GB2151980A

GB2151980A - Method of generating a curved surface by a cutting operation on wood working machine

Info

Publication number: GB2151980A
Application number: GB08414831A
Authority: GB
Inventors: Yukitomo Suzuki
Original assignee: HEIAN IRON WORKS; HEIAN IRON WORKS Ltd
Current assignee: HEIAN IRON WORKS; HEIAN IRON WORKS Ltd
Priority date: 1983-12-29
Filing date: 1984-06-11
Publication date: 1985-07-31
Also published as: IT1176313B; FR2557492A1; IT8421599A0; DE3445661A1; GB2151980B; DE8436666U1; JPS60146610A; KR850004926A; GB8414831D0; FR2557492B1; KR860000075B1

Abstract

In a method of generating a curved surface having any required geometrical configuration by operating a working machine (5) with a plurality of cutting tools mounted on a tool head, each of the cutting tools is displaced with reference to coordinate values of the latter in the vertical direction as well as in the horizontal direction. The centre axis of a main spindle of the tool head is displaced on each of the cutting tools in the three dimensional directions relative to a workpiece to be cut, processing coordinate values identifying the track of displacement of the cutting tools with the aid of a microcomputer (2) while the centre axis of each of the cutting tools is located at a right angle relative to the curved surface at all time with a radius of turning of the cutting tools being inputted into the microcomputer (2) and operating the working machine (5) in accordance with thus processed coordinate values relative to the track of displacement of the cutting tools. All data relative to the track of displacement of the cutting tools is processed numerically on a numerical control tape preparing machine (3) to prepare a numerical control tape which is then inputted into a numerical control apparatus (4). Further, the processed data is visually displayed on a graphic display apparatus. <IMAGE>

Description

SPECIFICATION Method of generating a curved surface by a cutting operation on wood working machine.

The present invention relates to a wood working machine and more particularly to a method of cutting the surface of a workpiece to a predetermined curved configuration on the wood working machine.

As is well know cutting tool mounted on conventional wood working machines are adapted to be displaced only in the vertical direction above a workpiece to be cut. This causes a number of stepped areas to be formed on the surface of the workpiece when the latter is to be worked in three-dimensional directions. Accordingly, it is impossible to cut the surface ofworkpieceto a required geometrically curved configuration smoothly on a conventional wood working machine.

Hence, the present invention has been made with the foregoing background in mind and its object resides in providing a method of generating on a workpiece a curved surface having any required geometrical configuration by operating a working machine, wherein cutting operation can be performed without any formation of stepped areas on the workpiece.

According to the present invention a method of generating a curved surface having any required geometrical configuration by operating a working machine with a plurality of cutting tools mounted thereon comprises the steps of processing the track of displacement of each of the cutting tools with reference to coordinate values of the latter relative to cutting operations in the forward and rearward directions as well as in the leftward and rightward directions and cutting operations in the upward and downward directions as seen from the surface to be worked, displacing the centre axis of a main spindle on each of the cutting tools in the forward and rearward directions, in the leftward and rightward directions and in the upward and downward directions relative to a workpiece to be cut, processing coordinate values identifying the track of displacement of the cutting tools with the aid of a microcomputer while the centre axis of each of the cutting tools is located at a right angle relative to the surface to be cut at all times with a radius of turning of the cutting tools being inputted into the microcomputer, and operating the working machine in accordance with thus processed coordinate values relative to the track of displacement of each of the cutting tools.

In a preferred embodiment of the invention all data relative to the track of displacement of each of the cutting tools is processed numerically to prepare a numerical control tape which is then inputted into a numerical control apparatus.

Preferably, the processed data relative to the track of displacement of the cutting tools can be visually reviewed on a graphic display apparatus.

The cutting tools are usually arranged in the radial direction relative to a tool head on which they are rotatably mounted.

Alternatively, they may be arranged in parallel relation with their axes located in parallel with one another.

This invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a view schematically illustrating a system for carrying out a method for generating a curved surface having any required configuration by cutting operation according to an embodiment of the invention; Figure 2-1 is a plan view schematically illustrating the track of displacement of a cutting tool on a horizontal plane; Figure 2-2 is a fragmental vertical sectional view schematically illustrating the track of displacement ofthe cutting tool on a vertical plane.

Figure 3 is a fragmental vertical sectional view schematically illustrating how cutting operation is performed on the workpiece with the use of three cutting tools, Figure 4 is a fragmental vertical sectional view of the workpiece schematically illustrating how a cutting tool is displaced by unit distance on the workpiece; and Figure 5 is a schematic view illustrating how an angle of turning of the tool head and coordinate values in the x-z coordinate are processed at one point on the track of displacement of the tool head along which a curved surface is cut.

Referring first to Figure 1 a wood working router machine to which the invention is applied includes a coordinate reading machine 1, a microcomputer 2, a numerical control tape preparing machine 3, a numerical control apparatus 4 and a working machine 5. Specifically, the working machine 5 essentially comprises a head 6 with a plurality of cutting tools and motors for rotating the latter mounted in the radial direction as seen from the head 6, a servo-motor 7 for turning the head 6, a holder 8 with the servo-motor 7 fixedly mounted thereon, a sliding member 10 with a motor 9 fixedly mounted thereon which serves to displace the holder in the vertical direction, a servo-motor 11 for displacing the sliding member in the horizontal direction and a servo-motor 12 for displacing a table T with a workpiece W fixedly mounted in the forward and backward direction.

A plan view (Figure 2-1) indicating a track along which a cutting tool M1 is adapted to move in the forward and backward direction as well as in the leftward and rightward direction relative to the workpiece W to perform cutting operation and a sectional view (Figure 2-2) indicating a track along which it is adapted to move in the upward and downward direction in conjunction with the foregoing movement thereof are incorporated into the coordinate reading machine 1 so that coordinate values of the cutting tools M1 are read in accordance with the order of cutting operations while the track on the plan view is taken as x-y coordinate and the track on the sectional view is taken as x-z coordinate.

Thus read values are then inputted into the microcomputer 2 as data.

The microcomputer 2 serves to process size of circular arc and length of straight line by indicating them with the use of points (coordinate values).

Specifically, circular arcs A, B and Care processed as curved line by inputting x-y coordinate values of point a (starting point), b (intermediate point) and c (end point) on the circular arc A and thos of points c tog on the circular arcs B and C after indicating them as curved line, wherein the points a to con the circular arc A and the points e tog on the circul circular arc C are considered to be located on the circular track of circles having the same radius, whereas straight line D is processed by inputting x-y coordinate values of two points g and h on the straight line D after indicating them as straight line.

Further, by repeated inputting coordinate values of points h to a the displacement track of the cutting tool M1 for cutting operations in the forward and rearward direction as well as in the leftward and rightward direction is displayed on the graphic display apparatus 2' attached to the microcomputer 2 (see Figure 5).

Next, the displacement track of the cutting tool M1 for cutting operations in the upward and downward direction performed in conjunction with the fore going displacement in the x-y coordinate as illus trated in Figure 2-2 is displayed on the graphic display apparatus 2' by processing x-z coordinate values in the same manner as described above.

Thus, the displacement track of the cutting tool M1 in the forward and rearward direction, in the leftward and rightward direction and in the upward and downward direction is obtained in the numerical form. In case where the displacement track of the cutting tool M1 is processed as curved line having a certain enlarged radius with the aid of the microcom puter 2, it can be displayed by inputting coordinate values of three points arbitrarily determined on the displacement track while an indication is given as straight line.

Due to the fact that the cutting tool M1 is linearly displaced during cutting operation and amount of displacementj of the cutting tool M1 is inputted into the microcomputer 2 as data. Since this represents the minimum amount of displacement of the cutting tool, there occurs no problem as long as the cutting tool moves along the linear track. However, when it moves along the curvec track, an amount of dis placement is reduced by way of the step of correc tive processing in dependence of the radius of circular arc, because the surface generated by cutting operation is caused to have polygonal sec tional configuration (see Figure 4).

Each of data as described above is concerned with track built by a number of so-called cut points relative to the cutting tool M1 which serves to cut workpiece W. Point P adapted to be displaced by means of the servo-motors mounted on the working machine 5 (hereinafter referred to as mechanical point) is located just above point k on the displace ment track of the cutting tool M1 in the x-y direction as seen in Figure 2-1, whereas mechanical point P corresponding to point k' on the displacement track in the x-z coordinate as seen in Figure 2-2 is located at the position spaced upright above the workpiece.

When a curved surface is to be worked by cutting operation, it is impossible to generate a curved surface having the required sectional configuration because cutting operation is performed while the cutting tool M1 comes in contact with workpiece in the vertical posture (see Figure 2-2). However, it is possible to generate a curved surface having the required sectional configuration by locating the cutting tool M1 above the surface to be worked in the vertical posture during cutting operation, that is, locating mechanical point P on the line extending upright from the surface to be worked.

Further, by inputting into the microcomputer 2 a distance between cutting point and mechanical point P, that is, a turning radius m of the head 6 turned by means of the servo-motor 7 on the working machine 5 (see Figure 5), an angle of turning of the head 6 and position of mechanical point P' in the x-z coordinate at point k located on the curved track n are processed in that way. Thus, numerical values relative to position of mechanical point P' in the x-, y-, and z directions and angle of inclination of the cutting tool on the working machine 5, that is, track of mechanical point on the latter are obtainable.After processing thus obtained numerical values with each of cutting tools Mt, M2, M3 and others, they are rearranged in the form of numerical control tape with the aid of the numerical control apparatus so as to operate the working machine. Thus, a product having the required curved surface is obtained.

It should of course be understood that coordinate reading machine, numerical control tape preparing machine, and others may be repiaced with other type of machine or apparatus having equivalent function and capability.

Since a curved track of the cutting tool M1 is processed by utilizing circular arcs having the same radius in the embodiment as illustrated in Figure 2-2 so as to display it on the graphic display apparatus 2', numerical values of their center points in the x-z coordinate as illustrated in Figure 5 are already known and therefore distance ok between centre o and pointkand distance between pointkand point P (having a radius m'of turning) located on an extension line (normal line) from pointkcan be known. Thus, by determining distances ko and ok with reference to difference between point k and point o in the x-z coordinate a right-angle triangle as seen in the drawing is obtainable. Since angles a and (x' are located opposite to one another, numerical values of point P' in the x-z coordinate and an angle of inclination of the cutting tool M1 relative to the surface to be cut are processed.

The present invention has been described above with respect to the illustrated embodiment where a wood working router machine having a turnable head with a plurality of cutting tools mounted thereon is exemplified but it should not be limited only to this embodiment. Alternatively, the present invention may be applied to a working machine with a plurality of cutting tools arranged thereon in parallel relation.

As will be readily understood from the above description, a curved having any required composite configuration can be automatically generated by employing the method of the invention so that a product having new and unique appearance and configuration can be easily produced.

Claims

1. A method of generating a curved surface having any required configuration by operating a working machine with a plurality of cutting tools mounted thereon comprising the steps; processing the track of displacement of the cutting tools with reference to coordinate values of the latter relative to cutting operations in the forward and rearward directions as well as in the leftward and rightward directions and cutting operations in the upward and downward directions as seen from the surface to be worked; displacing the centre axis of a main spindle on each of the cutting tools in the forward and rearward directions, in the leftward and rightward directions and in the upward and downward directions relative to a workpiece to be cut;; processing coordinate values identifying the track of displacement of the cutting tools with the aid of a microcomputer while the centre axis of each of the cutting tools is located at a right angle relative to the surface to be cut at all times with a radius of turning of the cutting tools being inputted into the microcomputer; and operating the working machine in accordance with thus processed coordinate values relative to the track of displacement of each of the cutting tools.

2. A method as claimed in claim 1, wherein all data relative to the track of displacement of each of the cutting tools is processed in the form of numerical control tape which is then inputted into a numerical control apparatus.

3. A method as claimed in claim 1 or 2, wherein processed data relative to the track of displacement of each of the cutting tools is visually observed on a graphic display apparatus.

4. A method as claimed in claim 1, 2 or 3, wherein the cutting tools are arranged in radially relative to a head on which they are operatively mounted.

5. A method as claimed in claim 1, 2 or 3, wherein the cutting tools are arranged in parallel relation with their axes being located in parallel with one another on said head.

6. A method as claimed in claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

7. Apparatus for carrying outthe method as claimed in any one of claims 1 to 6.