embedded bushes are processed using a CNC lathe machine with a cutting parameter of 100 min-1 in cutting speed and a feed rate of 350 mm/min. Oil for internal cooling is applied at the center of the lathe spindle.

Originally, the end user was using thread turning tools for the application. However, the strength of the turned thread failed to meet the latest design requirement. The wind power manufacturer complained and requested the bushes to be processed using forming taps rather than thread turning tools.

The annual production of the embedded bushes is estimated at around 500,000 pieces. Each part requires the threading of a through hole at a diameter of M30 and a thread length of 120 mm.

To comply with the client’s request, the end user switched from thread turning tools to forming taps. The end user initially switched to a competitor standard forming tap for the application, which averaged 1,800 to 2,500 holes per tool. However, tool life was very unstable, and the cost per hole was high. In addition, the delivery time of the product was unsatisfactory. Seeking to achieve repeatable performance and quality, the end user’s process supervisor contacted its tool distributor for assistance, and OSG’s applications engineers were dispatched to the site to investigate the cutting condition.

According to the on-site situation and requirements of the end user, OSG initially recommended the S-XPF standard forming tap for the cutting trial. The tool life ended up being 700 holes, with the tap worn and thread gauge inspected not well. The customer required tool life to exceed 1,500 holes. The unit cost would be too high if the tap life can only reach 700 holes.

A standard S-XPF forming tap. In addition to standard items, OSG also offers custom tooling as well as modification and coating services to help manufacturers maximize productivity and quality.

In order to enhance tool performance, OSG’s applications engineers decided to change the base material of the S-XPF forming tap from the original high speed steel (HSSE) to powder high speed steel (CPM) because the wear resistance of CPM is more superior than HSSE. In addition, the engineers also optimized geometric parameters such as the number of flutes and the tip diameter to further increase tool life.

Through the implementation of a custom product, tool life increased to 2,100 holes under identical cutting conditions, which brought great surprises to the end user. With consistent performance and quality, the unit cost is estimated to be approximately 10 percent lower than the previous tool.

In addition to standard items, OSG also offers custom tooling as well as modification and coating services to help manufacturers maximize productivity and quality. At OSG, we know what is expected from today’s manufacturers – repeatable quality, reliable delivery, and maximum cost performance.

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