DE2418288A1 - NUMERICAL TOOL CORRECTION IN A MACHINE CONTROLLER, IN PARTICULAR IN A FLUSH CUTTING MACHINE CONTROL - Google Patents

Description

11 APR

SIEMENS AKTIENGESELLSCHAFT Erlangen, * I. «ι η.

Berlin and Munich Werner-von-Siemens-Str. 50

Our reference: VPA 74/3078 Ch / Ar

Numerical tool correction in a machine tool control, in particular in a flame cutting machine control

The invention relates in particular to a numerical tool correction in a machine tool control in the case of a flame cutting machine control, in which the contour of the workpiece to be manufactured in a sequence of blocks is programmable and the center point of the tool, in particular the cutting torch, through each corrected blocks are guided on a path that is shifted by the tool radius in relation to the contour and in which the end point of the current corrected record and the starting point of the following corrected record from the The intersection of the corrected curves can be determined.

With the interpolation, the path section to be calculated point by point is in a block to be followed by the respective Path curve and start and end point of this curve are determined. When using a milling cutter or a burner must the center of this tool can be guided on a corrected path that is opposite to the tool radius the programmed workpiece contour is shifted. For this purpose, the individual blocks in which the workpiece contour is described, corrected accordingly and at the same time the end point of the current block and the start point of each The following corrected sentence from a minor discussion of the equations of the two associated corrected Records determined (see e.g. DT-OS 2 219 705). "

5098U / 01QQ

- 2 - VPA 74/3078

If a path section with a linear curve equation hits the workpiece, i.e. a straight line and a non-linear curve, such as a circle, result from the Equations of the corrected curve segments in general two intersection points for the end and start points, the are available to the controller.

The object of the present invention is to provide a criterion with which to control the technologically Usable intersection point, i.e. end point of the current or starting point of the following corrected block determined can be.

According to the invention, this object is achieved in that if there are several points of intersection, the distance between them is in each case Intersections and the predetermined intersection of the curves of the corresponding uncorrected sentences can be determined and that the end or starting point of the corrected sentences is that point of intersection which has the minimum amount of distance assigned.

In this way, the controller can determine automatically which value is useful for the subsequent interpolation, so that programming in this regard is simplified, or a subsequent ongoing change in the radius, e.g. by entering a correction value without special consideration of this circumstance is possible.

The invention will be explained in more detail with the aid of a drawing; show it:

Fig. 1 shows a conceivable course of the workpiece contour and Tool center point path and

2 shows the computation or control sequence in the machine control.

509844/0100 _ ₃ _

- 3 - VPA 74/3078

The contour K of the workpiece to be manufactured is described, for example, by a series of sentences S- ^ with starting point A- ") and end point E ^) (> ^ = 1,2..n, n + 1). As can be seen from the drawing , the end point of the current block, e.g. E, coincides with the starting point A * of the following _{block S n + 1. The} program now provides the control, e.g. a computer, with the start and end points and the equation of the curve to be traveled between The path B of the burner center point must be reached from this predetermined curve, which is offset by the correction value Δr with respect to the contour K. As can be seen from FIG. and S '+1 by determining the points of intersection of the curves of the current and the following corrected set, ie for example the corrected point of intersection A' from the points of intersection of the corrected curves of the sets S ^f _n _. and S _n angs- and end points always result in clear values if the interpolation curves are straight lines; but not when linear and non-linear curves or two non-linear curves collide. In the present case it is shown that a straight line described by the sentence S is followed by a circle described by the sentence S +1. The one around the correction

The offset circle then forms two intersections with the straight line of the set S offset by the correction value A. r, namely E ¹ and E ¹¹ . For the automatic determination of the point of intersection that can be used for the control, the distances d,., D "between the original end point E described by the sentence S, which results for A r = Ό, and the two calculated corrected end points E ' , e "is determined and taken as the one endpoint technologically brauohbar for control, the minimum amount of the d spacings of the. or associated dg.

509844/0100

- 4 - - VPA 74/3078

As from the schematic representation according to Pig. 2, the corresponding arithmetic process takes place in the computer in such a way that the contour description originating from the input E is taken over in the form of programmed sentences in a program memory part PS . By discussing the points of intersection of the curves described in the programmed blocks with the aid of the correction value A. r, the individual corrected points of intersection are calculated in the point of intersection calculation part SP and the difference to the uncorrected point of intersection is determined in a difference part D. From the values determined in this way, a minimum discriminator M selects that value which supplies the minimum amount and returns the result to the intersection calculation part SP, which then forwards the correspondingly corrected record to the correction memory KS. From this, the sentences corrected in this way are then sent to the interpolation part I, which provides the required trajectories in the form of pulse sequences for controlling the machine WM.

Advantageously, the individual processes described above will not be implemented in individual control elements, but rather let them be carried out by the computer, which has also taken over the other control processes of the machine.

2 figures
1 claim

5098AA / 010Q

Claims (1)

- 5 - VPA 74/3078 Claim Numerical tool correction in a machine tool control, in particular in a cutting machine control, in which the contour of the work piece to be manufactured can be programmed in a sequence of blocks and the center of the tool is guided by corrected blocks on a curve that is shifted by the correction value compared to the contour, in which the end point of the current corrected block and the starting point of the following corrected block can be determined at the intersection of the corrected trajectories predetermined intersection point (E) of the curves of the corresponding, _{incorrectly corrected sentences (S, S 1} ) can be determined and that the end or starting point of the corrected sentences is the sonic point to which the minimum distance is assigned. 509844/0100 Blank page