Dr. Scott Smith

Articles • February 1, 2014 • Dr. Scott Smith

Vibrations indicate bearing damage

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.

Articles • January 1, 2014 • Dr. Scott Smith

Counteracting gravity

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.

Articles • December 1, 2013 • Dr. Scott Smith

The basics of on-machine probing

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.

Articles • October 1, 2013 • Dr. Scott Smith

Seals protect spindles from contamination

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

Articles • September 1, 2013 • Dr. Scott Smith

Shrink-fit toolholder fundamentals

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

Articles • August 1, 2013 • Dr. Scott Smith

Spindle bearing preload increases stiffness

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.

Articles • July 1, 2013 • Dr. Scott Smith

Minimizing Abbé machine position errors

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.

Articles • June 1, 2013 • Dr. Scott Smith

Managing heat in spindle bearings

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

Articles • May 1, 2013 • Dr. Scott Smith

Measuring machine vibration

Measuring machine tool vibration with piezoelectric accelerometers.

Articles • April 1, 2013 • Dr. Scott Smith

Measuring machine errors with a ball bar

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

Articles • March 1, 2013 • Dr. Scott Smith

Measuring performance in real time

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.

Articles • February 1, 2013 • Dr. Scott Smith

The science of milling sounds

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.