JPH0271954A - Processing method for prepared hole in zone cutting - Google Patents

Abstract

PURPOSE:To perform satisfactory zone cutting by deciding a 2nd cutting start position at the position outside the island and coming into contact with the contour of the island, in case of an island like projection part existing under a 1st cutting start position, and finding the succeeding cutting start position in order until the island does not exist under the cutting start position similarly thereafter. CONSTITUTION:A 1st cutting start position Ps1 is decided, whether an island like projection ILPi exists under the 1st cutting start position Ps1 or not is judged, in case of the island ILDi existing a 2nd cutting start position Psi is decided at the position where is outside the island ILDi and brought into contact with the contour of the island ILDi, and similarly thereafter the succeeding cutting start position Psi in order until the island ILDi does not exist under the cutting start position Psi. The working of the prepared hole PRHi having the depth Mhi to the apex of the island ILDi is then performed at each cutting start position Psi and at the cutting start position Psi where no island ILDi exists the prepared hole processing having the depth DT to the pocket bottom is performed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for drilling a prepared hole in area cutting, and particularly to a method for drilling a hole in a region having a predetermined depth. This invention relates to a prepared hole machining method for cutting the area to be machined.

<Prior Art> As NC processing, there is area cutting processing (pocket processing) in which an area surrounded by a closed curve (referred to as a pocket) is cut to a predetermined depth. The NC data for darning pocket processing is (
i) Defining the machining shape, (it) Defining the machining method, such as unidirectional cutting, reciprocating cutting, or spiral cutting, (iii) Tools used and machining conditions (cutting direction,
It is automatically created using data input at each step, such as the step for defining pitch, etc.).

In such automatic programming, for example, as shown in FIG. 10, the machining shape of region TRR and depth DT is defined, and the machining method is spiral cutting.

When the direction from the inside to the outside is defined as the cutting direction, and the tool for pocket machining, one-time cut ff1Dt, machining width (pitch) P, etc. are defined, the N for pocket machining is defined.
Automatic creation of C program (CNC data) starts. That is, first, the center of the regions TR, R or the center of gravity 1 - the cutting start position fiPs is specified. Next, NC data for machining the prepared hole PRH of the machining depth DT at the cutting start position Ps is created. The reason for creating NC data for pilot hole machining is that due to the nature of tools for pocket machining (especially flat end mills), downward cutting is not desirable, and the machining accuracy may be reduced even if the hole cannot be cut properly. This is because it makes you After that, a spiral cutting path PTi (
- Create an NC program to perform area cutting along the direction of the dotted chain arrow). In addition, if the pocket is deep and cannot be processed with one spiral cutting, the pocket depth DT is divided by one cutting depth Dt, and spiral processing is performed while moving in the depth direction by the cutting depth Dt. Create NC data to perform pocket machining to the desired depth.

<Problem to be solved by the invention> By the way, as shown in FIG. 11, the region TR having the depth DT
An island-like convex portion (island) ILD with a depth of Mh (Mh<DT) to the top is defined in R, and the machining start position P
An island ILD may exist below s. In such a case, the conventional prepared hole machining method does not process the prepared hole PRH of depth Mh from the machining start position Ps to the top HP of the island ILD, which is inconvenient when machining a portion deeper than Mh. occurs. That is, after finishing machining up to the top of the island ILD with the tool TL, the point where the island was avoided (for example, P
S2) When cutting spirally along the shape of the island ILD 1
Since there is no pilot hole deeper than Mh, a flat end mill has to be used to cut in the depth direction, resulting in a problem that spiral cutting cannot be done well.

In view of the above, an object of the present invention is to provide a pilot hole machining method that can perform another pilot hole machining at a different position avoiding the island even if there is an island directly below the machining start position, thereby achieving good area cutting. It is to be.

<Means for solving the problem> The above problem consists of a step of determining a first cutting start position by taking into account the area cutting method, cutting direction, etc., and a step of determining an island-like protrusion under the first cutting start position. A step of determining whether a part (island) exists, and if an island exists, a step of determining a second cutting start position at a position outside the island and touching the outline of the island, and thereafter performing cutting in the same manner. 1@ until there are no more islands under the starting position
The process of finding the next cutting start position and drilling a prepared hole at each of these cutting start positions with a depth up to the top of the island, and if there is no island below the cutting start position, the depth to the bottom of the pocket. This problem can be solved by the process of drilling a prepared hole.

Action> Determine the first cutting start position Ps (Fig. 1) in consideration of the area cutting method, cutting direction, etc., and set the first cutting start position Ps.
It is determined whether an island-like convex portion (island) ILDi exists below s1, and if an island ILDi exists, a second cutting start position Psi is set at a position outside of the island ILDi and in contact with the outline of the island ILDi. After that, the next cutting start position Ps1 is determined in the same way until there is no island ILDi under the cutting start position Psi, and an island ■L is placed at each of these cutting start positions IPsi.
A prepared hole PRH1 having a depth Mhi to the top of Di is machined, and a prepared hole PRH1 having a depth DT to the bottom of the pocket is machined at the cutting start position Psi where no island ILDi exists.

<Embodiment> FIG. 2 is a block diagram of an automatic programming device for creating NC data for area cutting according to the present invention.

11a is a processor, llb is a ROM, and llc is a RAM
, 12 is a graphic display device, 13 is a tablet device, +4a is a keyboard, 14b is an XY plotter, 15 is a disk controller 1 to roller, and FLD is a floppy disk.

FIG. 3 is a flowchart of the process of creating NC data for preparing a hole in area cutting according to the present invention.6 Below, the process of creating NC data for preparing a hole in the present invention will be explained according to the flowchart in FIG.

In addition, prior to processing, in the step of defining the machining shape using the keyboard 14a using a well-known method, the external shape data of the pocket region TRR (FIG. 4), the island I in the region TRR, etc.
External shape data of LDi (i=1,2), pocket depth DT, depth to the top of island ILDi Mhi (i=1.2)
etc. are input, the spiral cutting method is input in the step of defining the machining method, and the cutting direction (for example, counterclockwise direction), Myojin 1 pitch, 1 cutting depth Dt, etc. are input in other data input steps. It is assumed that a flat end mill is input in the step of defining the tools to be used and stored in the RAM 11c.

In the NC data creation step, processor lla
The i-th cutting start position P is set at the center or center of gravity of the region TRR, taking into consideration the external shape data of the region TRR stored in the RAM 11c, the spiral cutting method, the cutting direction (inside → outside direction), etc.
si (the initial value of i is 1) is determined. In addition, in the case of unidirectional cutting, reciprocating zigzag cutting, or spiral cutting from the outside to the inside, the area boundary point of the area TRR is set as the cutting start position.

Then, processor 1], a is the i-th cutting start position Psi
It is determined whether or not there is an island-shaped convex portion (island) ILDi under the island ILDi (step 102), and if the island ILDi exists, 1+1→i is set (step 103), and if the island is outside the island ILDi, The i-th cutting start position P is located at a position touching the outline of the island.
After determining si (step 104), the process from step 102 onward is repeated until no island ILDi exists.

On the other hand, if the island ILDi no longer exists in step 102, all cutting start positions, that is, all prepared hole machining positions have been found.

When all the pilot hole machining positions are determined, the processor lla arranges the data of each pilot hole machining position by the deep machining depth Ilk (step 105), and sets 1→j (step 106).

Next, processor lla selects the j-th prepared hole machining position 'H
Pj is determined (step 107), and it is determined whether the processing flag of the determined data is "ON" (step 108).
Note that if the machining flag of the pilot hole machining position HPj is roNj, it is assumed that the output has already been performed as a pilot hole to be drilled at that position, or there is no need to drill a pilot hole at that position.

In the judgment at step 108, if the processing flag is rOJ, the processor lla sets j+1→j, step 109), and repeats the processing from step 107 onwards. On the other hand, if the machining flag is not roNJ, the allowable pressure iJ is centered around the prepared hole machining position 1HPj! The machining flag included in iL determines the pilot hole machining position of rOFFJ,
Let the processing flag be rONJ. For example, as shown in Fig. 5, the prepared hole machining position HP.

If the distance ml between the hole machining position IHP2 and the hole machining position IHP2 is 1<r=, the machining flag of the hole machining position HP is set to “ON”, and the machining flag of the hole machining position
H2 is not processed (step 110).

Next, the processor lla selects the j-th prepared hole machining position H.
Pj is output as the one to be machined for the pilot hole (step 111), and the output j-th pilot hole machining position HPj
The processing flag of is set to rONJ (step 112).

Next, processor lla processes all prepared hole machining positions HPj
Step 113) to judge whether the machining flags of the
N”, create NC data for machining the pilot hole PRHi at the output pilot hole machining position HPi, and create NC data for area machining with each cutting start position Psi as the starting point of spiral cutting. Create (step 114). still,
The NC data for area machining is obtained by determining a helical cutting path starting from the first cutting start position, and processing the NC data along the helical cutting path in increments of depth of cut Dt until reaching the top of the first island. Once you reach the top of the first island, find a spiral cutting path starting from the second cutting start position, and similarly
Create C data and create NC data up to the bottom of the pocket.

PTl in Fig. 4 is a spiral cutting path that performs machining by the depth of cut Dt from the cutting start position (starting point) Psl to the end point Pa, and PT2 in Fig. 6(a) is a spiral cutting path that cuts from the starting point Ps2 to the end point while avoiding the island ILD1. It is a helical cutting path that cuts the depth of cut Dt from the starting point Ps to the end point Pe, avoiding the island ILD in the same way as PT in FIG. 6(b). It is. Further, FIG. 7 shows an example where there is no island ILDi below the first cutting start position Ps1, and in this case, one pilot hole is created up to the bottom of the pocket. Further, until reaching the top of the island ILDi, the spiral cutting path is determined without considering the island, but when cutting deeper than the island, the spiral cutting path is determined so as to avoid the island.

Figure 8 shows an N for pilot hole machining created by the process of the present invention.
This is an example of C data and NC data for area processing. SPM in Fig. 8 is NC data for tool exchange, tool correction, coordinate meter setting, etc., TPM is NC data for area machining, and D
PM is NC data for pilot hole machining (subprogram ro1
00J).

Note that (a) is the calling command for the subprogram ro100J, and (b) to (d) are the NC data for preparing the hole machining output in step 114 (FIG. 3).

In the above, we have described the case where the machining method is spiral cutting, but as shown in Fig. 9, even when reciprocating cutting is used,
A first cutting start position Ps1 is determined in consideration of the cutting direction and the like, and the first cutting start position Ps is set.

It is determined that an island-like convex portion (island) ILDi exists below, and if the island ILDi exists, a second cutting start position Ps2 is set at a position outside of the island ILDi and in contact with the outline of the island ILDi. After that, the next cutting start position P is sequentially determined until there is no island ILDi under the cutting start position Psi.
si is determined, and an island ILDi is placed at each of these cutting start positions Psi.
Drill a prepared hole with a depth Mhi to the top of the hole. Island IL
Cutting start position Psi where Di does not exist (Ps in Fig. 9)
, ), a prepared hole is machined to a depth DT to the bottom of the pocket.

<Effects of the Invention> According to the present invention, the first cutting start position is determined in consideration of the area cutting method, the cutting direction, etc., and the island-shaped convex portion (island) is formed below the first cutting start position. If an island exists, a second cutting start position is determined at a position outside the island and in contact with the outline of the island, and thereafter, similarly, an island exists below the cutting start position. Find the next cutting start position in sequence until the hole stops, and drill a prepared hole at each of these cutting start positions with a depth up to the top of the island, and at the cutting start position where no island exists, have a depth up to the bottom of the pocket. Since the structure is configured to perform pilot hole machining, even if there is an island directly below the machining start position, another pilot hole is machined at a different position avoiding the island, thereby achieving good area cutting.

Further, according to the present invention, when the distance between the cutting start positions is smaller than the allowable value, the pilot hole is machined only for the cutting start position where the machining depth is deep. The number of can be minimized.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the present invention. Fig. 2 is a block diagram of an automatic programming device for creating NC data for area cutting according to the present invention, Fig. 3 is a flow chart of prepared hole machining processing by area cutting according to the present invention, and Figs. 4 to 7 are according to the present invention. Figure 8 is an explanatory diagram of an example of NC data created by the process of the present invention. Figure 9 is an explanation of determining the position of pilot hole machining in the case of reciprocating cutting. 10 and 11 are explanatory diagrams of conventional examples. TRR... Cutting area. ILDi...Island-shaped protrusion, DT...Pocket depth, Psi... Cutting start position, - Predetermined depth of cut, Mhi... Depth to the top of island-shaped protrusion ILD

Claims (3)

[Claims] (1) In a prepared hole drilling method for area cutting in which a pocket in which one or more island-like convex portions are provided in an area having a predetermined depth is machined, the first Determine the cutting start position, determine whether an island-like protrusion exists below the first cutting start position, and, if an island-like protrusion exists, place the island-like protrusion outside the island-like protrusion. The second cutting start position is determined at a position that is in contact with the contour of the convex part, and the next cutting start positions are determined in the same way until there are no island-like protrusions below the cutting start position, and each of these cutting start positions A prepared hole machining method for area cutting, characterized in that a preparatory hole is machined with a depth up to the top of an island-like convex portion. (2) The method for machining a prepared hole in area cutting according to claim (1), wherein the depth of the prepared hole at the final cutting start position is the depth to the bottom of the pocket. (3) If the distance between the cutting start positions is smaller than an allowable value, the pilot hole is machined only at the cutting start position where the machining depth is deep, as claimed in claim (1). Prepared hole machining method for cutting the area described.