阅读说明：本技术 用于运行机床的方法 (Method for operating a machine tool ) 是由 托马斯·贝特尔曼 于 2020-03-25 设计创作，主要内容包括：本发明涉及一种用于运行机床的方法,尤其用于运行磨床的方法,所述方法包括如下步骤：检测要加工的工件和设定机床的多个设定值；执行工件的加工；在执行加工期间或在执行加工之后检测第一实际值和第二实际值,其中为第一实际值分配比第二实际值更高的优先级；将第一实际值与第一期望值范围比较和将第二实际值与第二期望值范围比较；以及改变机床的设定值,使得这些实际值根据优先级满足相关联的期望值范围。(The invention relates to a method for operating a machine tool, in particular a grinding machine, comprising the following steps: detecting a workpiece to be machined and setting a plurality of set values of a machine tool; performing machining of the workpiece; detecting a first actual value and a second actual value during or after the machining is performed, wherein the first actual value is prioritized over the second actual value; comparing the first actual value to a first expected value range and the second actual value to a second expected value range; and changing the set values of the machine tool so that the actual values satisfy the associated desired value ranges according to the priorities.)

1. Method for operating a machine tool, in particular a grinding machine, comprising the following steps:

detecting a workpiece (W) to be machined and setting a plurality of set values of the machine tool;

performing machining of the workpiece;

detecting a first actual value and a second actual value during or after performing machining, wherein the first actual value is prioritized over the second actual value;

comparing the first actual value to a first expected value range and the second actual value to a second expected value range;

the set values of the machine tool are changed so that these actual values satisfy the associated desired value ranges according to the priority.

2. The method of claim 1, wherein the first desired range of values is selected from the group consisting of: the thickness of the workpiece (W) to be machined, the surface quality of the workpiece (W) to be machined, and the flatness of the surface of the workpiece (W).

3. Method according to claim 2, wherein the workpiece (W) to be machined and/or the workpiece (W) to be machined is detected using a camera or a radar sensor.

4. Method according to claim 2 or 3, wherein the thickness of the workpiece (W) being machined is detected by a contact sensor or a non-contact sensor (60), in particular a laser sensor.

5. The method of any of the above claims, wherein the second desired range of values is selected from the group consisting of: the energy consumption of the machine tool, the wear of the machining elements, in particular of the grinding belt, the suction speed, the feed speed.

6. The method of any of the above claims, wherein the set point is selected from the group consisting of:

the feed rate of the workpiece, the cutting speed by height, the cutting speed of the grinding belt, the pressing pressure, the pressing force, the number, selection and/or combination of the processing devices used, the feed value of the devices, the type of the processing devices,

wherein the set value is changed by comparing the first actual value with a first desired value range and comparing the second actual value with a second desired value range, including the feed speed of the workpiece, the pass height, the workpiece width, the cutting speed of the grinding belt, the pressing pressure, the pressing force, the ambient temperature and/or the air humidity.

7. The method according to any of the preceding claims, wherein the step of comparing is performed by means of a control device using artificial intelligence.

8. The method according to one of the preceding claims, wherein the machine tool is designed as a grinding machine, wherein preferably the grinding machine has a belt grinding device, a disk brush, a grinding roller, a brush roller, a cross belt grinding device, a fine grinding device or a combination thereof as the grinding device.

9. The method according to claim 8, wherein a plurality of grinding devices of the grinding machine are controlled by respectively setting at least one set point of the respective grinding apparatus.

10. Method according to one of the preceding claims, wherein the changed set value is stored in a memory means, wherein preferably the actual value and the associated desired value are also stored in the memory means.

11. A machine tool, in particular a grinding machine, having at least one grinding device, in particular provided for carrying out a method according to one of the preceding claims, comprising:

first detection means for detecting a first actual value of the workpiece (W) after or during the execution of the machining of the workpiece;

second detection means for detecting a second actual value of the workpiece (W) after or during the execution of the machining,

wherein the first actual value is prioritized over the second actual value,

a control device which is provided for comparing the first actual value with a first desired value range, for comparing the second actual value with a second desired value range, and for changing the set value of the machine tool such that the actual value satisfies the associated desired value range in accordance with the priority.

Technical Field

The invention relates to a method for operating a machine tool, in particular a grinding machine. Such grinding machines are used, for example, for grinding plate-like workpieces, which preferably comprise wood or wood-based materials. The invention also relates to a machine tool.

Background

When grinding plate-shaped workpieces, such as wood plates or wood chips, manufacturers are always striving to achieve high-quality machining results within manufacturing tolerances. The quality of the machining obtained when grinding such workpieces is also relevant for downstream machining steps, for example when coatings, such as paints, are applied to such workpieces. For this purpose, it is necessary for the workpiece to have a specific thickness, a flat surface and a specific surface quality after the grinding process.

The setting of the grinding machine performing the machining is made according to the particular material to be machined and empirical values relating to the dimensions of the workpiece. The operator of the grinding machine may also change the settings of the grinding machine during machining of a large number of workpieces if the machining results are out of tolerance.

The operator of the machine tool has a variety of setting options to influence the machining result. For example, the pressing pressure may be set to a certain amount value or the feed speed may be changed.

However, it has been shown that the setting of a specific target value, i.e. for example a specific workpiece thickness after the machining has been performed, is associated with a plurality of influencing variables which at least partially influence one another. In particular the feed speed, the pressing pressure, the speed of the grinding belt, the width and the thickness of the workpiece have an influence on the machining result.

A grinding machine is known from EP 2815844 a1, which comprises a grinding device, a conveying device and a control device. The grinding machine further comprises a thickness determination device which is arranged downstream of the at least one grinding device in the direction of passage and by means of which the finished dimension actual thickness of the workpiece to be machined by the at least one grinding device can be determined. The control device is provided for comparing the finished dimension actual thickness of the workpiece with the finished dimension desired thickness and for controlling the operation of the at least one grinding device such that the finished dimension actual thickness matches the finished dimension desired thickness. Further, the second thickness determining means may determine the original-size actual thickness of the unprocessed workpiece.

In order to vary the machining result, it is indicated in EP 2815844 a1 that the grinding machine is adapted to co-act with the pressure beam and to manipulate the pressure beam on the basis of the measurement of the original dimension actual thickness and/or the finished dimension actual thickness.

Although the method described in EP 2815844 a1 has proven to be a viable solution, users are faced with increasingly higher quality requirements. This is the starting point of the present invention.

Disclosure of Invention

The object of the invention is to provide a method for operating a machine tool, by means of which a high machining quality can be ensured on a large number of workpieces.

The subject matter of claim 1 provides a corresponding method. Further preferred embodiments are listed in the dependent claims. The invention also relates to a machine tool.

A method of operating a machine tool (e.g. a grinding machine) comprises the steps of: detecting a workpiece to be machined and setting a plurality of set values of a machine tool; performing machining of the workpiece; detecting a first actual value and a second actual value during or after the machining is performed, wherein the first actual value is prioritized over the second actual value; comparing the first actual value to a first expected value range and the second actual value to a second expected value range; and changing the set values of the machine tool so that the actual values satisfy the associated desired value ranges according to the priorities.

The method according to the invention has the advantage that a high processing quality can be maintained when large numbers of pieces are produced. The proportion of workpieces classified as defective can also be significantly reduced, since the setting options can be improved continuously. In addition or alternatively, the setting of at least one set value of the machine tool, in particular of the grinding machine, can be carried out in a predictive manner to some extent.

"surface texture" refers to the surface roughness determined by the number, orientation and depth of the grooves or depressions present in the surface.

According to one embodiment, a neural network is used which is optimized on the basis of the feedback of the system about the target values which have been reached or not reached, and in this case leads to a further improvement of the system. By means of such an algorithm, a large number of possibilities of influencing the quality of the machining can be taken into account.

According to one embodiment, the first desired value range is selected from: the thickness of the workpiece being machined, the surface quality of the workpiece being machined, and the flatness of the workpiece surface. Accordingly, the thickness of the workpiece to be machined, the surface quality of the workpiece to be machined, or the flatness of the workpiece surface is detected as the first actual value.

Preferably, a camera or a radar sensor is used to detect the workpiece to be machined and/or the surface structure of the workpiece to be machined. For example, a camera may be used to detect the workpiece size and surface gloss. Radar sensors may be used to determine surface roughness.

In a further embodiment, it is provided that the thickness of the workpiece to be machined is detected by a contact sensor or a contactless sensor, in particular a laser sensor.

According to another embodiment, it is proposed that the second desired range is selected from: the energy consumption of the machine tool, the wear of the machining elements, in particular of the grinding belt, the suction speed for sucking machining residues, the feed speed.

For example, it can be provided that the energy consumption of the machine tool should be kept within a certain range in order to ensure that the machine tool operates in an energy-saving manner. The desired value range of the energy consumption may for example depend on external conditions, such as the current electricity price, which may fluctuate depending on the time of day.

The wear of the processing elements, in particular of the grinding belt, can be selected such that the processing elements are replaced at an advantageous point in time, for example after the production of a particular order. Less wear of the machined components results in longer production times per workpiece, but higher quality of the machined results, as well as longer service life of the machined components.

The suction speed at which machining residues are sucked affects the energy consumption of the machine tool and the quality of the machining result.

Reaching a certain feed rate results in a corresponding increase or decrease of the number of internals per unit time. Even if a higher number of workpieces per unit time is aimed at in general, the production speed can be coordinated with the entire process, for example in order to ensure a friction-free material supply and a coordinated removal of the workpieces.

According to a further embodiment, it is provided that the set value is selected from: the feed rate of the workpiece, the pass height, the cutting speed of the grinding belt, the pressing pressure, the pressing force, the number, selection and/or combination of the machining devices used, the feed value of the devices and the type of machining device. In this case, it can be provided that the set values are changed by comparing the first actual value with a first desired value range and by comparing the second actual value with a second desired value range, with the feed speed of the workpiece, the pass height, the workpiece width, the cutting speed of the grinding belt, the pressing pressure, the pressing force, the ambient temperature and/or the humidity being included.

In one embodiment, it is provided that the steps of comparing and setting are performed by using an artificial intelligence control device. The artificial intelligence mentioned can be implemented by means of neural networks. After the learning phase, the neural network may make a decision to determine which settings must be altered to reach the desired value range.

In this case, the neural network can change a plurality of set values that influence the overall result, so that a range of desired values is achieved. As a specific example, a specific thickness or a specific surface quality of the workpiece can be selected as the first desired value range, wherein a specific priority, the service life of the grinding belt or the energy consumption of the machine tool is also selected as the second desired value range. This is done in accordance with the priority, so long as the first range of settings is met, the system will meet the second range of settings as much as possible. If the first range of set values is no longer met, the set values are changed so that the first range of set values is still met.

According to one embodiment, the machine tool is designed as a grinding machine. In this case, the grinding machine preferably has a belt grinding device, a disk brush, a grinding roller, a brush roller, a cross belt grinding apparatus, a fine grinding apparatus or a combination of a belt grinding device, a disk brush, a grinding roller, a brush roller, a cross belt grinding apparatus and a fine grinding apparatus as the grinding device.

In this case, it can be provided that a plurality of grinding devices of the grinding machine are controlled by setting at least one setpoint value of the respective grinding device. In this way, the processing result can be influenced by different measures.

In one embodiment, it is provided that the changed set value is stored in a memory device, wherein preferably the actual value as well as the set value is also stored in the memory device. Thereby, changed values for further processing are provided.

The invention also relates to a machine tool, in particular a grinding machine. The machine tool can be configured to carry out the previously described features of the method and/or the features of the dependent method claims, individually or in combination.

Drawings

Fig. 1 shows a schematic configuration of a wide belt grinding machine provided for carrying out the method according to the invention.

Detailed Description

Preferred embodiments of the method according to the present invention are described with reference to the accompanying drawings. Although the embodiments described below are to be understood as purely illustrative and not restrictive, the invention may also be specified taking into account individual features. Furthermore, the embodiments may be combined with each other to form other embodiments of the invention.

The embodiments relate to grinding in order to clearly describe the present invention. However, the present invention is not limited thereto.

The grinding machine according to this embodiment includes a housing case 10 that houses a first grinding device 20 and a second grinding device 30. The grinding machine also includes a transfer mechanism 40 that moves the workpiece W through the housing 10 of the grinding machine.

The workpiece to be machined by the grinding machine is preferably plate-shaped. In particular, these are workpieces made of wood or wooden materials, for example for the furniture or construction element industry. As a specific example, it may be a furniture front panel, shelf, ceiling, floor or wall panel, etc.

A first thickness measuring sensor 50 is arranged in the inlet region of the housing 10. The thickness measurement sensor 50 is provided for determining the thickness of the workpiece W before it is machined by the grinding machine. The thickness measuring sensor 50 may be a contact sensor or a non-contact sensor, with which the thickness of the workpiece W to be processed is detected.

A second thickness measuring sensor 60, which is of similar design to the first thickness measuring sensor 50, is arranged in the outlet region of the housing 10. The second thickness measuring sensor 60 is provided for determining the thickness W of the workpiece after it has passed through the grinding machine.

Furthermore, the grinding machine is equipped with further sensors, by means of which the following parameters can be determined individually or in combination.

The quality of the grinding belt can be determined during the machining by means of the grinding belt sensor. Here, the condition of the granularity and thus the degree of wear may be determined. For example, the grinding belt sensor may be a radar sensor, by means of which the grinding belt is continuously monitored and correspondingly evaluated. In the case of a radar sensor, conclusions about the grain size or roughness of the grinding belt can be determined from the detected radiation intensity reflected at the grinding belt and, depending on the further application, it can be recognized when the grain size decreases due to wear of the grinding belt.

Alternatively to the grinding belt sensor, the quality of the grinding belt can also be calculated on the basis of the determined engagement time of the grinding belt and the determined service life. For this purpose, the duration of each engagement at the workpiece is detected, in particular by detecting the respective workpiece length in the transport direction.

The height of passage between the conveying device and the grinding belt can be determined by a grinding shoe position sensor and/or a position sensor for detecting the position of the grinding roller.

Further, the feed speed of the conveying mechanism 40 is detected by a sensor. Alternatively or additionally, the feed rate may be determined by a control command for driving the transport mechanism 40.

A contact-type or optical width measuring sensor in the inlet region of the housing determines the component dimensions in a direction perpendicular to the direction of passage. Specifically, whether a wide workpiece or a narrow workpiece is fed to the grinding device 20, 30 is determined.

The normal force of the grinding belt on the workpiece is determined by means of a pressing pressure sensor.

One or more temperature sensors determine the ambient temperature and the temperature of the workpiece that heats up during processing.

Furthermore, the air humidity in the processing area can be determined by means of an air humidity sensor.

The machine tool may have a sensor for determining the suction speed. This is done, for example, by detecting the number of rotations of the fan.

The machine tool may also have a sensor that determines the energy consumption of the machine tool.

As further sensors, the first optical sensor in the inlet region and the second optical sensor in the outlet region of the housing 10 can be designed such that the surface structure and thus the surface quality can be determined before and after the grinding process by means of the optical sensors.

The grinding machine according to an embodiment comprises a control device arranged to control the operation of the grinding machine. The sensors are connected to the control device and accordingly transmit information continuously or at specific intervals, in particular information about the quality of the grinding belt, the pass height, the feed speed, the component dimensions, the cutting speed of the grinding belt or belts, the difference between the input thickness of the workpiece and the actual thickness after the grinding process, the pressing pressure, the temperature or temperatures and humidity.

Furthermore, the number and combination of the grinding devices is managed and/or monitored by the control device. In an embodiment, the grinding device 20 is a so-called contact roller apparatus. The lower roller of the contact roller arrangement presses the grinding belt in the vertical direction against the workpiece W moved by the conveying device 40.

In the case of the grinding device 30, three rollers are provided for moving the grinding belt, wherein the rollers facing the workpiece are a calibration roller and a deflection roller. A grinding shoe is arranged between the calibration roller and the deflection roller, said grinding shoe pressing the grinding belt against the workpiece to be ground.

The information detected by the various sensors is collected in the control unit of the grinding machine and evaluated in order to control the operation of the grinding machine. Thus, different information may be associated and coordinated with each other.

The control device comprises a module for performing calculations by means of an artificial intelligence based algorithm. This means that the values recorded by the sensors and the action commands derived therefrom are constantly detected and corrected, wherein the workpiece thickness and the surface structure (and thus the surface quality) of the workpiece W serve as the desired value range.

The artificial intelligence mentioned can be implemented by means of neural networks. After the learning phase, the neural network may make a decision to determine which settings must be changed to reach the desired value range. In this case, the neural network can change a plurality of set values that influence the overall result, so that a range of desired values is achieved.

The expected value ranges are prioritized relative to each other. Thus, the first expected value range may be assigned a higher priority than the second expected value range. The machine tool is thus operated in such a way that the first actual value lies within the first desired value range. If this is ensured, the set value can be further changed so that the second actual value lies within the second desired value range.

As a specific example, a particular thickness or a particular surface quality of the workpiece may be selected as the first desired value range. It is also possible in this case to determine a plurality of first desired value ranges, for example workpiece thickness, surface quality and surface flatness.

A high feed speed may be selected as the second desired value range.

Depending on the priority, this results in the system satisfying the second range of desired values as far as possible as long as the first range of desired values is satisfied. If the first desired value range is no longer met, the set point is changed such that the first desired value range is still met.

The control device determines in this case which variations in the parameters influencing the grinding result should be changed in order to achieve the highest possible quality (low tolerance of the workpiece thickness and a specific desired value of the surface structure) while achieving high productivity or low energy consumption (for example a second desired value range).

When the grinding machine is operated, the pressure section in the pressure beam of the grinding machine is activated after the workpiece is detected. The detection here is: the pressure section of the grinding belt which is pressed against the workpiece either completely or only partially. Accordingly, the pressure section is loaded with a higher or lower force to achieve a specific pressing pressure.

In this case, it can be provided that the pressing force is detected. In combination with the inspection of the ground workpiece surface, the machining result can be optimized. In this case, it can be determined that a specific surface is reached in a specific pressure range as the desired value range.

With workpieces of the same size, an increase in pressure can lead to greater wear of the grinding belts of the grinding devices 20, 30, which also requires shorter maintenance intervals for the replacement of the grinding belts. Thus, the control device may decide: the combination of a specific pressing force with a favorable feed rate ensures a high processing quality with little wear of the grinding belt.