JPH05131311A - Drilling method - Google Patents

Abstract

PURPOSE:To prevent occurrence of inferior machining by issuing a signal for changing drills when a difference between a drill position upon detection of a machining resistance during a first drilling stroke and a drill position upon detection of a machining resistance on and after the second drilling stroke exceeds an allowable value. CONSTITUTION:A first drilling step is carried out (step 150), a position P1 of a drill in a cutting direction upon detection a machining resistance is stored in a memory A (step 170), 1 is added to a counter N (step 200) and then, the next drilling step is carried out (210), and a drill position in the cutting direction upon detection of a machining resistance is stored in a memory B (step 220). Further, an abrasion loss delta caused by the present drilling step is obtained from the difference between the values stored in the memories A, B (step 230), and the cumulated abrasion loss is substituted with delta0=delta0+delta (step 240). If he cumulated abrasion loss delta0 exceeds an allowable value E (step 250), the process is interrupted, and an indication such that the replacement of drills are required is displayed on the screen 15 of a numerical control device 14 (step 260).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hole drilling method using a diamond drill or a diamond core drill.

[0002]

2. Description of the Related Art For drilling small diameter holes in ceramics, mainly drills and core drills (hereinafter referred to as
The two are collectively called a drill). Since the number of diamond abrasive grains electrodeposited on these drills is usually one layer, if the diamond abrasive grains fall off and the abrasive grain layer disappears, the machining ability will be lost, and if machining continues, the drill will be damaged and the workpiece will be defective. become. For this reason,
Conventionally, the number of holes that can be machined until the drill loses its processing capability is experimentally determined, and when the number of holes is reached, the drill is replaced, or machining is periodically interrupted to observe the state of the drill. It was

[0003]

However, there are performance differences between individual drills. Therefore, when exchanging the drill every time a predetermined number of holes are processed, the number of processed holes must be set on the safe side based on the drill with the worst performance, which is economically problematic. .. Further, if the number of holes to be machined is set according to a drill with poor performance, the frequency of replacement increases and there is a problem in terms of efficiency. On the other hand, the method of regularly observing the drill has problems that it is inefficient because the machining is interrupted each time it is observed, and that it is difficult to automate. The object of the present invention is to solve the above-mentioned problems of the prior art, to carry out hole drilling economically and efficiently by using individual drills up to the performance limit, and to prevent machining defects in advance. To provide.

[0004]

In order to achieve the above object, the present invention provides a drill position when a machining resistance is detected during the first hole machining and a drill position when the machining resistance is detected during the second and subsequent hole machining. The difference between the drill position and the drill position is calculated, and when the difference exceeds the allowable value, a drill replacement signal is generated.

[0005]

Function The machining resistance during hole machining is as shown in FIG. Here, the contact position between the drill and the workpiece can be known by reading the drill position in the cutting direction when the machining resistance reaches a predetermined detection level (point A in FIG. 3). Since the contact position between the drill and the workpiece changes as the drill wears, the wear amount of the drill can be obtained from the amount of change. That is, by calculating the difference between the drill position in the cutting direction when the machining resistance is detected in the first hole machining after exchanging the drill and the drill position in the cutting direction when the machining resistance is detected in the subsequent hole machining It is possible to know the wear amount of the drill. on the other hand,
As the machining progresses, the diamond abrasive grains gradually wear and the grain size becomes smaller, so the force for holding the abrasive grains becomes smaller, and the tips of the abrasive grains become smoother, increasing the machining resistance. Then, when the processing resistance becomes larger than the holding force of the abrasive grains, the abrasive grains fall off. Therefore, the limit wear amount at which such abrasive removal occurs is set as an allowable value, and when the actual drill wear amount measured as described above is greater than this allowable value, the drill By exchanging, it is possible to prevent damage to the drill and defective machining.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front view showing a configuration when the present invention is applied to a vertical numerical control boring machine. 1 is a bed. Reference numeral 2 denotes a table, which is slidably held in the bed 1 in the left-right direction in the figure and driven by a motor 3. Reference numeral 4 denotes an attachment, which is attached to the table 2 via a load meter 5. A work 6 is fixed to the fixture 4. 7
Is a column, which is slidably held on the bed 1 in a direction perpendicular to the plane of the drawing and is driven by a motor (not shown). Reference numeral 8 denotes a spindle head, which is slidably held in the column 7 in the vertical direction in the figure and driven by a motor 9. A rotary encoder 10 detects the position of the spindle head 8 and is attached to the motor 9. A spindle 11 is rotatably held by a spindle head 8 and is driven by a motor 12. A diamond core drill 13 is attached to the spindle 11. Reference numeral 14 is a numerical controller, which controls the movement of each axis of the machine and the spindle 11 according to a program input in advance.
Is controlled, and the outputs of the load meter 5 and the rotary encoder 10 are taken in. Further, the numerical control device 14 is preset with an allowable value of the wear amount of the drill. The setting of the allowable value and the instruction for exchanging the drill are performed interactively with the display contents of the screen 15 of the numerical control device 14.

Next, the operation will be described with reference to FIG. 2, which is a flow chart of the operation procedure in this embodiment. First, when the work is to be started for the first time, whether or not the drill should be replaced is entered by interacting with the screen 15 of the numerical controller 14 (step 100). When using the drill during continuous machining, enter the accumulated wear amount δ ₀ (step 1
30). The cumulative wear amount δ ₀ can be known in step 270 described later. When a new drill is used, the drill is replaced (step 110), the cumulative wear amount δ _{0 is set} to 0 (step 120), the counter N is set to 1 (step 140), and the first hole drilling is performed (step 140). Step 15
0). At this time, the position P ₁ in the cutting direction of the drill when the machining resistance is detected is stored in the memory A (step 160). When the hole being machined is to be continuously machined (step 170), 1 is added to the counter N (step 200) and the next hole is machined (210). At this time, the position P _N in the cutting direction of the drill at the time when the machining resistance is detected is stored in the memory B (step 220). Then, the wear amount δ due to this machining is obtained from the difference between A and B (step 230), and the cumulative wear amount is replaced with δ ₀ = δ ₀ + δ (step 240). The cumulative wear amount δ ₀ is the allowable value E
If smaller than (step 250), step 170
Return to and continue processing. When the accumulated wear amount δ ₀ becomes equal to or more than the allowable value E (step 250), the machining is interrupted and the screen 15 of the numerical controller 14 indicates that drill replacement is required (step 260), and the process returns to step 110. on the other hand,
In step 170, if all holes of the workpiece currently being machined are finished and it is necessary to machine the next workpiece (step 180), the workpiece is replaced (step 19).
0), and proceeds to step 210. When all the machining is finished (step 180), the cumulative wear amount δ ₀ is displayed on the screen 15 of the numerical controller 14 and the work is finished (step 270). This accumulated wear amount δ ₀ can be used as an input to step 130.

Although the working resistance is measured by the load meter in the above-mentioned embodiment, other physical quantities generated by the working resistance such as the motor current value, the vibration value, and the displacement amount of each part may be used. Further, in the above embodiment, the case of manually exchanging the drill has been described, but an automatic drill exchanging device may be attached so that the drill is automatically exchanged when the accumulated wear amount exceeds the allowable value. Further, in the above embodiment, the case of the electrodeposition drill was shown, but in the case of drills such as resin bond, vitrified bond, and metal bond, it is said that if the allowable wear amount is set accordingly, control can be performed in exactly the same manner. There is no end.

[0009]

As described above, in the present invention, the drill is replaced when the amount of wear of the drill exceeds the allowable value. There is an effect that it can be used up to the limit, that hole can be drilled economically and efficiently, and at the same time, defective machining can be prevented.

[Brief description of drawings]

FIG. 1 is a front view showing the configuration when the present invention is applied to a vertical numerical control drilling machine.

FIG. 2 is a flowchart showing an operation procedure in FIG.

FIG. 3 is an explanatory view showing a transition of machining resistance in machining one hole.

[Explanation of symbols]

 5 Load cell 6 Workpiece 10 Rotary encoder 11 Core drill 14 Numerical control device

Claims (1)

[Claims] 1. A difference between a drill position when a machining resistance is detected during the first hole drilling and a drill position when a machining resistance is detected during the second and subsequent hole drilling is calculated, and this difference is an allowable value. A hole drilling method characterized in that a drill replacement signal is generated when the drilling time is exceeded.