JP2013066956A - Drilling device and drilling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drilling device and method capable of estimating the height of burrs generated when holes are formed by drilling.SOLUTION: A drilling device 1 includes: a cutting resistance-measuring unit 4 for measuring a cutting resistance based on a driving state of a cutting tool for drilling a workpiece; a memory unit 6 for storing a correlation between the cutting resistance and the height of burrs generated around a hole being formed in the workpiece; and a burr height estimation unit 7 for estimating the height of the burrs generated during drilling based on the correlation of the cutting resistance measured during the drilling by the cutting tool.

Description

  The present invention relates to a drilling apparatus and a drilling method for forming a hole by cutting a workpiece.

  When assembling multiple parts with fastening members such as rivets and bolts in the assembly process of an aircraft, etc., high-accuracy hole tolerances are required, so multiple parts can be assembled without drilling each single part. Drill holes in the combined state.

  Note that Patent Document 1 discloses an invention relating to a boring unit, and discloses a technique for improving maintainability without requiring a disassembly / assembly process for replacing a spindle motor.

JP 2009-50942 A

  When the drilling process is completed, burrs are generated around the formed holes. For this reason, after drilling in a state where a plurality of components are combined, the plurality of combined components are once released to deburr and clean the inside of the hole. However, depending on the shape of the part, the positional relationship between the parts, the combined state, etc., deburring or cleaning may not be possible after drilling.

  If burrs cannot be removed after drilling, the confirmation test was repeated to establish the processing conditions to keep the burr height within a predetermined value, and then actual processing was performed. For this reason, a separate confirmation test is performed every time drilling is performed, and the time required for processing is prolonged.

  The present invention has been made in view of such circumstances, and a boring device and a boring device capable of predicting in advance the height of burrs generated when a hole is formed by boring. An object is to provide a processing method.

In order to solve the above problems, the drilling apparatus and drilling method of the present invention employ the following means.
That is, the drilling device according to the present invention includes a measuring unit that measures cutting resistance based on a driving state of a cutting tool that drills a workpiece, and a hole around the hole formed in the cutting resistance and the workpiece. A storage unit for storing the correlation with the height of the generated burr, and a prediction unit for predicting the height of the burr generated at the time of drilling based on the cutting resistance and the correlation measured at the time of drilling with a cutting tool. Prepare.

  According to the present invention, based on the fact that there is a correlation between the cutting force and the burr height, the burr height generated around the hole formed in the workpiece is measured by the cutting resistance measured during drilling. Is predicted based on the correlation stored in the storage unit. Therefore, by applying the present invention, a confirmation test for confirming the height of a burr generated in a certain workpiece can be omitted. Here, the cutting resistance based on the driving condition of the cutting tool means that, when the cutting tool is a drill, a load based on a current value of a feed motor that drives the drill in the axial direction or a spindle motor that drives around the axis, and provided on the spindle Load measured by a given load cell.

  The said invention WHEREIN: You may further provide the control part which controls the drive of a cutting tool based on the height of the estimated burr | flash.

  According to this invention, the driving of the cutting tool is controlled based on the predicted burr height, and the driving state of the cutting tool changes, so that the cutting resistance during drilling also changes. As a result, the height of burrs generated during drilling can be changed. For example, when the predicted burr height approaches a predetermined value, the burr height can be suppressed within a predetermined value by changing the driving state of the cutting tool.

  In the above-described invention, a position calculation unit that calculates the position of the cutting tool in the workpiece may be further provided, and the control unit may control the driving of the cutting tool based on the position of the cutting tool.

  According to this invention, the driving state of the cutting tool changes according to the position of the cutting tool. In general, burrs generated around a hole formed in a workpiece are generated when the cutting tool forms a hole on the inlet side or the outlet side. In the present invention, when the tip of the cutting tool is in the workpiece, the tip of the cutting tool begins to enter the workpiece, forming an inlet-side hole, or the tip of the cutting tool penetrates the workpiece. By changing the driving state of the cutting tool between when the hole on the outlet side is formed, the time required for machining can be changed while changing the height of burrs generated during drilling.

  In addition, the drilling method according to the present invention includes a step of measuring a cutting resistance based on a driving condition of a cutting tool for drilling a workpiece, and a hole around the hole formed in the workpiece and the cutting resistance. The step of storing the correlation with the height of the burr and the step of predicting the height of the burr generated at the time of drilling based on the cutting resistance and the correlation measured at the time of drilling by the cutting tool are provided.

  According to the present invention, the height of a burr generated when a hole is formed by drilling can be predicted in advance.

It is a block diagram which shows the drilling apparatus which concerns on one Embodiment of this invention. It is a side view which shows the drilling apparatus which concerns on the same embodiment. It is a graph which shows the relationship between the load at the time of cutting, and time. It is sectional drawing which shows the workpiece | work and drill at the time of drilling. It is sectional drawing which shows the workpiece | work and drill at the time of drilling. It is a graph which shows the relationship between a burr height and a thrust load. It is a graph which shows the relationship between burr height and rotation speed. It is a graph which shows the relationship between burr height and the number of holes (use time). It is a graph which shows the relationship between burr height and the number of holes (use time).

Hereinafter, a drilling apparatus 1 according to an embodiment of the present invention will be described with reference to the drawings.
The drilling device 1 cuts the workpiece 17 (object to be processed) with a drill 14 (cutting tool) to form a circular hole in the workpiece 17. By using the drilling device 1, a drilled product in which holes are formed in the workpiece 17 can be manufactured. When holes are formed in the workpiece 17 by cutting, burrs are generated around the holes on the inlet side and the outlet side of the drill 14. The drilling device 1 of the present embodiment predicts the height of burrs generated during drilling and performs drilling based on the predicted result. The workpiece 17 may be a single member or a laminate of a plurality of members. This embodiment may be applied to a portion where it is difficult to deburr after drilling, such as a structural member (for example, a wing box) of a main wing of an aircraft or a structural member of a fuselage.

  As shown in FIG. 2, the drilling device 1 includes a main shaft motor 2, a feed motor 3, a support portion 10, a head portion 11, a main shaft 12, a chuck 13, a drill 14, a base portion 15, and the like.

  The spindle motor 2 is driven by receiving electric power, and rotates the spindle 12 around the axis. The spindle motor 2 is provided in the head unit 11, for example. The feed motor 3 is driven by receiving electric power, and moves the main shaft 12 in the axial direction (feed direction). The feed motor 3 is provided in the support part 10, for example.

  The support unit 10 is installed on the base unit 15 and supports the main shaft 12 via the head unit 11. As shown in FIG. 2, the head portion 11 is provided on the side surface of the support portion 10, for example, and supports the main shaft 12. The head unit 11 receives the driving force from the feed motor 3 and moves upward or downward along the side surface of the support unit 10. 2, the head unit 11 may be provided on the extension of the support unit 10. At this time, the head unit 11 moves upward or downward on the extension of the support unit 10.

  An upper end of the main shaft 12 is provided on the head portion 12, and the head portion 12 receives the driving force of the main shaft motor 2 and rotates around the axis. Further, the main shaft 12 moves upward or downward in accordance with the movement of the head portion 12 as it moves up and down. A chuck 13 is provided at the lower end of the main shaft 12.

  The chuck 13 is provided at the tip of the main shaft 12 and sandwiches the drill 14. The drill 14 can be replaced by opening and closing the chuck 13. The drill 14 provided at the tip of the main shaft 12 via the chuck 13 moves in the feeding direction as the head unit 11 moves. The drill 14 is an example of a cutting tool and can cut the workpiece 17 by moving in the feed direction while rotating around the axis. The table 16 is installed on the pedestal 15 and holds the workpiece 17 during drilling. In addition, the drilling apparatus 1 may be configured to directly fix the workpiece 17 to the support portion 10 instead of the normal drilling machine type.

  In the drilling device 1 having the above configuration, the drill 14 descends to the work 17 and penetrates while cutting the work 17, whereby a through hole is formed in the work 17.

  As shown in FIG. 1, the drilling device 1 further includes a cutting resistance measurement unit 4, a position calculation unit 5, a storage unit 6, a burr height prediction unit 7, a spindle rotation speed control unit 8, a feed A speed controller 9 is provided.

  The cutting resistance measuring unit 4 measures the cutting resistance based on the driving state of the drill 14 that drills the workpiece 17. The drive status of the drill 14 includes the rotation speed and feed speed of the drill 14. The cutting resistance is, for example, a load calculated based on the current value of the feed motor 3 that drives the drill 14 in the axial direction, a load calculated based on the current value of the spindle motor 2 that drives the drill 14 around the axis, The load is measured by a load cell (not shown) provided on the main shaft 12.

  The position calculation unit 5 calculates the tip position of the drill 14 in the workpiece 17 at the time of drilling. The position calculation unit 5 calculates the position of the drill 14 in the feed direction based on, for example, the initial position at the start of driving of the drill 14, the surface position of the work 17, the plate thickness of the work 17, the feed speed of the drill 14, and the like. To do. Further, the position calculating unit 5 forms a hole on the entrance side based on the measured change in cutting resistance, whether the tip of the drill 14 is inside the workpiece 17 or the tip of the drill 14 starts to enter the workpiece 17. Or you may calculate whether the front-end | tip of the drill 14 penetrates the workpiece | work 17 and forms the hole by the side of an exit.

  The storage unit 6 stores a correlation between the cutting force and the height of burrs generated around the holes on the inlet side and the outlet side of the drill 14 formed in the workpiece 17. Generally, since there is a correlation between the cutting force and the burr height, each correlation is used for prediction of the burr height for each workpiece 17 by preparing and storing the correlation for each workpiece 17 in advance. be able to. The correlation of the workpiece 17 varies depending on the material and thickness of the workpiece 17, the diameter of the hole formed in the workpiece 17, and the like. The correlation between the cutting force and the burr height stored in the storage unit 6 is acquired from a confirmation test using a test piece.

  FIG. 6 is a graph showing the relationship between the burr height [inch] and the thrust load [N], and the measurement results obtained by the confirmation test are plotted. The measurement conditions in FIG. 6 are that the material of the workpiece 17 is Al7075, the plate thickness is 7.6 mm, and the hole diameter is 16 mm. According to FIG. 6, it can be seen that the higher the thrust load, that is, the higher the cutting resistance, the higher the burr height. The correlation stored in the storage unit 6 is obtained by extracting the maximum value of the burr height in each setting condition (in the example of FIG. 6, the rotational feed amount [ipr] per inch) from the measurement result. It is done.

  FIG. 7 is a graph showing the relationship between the burr height [inch] and the rotational speed [rpm], in which the measurement results obtained by the confirmation test are plotted. The measurement conditions in FIG. 7 are that the material of the workpiece 17 is Ti-6Al-4V, the plate thickness is 5 mm, and the hole diameter is 16 mm. According to FIG. 7, it can be seen that the burr height tends to increase as the rotational speed decreases, that is, as the cutting resistance increases. The correlation stored in the storage unit 6 is obtained by extracting the maximum burr height value in each setting condition (in the example of FIG. 7, the rotation speed [rpm]) from the measurement result. Depending on the material, the cutting resistance may increase as the rotational speed decreases, or the cutting resistance may increase as the rotational speed increases.

  The burr height predicting unit 7 predicts the height of burrs generated during drilling based on the cutting resistance measured during drilling with the drill 14 and the correlation stored in the storage unit 6.

  The spindle rotation speed control unit 8 adjusts the driving of the spindle motor 2 based on the burr height predicted by the burr height prediction unit 7 and controls the rotation speed of the spindle 12. The feed speed control unit 9 adjusts the drive of the feed motor 3 based on the burr height predicted by the burr height prediction unit 7 and controls the feed speed of the main shaft 12. The spindle rotation speed control unit 8 and the feed speed control unit 9 control the driving of the spindle motor 2 and the feed motor 3 based on the position of the drill 14 calculated by the position calculation unit 5. The control by the spindle rotational speed control unit 8 and the feed speed control unit 9 may be either one or both.

Next, a drilling method according to this embodiment will be described.
First, the workpiece 17 to be processed is set on the table 16 of the drilling apparatus 1. Further, the drill 14 is selected according to the diameter of the hole to be formed, and the drill 14 is installed on the chuck 13.

  Then, the correlation corresponding to the material, plate thickness, hole diameter to be formed, and the like is read from the storage unit 6 and set in the burr height prediction unit 7. Then, the driving of the main shaft 12 is started, and the workpiece 17 is cut while the drill 14 is driven to rotate and feed. As shown in FIG. 4, there is no factor for forming burrs until the tip of the drill 14 is in contact with the workpiece surface until it is inside the workpiece 17. Therefore, the position calculator 5 cuts the workpiece 17 while increasing the feed speed of the drill 14 while calculating the tip position of the drill 14. 4 shows a case where a plurality of plate-like members 18 and 19 are stacked. In addition, the data of the load at the time of the process of this specification are data in case the workpiece | work 17 is a single plate-shaped member. As shown in FIG. 3, the cutting resistance increases or is a substantially constant value during the period from when the tip of the drill 14 comes into contact with the workpiece surface until it is inside the workpiece 17 (period until (1) in FIG. 3). It becomes. FIG. 3 shows the relationship between the load (cutting resistance) and the cutting time, and shows the load in the rotational direction around the axis and the load in the feed direction that is the axial direction.

  Then, based on the tip position calculated by the position calculation unit 5, the tip of the drill 14 starts to enter the workpiece 17, forming a hole on the inlet side, or the tip of the drill 14 penetrates the workpiece 17 and is on the outlet side. When it is determined that a hole is formed, the feed rate of the drill 14 is reduced. As shown in FIG. 3, the cutting resistance rises while the tip of the drill 14 starts to enter the workpiece 17 and forms a hole on the inlet side, and the tip of the drill 14 passes through the workpiece 17 and passes through the hole on the outlet side. 3 (the period from (1) to (2) in FIG. 3), and as shown in FIG. 5, when the drill 14 comes out of the hole, the cutting resistance becomes close to zero. Further, the height of the burr is predicted based on the measured cutting resistance and correlation. When the predicted burr height is likely to be lower than a predetermined value set in advance, the current rotational speed and feed speed of the drill 14 are continued. On the other hand, if the predicted burr height is likely to be higher than the predetermined value, the current rotation speed and feed rate of the drill 14 are decreased to adjust the burr height to be lower than the predetermined value. To do.

  From the above, in the drilling process, after setting the material, plate thickness, hole diameter, etc. in the workpiece 17, based on the fact that there is a correlation between the cutting resistance and the height of burrs on the inlet side and outlet side of the drill 14, By using the correlation according to the setting conditions, the height of burrs generated around the holes on the inlet side and the outlet side of the drill 14 formed on the workpiece 17 is reduced to the cutting resistance measured at the time of drilling. Predicted based on.

  Conventionally, unlike the present embodiment, the burr height has not been predicted using the correlation between the cutting force and the burr height. On the other hand, this embodiment not only reduces the cutting resistance and prevents the occurrence of burrs on the inlet side and the outlet side of the drill 14, but also around the hole based on the actually measured cutting resistance. The “height” of the burr that occurs can be predicted.

  Conventionally, a confirmation test has been performed in which a rotation speed or a feed speed of the spindle 12 is set in a certain workpiece 17 and a burr generated according to the setting condition is confirmed. And since the conventional confirmation test did not consider the influence of cutting resistance, it had to be performed for every drilling work. On the other hand, the present embodiment can predict the height of burrs generated in the holes on the inlet side and the outlet side of the drill 14 by the measured cutting resistance even if the cutting resistance changes for each drilling operation. A confirmation test is not required for each drilling operation.

  In the present embodiment, the drive of the drill 14 is controlled based on the predicted burr height. Then, when the drive of the drill 14 is controlled and the drive state of the drill 14 changes, the cutting resistance during drilling also changes. As a result, the height of burrs generated during drilling can be changed. For example, when the predicted burr height approaches a predetermined value, the burr height can be suppressed within a predetermined value by changing the driving state of the drill 14. For example, the height of the burr can be suppressed by reducing or increasing the rotation speed or feed speed of the drill 14.

  Conventionally, a setting condition for suppressing the burr height within a predetermined value was obtained by repeating the confirmation test a plurality of times, but in this embodiment, the drill 14 is based on the predicted burr height. Since the burr height can be changed by the cutting resistance at that time, the burr height can be suppressed within a predetermined value without using a confirmation test.

  Furthermore, even when the same type of workpiece 17 is cut, the cutting resistance tends to change as the number of times increases (as time passes). 8 and 9 show the relationship between the burr height and the number of drilling operations (number of holes). The measurement conditions in FIG. 8 are as follows. The material of the workpiece 17 is Ti-6Al-4V, the plate thickness is 8.9 mm × 2 and the hole diameter is 16 mm. The burr height inside the workpiece 17 is measured. The measurement conditions in FIG. 9 are that the material of the workpiece 17 is Al7075-T6, the plate thickness is 8.9 mm, and the hole diameter is 11 mm. Conventionally, even if the setting condition for each workpiece 17 is obtained by the confirmation test, it is troublesome to obtain the setting condition corresponding to the number of drilling operations (elapsed time). On the other hand, in this embodiment, the drive of the drill 14 is controlled based on the cutting resistance at the time of drilling, and the height of the burr can be changed. Therefore, even when the same type of workpiece 17 is cut a plurality of times and the cutting resistance changes, the burr height can be suppressed within a predetermined value.

  Furthermore, in this embodiment, the drive of the drill 14 is controlled based on the position of the drill 14 in the workpiece 17. Therefore, the driving state of the drill 14 changes according to the position of the drill 14. Generally, burrs that occur around the holes on the inlet side and the outlet side of the drill 14 formed in the workpiece 17 occur when the drill 14 forms holes on the inlet side or the outlet side. Therefore, when the tip of the drill 14 is in the workpiece 17, the tip of the drill 14 starts to enter the workpiece 17 and forms a hole on the inlet side, or the tip of the drill 14 penetrates the workpiece 17 and forms a hole on the outlet side. By changing the driving condition of the drill 14 between the time of forming the burrs, the time required for machining can be changed while changing the height of burrs generated during drilling.

  For example, as shown in FIG. 4, when the tip of the drill 14 is in the workpiece 17, the rotation speed and feed rate of the drill 14 are increased, and the tip of the drill 14 begins to enter the workpiece 17 to form a hole on the inlet side. The rotation speed and feed speed of the drill 14 are reduced while the tip of the drill 14 passes through the workpiece 17 and starts to form a hole on the outlet side until the drilling finishes as shown in FIG. To. At this time, based on the correlation with the measured cutting force, the height of burrs generated in the holes on the inlet side and the outlet side of the drill 14 is predicted, and the rotational speed and the feed speed are adjusted. As a result, in the present embodiment, the height of burrs generated during drilling can be suppressed while shortening the machining time as compared with the case where the rotation speed and feed speed of the drill 14 are controlled to be constant.

DESCRIPTION OF SYMBOLS 1 Drilling apparatus 2 Spindle motor 3 Feed motor 10 Support part 11 Head part 12 Spindle 13 Chuck 14 Drill 15 Base part 16 Table 17 Workpiece (working object)

Claims (4)

A measuring unit that measures cutting resistance based on a driving state of a cutting tool for drilling a workpiece;
A storage unit for storing a correlation between the cutting force and the height of burrs generated around a hole formed in the workpiece;
A predicting unit that predicts the height of the burr generated at the time of drilling based on the cutting resistance measured at the time of drilling by the cutting tool and the correlation;
Drilling device equipped with.   The drilling device according to claim 1, further comprising a control unit that controls driving of the cutting tool based on the predicted height of the burr. A position calculator that calculates the position of the cutting tool in the workpiece;
The drilling device according to claim 2, wherein the control unit controls driving of the cutting tool based on a position of the cutting tool. Measuring a cutting resistance based on a driving state of a cutting tool for drilling a workpiece; and
Storing a correlation between the cutting force and the height of burrs generated around a hole formed in the workpiece;
Predicting the height of the burr generated during drilling based on the cutting resistance measured during drilling with the cutting tool and the correlation; and
A drilling method comprising:

Images