JPH0428497B2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) This invention relates to a method for generating an optimal cutting path for a workpiece such as a cast or forged product in machining with a numerically controlled lathe. .

(Technical background of the invention and its problems) In automatic programs and interactive manual data input for numerically controlled lathes, one method has traditionally been to automatically determine the cutting path for cutting using the workpiece shape as a model. It is starting to be generated. This applies to material shapes with a uniform machining allowance relative to the workpiece shape, and for arbitrary material shapes, processing is required to correct unnecessary movement due to idle cutting and to prevent overload. The actual situation is that the range has to be divided into small parts, which places a great burden on operators and the like.

FIG. 9 is a diagram for explaining the generation of a conventional cutting path, in which the shaded area 100 is the workpiece shape,
The part indicated by the dashed line 200 is the shape of the material. The cutting path will ultimately be the path LF (SF1→SF2) along the workpiece shape 100, but
In the figure, in order to make the cutting path LF easier to understand, it is shown shifted slightly above the workpiece shape 100 to provide a gap. If the material 200 is suddenly cut using the cutting path LF, the load on the cutting tool 101 will become extremely large, so conventionally, the cutting path LF1 (SF3 →
SF4), LF2 (SF5 → SF6), LF (SF1 → SF
2) is generated and shifted downward by a predetermined depth of cut for cutting. That is, first, the material 200 is cut using the cutting path LF1 (SF3→SF4), and then it is cut using the next cutting path LF2 (SF5→SF6) shifted in the X-axis direction by a predetermined depth of cut.
Furthermore, the cutting path LF (SF
Cut using 1→SF2). In this case, the cutting path LF
Regarding 1, path SF3 → SF10, SF11 →
Dry cutting occurs from SF12, SF13 to SF14, and the number of dry cutting increases.

Further, FIG. 10 is a diagram for explaining generation of a cutting path for another workpiece shape, in which the shaded area 102 is the workpiece shape, and the portion indicated by a dashed line 201 is the material shape. In the conventional cutting path generation method, the cutting path is created along the shape of the workpiece 102.
LF10, LF11, LF12 are generated, but if you cut with cutting path LF12 from the beginning, tool 101
The load at position A becomes too large. For this reason, first, in the cutting path LF10, SF20 → SF21
Then, with the cutting path LF11 shifted by a predetermined depth of cut in the X-axis direction, cutting is performed from SF22 → SF26, and then the cutting path LF is shifted by a predetermined depth of cut.
At step 12, cut SF23 → SF27. According to such a method, overload of the tool 101 at position A can be prevented, but empty cutting SF20→SF24 occurs in the cutting path LF10, and empty cutting SF22→SF25 occurs in the cutting path LF11.

(Objective of the Invention) This invention was made in view of the above-mentioned circumstances, and an object of the present invention is to change the shape of the material as well as the workpiece shape for any material shape including a round bar shape and a shape with uniform machining allowance. By inputting , the planned cutting line is set based on the material shape, the presence or absence of an undetermined path is determined, and if there is an undetermined path, the cutting path is determined by also referring to the workpiece shape. To provide a method for generating an optimum cutting path in a numerically controlled lathe, which automatically generates an optimum cutting path with no waste and no empty cutting and no overload cutting.

(Summary of the Invention) The present invention relates to a method for generating an optimal cutting path in a numerically controlled lathe, by inputting the material shape of a workpiece and the workpiece shape, as well as inputting depth of cut and clearance data. A master path shifted by the clearance data is generated, and it is determined whether or not there is any remaining cutting part of the workpiece shape with respect to the master path, and if there is any remaining cutting part, the cutting part is shifted from the master path. A first scheduled cutting line shifted by an amount of , the part where the first scheduled cutting line is inside the workpiece shape uses the workpiece shape as the cutting path, and the part where the first scheduled cutting line is outside the workpiece shape uses the first cutting line as the cutting path.
The cutting path is determined sequentially using the scheduled cutting line as the cutting path, and then it is determined whether there is a closed uncut shape with respect to the workpiece shape, and if there is the closed uncut shape, the A second planned cutting line is set from the master path, and the part where the second planned cutting line is included in the workpiece shape is cut from the workpiece shape with respect to the set second planned cutting line. the second path;
For the part where the planned cutting line is outside the workpiece shape, the second planned cutting line is determined as the cutting path, and the planned cutting line is set by sequentially shifting by the depth of cut until the closed uncut shape disappears. and repeating the determination of the cutting route, and if there is no closed uncut shape, it is determined whether there is an undetermined route part, and if there is no undetermined route part, it is determined whether or not the cutting part remains. The cutting path is determined and copy cutting is performed until there is no closed uncut shape, there is no path undetermined part in each scheduled cutting line, and there is no remaining part to be cut. be.

Conventional general profile cutting uses the workpiece shape as a model, but in this invention, the cutting path is generated based on the material shape, and this difference allows the removal of the empty cutting path portion and the overloaded cutting portion. ing.

(Example of the invention) FIG. 1 is a diagram explaining the principle of this invention,
A state in which a material 21 indicated by a dashed line is cut with a tool 22 and processed into a workpiece shape 20 indicated by diagonal lines is shown. In this invention, first, a master path MP (same as the material shape 21) is generated based on the material shape 21, and a planned cutting line CT1 shifted in the X-axis direction by the depth of cut d is generated to perform cutting (point P1→ P2) Do.
For this cutting, since there is a remaining cutting part in the material shape 21, the planned cutting line is cut by the depth of cut d.
Planned cutting line shifted in the X-axis direction from CT1
CT2 is set, but there is an undetermined path part in this planned cutting line CT2, so when the cutting path is determined from P5 → P6 → P7, it hits the workpiece shape, so the uncut part is closed here. Determine whether the shape exists. In this case, there is a closed uncut shape indicated by diagonal lines on the right, so the planned cutting line CT2
Cutting schedule line shifted further by depth of cut d
CT3 is set, and the route within the scheduled cutting line CT3 is determined as points P6→P6A→P7, thereby eliminating the closed uncut shape. Return to the planned cutting line CT2 at point P7, but since there is an undetermined route, the point
P7 → P8 determines the cutting path along the workpiece shape 20, and intersects the planned cutting line CT2 at point P8, so when it reaches the point P8 → P9 along the planned cutting line CT2, it hits the workpiece shape 20 and the right Since a closed uncut shape shown by diagonal lines remains, a cutting path P8→P9 along the workpiece shape 20 is determined based on the planned cutting line CT3. Then, based on the planned cutting line CT2 from point P9, the cutting path P9→P10
→P11 is determined, but since there is a closed uncut shape when it hits the workpiece shape 20, the cutting path P10→P12 is determined based on the planned cutting line CT3.
→ P13 is determined, but since there is still a closed uncut shape, a scheduled cutting line CT4 (not shown) is further shifted by the depth of cut d, and the cutting path P12 along the workpiece shape 20 is set → P12A→P13
Confirm. This eliminates the closed uncut shape, so cutting is performed by setting a cutting path P13→P11→P2→P3 along the workpiece shape 20 from point P13.

The apparatus for realizing the method of the present invention has a configuration as shown in FIG. Part data such as clearance c (described later) is input, and these input data are stored in the work shape memory section 4, material shape memory section 5, and part data memory section 6, respectively. A display 1 such as a CRT is connected to the input control unit 3.
A guide display for interactive input and a confirmation display for input data are performed. That is, the operator inputs data from the keyboard 2 according to the dialog guide on the display 1, and this input data is sent to the input control unit 3.
The information is determined and stored in the corresponding storage units 4-6. Further, the data read from the storage units 4 to 6 is input to the master path generation unit 7 and the material copying cycle path generation unit 9, and the cutting path CP generated here is provided to the cutting path storage unit 10. Then, the cutting path stored in the cutting path storage unit 10
The CP is read out during cutting on the numerically controlled lathe, and the optimum cutting path generated by the material copying cycle path generating section 9 is processed. In addition,
Master route MP generated by master route generation unit 7
is once stored in the master path storage section 8 and then sent to the material copying cycle path generation section 9.

Next, the manner in which the cutting paths are generated by the path generating sections 7 and 9 according to the present invention will be explained with reference to FIGS. 3 to 6.

First, the master path generation unit 7 generates material shapes (A, B, C, D, H, H, F) as shown in FIG.
, the master path MP (le,
A, G, C, C, R, N, F) are generated and this master route MP is stored in the master route storage unit 8.
In this case, among the lines of the material shape, lines that are not parallel to the Z axis (for example, the lower and knee lines in Fig. 3)
(H-HE) to the right by clearance c. Inputting the clearance c and shifting it in the Z-axis direction requires no tools because when cutting part B parallel to the X-axis as shown in Figure 4, the material is moved while touching the surface of the material. This is because it is necessary to prevent it from being worn out.
In addition, using the master path MP read from the master path storage unit 8 as a model, the material copying cycle path generating unit 9 is set to a cutting scheduled line L1 shifted in the X direction by the cutting depth d of the input data input from the keyboard 2. Set as shown in Figure 5. In addition, in FIGS. 3 and 5, the shaded areas A, B, C, D,
E and F indicate the shape of the workpiece. The above planned cutting line L1 is compared with the workpiece shape (A, B, C, D, E, F) as the first cutting path, and the part where the planned cutting line L1 is included in the workpiece shape is the workpiece shape. Cutting path. Further, in a portion where the planned cutting line L1 is outside the workpiece shape, the planned cutting line L1 is determined as the cutting path. Therefore, in the example of FIG. 5, the cutting path is A→B→C→
C1→C2→C3. Since this cutting path has a closed uncut shape shown by diagonal lines on the right, a planned cutting line L2 is further shifted by the depth of cut d, and the cutting path generation for the part not cut by the planned cutting line L1 is performed as described above. Do the same thing. In this case, since the scheduled cutting line L2 is all within the workpiece shape, C1→E→C3→F is determined as the cutting path and cutting is performed. FIG. 6 is an example of data of the cutting path CP generated by the material copying cycle path generating section 9 as described above, and shows data of D1→D2→D3→D4→D5.
The tool moves as follows: →D6→D7→D8→D9→D10→D11. Then, the thick solid line part (D1→D2→D3→D4→
D5→D6, D4→D9→D10→D11) indicate the cutting feed section, and the broken line section (D6→D7→D8→D4) indicates the rapid feed section.

Next, with reference to the flowchart of FIG. 7, the path generation operation of the present invention for the material shape 40 and workpiece shape 41 shown in FIG. 8 will be specifically explained.

First, the memory units 4 to 6 entered using the keyboard 2
Material shape 40 and clearance c stored in
From this, a master path MP is generated (step S1),
Determine whether there is any remaining cutting area (step
S2), if there are remaining cutting locations, the first scheduled cutting line L1 is set (step S3). next,
A check is made to see if there is an undetermined path portion within the planned cutting line L1 (step S4), and of course it is found to be present at first, and the path 1→2 is determined along the planned cutting line L1 (step S5). Here, the closed uncut shape is determined to be absent because the scheduled cutting line L1 has reached the final shape element (step
S6), the process returns to step S4, and since there is no route undetermined portion for the planned cutting line L1, the process returns to step S4.
Return to S2. In this state, there are still cutting areas, so in step S3 the next scheduled cutting line L2 is cut.
Set. Then, it is determined whether or not there is an undetermined route part within the set cutting plan line L2 (step S4), and if there is no undetermined route part, the process returns to step S2, and there is an undetermined route part. If so, determine the cutting path one by one (step
S5). In the example of Fig. 8, when the planned cutting line L2 is set, there is an undefined part of the route, so the tool is moved along the route 3.
→4, the cutting paths 5→6 are sequentially determined on the planned cutting line L2. Then, it is determined whether or not there is an uncut shape that is closed when the workpiece shape is hit (step S6). In this example, since there is an uncut shape, the next cut depth of cut 3d from the master path MP is determined. A planned cutting line L3 is set (step S7), the tool is moved from path 7 to 8, and cutting paths 9 to 10 are determined sequentially on the planned cutting line L3. As is clear from the figure, the locations where the scheduled cutting line exists within the workpiece shape are determined by employing the workpiece shape as the cutting path. Then, it is determined whether or not there is an uncut shape that is closed when the workpiece shape is hit (step S6). In this example, since there is an uncut shape, cutting with a depth of cut of 4d further than the master path MP is performed. A schedule line L4 (not shown) is set (step S7). In this case, the planned cutting line L4 is all within the workpiece shape, so the tool is moved along the path 11 → 12 → 13, and the workpiece shape 4 is
Determine the cutting path 13A along 1 (step
S8).

As a result, there is no closed uncut shape, so the process returns to step S4 and it is determined whether or not there is a route defined part within the planned cutting line L2 (step S4), but in this example, there is still no route determined. Since there is a definite part, when the cutting path 14→15 is set (step S5), it corresponds to the workpiece shape, so it is determined whether there is a closed uncut shape (step S6). In this example, since there is a closed uncut shape, a planned cutting line L3 is further set, the tool is moved from path 16 to 17 to 18, and cutting path 19 to 20 is determined (step S5). When the cutting path 20 hits the workpiece shape, it is determined whether there is a closed uncut shape (step S6). In this example, since there is still a closed uncut shape, the tool is moved along the workpiece shape. 21 → 2
2→23, and the cutting path 23A is determined according to the setting of the next planned cutting line L4 (step S7) (step S8). As a result, the closed uncut shape is eliminated, so the process returns to step S4, and the cutting path 2 on the planned cutting line L2 is removed.
4 → Confirm 25 (steps S4, S5). below,
In the same way as above, it is determined whether there is an undetermined cutting path in the scheduled cutting line or whether there is a closed uncut shape, and when both of them are eliminated and there is no remaining cutting location, Finish cutting path generation. In addition, after the cutting path 25, 26 →
27→28→29→30→31→32→33→3
Return to the cycle reference point via route 4→35.

In the above description, outer diameter cutting is taken as an example, but the present invention is not limited to outer diameter cutting, but can naturally be applied to inner diameter cutting, end face cutting, etc. In addition, the cutting path generation method of the present invention is a method for automatically generating a rough cutting path for an arbitrary material shape, and is actually used for finishing machining after rough cutting (final machining along the workpiece shape) and for finishing during rough cutting. This is done in conjunction with conventional techniques such as leaving allowances and considering nose radius.

(Effects of the Invention) As described above, according to the cutting path generation method of the present invention, it is possible to handle any material shape by inputting the material shape, which reduces the burden on the operator and significantly reduces the man-hours for creating programs. There are advantages that can be achieved. In addition, when generating a cutting path, a master path and planned cutting line are set based on the material shape, depth of cut and clearance, and the cutting path is created by taking into account the shape of the workpiece depending on the presence or absence of undefined path parts. At the same time, the next scheduled cutting line and cutting path are determined in sequence based on the presence or absence of the closed uncut shape, so it is possible to remove the empty cutting path portion and the overloaded cutting portion. can.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the principle of the method of this invention, Fig. 2 is a block diagram showing an example of a device for realizing the method of this invention, and Figs. FIG. 7 is a flowchart showing an example of the operation of this invention.
FIG. 8 is a diagram showing a specific example of cutting path generation according to the present invention, and FIGS. 9 and 10 are diagrams for explaining conventional profile cutting. 1...Display, 2...Keyboard, 3...
...Input control section, 4...Work shape memory section, 5...
Material shape memory section, 6... Part data storage section, 7
...Master route generation section, 8...Master route storage section, 9...Material copying cycle route generation section, 10...
...Cutting path memory section.

Claims (1)

[Claims] 1 In a method for generating a cutting path in a numerically controlled lathe, input the workpiece material shape and workpiece shape, input the depth of cut and clearance data, and generate a master path shifted by the clearance data from the material shape. Then, it is determined whether or not there is any remaining cutting portion of the workpiece shape with respect to the master path, and if there is any remaining cutting portion, a first planned cutting line is shifted from the master path by the cutting amount. is set, and it is determined whether or not there is an undetermined route part within the set first cutting scheduled line, and if there is an undetermined route part, the first cutting line is set within the workpiece shape. In the part where the planned line is included, the workpiece shape is used as the cutting path, and in the part where the first planned cutting line is outside the workpiece shape, the cutting path is sequentially determined using the first planned cutting line as the cutting path, Next, it is determined whether there is a closed uncut shape with respect to the workpiece shape, and if there is a closed uncut shape, a second planned cutting line is set from the master path, and this setting is made. With respect to the second scheduled cutting line, the part where the second scheduled cutting line is inside the workpiece shape uses the workpiece shape as the cutting path, and the second scheduled cutting line is outside the workpiece shape. For the part located in , the second scheduled cutting line is determined as the cutting path, and the setting of the scheduled cutting line shifted by the depth of cut and the determination of the cutting path are repeated until the closed uncut shape disappears. If there is no closed uncut shape, determine the presence or absence of the route undetermined portion,
If there is no route undetermined portion, it is determined whether or not the cut portion remains, so that there is no closed uncut shape, there is no route undetermined portion within each scheduled cutting line, and there is no remaining cut portion. A method for generating an optimal cutting path in a numerically controlled lathe, characterized in that the cutting path is determined until the cutting path is determined, and then copy cutting is performed.