The Sweet and Sour of Parting-Off Operations
Understanding parting-off operations.
Magazine Column
Feature Article
Tool, Mold & Die City
Meadville, Pa., and the area surrounding the city are home to approximately 150 precision tooling and machine shops. The article explains why this city of 14,000 is such a hotbed of precision machining and entrepreneurship.
Enhanced Performance
The use of compacted graphite iron is continuing to grow, particularly for automobile castings. The benefits of CG iron vs. gray cast iron are its ability to handle heat better and better machinability. The author gives an overview of the material's characteristics and discusses feed-and-speed considerations when machining CG iron.
Farewell to BUE
A new drill point geometry developed by a tool and cutter grinder. The through-coolant drill is ground in such a way that a hollowed out chamber on the face of the tip retains coolant in the cutting zone while hydraulic forces that are created push fluid to the cutting edge.
Under Development
Examined are four recent developments in cutting tool coatings: "smooth" diamond coatings, which incorporates that are nanometer-sized; a process that deposits diamond on carbide substrates via a laser; highly lubricious coatings for dry-machining operations; and a patented system for "locking" conventional coatings together.
Hardness at Work
The author gives an overview of the most common hardness testing methods: Rockwell, Brinell, Vickers and Knoop.
Heated Exchange
An expert on heat treating write about the advantages and disadvantages of available approaches and systems: stainless steel foil, atmospherically controlled furnaces, pressure-quench vacuum furnaces and two-zone vacuum furnaces. There's also a sidebar on cryogenic treatment of metals.
Going Deep
Tips for deep-hole tapping in titanium and other aerospace-grade materials. Advice is provided by NIST and the International Titanium Association.
Plugging In
A new turning tool emits an electric signal when its insert reaches a predetermined wear point or breaks. Called Sensor Tool, sections of the coated insert are ablated by a laser, thereby creating an electronic circuit.
CNC Lathe Options: What to Know Before Upgrading from Manual
A look at the various types of CNC lathes available to shops contemplating stepping up from a manual machine. The pros and cons of the following lathes are discussed: combination, cutoff, slant-bed, twin-spindle and turn/mill. The author also touches on available options.
Know Your Capabilities
Capability is determined by how well a process produces parts. Three measures of capability are important to a machinist: gage, machine and process. The author provides a detailed description of capability and suggests ways to quantify if a process is or isn't capable.
Steadying the Bar
Cutting forces cause the boring bar to deflect, which can lead to vibration and damaged workpieces. The author gives an overview of available boring bars and offers guidelines for selecting one for a specific application.