News Releases

October 18, 2004

Development of "Hard Broaching System" for High Speed and High Precision Finishing of Hardened Works After Quenching

NACHI-FUJIKOSHI CORP. developed "Hard Broaching System" for high speed and high precision finishing of hardened works (50 to 62 HRC) after quenching, and brought it to the market.
A machine tool "Hard Broaching Machine" which responds to high speed with highly rigid structure and a precision cutting tool "Hard Broach" with high precision and long life were combined, and it will be provided to customers as a machining system. It efficiently removes deformation of works which occurs at quenching, providing a highly precise finishing surface.
Moreover, it substitutes for grinding finishing which was mainly used, enabling substantial reduction of initial and running costs.
We are going to work on the development of markets for hard broaching system in the machining fields of various high precision parts which need heat treatment.

1.Backgrounds and aims of development
(1)Accumulation of high speed, high precision and dry machining technology
  • Utilizing the synergy of cutting tools and machine tools, we have provided various machining technology as a system. We were quick to work on dry machining without cutting oil, and developed series of cutting tools and machine tools for dry machining.
  • We also made high speed MQL (semi-dry) machining practicable for high precision and high efficient broaching of complex-shaped works before quenching, and established a position with the biggest market share in the global market of both cutting tools and machine tools.
  • In promoting the market extension of broaching, we have worked on the development of hard machining technology to expand it into a field of finishing in which more precision and high efficiency are required.
(2)Sophistication of need for parts in auto-industry.
  • In the auto industry, need for high precision and high strength of parts has been recently increasing in order to pursue amenity of automobiles such as reduction of noise and vibration, and to improve fuel cost.
  • Demands for the reduction of cutting oil, longer life of cutting tools, and improvement of machining efficiency are also intensifying to reduce machining cost.
(3)Development of "Hard Broaching System" and its introduction in market

By the development of "Hard Broaching System" and its introduction in the market, we will provide a machining system with high precision, high efficiency and low cost for the finishing process of complex-shaped parts after quenching such as involute spline holes of transmission gears and ball grooves of CVT movable pulleys, which were difficult to machine in a cutting process.

2.Features of hard broaching
(1)"Hard Broaching Machine" achieved substantial high speed and high rigidity compared to conventional machines.
  • By applying an NC control servo motor, high speed cutting at 60 m/min is possible, and cycle time was drastically shortened. Actual machining time is only one second, and machining efficiency was significantly improved compared to grinding.
  • Machine rigidity and broach holding rigidity were improved. Tool life and machining precision were drastically elevated by reducing vibration at cutting.
  • MQL (semi-dry) machining is applied, so coolant is not necessary, and disposition of cutting chips is easy.
  • It is work move type, so the working place is lower and operationality is improved.
(2)"Hard Broach" is a coated carbide broach with high precision and long life.
  • Tungsten carbide which was cooperatively developed with Sumitomo Electric Hardmetal Corp. is applied for a cutting edge. It reduces abnormal abrasion such as chipping, and achieved longer life.
  • New coating with enhanced abrasion resistance and flaking resistance was applied and it enabled stable machining precision and longer life even in high speed machining.
  • It can be repeatedly used by re-grinding. (Re-coating is not necessary.)
  • Special design reduced broaching load and vibration at high speed cutting.
3.Target market and sales in future
  1. We will expand application to automobile parts and parts of various machines for which high precision is required after quenching. We will also work on the expansion of market and application. For example, we will encourage the switch from grinding to improve machining efficiency and reduce cost.
  2. We will develop this hard machining technology to other machining methods besides broaching.
  3. We will aim for the sales of 300 million yen in the fiscal 2005 and 1 billion yen in the fiscal 2007 as a hard machining system.