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In a typical machine-tool-axis positioning system, the workpiece is mounted on a table that slides along flat, straight guide ways. The table may be supported on the guide ways by rolling elements or by a thin film of oil or grease. A screw controls the table position along the guide way. The rotation of the screw in the nonrotating nut that is fixed to the table drives the table left or right. The rotation of the motor translates into linear table position through the pitch of the screw.

The cutting zone in a machine tool is dangerous. Hot chips and large quantities of coolant are often safety threats, but a tool rotating at a high speed is an even greater one.

Capacitance sensors are noncontact sensors used in machine tools to measure the distance between a noncontact probe and a target sensor. Because the probe does not physically touch the target, capacitance sensors are beneficial in instances where the target surface is moving, such as a rotating spindle, or delicate, such as a silicon wafer.

The Machine Technology column in the December 2014 issue of Cutting Tool Engineering discusses the essentials of tapered spindle connections.

The advantages of preloading ball nuts.

Scraping is one of the oldest and most historically significant metal-removal processes, notes Dr. Scott Smith in his Machine Technology column of the September 2014 issue of Cutting Tool Engineering magazine.

The Machine Technology column in the August 2014 issue of Cutting Tool Engineering magazine reviews the use of the reversal technique in machine measurement.

Dr. Scott Smith of the University of North Carolina at Charlotte discusses the benefits of hydrostatic bearings in his Machine Technology column for the July 2014 issue of Cutting Tool Engineering.

There are many reasons for cutting force to vary, even during stable milling. These include tool teeth entering and exiting the cut, instantaneous changes in chip thickness, and tooth orientation changing as the tool rotates. However, it is possible to arrange the cutting conditions in a simple way and keep the cutting force constant.

The importance of using dry compressed air.

The rotating elements in machine tools often generate unacceptable forces due to unbalance, and manufacturers usually take corrective action to reduce the forces.

Spindle designers deal with lubrication and heat problems in three common ways: chilled oil, oil mist and air/oil injection.

Many machine tool spindles are supported in the housing by rolling-element bearings. Cutting forces, spindle unbalance and spindle preload impose cyclic loads on the bearing's balls and races. Over time, the cyclic loading produces fatigue failure, damaging the surfaces of races and balls. This kind of damage causes vibration and noise, limits bearing life and eventually requires bearing replacement.

The vertical linear axes on machine tools are fundamentally different than those that operate parallel to the ground. This is because the actuators on the vertical axes have to overcome the effects of gravity.

Many machine tools are equipped with touch-trigger probes to measure parts while they are still on the machine. The probe is often stored in the tool magazine and can be installed in the spindle like any other tool.

The Machine Technology column in the October 2013 issue of Cutting Tool Engineering offers guidance for protecting spindles from contamination.

Part manufacturers are always challenged to achieve toolholding connections that are simple, repeatable and stiff, and shrink-fit toolholders provide those requirements.

Spindle bearings support the spindle in the housing and transmit cutting forces to the machine structure. The bearings are intended to hold the spindle accurately in position.

Two basic strategies exist to minimize the Abbé error in machine tools: eliminate the causes or compensate the result, according to the Machine Technology column in the July 2013 issue of Cutting Tool Engineering magazine.

Getting a handle on heat in high-speed spindle bearings.

Measuring machine tool vibration with piezoelectric accelerometers.

A telescoping ball bar is a simple, but useful device that provides a quick and inexpensive way to characterize machine tool errors.

Real-time measurements during metalcutting can offer significant insight into machine tool performance. The parameters to be measured include position, velocity and acceleration of the axes; cutting force; sound; temperature; and acoustic emission, which is not the same as sound, but rather a high-frequency, structure-borne vibration.

Milling sounds range from loud to quiet, and experienced machinists <br />often use those sounds to judge what is occurring in the cutting zone. It is difficult to position a sensor such as an accelerometer or a displacement probe close to the cutting zone, and it is often a challenge to see the cutting zone, but the sounds are pervasive.

The accurate positioning of the cutting tool with respect to the workpiece partly controls the accuracy of a machined part.

The moving elements of a machine tool have mass. Forces from the actuators cause the masses to move and accelerate. As the speed of the machine tool motion increases, the ability of the actuators to cause acceleration becomes more important.

The Machine Technology column from the April 2011 issue of Cutting Tool Engineering magazine suggests that successful milling requires managing multiple constraints.

Machine Technology column for December 2009 issue.

Machine Technology column in October 2009 issue of Cutting Tool Engineering magazine.

In recent years, monolithic machined aluminum components have been replacing sheet metal assemblies throughout the aerospace industry. The monolithic structures are lighter, less expensive and stronger than their conventional sheet metal counterparts. Machining the components requires fewer special tools, fewer hand operations and less assembly time.

The creation of a part program for a CNC machine tool usually starts with a part drawing or model that contains the part material, geometry and tolerances.

Machine tool users can access the information contained in a stability lobe diagram to greatly increase productivity.

Machine Technology column for June 2009 issue.

Machine Technology column for May 2009 issue of Cutting Tool Engineering