Feature Article

Part I: The author discusses how to maintain and repair machine tool spindles and what causes spindles to run out of round. Common sources of out-of-round spindles include loose bearings and improperly ground spacers. In-machine spindle repair is also discussed. Part II: There are three common ways to repair tapered toolholders: regrinding, replacing damaged material and chrome-plating.

The author discusses three recent advancements in electrical discharge machining: the use of linear motors on EDMs, wire EDMs with an automatic slug-removal capability and dielectric fluid additives that yield finer part finishes.

DNC can mean either Direct Numeric Control or Distributed Numeric Control. Either way, a DNC links a shop's computers and machine tools and saves times. A DNC eliminates manual transcription of NC data, the downtime caused by shop personnel having to make programming entries and transporting part programs between engineering and their machines.

The use of shrink-fit toolholders continues to grow, mainly because, compared to conventional holders, they secure tools more tightly and extend the life of cutting tools. Article includes an overview of available systems and comments from users of shrink-fit holders.

Due to the exceptional strength of IN 100, INCO 718 and other nickel-based alloys, they're difficult to machine. The author, who spent 40 years endmilling these aerospace materials, discusses their unique characteristics and methods for successfully machining them.

The author provides guidelines shops can follow when selecting a PC-based CAD/CAM system. Selection guidelines include: CAD functionality, CAM functionality, NC code output, vendor evaluation and hardware selection.

Metalworking companies have a "cradle-to-grave" responsibility for the fluids they use. Improper disposal can lead to costly fines. Article discusses the ramifications of improper disposal and how to develop a plan to constantly improve the condition of a shop's metalworking fluid.

Overview of the new machine tool technologies introduced at IMTS 2000. Among them are linear motors for axes travels, ballscrew chillers, a new way to lubricate linear guideways and controlling machining processes via the Internet.

Author discusses the advantages of CVD-diamond tools compared to other types of diamond tools. He also explains how CVD-diamond tools are manufactured and gives case histories involving their usage.

Equipping toolchangers with nylon abrasive-filament brushes can greatly enhance process economics and the flow of parts. Case histories of in-machine deburring operations support these contentions, and the author describes how such systems should work.

How to recognize the signs that lead to bandsaw breakdowns.

Discussion of different types of bonds used to make superabrasive grinding wheels. Author provides tables with price comparisons, physical properties and operating parameters for various bonds.