Thread control method and system therefor
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsYuji Mizukami, Hiroshi Hashimoto
Life of this patent
Estimating the term…
Abstract
In a threading control system for performing a threading operation by moving, in synchronization with rotation of the main-spindle, either a cutter or a workpiece in the feeding spindle direction so that the ridge is not damaged nor the dimensional accuracy of the thread is lowered even if the main-spindle speed is variable, a threading computing section 3 and a main-spindle angle computing section 4 are provided to alter the threading start timing based on the servo-spindle acceleration time-constant of the feeding spindle.
Claims14
A threading control method for performing a threading operation on a workpiece by moving, in synchronization with rotation of a main spindle on which the workpiece is mounted, either a cutter or the workpiece in a feeding spindle direction which is a central axis direction of the workpiece rotated by the main spindle, the method comprising:
- outputting a thread-pitch command value and a programmed main-spindle rotation frequency by using a machining program;
- calculating a first servo feed rate of a feeding spindle that controls the cutter based on the thread-pitch command value and the programmed main-spindle rotation frequency;
- calculating a second servo feed rate of the feeding spindle based on the thread-pitch command value, the programmed main-spindle rotation frequency and a main-spindle override value received from an external source;
- calculating, when the workpiece is threaded either at a second feed rate different from a previous first feed rate, or on a second machine different from a previously used first machine, a main-spindle threading-start timing shift based on the first servo feed rate, the second servo feed rate, and a servo-spindle acceleration time-constant of the feeding spindle;
- and
- altering a threading-start timing to thread the workpiece based on the calculated main-spindle threading-start timing shift.
A threading control system for performing a threading operation on a workpiece by moving, in synchronization with rotation of a main spindle on which the workpiece is mounted, either a cutter or the workpiece in a feeding spindle direction which is a central axis direction of the workpiece rotated by the main spindle, the system comprising:
- a machining program analyzing section which outputs a thread-pitch command value and a programmed main-spindle rotation frequency;
- a threading computing section which receives the thread-pitch command value and the programmed main-spindle rotation frequency output by the machining program analyzing section, and which calculates a first servo feed rate of a feeding spindle that controls the cutter based on the received thread-pitch command value and the programmed main-spindle rotation frequency, and which calculates a second servo feed rate of the feeding spindle based on the thread-pitch command value, the programmed main-spindle rotation frequency, and an override input received from an external source;
- and
- a main-spindle angle computing section which calculates, when the workpiece is threaded either at a second feed rate different from a previous first feed rate, or on a second machine different from a previously used first machine, a main-spindle threading-start timing shift based on the first servo feed rate, the second servo feed rate, and a servo-spindle acceleration time-constant of the feeding spindle, and which alters a threading-start timing to thread the workpiece based on the calculated main-spindle threading-start timing shift.
Dependencies are inferred from the claim text.