Several interconnected factors drive advances in cutting tool technology, including the demand for higher productivity and reduced cycle time, the emergence of new workpiece materials, the evolution of manufacturing processes, and government regulations.

 

The need to deliver higher volumes of product in less time is a permanent fact of today's manufacturing environment. And, as increased product demands exceed the capabilities of some large manufacturers, the practice of outsourcing to primary (Tier 1) and secondary (Tier 2) suppliers is rising steadily. It should also be noted that more than 50 percent of these suppliers consist of 100 employees or less. In order to stay competitive, these companies need tools and processes that can cost-effectively reduce manufacturing lead time while improving product quality.

 

Considering these requirements, it is obvious that machine tool designers and manufacturers have a tall order to fill. But the challenge doesn't end with meeting high production goals more quickly. For example, to achieve greater fuel efficiency and reduce engine noise, the automotive and aerospace industries are demanding stronger, lighter and more compact components with the ability to resist wear and heat. Consequently, as durability increases, these materials are also more difficult to machine. The resulting impact on the cutting tool industry is of significant concern in the areaofmilling tool inserts, where chip groove geometries and coatings, along with substrate composition, play a key role in tool performance.

 

The demand for more fuel-efficient cars and tracks, as well as European auto recycling mandates, has led to increased use of lightweight, abrasive materials such as plastics and aluminum. From 1980 to 1990, use of aluminum components in the typical mid-sized car rose from 3 to 5 percent. Plus, studies predict that aluminum components will soon make up 10 to 20 percent of a vehicle's total body weight, with engine blocks and cylinder heads as the weightiest contributors.

 

The production of quieter, more fuel-efficient aircraft engines and the replacement of aluminum with higher strength titanium alloys in airframe fabrication has led to the development of superalloys with higher purity, high temperature strength and toughness--three characteristics that make workpiece materials more difficult to machine.

 

Advances have also been made in the machining of superalloys and titaniumbased alloys. Development of microgram carbides and PVD coatings, along with improved understanding of how to apply ceramic and CBN cutting materials, have all contributed to higher metal removal rates and improved surface finishes.

 

These advances have been particularly useful for more effective machining of alloys that retain strength at high temperatures, such as those used in turbine engine production and other aerospace applications. Increasingly sophisticated production and processing methods make superalloys and titanium-based alloys both cleaner and tougher. As a result, average high temperature. strength is on the rise by about 12 degrees per year. These improvements, however, have a negative effect on machinability.

 

As high temperature strength increases, forces exerted on the insert cutting edge also increase, making C-2 carbide tools ineffective for machining many titanium and nickel-based alloys. However, these superalloys may be effectively machined using microgram carbides, which combine higher compressive strength and hardness than traditional carbide grades. By eliminating crushed cutting edges and severe depth-of-cut line notching, microgram carbide inserts provide longer tool life and enhanced performance in high temperature applications.

 

A fast-growing coating, PVD (physical vapor deposition), is another innovation for machining high temperature alloys.

 

As environmental laws grow more stringent, reducing the amount of coolant used has become a necessary concern for many parts suppliers, contributing to the growth of dry machining. Plus, in applications where its use is appropriate, dry machining can reduce total product cost by up to 15 percent, while eliminating the "hidden" costs associated with the disposal and pretreatment of metalcutting fluids.

 

For dry machining of steel at high feed rates, cutting inserts featuring alumina, PVD or TiAlN coatings, such as T150M, T250M and F30M from Seco-Carboloy (Detroit, Michigan), are suitable. High speed and feed rates reduce contact time with the workpiece, minimizing the tool's exposure to high cutting temperatures.

 

In addition to enhanced metalworking materials, the trend toward maximum productivity in minimal time has spurred the development of application-specific tools and specialized processes for various markets. For example, Seco-Carboloy now offers a comprehensive machining, product application and technical guide for the aerospace industry, as well as the Octomill OCM for enclosed cavity milling. The Octomill OCM features new inserts adapted for high feed machining of aluminum and operates with low power demand. Plus, for aerospace blisk milling of turbine engines, the company offers the Minimaster with new plunge milling inserts and geometries. For high speed machining of complex dies and injection molds, Seco-Carboloy has also added its new family of button cutters, including the CombiMaster end mill and shell mill styles, with a wide range of grades and geometries specific to the mold and die industry.

 

From: findarticles