US 5,329,457 A · Comprehensive three-dimensional rotary tool point compensation

Abstract

The present invention provides a system and method to accurately provide three-dimensional rotary tool point compensation by evaluating a CNC machining center's geometric condition with respect to a trunnioned spindle mechanism of the machining center as it applies to the degrees of freedom of motion that affect the rotary tool point positioning of a cutting tool mounted in a tool holder of the spindle mechanism. The present invention evaluates the geometric condition of the trunnioned spindle mechanism by positioning the tool point in contact with a reference point or datum and recording a first coordinate position, then rotating the spindle mechanism 90.degree. about a trunnion axis and positioning the tool point in contact with the same reference point a second time. A second coordinate location is recorded when the tool point contacts the reference point the second time. The rotary tool point offsets are then determined from the two recorded coordinate locations and the coordinates of the tool point may be appropriately automatically compensated for the offsets during a machining operation.

Claims19

Dependent claims

A method for compensating for tool point position offsets of a computer numerical controlled (CNC) machining center of the type having a rotary spindle, wherein the spindle includes a tool holder at one end and is pivotably mounted for rotation about a spindle trunnion axis at an opposite end, the method comprising the steps of:

(a) mounting a spindle alignment bar in the tool holder of the spindle;
(b) positioning the spindle alignment bar in contact with a reference point;
(c) storing or recording a first coordinate location when the spindle alignment bar is in contact with the reference point;
(d) rotating the spindle alignment bar 90.degree. about the trunnion axis;
(e) positioning the spindle alignment bar in contact with the same reference point;
(f) storing or recording a second coordinate location when the rotated alignment bar is in contact with the reference point;
and
(g) determining at least one rotary tool point offset related to at least one degree of freedom of motion of the machining center from the first and second coordinate locations if the stored or recorded locations are different.

5 more elements

An apparatus for compensating for tool point position offsets of a computer numerical controlled (CNC) machining center of the type having a rotary spindle, wherein the spindle includes a tool holder at one end and is pivotably mounted for rotation about a trunnion axis at an opposite end, said apparatus comprising:

a spindle alignment bar mounted in the tool holder of the spindle;
means for positioning the spindle alignment bar in contact with a reference point a first time and for rotating the spindle alignment bar 90.degree. about the trunnion axis and for positioning the rotated alignment bar in contact with the same reference point a second time;
computer means for recording a first coordinate location when the alignment bar contacts said reference point the first time and for recording a second coordinate location when the alignment bar contacts said reference point the second time;
means for determining at least one rotary tool point offset related to at least one degree of freedom of motion of the machining center from the first and second coordinate locations;
and
means for compensating for said at least one rotary tool point offset by adjusting the coordinate locations of a tool point as the tool point moves to different locations during a machining operation.

3 more elements

Dependencies are inferred from the claim text.

Comprehensive three-dimensional rotary tool point compensation

Life of this patent

Comprehensive three-dimensional rotary tool point compensation

Life of this patent

Abstract

Claims19