TABLE OF CONTENTS Dwell is another name for a pause in the program - it is an intentional time delay applied during program processing. In this period of time - specified in a CNC program - any axis motion is stopped, while all other program commands and functions remain unaffected. When the designated time expires, the control system resumes processing the program with the block immediately following the block that contains the dwell.
Programming a dwell is very easy and can be quite useful in two main applications:
During actual cutting, when the tool is in contact with material
For operation of machine accessories, when no cutting takes place
Each application is equally important to programmers, although the two are not used simultaneously.
When cutting tool is removing material, it is in contact with the machined part. A dwell can be applied during machining for a number of reasons. If the spindle is running, the spindle rotation is very important.
In practice, the application of a dwell during a cut is mainly used for breaking chips while drilling, counterboring, grooving or parting-off. Dwell may also be used while turning or boring, in other to eliminate the physical marks left on the part by end thrust of the cutting tool. This thrust is the result attributed to the tool pressures during cutting. In many other applications, the dwell function is useful to control deceleration of the cutting feed on a corner during fast feedrates, for example.
