JPS61236468A - Free curved-surface machining equipment - Google Patents

Abstract

PURPOSE:To automatically carry out all the machining along a finished configuration by controlling machining means based on the amount of machining obtained from the difference between the finished configuration and an actual configuration. CONSTITUTION:Workpiece configuration measuring means C2 measures the three-dimensional curved-surface configuration of a workpiece W. Finished configuration storing means C3 stores a finished three-dimensional curved-surface as a target configuration of the workpiece W. Configuration comparing means C4 compares a workpiece configuration measured by the workpiece configuration measuring means C2 with the finished three-dimensional curved-surface configuration which is stored in the finished configuration storing means C3. Control means C5 actuates machining means C1 based on the result of the comparison.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a free-form surface machining machine that realizes a desired three-dimensional free-form surface by machining, and in particular, the invention relates to a free-form surface machining machine that realizes a desired three-dimensional free-form surface by machining, and in particular, the freedom to achieve complete automation without requiring manual labor. This relates to curved surface processing machines.

[Prior Art] Conventionally, machining that requires high precision on three-dimensional free-form surfaces, such as manufacturing molds, has been performed manually and by the intuition of skilled workers, requiring a lot of time and effort. For example, after only rough engraving is performed using a processing machine or the like, rough finishing is performed using a hand-held grinder, and then grinding and polishing are performed using a whetstone or the like, relying on the sense of touch and vision of an expert.

For this reason, three-dimensional free-form surface grinding machines have been developed in recent years for the purpose of mechanizing the above-mentioned manual work. This type of equipment learns the details of the grinding work through constant-pressure self-guided tracing or by teaching by tracing typical working points, and attempts to accomplish the desired work.
It is necessary to input information on the machined surface by moving the machine while tracing the machined surface at a constant pressure, or by manually teaching the work point in advance.

[Problems to be Solved by the Invention] Therefore, the above-mentioned conventional machining of a three-dimensional free-form surface has the following problems.

First, a grinding machine using constant pressure self-guided profiling can achieve a certain level of roughness on the machined surface, but it can only grind according to the shape of the previous process, and ultimately requires the work of the above-mentioned expert. In other words, the effect is limited to shortening the time required for the work to some extent.

Further, in a grinding machine in which the work content is taught by teaching, it is complicated to manually teach typical work points for each work, which poses a problem in application to high-mix, low-volume production.

Furthermore, both of the above grinding machines have a low degree of freedom,
In order to grind one workpiece, the workpiece must be chucked many times, resulting in low productivity and inability to achieve complete automation.

In other words, all conventional processing machines have open control with a low degree of freedom, are not sufficient in terms of application to automation, processing accuracy, etc., and cannot keep up with today's automation.

The present invention has been made in view of the above-mentioned problems, and provides an excellent free-form surface machining machine that can quickly and accurately perform desired machining on a three-dimensional free-form surface metal with a single workpiece chuck. That is its purpose.

[Means for solving the problems] The means configured by the present invention to solve the above problems are as follows:
As shown in the basic configuration diagram of FIG. 1, processing means C1 moves a processing tool that changes the shape of the workpiece W to an arbitrary position on the workpiece, and changes the amount of processing performed by the processing tool on the workpiece; A workpiece shape measuring means C2 that measures the three-dimensional curved shape of the workpiece W; a finished shape memory means C3 that stores the finished threedimensional curved shape that is the target shape of the workpiece W; and a workpiece measured by the workpiece shape measuring means C2. a shape comparison means C4 for comparing the shape with the finished three-dimensional curved surface shape stored in the finished shape storage means C3; and a shape comparison means C4 for comparing the shape with the finished three-dimensional curved surface shape stored in the finished shape storage means C3;
The gist of the present invention is a free-form surface machining machine characterized by comprising a control means C5 for operating the control means C5.

[Operation] The processing means C1 in the present invention changes the shape of the workpiece W, and therefore controls the ability to move a processing tool that changes the shape to any position on the workpiece W and the operation of the processing tool. have the ability. For example, when the shape of the workpiece W is only slightly machined, a processing tool such as a grindstone is moved to a predetermined position on the workpiece W, and the rotation speed and pressing pressure of the grindstone etc. are changed to What controls the operation of the grindstone etc. corresponds to the processing means C1.

Further, since the processing means C1 has the ability to move the processing tool to any position on the workpiece W, the portion that holds the processing tool, the so-called arm or head portion, has a three-dimensional degree of freedom. For example, in order to move the processing tool, a moving mechanism is employed that can freely control five axes: the X-axis, Y-axis, Z-axis, and contact angle control axes A-axis and C-axis. Furthermore, it is preferable that one of the pressing force control axes of the processing tool can be controlled in order to change the amount of processing performed by the processing tool, and a 6-axis processing means in combination with the above-mentioned movement control axis is a more preferable embodiment. Furthermore, as a means for changing the amount of processing, it is preferable that the processing tool itself to be held is selected and changed. That is,
When the amount of machining is coarse and large, it is possible to select a special tool for grinding, etc., and when the amount of machining is fine and small, it is possible to select a special tool for polishing, etc. This can be implemented, for example, by a known automatic tool change.

Further, the workpiece shape measuring means C2 measures the three-dimensional curved shape of the workpiece W. For example, various currently available shape recognition devices can be used for this purpose. Note that this workpiece shape measuring means C2 is not limited to being constituted by a single device;
For example, it is composed of two mechanical parts: a relative shape measurement section that performs relative shape measurement within the machining execution range of the processing tool, and an absolute shape measurement section that performs absolute shape measurement of the overall shape of the workpiece. It may be something that When performing grinding or the like to cause a large change in the shape of a workpiece, it is necessary to always absolutely detect the shape of the entire workpiece. Therefore, an absolute shape measurement unit is essential, but in order to detect in real time how much shape change has occurred in the part that is actually being ground, and to know the usage status of the grinding tool, it is necessary to It is sufficient to detect changes in the shape of the object. That is, real-time detection is simple and effective for detecting that the grinding ability has decreased due to clogging, wear, etc. of the grinding tool. Furthermore, in a polishing process for simply achieving surface accuracy without changing the shape of the workpiece W, simple partial or relative shape detection is performed rather than absolute shape detection, which requires time. This is more preferable in terms of improving workability. Therefore, as described above, it is preferable to have two types of measuring sections, an absolute shape measuring section and a relative shape measuring section, so that detection suitable for the work can be performed.

The finishing shape memory means C3 stores the final shape of the workpiece W and the shape at the time of finishing. Therefore, it is constructed by using various known memory elements, for example. Shape memory usually involves a huge amount of information. Therefore, in order to memorize the shape more accurately and quickly, the shape of the workpiece W is created using CAD (Computer Aided Design) in advance.
It is preferable to configure a data flow such as designing by CAD (Design) and writing the CAD data (numerical data) directly into the finishing shape storage means C3.

Furthermore, the shape comparing means C4 in the present invention refers to the detection information of the workpiece shape measuring means C2 and the finished shape storing means C.
A comparison is made with the stored information of No. 3. Comparison of these two pieces of information reveals the difference between the finished shape and the actual shape, that is, the amount of processing currently required.

The control means C5 controls the processing means C1 according to the amount of processing determined as described above. The required amount of processing is performed by the processing means C1. Therefore, for example, if the amount of processing is extremely large and requires a rough material, the processing means C1 should select a coarse grindstone or grinder that can handle a large amount of processing, and increase the pressing pressure and rotation speed. It sends control signals such as In this way, the present control means C5 centrally manages the control amounts as appropriate in order to operate the various means described above more efficiently. With recent advances in computer technology, it is preferable in terms of accuracy and processing speed to use this computer as the control means C1 and numerically control each of the above means.

EXAMPLES In order to explain the present invention more specifically, the present invention will be described in detail with reference to Examples.

[Embodiment] FIG. 2 is an explanatory diagram schematically showing each function of a free-form surface machining machine according to an embodiment.

In the figure, reference numeral 1 denotes a so-called gate-shaped processing machine main body, and a gate-shaped support 3 has a beam member 5 that can be moved in the vertical direction (hereinafter referred to as two directions) across the frame, and the frame is designed to wrap around the beam member 5. A head 7 is provided.

Further, the head 7 is freely movable on the beam 5 and can be moved to any position in the horizontal direction (hereinafter referred to as the Y direction) in the drawing. Further, the pallet 11 on which the workpiece 9 is placed can be moved by a moving table 13 in the front and back directions of the page (hereinafter referred to as the X direction). With the above-mentioned components, the free-form surface machining machine of this embodiment can achieve free operation in the three axes of X, Y, and Z.

Furthermore, when the head 7 moves rightward on the beam 5 and reaches an automatic attachment changer 15 (hereinafter referred to as AAC) installed next to the gate-shaped support 3, the most suitable attachment 17 for various processing is selected. It is attached. Similarly, tools held by the attachment 17, such as whetstones, grinders, etc., are transferred to an automatic tool changer 19 (with the attachment 17 attached to the head 7 that moves leftward on the beam 5 and is installed in parallel on the side of the support 3).
(hereinafter referred to as ATC), it is automatically replaced with the most suitable one. 21 is a gate-shaped device similar to the processing machine main body, and has a head 23 that can freely move in the X, Y, and Z directions, and has a distance sensor 25 at its tip for three-dimensionally determining the shape of the workpiece 9. This is a shape measuring machine for measuring. The shape measuring machine 21 and the processing machine main body 1 are connected online by the moving table 13 mentioned above, and constitute a so-called automatic pallet changer (hereinafter referred to as APC). 27 and 29 are controllers consisting of computers that communicate information with each other;
Control of the movement amount of the three axes and ATC19, A
Controls the AC 15 and the moving table 13. The controllers 27 and 29 also communicate with external equipment, forming a closed loop with the external equipment.

Details of the attachment 17 will be explained based on the explanatory diagram of FIG. 3. As shown, this embodiment includes a special grinding and measuring tool 30. This grinding/measuring tool 30 is held by an attachment 17, and the contact angle with respect to the workpiece 9 can be freely changed by the operation of the attachment 17 (by driving in the hexagonal and caxial directions in the figure). The grinding/measuring tool 30 is shown with a rough grinding wheel 31 attached thereto, by way of example.

This grinding and measuring tool 30 has a simple shape sensor 33 on its side wall. This is to detect, for example, the grinding status of the surface of the workpiece 9 processed by the rough grinding wheel 31 by capturing it with a camera or by measuring its surface roughness. Furthermore, the grinding/measuring tools 30 are each driven to rotate at a predetermined rotational speed by a high frequency motor 37, and the pressing pressure of each tool against the workpiece 9 can be adjusted by controlling an air cylinder 39 that supports the high frequency motor 37. .

With such a special grinding/measuring tool 30, the workpiece 9
This allows the amount of processing to be finely adjusted. Furthermore, in addition to the special attachment 17 described above, the AAC' 15 of this embodiment also shares an attachment without a pressing pressure adjustment mechanism that a normal five-axis machine has.

The controller 27, 29 and various devices detailed above are
The explanatory diagram in FIG. 4 is a block diagram showing what kind of information is exchanged.

As is clear from the figure, the free-form surface machining machine of this embodiment is CA
It is configured to form part of the D system, and the two controllers 27 and 29 are positioned below the CAD. 4
0 is a central monitoring system that links CAD and this free-form surface processing machine to ensure compatibility of information, and directly below it is a grinding condition system 42 that calculates grinding conditions according to commands from the central monitoring system 40, and a processing machine. A measuring machine drive system 46 that controls the operation of the drive data needle barrel system 44 and the shape measuring machine 21 is provided. First, to explain from the processing machine side, the grinding condition calculation system 42, which inputs information on how much grinding should be performed from the central monitoring system 40, calculates conditions for grinding, such as pressing Determine the force F, tool moving speed V, contact angle θ with the workpiece, etc. The correlation between the tool operation and the corresponding grinding amount, which is the basis of this condition calculation, is determined in advance theoretically or experimentally, and is input as the above-mentioned grinding correlation. When the calculation result of this grinding condition calculation system 42 or the output from the central monitoring system 40 is simply surface polishing that does not require calculation of grinding conditions, the output is input as is to the processing machine drive data calculation system 44. . Here, calculations are made on how to drive the processing machine and how to respond to commands from each host machine, and the results are input to the controller 27 mentioned above.

On the shape measuring machine side, the measuring machine drive data calculation system 46 instructs the controller 29 to start up in response to a signal from the central monitoring system 40, and detects the shape of the given workpiece 9 in three dimensions.

On the other hand, there is information that is transmitted toward the central monitoring system 40 side. When an attachment having the aforementioned shape sensor 33 is used, the detection output from the sensor 33 is input to the grinding state determination system 48 and the polishing state determination system 50.

The grinding state determination system 48 provides data indicating the grinding state to the grinding condition calculation system 42, and a feedback system for grinding is configured here. The polishing state determination system 50 is for transmitting the polishing state to the upper central monitoring system 40, and its output is sent to the repolishing command system 5.
Give to 2. This regrinding command system 52 determines whether the polishing state of the workpiece 9 is sufficient, that is, whether or not regrinding is required. It gives information.

Further, the controller 29 of the shape measuring machine 21 provides the output from the measuring machine, that is, shape information, to the measurement data determination system 54. This measurement data judgment system 54 also simultaneously inputs CAD data, that is, data on the final shape of the workpiece 9 via the central monitoring system 40, compares these two data, and uses this result to issue a re-grinding command. Inform system 56. Then, this re-grinding command system 56 makes a judgment as to whether or not re-grinding is necessary based on the comparison result of the data, and this judgment and the data of the part of the workpiece 9 on which the judgment was made are sent to the central monitoring system 4.
Transmit to 0.

Next, the operation of the free-form surface machining machine of this embodiment having the above configuration will be explained.

For example, in order to manufacture a mold, the free-form surface machining machine of this embodiment proceeds with the basic routine shown in FIG.

First, information about the shape of the mold to be manufactured is input from a database created using a higher-level CAD (step 100). Next, based on this obtained information, die-sinking (step 200) is performed to roughly approximate the shape of the workpiece to the above-mentioned shape information, and rough finishing is performed to make the shape after die-sinking have higher surface accuracy. (Step 300), Shape Step 400), II
Step 500) is executed sequentially. As a result, what is drawn on a drawing using CAD can be transformed into a product with an actual three-dimensional shape.

FIG. 6 is an explanatory diagram for explaining the function of each step described above. As shown in the figure, the workpiece 9 is shaved into a thin band shape using a die-sinking tool to form a rough shape. After that, in order to eliminate the many cutter marks caused by the engraving, rough polishing, which is an extremely rough polishing process, was performed (approximately
oamm depth grinding), and then finish the shape according to the information from CAD, so-called shape-cutting of about 0.15 mm.
depth grinding) is performed. Final polishing (about O0O'1m
m-depth polishing) does not involve any change in the shape of the workpiece 9, but is polishing performed using an extremely fine grindstone in order to further improve the surface precision of the workpiece 9.

The above-described die engraving (step 200) is performed using a commonly used ball end mill or the like. This is because as long as the machine has three-dimensional degrees of freedom in the X, Y, and Z axes, there is no need for precision in the machined surface, and for this reason, a simple three-dimensional automatic grinding machine has been proposed. For this reason, the details of its operation will not be described here, but the free-form surface machining machine of this embodiment has a major feature in the subsequent processing (steps 300 to 500).

The workpiece 9 whose approximate shape has been formed by die-sinking is then automatically rough-finished (step 300). Grinding and measuring tool 3 of a free-form surface processing machine performing rough finishing
The above-mentioned FIG. 3 shows the operating state of 0. As described above, the grinding/measuring tool 30 to which the rough grinding wheel 31 is attached can be moved to any position relative to the workpiece 9 by five-axis control using the X-axis, Y-axis, Z-axis, A-axis, and C-axis. . The grinding/measuring tool 30 has a variable pressing pressure against the workpiece 9 by operating an air cylinder 39 built therein. Such a grinding/measuring tool 30 is controlled as follows to perform rough cutting work.

FIG. 7 is a flowchart of the control for grinding, and as shown in the figure, step 300 mainly consists of three processes. Step 301 is a process of driving the grinding/measuring tool 30 according to the CAD information to grind a three-dimensional curved surface, and once the grinding has been completed through this process, the next step 302 is a shape measurement process. . This is done by moving the workpiece 9 to the shape measuring machine 21 using the APC operation. Then, the three-dimensional information measured by this process is compared with the information from the CAD, and as long as it is determined that re-grinding is necessary, the process returns to step 301 and repeats the above process.

That is, to explain based on the block diagram shown in FIG. 4, the grinding condition calculation system 42, which inputs data on how much grinding should be performed from the central monitoring system 40 based on CAD information, calculates the amount of grinding that is faithful to the data. The grinding conditions for performing the grinding are calculated and the results are sent to the processing machine drive data calculation system 44. In accordance with this, the processing machine drive data calculation system 44 instructs the controller 27 to control the amount, and the processing machine 1 operates. After a certain amount of grinding has been performed in accordance with the CAD information in this manner, the workpiece 9 is moved to the shape measuring machine 21 by the APC and subjected to shape measurement. This measurement result is compared with CAD information by the operation of the controller 29, the measurement data judgment system 54, and the re-grinding command system 56, and the location where grinding is still insufficient and the degree of the shortage are sent to the central monitoring system 40. It is sent. After that, the central monitoring system 4
0 operates in the same manner as described above.

Step 400 shown in FIG. 5 also performs almost the same operation as step 300 described above, and a similar control section operates according to a flow chart similar to that of FIG. 7 to perform grinding. However, what differs from rough finishing here is the precision of the surface.
In step 400, a finer grindstone is used as a tool to form the shape, and a more accurate shape measurement is used to create the shape.
This is to realize a shape as close to the AD information as possible.

FIG. 8 shows the calculation method of the grinding condition calculation system 42 performed in steps 300 and 400 above.

(A) Any point on the surface of the workpiece 9 as shown in the figure, the coordinates (
When the degree to which points X, V, Z) are to be ground is input from the central monitoring system 40, the normal vector (i, J, k>) of the point to be ground is determined as shown in FIG. Calculated.

This is the coordinate (X) based on the information from the shape measuring device 21.

Since the shape of the point (y, z) is known three-dimensionally, it can be obtained by normal graphic processing. And this (x,
The control amounts for all six axes of the processing machine mentioned above are determined from the values of y, z) and (i, j, k). First, among the six axes, the control amounts for the X, Y, and Z axes are uniquely determined by moving the tool to the point (X, V, Z)17) on the workpiece 9, and the The contact area between the workpiece 9 and the tool is determined by the control amount of the axis. Next, the control amount of the pressing pressure (Fa) on the workpiece 9 necessary to perform the desired grinding is determined.

Furthermore, when the grinding is being executed in step 300 or step 400, the present free-form surface machining machine also executes learning control at the same time. The block diagram shown in FIG. 9 is an extraction of only the blocks involved in this learning control. As shown in the figure, this learning control is to learn the grinding conditions based on the detection results of the shape sensor 33. First, shape information of the workpiece 9 detected by the shape sensor 33 is input to the grinding state determination system 48 . This grinding state determination system 48 detects the grinding state from the information,
A comparison is made to see how much difference there is between the grinding calculated by the grinding condition calculation system 42 and the grinding currently being executed. Then, from the comparison results obtained in this way, a so-called learning correction amount is calculated to determine how much the basic formulas and constants of grinding used for calculation in the grinding condition calculation system 42 should be changed, and the result is It is input into the grinding condition calculation system 42 and reflected in subsequent condition calculations. This learning control allows the control amounts for the six axes of the processing machine to always maintain the best conditions, making it possible to achieve highly accurate processing.

After the grinding, rough finishing, and shaping based on the control described above are completed, polishing (step 500 in FIG. 5) is performed. This polishing is not intended to change the shape of the workpiece 9, but merely improves its surface precision. Therefore, the shape measuring machine 21 as described above
Control is performed according to a flowchart as shown in detail in FIG. 10, without performing measurements of three-dimensional shapes using the . That is, a three-dimensional curved surface is polished (step 501), the surface roughness of the polished portion is detected (step 502), and the process returns to step 501 again to repeat the same control until the surface roughness becomes less than a desired value. (Step 503). As is clear from the control of each step described above, it is not necessary to grasp the absolute three-dimensional shape of the workpiece 9 for this control, but simply to determine the surface roughness within a narrow range of the part being polished. Measuring degrees is sufficient. Further, since the polishing is an operation of uniformly polishing the surface of the workpiece 9, control of the amount of processing such as pressing pressure is not required as compared to rough finishing. Therefore, during this work, an air cylinder 39 is provided as a tool, and constant pressure tracing control can be adopted. What executes this control is a polishing state determination system 50 that inputs the output of the shape sensor 33 shown in the block diagram of FIG. 4, a repolishing command system 52 that determines whether repolishing is required from the output, and This is a central monitoring system 40 that operates a processing machine drive data calculation system 44 based on instructions.

According to the free-form surface machining machine configured and controlled as described above, any three-dimensional shape can be realized without any manual intervention. What's more, since the entire process from engraving to polishing is fully automated, no human intervention is required during this process. Furthermore, since the control is accurately executed based on digitized information called CAD data, human errors and unevenness are eliminated, the precision of the three-dimensional curved surface is extremely high, and troublesome work such as teaching is not required. Furthermore, by adopting a simple shape sensor 33 that detects the shape, learning control is simultaneously executed during grinding to maintain high precision machining, and constant pressure tracing control is also executed during polishing to shorten the time required for machining. It is possible to do so.

[Effects of the Invention] As described above in detail with reference to the embodiments, the free-form surface processing machine of the present invention moves a processing tool that changes the shape of a workpiece to an arbitrary position on the workpiece, and also moves the processing tool that changes the shape of the workpiece to an arbitrary position on the workpiece. processing means for changing the amount of processing on the workpiece; workpiece shape measuring means for measuring the three-dimensional curved surface shape of the workpiece; finishing shape memory means for storing the finished three-dimensional curved surface shape that is the target shape of the workpiece; Shape comparison means for comparing the workpiece shape measured by the shape measurement means and the finished three-dimensional curved surface shape stored in the finished shape memory means; and control means for operating the processing means according to the comparison result of the shape comparison means. It is characterized by comprising the following.

Therefore, all machining according to the finished shape is automatically completed. Moreover, since even the amount of machining can be controlled, the accuracy of the machined surface is high, and even processes such as polishing that were dependent on skilled workers can be replaced by this free-form surface machining machine. It becomes possible.

[Brief explanation of the drawing]

Figure 1 is a basic configuration diagram of the present invention, Figure 2 is a schematic diagram of the configuration of an embodiment, Figure 3 is an explanatory diagram of its attachment, Figure 4 is a block diagram of its control system, and Figure 5 is its control. Flowchart of the basic routine, Figure 6 is an explanatory diagram of the work,
Figure 7 is a detailed flowchart of the grinding work, Figure 8 is an explanatory diagram of the control amount calculation method, Figure 9 is an explanatory diagram of learning control during grinding, and Figure 10 is a detailed flowchart of the polishing work. show. C1... Processing means C2... Work shape measuring means C3... Finished shape memory means C4... Shape comparison means C5... Control means 1... Processing machine 9... Work 15... AAC 17... Attachment 19... ATC 27, 29... Controller

Claims (1)

[Scope of Claims] 1. Processing means for moving a processing tool that changes the shape of the workpiece to an arbitrary position on the workpiece and changing the amount of processing performed by the processing tool on the workpiece; A workpiece shape measuring means to measure; a finished shape memory means for storing a finished three-dimensional curved surface shape which is a target shape of the workpiece; a workpiece shape measured by the workpiece shape measuring means and a finish stored in the finished shape memory means. A free-form surface machining machine characterized by comprising a shape comparing means for comparing the shape of a three-dimensional curved surface, and a control means for operating the machining means according to the comparison result of the shape comparing means. 2. The processing means moves the processing tool to an arbitrary position with respect to the workpiece using five axes: The free-form surface machining machine according to claim 1, which is a 6-axis machining machine in which six axes including one pressing force control axis of a machining tool to be changed are controlled. 3. The free-form surface processing machine according to claim 1 or 2, wherein the processing means has a plurality of processing tools, and selects a predetermined processing tool according to a control signal from the control means. 4. The workpiece shape measuring means includes a relative shape measurement section that performs relative shape measurement within a processing execution range of the processing tool, and an absolute shape measurement section that performs absolute shape measurement of the overall shape of the workpiece. A free-form surface machining machine according to any one of claims 1 to 3. 5. According to any one of claims 1 to 4, the finished shape memory means inputs and stores the target shape of the workpiece as numerical data, and the control means executes numerical control on the processing means. Free-form surface processing machine.