JP2021031704A - Additive processing apparatus, method for controlling additive processing apparatus, and control program for additive processing apparatus - Google Patents

Abstract

To provide such technology that can reduce the number of times of measuring a height of a three-dimensional molded article while maintaining molding accuracy of the three-dimensional molded article.SOLUTION: An additive processing apparatus includes: a laser head for supplying a powder material and emitting a laser beam; a drive unit for driving the laser head in a layer stacking direction of a three-dimensional molded article in accordance with a predetermined command value each time when the additive processing of each layer of the three-dimensional molded article is finished; and a measurement unit for measuring an actual dimension of the three-dimensional molded article in the layer stacking direction. A control device for the additive processing apparatus controls the measurement unit to measure an actual dimension of the three-dimensional molded article at a first timing when the number of stacked layers of the three-dimensional molded article reaches a first number of stacked layers, estimates an error per one layer between the actual dimension and the dimension in the layer stacking direction of the three-dimensional molded article recognized by the additive processing apparatus at the first timing using at least the measured actual dimension, and determines a second number of stacked layers that indicates a second timing to allow the measurement unit to perform the measurement process based on a maximum error.SELECTED DRAWING: Figure 8

Description

The present disclosure relates to a technique for forming a three-dimensional model by melting and laminating a supplied powder material.

In recent years, an additional processing device capable of forming a three-dimensional model by melting and laminating the supplied powder material has become widespread. Such a modeling method is called a DED (Directed Energy Deposition) method. The DED type additional processing apparatus has a laser head. The laser head ejects the powder material to the three-dimensional model while moving, and irradiates the laser beam toward the three-dimensional model. As a result, the three-dimensional model is locally melted, the powder material is supplied to the melted portion, and the powder material is melted and solidified together, so that the powder material is laminated on the three-dimensional model.

When the additional processing of one layer is completed, the laser head is preferably driven in the stacking direction by the thickness of the layer. At this time, if there is an error between the actual height of the layer and the amount of movement of the laser head, the error is accumulated every time stacking is performed. As this error increases, the focal position of the laser beam deviates from the surface of the three-dimensional modeled object, and as a result, the modeling accuracy decreases.

As a method of solving this problem, there is a method of correcting the above error based on the height of the work actually measured by the sensor. Regarding this method, Japanese Patent Application Laid-Open No. 2018-8403 (Patent Document 1) discloses a three-dimensional object manufacturing apparatus having a modeling speed priority mode and a modeling accuracy priority mode. The three-dimensional object manufacturing apparatus measures the height of the work for every five layers in the modeling speed priority mode. On the other hand, the three-dimensional object manufacturing apparatus measures the height of the work for each layer in the modeling accuracy priority mode.

Japanese Unexamined Patent Publication No. 2018-8403

If the height measurement interval of the three-dimensional modeled object is short, the time required for additional processing becomes long. On the other hand, if the interval of height measurement of the 3D model is long, the error between the height of the 3D model recognized by the addition processing device and the actual height of the 3D model becomes large. The modeling accuracy of a three-dimensional model is reduced.

Therefore, there is a demand for a technique capable of reducing the number of height measurements of a three-dimensional model while maintaining the modeling accuracy of the three-dimensional model.

In one example of the present disclosure, the addition processing apparatus capable of forming a three-dimensional model by melting and laminating the supplied powder material supplies the powder material to the three-dimensional model during the addition process. In addition, each time the laser head that irradiates the laser beam and the additional processing of each layer of the three-dimensional model are completed, the laser head is driven in the stacking direction of the three-dimensional model according to a predetermined command value. A driving unit, a measuring unit for measuring the actual size of the three-dimensional modeled object in the stacking direction, and a control device for controlling the additional processing device. The control device performs a process of causing the measuring unit to measure the actual size of the three-dimensional model at the first timing when the number of layers of the three-dimensional model reaches the first number of layers, and the first method. Using at least the actual size measured at the timing, the one-layer hit between the actual size and the dimension in the stacking direction of the three-dimensional model recognized by the additional processing apparatus at the first timing. The process of estimating the error and the process of determining the number of second layers indicating the second timing at which the measuring unit should execute the measurement process after the first timing are executed based on the error. ..

In one example of the present disclosure, the measuring unit measures the dimensions of the three-dimensional modeled object at a plurality of locations in the stacking direction at the first timing. The control device executes a process of calculating the standard deviation of the dimensions per layer of the three-dimensional model based on the plurality of dimensions measured at the plurality of locations, and calculates the error based on the standard deviation. presume.

In one example of the present disclosure, the control device further performs a process of calculating an average value of the dimensions per layer of the three-dimensional model based on a plurality of dimensions measured at the plurality of locations, and the average value. As a reference, the process of updating the above command value is executed.

In one example of the present disclosure, the control device divides the difference between the dimensions in the stacking direction of the three-dimensional model and the actual dimensions recognized by the additional processing device by the first stacking number, and the division is performed. The result is calculated as the above error.

In one example of the present disclosure, the control device further updates the command value based on the actual size measured at the first timing and the actual size measured at the second timing. Execute the process.

In one example of the present disclosure, the control device further adjusts to the actual size measured at the first timing, and the three-dimensional model recognized by the additional processing device at the first timing. The process of correcting the dimensions in the stacking direction is executed.

In one example of the present disclosure, the control device further does not correct the dimension in the stacking direction of the three-dimensional model recognized by the additional processing device at the first timing at the first timing.

In one example of the present disclosure, the control device further executes a process of correcting the second stacking number to the upper limit value when the second stacking number is equal to or more than a predetermined upper limit value.

In one example of the present disclosure, the powder material is a metal powder or a resin powder.

In another example of the present disclosure, there is provided a method for controlling an additional processing apparatus capable of forming a three-dimensional model by melting and laminating the supplied powder material. The additional processing apparatus supplies the powder material to the three-dimensional modeled object being subjected to the additional processing, and determines each time the laser head that irradiates the laser beam and the additional processing of each layer of the three-dimensional modeled object are completed. A driving unit for driving the laser head in the stacking direction of the three-dimensional model and a measuring unit for measuring the actual size of the three-dimensional model in the stacking direction are provided according to the command value of. The control method includes a step of causing the measuring unit to measure the actual size of the three-dimensional model at the first timing when the number of layers of the three-dimensional model reaches the first number of layers, and the first step. Using at least the actual size measured at the timing, the one-layer hit between the actual size and the dimension in the stacking direction of the three-dimensional model recognized by the additional processing apparatus at the first timing. It includes a step of estimating an error and a step of determining a second stacking number indicating a second timing at which the measuring unit should execute a measurement process after the first timing based on the error.

In another example of the present disclosure, a control program of an additional processing apparatus capable of forming a three-dimensional model by melting and laminating the supplied powder material is provided. The additional processing apparatus supplies the powder material to the three-dimensional modeled object being subjected to the additional processing, and determines each time the laser head that irradiates the laser beam and the additional processing of each layer of the three-dimensional modeled object are completed. A driving unit for driving the laser head in the stacking direction of the three-dimensional model and a measuring unit for measuring the actual size of the three-dimensional model in the stacking direction are provided according to the command value of. The control program is a step in which the additional processing apparatus causes the measuring unit to measure the actual size of the three-dimensional model at the first timing when the number of layers of the three-dimensional model reaches the first number of layers. And, using at least the actual size measured at the first timing, the actual size and the dimension in the stacking direction of the three-dimensional model recognized by the additional processing apparatus at the first timing. Based on the step of estimating the error per layer between the above and the error, the number of second layers indicating the second timing at which the measuring unit should execute the measurement process after the first timing is determined. To perform the steps to be performed.

The above and other objectives, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention as understood in connection with the accompanying drawings.

It is a front view which shows the additional processing apparatus. The cross-sectional view of the laser head during the additional processing is shown. It is a perspective view which shows the work W during additional processing. It is a diagram visually showing a relationship between the actual height "H _a" and the command height "H _c" and height error "E _H". It is a figure which shows the transition of _{the height error "E H} " until the number of stacks "N" reaches 100 layers for a plurality of stacking conditions. It is a graph which shows the transition of _{the height error "E H} " according to the number of stacks "N". m-1 Visually shows the relationship between the actual height "Ha _{, m-1} " measured during the first feedback process and the actual height "Ha _{, m" measured during the m-th feedback process.} It is a figure. It is a graph which shows the transition of _{the height error "E H} " according to the number of stacks "N". It is a figure which shows the simulation result 1 based on the additional processing condition 1. It is a figure which shows the simulation result 2 based on the additional processing condition 2. It is a figure which shows the simulation result 3 based on the additional processing condition 3. It is a figure which shows the simulation result 4 based on the additional processing condition 4. It is a block diagram which shows the main hardware composition of an additional processing apparatus. It is a flowchart which shows the feedback process which is executed for the first time. It is a flowchart which shows the feedback processing which is executed after the second time. It is a graph which shows the transition _{of the height error "E H} " when the feedback processing according to the modification 1 is executed. It is a flowchart which shows the feedback processing according to the modification 1. It is a figure which shows the element considered at the time of determining the upper limit value "maxN _f".

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the following description, the same parts and components are designated by the same reference numerals. Their names and functions are the same. Therefore, the detailed description of these will not be repeated. In addition, each embodiment and each modification described below may be selectively combined as appropriate.

<A. Additional processing equipment 100>
First, with reference to FIG. 1, the additional processing apparatus 100 according to the embodiment will be described. FIG. 1 is a front view showing the additional processing apparatus 100.

For ease of understanding, in the following, one direction on the horizontal plane is referred to as "X direction", the direction on the horizontal plane orthogonal to the X direction is referred to as "Y direction", and is orthogonal to both the X direction and the Y direction. The direction (that is, the direction of gravity) is referred to as the "Z direction".

The add processing apparatus 100 is an AM / SM hybrid processing machine capable of performing work add processing (AM (Additive manufacturing) processing) and work removal processing (SM (Subtractive manufacturing) processing). The additional processing device 100 has a milling function using a rotary tool as a function of SM processing.

Hereinafter, an AM / SM hybrid processing machine having a milling function will be described as an example of the additional processing device 100, but the additional processing device 100 is not limited to this. As an example, the additional processing apparatus 100 may be an AM / SM hybrid processing machine having a turning function using a fixing tool instead of the milling function. Alternatively, the additional processing apparatus 100 may be an AM / SM hybrid processing machine having both a milling function and a turning function. Alternatively, the additional processing device 100 may be a device that does not have a removal processing function, such as a 3D printer.

The additional processing device 100 includes a machine bed 11. A swivel table 12 is provided on the machine bed 11. The swivel table 12 has a swivel table 13. The rotary table 13 is rotatably attached to the swivel table 12. The work W to be added is clamped on the rotary table 13.

As an example, the additional processing apparatus 100 has two axes (swivel axis and rotation axis) that can be controlled with respect to the rotation of the work W clamped on the rotary table 13. The swivel axis is an axis parallel to the upper surface of the machine bed 11. The rotation axis is an axis orthogonal to the upper surface of the swivel table 12. The rotary table 13 is configured to be rotatable around the swivel axis and around the rotary axis.

The additional processing device 100 has a first slide mechanism 14. The first slide mechanism 14 is arranged in the machine column on the rear side of the machine bed 11. The first slide mechanism 14 is configured to be movable in the X direction along a slide guide attached to the mechanical column.

A plurality of slide guides aligned in the Y direction are arranged in the first slide mechanism 14. The second slide mechanism 15 is configured to be movable in the Y direction along the plurality of slide guides.

The second slide mechanism 15 is provided with a removal processing head 16. The removal processing head 16 is configured to be driveable in the Z direction along the second slide mechanism 15. The additional processing device 100 controls the drive of the first slide mechanism 14 in the X direction, the drive of the second slide mechanism 15 in the Y direction, and the drive of the removal processing head 16 in the Z direction. The removal processing head 16 is driven at arbitrary positions in the Y direction and the Z direction. These drives are driven by, for example, a servomotor.

The additional processing device 100 includes a magazine 18 that houses various units such as the tool 18A and the measuring mechanism 125, and an automatic tool changer (ATC) 19. The tool 18A and the measuring mechanism 125 are housed in the magazine 18 when not in use. Based on the reception of the tool change instruction, the automatic tool change device 19 pulls out the unit to be mounted from the magazine 18 and mounts the unit on the spindle 124.

In the example of FIG. 1, the measuring mechanism 125 selected from the magazine 18 is mounted on the spindle 124. FIG. 1 shows the measuring mechanism 125 as a touch probe. The measuring mechanism 125 has a stylus 126. The stylus 126 is driven in the X, Y, and Z directions in conjunction with the removal processing head 16. The measuring mechanism 125 measures the contact position between the stylus 126 and the work by reading the amount of movement of the stylus 126 at the time of contact between the stylus 126 and the work. The measuring mechanism 125 measures the distance in the Z direction from a predetermined reference point to the contact position as the actual size of the work.

The measuring mechanism 125 is not limited to the contact type position measuring device, and may be a non-contact type position measuring device. Examples of non-contact position measuring instruments include displacement sensors, 3D scanners, cameras and the like.

The additional processing apparatus 100 further includes a laser head 21 for performing additional processing by the DED method. The laser head 21 supplies metal powder to the work W being subjected to additional processing, and irradiates the work surface with laser light.

The laser head 21 has a head body 22 and a laser tool 26. Metal powder is supplied to the head body 22 via the cable 31. The laser tool 26 irradiates the work with the laser light and determines the irradiation region of the laser light on the work. The metal powder supplied to the laser head 21 is discharged toward the work through a nozzle (not shown).

The laser head 21 is provided in the third slide mechanism 24. The third slide mechanism 24 is provided on the slide guide 23 and is configured to be driveable in the Y direction. The laser head 21 is driven to an arbitrary position in the Y direction in conjunction with the drive of the third slide mechanism 24. The laser head 21 is driven so as to be located below the spindle 124 during additional processing, and is attached to the spindle 124. The laser head 21 mounted on the spindle 124 is driven in the X direction, the Y direction, and the Z direction in conjunction with the removal processing head 16.

<B. Laser head 21>
The additional processing by the laser head 21 will be described with reference to FIG. FIG. 2 shows a cross-sectional view of the laser head 21 during the additional processing.

In FIG. 2, the work W being subjected to additional processing is shown on the reference surface 140. The reference plane 140 represents the surface of any object. As an example, the reference surface 140 may be the surface of a substrate or the surface of a work being subjected to additional processing.

The laser head 21 supplies the metal powder 312 to the work W while moving in the Y direction. The supplied metal powder 312 is guided to the focal position of the laser beam 311 by the gas 313 discharged from the laser head 21. As a result, the metal powder 312 is melted on the work W, and a melt pool 314 is formed on the surface of the work W. The melt pool 314 is a place where the metal powder 312 and the work W are melted and liquefied. When the molten metal powder 312 and the work W are solidified, a layer SL is formed on the work W.

When the additional processing of the layer SL is completed, the laser head 21 is driven in the stacking direction of the work W according to a predetermined height command value defined on the control program of the additional processing apparatus 100. The "stacking direction" means a direction orthogonal to the stacking surface. Hereinafter, the description will be made on the assumption that the stacking direction is the Z direction (that is, the gravity direction), but the stacking direction is not limited to the Z direction.

By repeating the driving in the Y direction and the driving in the Z direction, the metal powder 312 is laminated in a wall shape. If the driving amount of the laser head 21 in the Z direction does not match the height of the formed layer SL, the focal position of the laser beam 311 will deviate from the work surface each time the laser beam is laminated. As a result, the molding accuracy is lowered. On the other hand, when the driving amount of the laser head 21 in the Z direction coincides with the height of the formed layer SL, the focal point of the laser beam 311 is always located on the work surface, and the molding accuracy is lowered. do not do. Therefore, it is preferable that the driving amount of the laser head 21 in the Z direction coincides with the height of the formed layer SL.

<C. Definition of terms>
Next, for ease of understanding, definitions of terms used herein will be described with reference to FIG. FIG. 3 is a perspective view showing the work W during the additional processing.

In the following, the number of laminated works W is defined as “N”. The number of layers "N" represents the total number of layers from the first layer formed on the reference surface 140.

Further, the command stacking height _{is defined as "LH c} " (command value). The command stacking height “LH _c ” represents the driving amount per work layer of the laser head 21 in the Z direction. That is, the addition processing apparatus 100 drives the laser head 21 in the Z direction according _{to the command stacking height “LH c} ” each time the addition processing of each layer of the work W is completed. Typically, the command stacking height "LH _c " is defined in the control program within the add processing apparatus 100.

In addition, the height of the actual layer is defined _{as "LH a".} The actual height of the layer "LH _a " represents the actual height of the layer (that is, a single line) formed on the work W.

In addition, the command height is defined _{as "H c".} The command height “H _c ” represents the height of the work W in the Z direction from the reference surface 140, which is recognized by the addition processing apparatus 100. The command height “H _c ” is the height of the work W commanded to the additional processing apparatus 100. The command height “H _c ” coincides with the height of the focal point of the laser beam 311 from the reference plane 140. Specifically, the command height "H _c " is expressed by the following equation (1).

In addition, to define the actual height of the workpiece W as "H _a". Actual height "H _a" represents the actual height of the workpiece W in the Z direction from the reference surface 140 to the work surface. That is, the actual height "H _a" is represented by the accumulated value of the as shown in the following formula (2), the actual bed height from the first layer up to the N th layer "LH a _(N)" ..

The height error is defined _{as "E H".} The height error “E _H ” represents the difference between the actual height “H _a ” of the work W and the command height “H _{c” of the work W recognized by the additional processing apparatus 100.} Specifically, the height error "E _H " is expressed by the following equation (3).

In addition, the ideal command stacking height is defined _{as "LH c, ideal".} The ideal command stack height "LH _{c, ideal} " corresponds to the command stack height "LH _{c " when the height error "E H} " is zero, as shown in the following equation (4).

Further, the command stacking height error is defined _{as "ELH".} Command stack height error _{"E LH"} represents a command stack height "LH _c", the ideal command stack height _{"LH c, ideal"} the difference between. Specifically, the command stacking height error " _ELH " is expressed by the following equation (5).

In the above, the term "height" is used, but the concept of "height" used in the present specification is an example of "dimensions". The concept of "dimensions" includes not only the height of the work in the Z direction, but also the width of the work in various directions such as the horizontal direction.

<D. Principle explanation>
Figure 4 is a diagram visually showing a relationship between the height error actual height as the "H _a" and the command height "H _c", "E _H".

As described above, the height error "E _H" corresponds to the difference between the actual height "H _a" and the command height "H _c". If this height error "E _H " exceeds the permissible value, the modeling accuracy will decrease. Therefore, additional processing device 100, before the height error "E _H" exceeds the allowable value is measured actual height of the workpiece W to "H _a" to the measurement mechanism 125, the actual measured height in the "H _a" At the same time, it is necessary to correct the _{command height "H c".} Hereinafter, based on the actual measured height "H _a" processing for correcting the error parameter is also referred to as a "feedback process".

Ideally, the feedback process should be performed layer by layer. However, if the height measurement interval of the work W is short, the time required for the additional processing becomes long. On the other hand, if the interval for measuring the height of the work is long, the height error "E _H " may exceed the permissible value, and the molding accuracy of the work may be lowered.

Therefore, the feedback process, it is necessary to height errors "E _H" is executed prior to exceeding the permissible value. This makes it possible to reduce the number of times the height of the work is measured and to suppress a decrease in the molding accuracy of the work. In order to achieve this, it is necessary to estimate the number of layers in which the _{height error "E H" is likely to exceed the permissible value.}

We have examined the height error "E _H" to estimate the number of stacked likely to exceed the allowable value, the height error "E _H" is experimentally how changing the according to the number of lamination It was. Results of the experiment, the inventors in the number of stacked layers is small step height error "E _H" is minute error in command stack height "LH _c", and found to be accumulated in each layer. In addition, we, as the number of laminated layers increases, the height error "E _H" is found to converge to a constant value. These discoveries themselves are new.

To prove these, the inventors show how the height error "E _H " changes according to the number of stacks "N" _{when there is an error in the command stack height "LH c".} Was investigated by experiment. The experiment will be described below with reference to FIG. _{FIG. 5 is a diagram showing the transition of the height error “E H} ” until the number of stacks “N” reaches 100 layers for a plurality of stacking conditions.

In the following, the average height at a plurality of points of the single line of the fifth layer is represented as “μ”, and the standard deviation of the height at the plurality of points is represented as “σ”.

_{In FIG. 5, the transition of the height error “E H} ” when the command stacking height “LH _c ” is set to “μ” is shown by “*” as the graph G1. The fact that the command stacking height “LH _c ” is set to “μ” means that the laser head 21 is driven in the Z direction by the height of the formed layer. In the graph G1, the height error “E _H ” changes near zero.

Further, in FIG. 5, _{the transition of the height error “E H ” when the command stacking height “LH c} ” is set to “μ−σ” is shown by “◯” as the graph G2. The fact that the command stacking height “LH _c ” is set to “μ−σ” means that the driving amount of the laser head 21 in the Z direction is deviated by “σ” per layer. That is, in this case, the command stacking height error “ _ELH ” becomes “σ”.

In the graph G2, in the initial stage before the number of layers “N” becomes 30 layers, the height error “E _H ” is integrated by the error “σ” for each layer. In other words, the _{rate of change per layer of the height error "E H} " is the error "σ". When lamination number "N" is more than 50 layers, height error "E _H" is converged to a constant value.

FIG. 6 is a graph showing the transition of _{the height error “E H} ” according to the number of layers “N”. As shown in FIG. 6, the rate of change per layer _{of the height error “E H} ” does not exceed the _{command stacking height error “EL H”.}

Focusing on this point, the maximum value of the command stack height error "E _LH" (hereinafter, the maximum error "max | E LH _|". Also referred to as) if it is possible to estimate the height error "E _H" is allowed The number of stacks before exceeding the value can be estimated. More specifically, when the height tolerance of errors "E _H" and "d", the number of stacked before height error "E _H" exceeds the allowable value "d", "N _f" is below It is expressed by the equation (6) of.

Until the number of layers _{reaches "N f} ", the height error "E _H " does not exceed the permissible value "d", and it is not necessary to perform feedback processing. Therefore, the addition processing apparatus 100 _{does not execute the feedback process until the number of layers reaches "N f} ", and executes the feedback process when the number of layers _{reaches "N f} ". As a result, the additional processing apparatus 100 can reduce the number of times of measuring the height of the work while ensuring the molding accuracy.

The permissible value "d" may be set in advance at the time of initial setting or the like, or may be arbitrarily set by the user.

Further, the number of layers "N _f " does not necessarily have to be determined based on the above formula (6). The number of layers "N _f " may be equal to or less than the allowable value "d" _{divided by the maximum error "max | ELH |".}

<E. How to determine the execution timing of feedback processing>
According to the above equation (6), it is necessary to estimate the _{maximum error “max | ELH} |” in order to determine the execution timing of the next feedback process. Therefore, additional processing device 100, at least using the actual height _{"H a"} of the work obtained from the measurement mechanism 125, the maximum error "max _{| E LH} |" estimated.

More specifically, first, the addition processing apparatus 100 is a process of measuring the actual height of the work by the measuring mechanism 125 at the first timing when the number of laminated works reaches a predetermined number (the first number of laminated works). To execute. Then, the additional processing device 100, the using at least the measured actual height of the workpiece to "H _a" at the first timing, the maximum error to execute a process of estimating the "max | _| E LH". After that, the addition processing apparatus 100 indicates the number of layers "2" indicating the second timing at which the measuring mechanism 125 should execute the measurement process after the first timing, based on _{the estimated maximum error "max | ELH |".} The process of determining " _{N f" is executed.}

Typically, the additional processing apparatus 100 changes the method of estimating the _{maximum error "max | ELH} |" between the first feedback processing and the second and subsequent feedback processing.

More specifically, at the time of the first feedback processing, the addition processing apparatus 100 _{estimates the maximum error "max | ELH} |" by using the height measurement result of one layer. At the time of the second and subsequent feedback processing, the addition processing apparatus 100 _{estimates the maximum error "max | ELH} |" by using the height measurement results of two or more layers.

Hereinafter, a method of determining the number of stacked layers "N _f" at first feedback process, for a method of determining the number of stacked layers "N _f" at the second and subsequent feedback process will be described in order.

(E1. Method for determining the number of layers "N _{f" 1)}
First, a method of determining the _{number of layers "N f} " at the time of the first feedback processing will be described.

First, the addition processing apparatus 100 executes the addition processing process according to a predetermined command stacking height “LH _c”. Next, at a predetermined timing when the number of laminated workpieces reaches a predetermined number (≧ 1), the addition processing apparatus 100 causes the measuring mechanism 125 to measure _{the actual height “Ha” of a plurality of workpieces.} Thereafter, additional processing device 100, based on the actual height of the workpiece measured for the plurality of locations "H _a", calculates the "LH _a" real stack height in each location.

In a certain aspect, at the start of the addition processing, the addition processing apparatus 100 executes the measurement process by the measuring mechanism 125 for each layer at a plurality of points, and differs from each of the current measurement results by the previous measurement result at the same place. By doing so, the actual stacking height "LH _a " at each location is calculated. Preferably, the addition processing apparatus 100 performs addition processing only on a single line (one layer). In this case, the additional processing apparatus 100 acquires the measurement result of the measuring mechanism 125 at each position of the single line as the actual stacking height “LH _a ”.

Calculated in another aspect, the additional processing device 100, by dividing the actual height "H _a" of the measured workpiece for each location in the current number of layers, the "LH _a" real stack height in each location To do.

After that, the addition processing apparatus 100 uses _{the measured value of the actual stacking height “LH a} ” as a sample, and sets the average value _{of the actual stacking height “LH a} ” at each location of the single line and the actual stacking height at each location. Calculate the standard deviation of "LH _a". Next, the additional processing apparatus 100 differentiates the standard deviation from the average value according to the following equation (7), and sets the difference result in the additional processing apparatus 100 as the _{command stacking height “LH c, 0”.}

The “x” with an overline shown in the above formula (7) indicates the average value of _{the actual laminated height “LH a” of the single line.} “S” indicates the standard deviation of the actual stacking height “LH _{a” of the single line.}

As shown in the above equation (7), the addition processing apparatus 100 updates the _{command stacking height “LH c, 0” with reference to the calculated average value.} Although the above equation (7) shows an example in which the value obtained by subtracting the standard deviation from the average value of the actual heights of the single lines is set as the command stacking height “LH _{c, 0} ”, it is set. The command stacking height “LH _{c, 0} ” is not limited to this. As an example, the addition processing apparatus 100 may set the calculated average value to the command stacking height “LH _{c, 0} ”, or the value obtained by subtracting N times the standard deviation from the average value as the command stacking height. It may be set to "LH _{c, 0".}

Subsequently, the addition processing apparatus 100 estimates the _{maximum error “max | ELH, 0} |” based on the 95% confidence interval of the population average “μ” of the actual height of the single line. The percentage of the confidence interval does not necessarily have to be 95%, and may be, for example, 80% or more. The maximum error "max | _{ELH, 0} |" is estimated based on the following equation (8).

“N” shown in the formula (8) indicates the number of measurement points of the single line. “T _0.025 (n-1)” indicates the t value at the upper 2.5% point used when obtaining the 95% confidence interval of the t distribution having (n-1) degrees of freedom.

The additional processing apparatus 100 considers the value on the right side represented by the equation (8) as the maximum error “max | _{ELH, 0} |” and substitutes the value into the above equation (6). As a result, the addition processing apparatus 100 calculates the _{number of layers "N f, 1} " indicating the next measurement timing based on the following formula (9).

As described above, in this example, the measuring mechanism 125 measures the actual heights of a plurality of places of the work at the timing when the number of laminated works reaches a predetermined number (≧ 1). Next, the additional processing apparatus 100 calculates the standard deviation of the actual height of the single line of the work based on the actual height of the work measured at the plurality of locations. Subsequently, the additional processing apparatus 100 estimates the _{maximum error “max | ELH, 0 |” based on the calculated standard deviation.} After that, the addition processing apparatus 100 calculates the _{number of stacks “N f, 1} ” indicating the next measurement timing by the measuring mechanism 125 based on _{the calculated maximum error “max | ELH, 0 |”.}

In the above description, the description has been made on the premise that the calculation process is executed at the time of the first feedback process, but the calculation process may be performed at the time of the second and subsequent feedback processes.

(E2. Method for determining the number of layers "N _{f" 2)}
Next, with reference to FIGS. 7 and 8, a method for determining the _{number of layers “N f” in the second and subsequent feedback processes will be described.}

FIG. 7 shows the relationship between the actual height “Ha _{, m-1} ” measured during the m-1st feedback process and the actual height “Ha _{, m” measured during the m-1st feedback process.} It is a figure which shows visually.

The additional processing apparatus 100 updates the command stacking height “LH _{c ” based on the actual height “Ha, m-1} ” and the actual height “Ha _{, m”.} More specifically, the addition processing apparatus 100 first differentiates the _{actual height "Ha, m-1} " from the actual height " _{Ha, m" as shown in the following formula (10).} Next, the addition processing apparatus 100 divides the difference result by the number of stacks "N _{f, m} ", and calculates the division result as a new command stack height "LH _{c, m} ". The number of layers "N _{f, m} " represents the number of layers formed in the work from the time of m-1st feedback processing to the time of mth feedback processing.

_{The command stack height error "ELH, m " when the command stack height "LH c, m} " after the update is used is the case where the command stack height _{"LH c, m-1} " before the update is used. It becomes smaller than the command stacking height error " _{ELH, m-1" of.} That is, the relationship of the following equation (11) holds.

FIG. 8 is a graph showing the transition of _{the height error “E H} ” according to the number of layers “N”. In the example of FIG. 8, feedback processing is performed _{at the timing T1 when the number of stacks reaches "N f, 1} " and the timing T2 when the number of stacks reaches "N _{f, 1} + N _{f, 2".} .. As a result, at timing T1, T2, height error _{"E H"} is set to zero.

According to the above equation (11), the _{height error "E H, 1} " accumulated during the additional processing for the _{"N f, 1} " layer is the additional processing for the next "N _{f, 2} " layer. It becomes smaller than the height error "E _{H, 2" integrated between.} Focusing on this point, the addition processing apparatus 100 sets the command stacking height error " _{ELH, m-1} " before the update to the maximum error "max | _ELH |" as shown in the following equation (12). Consider it as.

Next, the additional processing apparatus 100 calculates a _{new command stacking height error "ELH, m-1} " based on the following formula (13).

Subsequently, the addition processing apparatus 100 calculates the _{number of layers "N f, m + 1} " indicating the next measurement timing based on the following formula (14).

As described above, in this example, the addition processing apparatus 100 _{divides the height error "E H, m} " by the number of stacks "N _{f, m} ", and the division result is the maximum error "max | _EL H |". Calculate as. After that, the addition processing apparatus 100 calculates the _{number of layers "N f, m + 1} " indicating the next measurement timing based on _{the calculated maximum error "max | ELH |".}

<F. Simulation result>
The inventors confirmed the effectiveness of the above-mentioned feedback processing by simulation. The results of the simulation will be described below.

The inventors performed four patterns of simulations by changing the additional processing conditions. Hereinafter, the simulation results 1 to 4 of the four patterns will be described in order.

As common additional processing conditions for simulations 1 to 4, the inventors set the target number of layers to 100, the single line measurement points to 10 points, and the work (wall) height to 10 measurement points. The average of the actual heights of the single lines is 0.425 mm, the standard deviation of the actual heights of the single lines is 0.0465 mm, and the ideal command stacking height is "LH _{c, ideal} " 0. It was set to 4111 mm.

(F1. Simulation result 1)
First, the simulation result 1 will be described. FIG. 9 is a diagram showing a simulation result 1 based on the additional processing condition 1.

As the additional processing condition 1, the inventors set the initial command stacking height "LH _{c, 0} " to 0.364 mm, and set the allowable value "d" for the height error "E _{H" to 1.0 mm.} did.

As a result of the simulation, the command stacking height "LH _{c, 1} " was set to 0.401 mm at the time of the first feedback processing, and the command stacking height "LH _{c, 2} " was 0.409 mm at the time of the second feedback processing. Was set to.

In the simulation result 1, the _{feedback process is executed before the height error “E H} ” exceeds the allowable value “d”. Further, every time the feedback processing is executed, height error "E _H" is approaching zero. That is, the command stacking height "LH _c " is approaching the optimum value.

(F2. Simulation result 2)
Next, the simulation result 2 will be described. FIG. 10 is a diagram showing a simulation result 2 based on the additional processing condition 2.

As the additional processing condition 2, the inventors set the initial command stacking height "LH _{c, 0} " to 0.458 mm and the allowable value "d" for the height error "E _{H" to 1.0 mm.} did.

As a result of the simulation, the command stacking height "LH _{c, 1} " was set to 0.407 mm at the time of the first feedback processing, and the command stacking height "LH _{c, 2} " was 0.409 mm at the time of the second feedback processing. Was set to.

In the simulation result 2, the _{feedback process is executed before the height error “E H} ” exceeds the allowable value “d”. Further, every time the feedback processing is executed, height error "E _H" is approaching zero. That is, the command stacking height "LH _c " is approaching the optimum value.

(F3. Simulation result 3)
Next, the simulation result 3 will be described. FIG. 11 is a diagram showing a simulation result 3 based on the additional processing condition 3.

As the additional processing condition 3, the inventors set the initial command stacking height "LH _{c, 0} " to 0.364 mm and the allowable value "d" for the height error "E _{H" to 0.4 mm.} did.

As a result of the simulation, the command stacking height "LH _{c, 1} " was set to 0.401 mm at the time of the first feedback processing, and the command stacking height "LH _{c, 2} " was 0.416 mm at the time of the second feedback processing. At the time of the third feedback processing, the command stacking height "LH _{c, 3} " was set to 0.414 mm.

Compared with the above simulation results 1 and 2, in the simulation result 3, since the permissible value "d" is changed from 1.0 mm to 0.4 mm, the number of times the feedback process is executed is increased from 2 to 3. .. Also in the simulation result 3, the _{feedback process is executed before the height error “E H} ” exceeds the allowable value “d”.

(F4. Simulation result 4)
Next, the simulation result 4 will be described. FIG. 12 is a diagram showing a simulation result 4 based on the additional processing condition 4.

As the additional processing condition 4, the inventors set the initial command stacking height "LH _{c, 0} " to 0.458 mm and the allowable value "d" for the height error "E _{H" to 0.4 mm.} did.

As a result of the simulation, the command stacking height "LH _{c, 1} " was set to 0.402 mm at the time of the first feedback processing, and the command stacking height "LH _{c, 2} " was 0.416 mm at the time of the second feedback processing. At the time of the third feedback processing, the command stacking height "LH _{c, 3} " was set to 0.414 mm.

Also in the simulation result 4, _{the feedback process is executed before the height error “E H} ” exceeds the allowable value “d”.

<G. Hardware configuration of additional processing device 100>
An example of the hardware configuration of the additional processing apparatus 100 will be described with reference to FIG. FIG. 13 is a block diagram showing a main hardware configuration of the additional processing apparatus 100.

The additional processing device 100 includes a laser head 21, a control device 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a storage device 120, a spindle 124, the above-mentioned measuring mechanism 125, and the like. Includes servo drivers 141A-141D, servomotors 142A-142D, and encoders 143A-143D. These devices are connected via a bus (not shown).

The control device 101 is composed of at least one integrated circuit. The integrated circuit includes, for example, at least one CPU (Central Processing Unit), at least one PLC (Programmable Logic Controller), at least one CNC (Computer Numerical Control), at least one MPU (Micro Processing Unit), and at least one ASIC. , At least one FPGA or a combination thereof and the like.

The control device 101 controls the operation of the additional processing device 100 by executing various programs such as the control program 122. The control device 101 reads the control program 122 from the storage device 120 into the ROM 102 based on the reception of the execution command of the control program 122. The RAM 103 functions as a working memory and temporarily stores various data necessary for executing the control program 122.

The control device 101 controls the servo driver 141A according to the control program 122. The servo driver 141A sequentially receives an input of a target rotation speed (or a target position) from the control device 101, controls the servo motor 142A so that the servo motor 142A rotates at the target rotation speed, and controls the first slide mechanism 14. Drive in the X-axis direction. More specifically, the servo driver 141A calculates the actual rotation speed (or actual position) of the servo motor 142A from the feedback signal of the encoder 143A, and when the actual rotation speed is smaller than the target rotation speed, the servo motor 142A If the actual rotation speed is larger than the target rotation speed, the rotation speed of the servomotor 142A is decreased. In this way, the servo driver 141A brings the rotation speed of the servomotor 142A closer to the target rotation speed while sequentially receiving feedback of the rotation speed of the servomotor 142A. The servo driver 141A moves the first slide mechanism 14 in the X-axis direction, and moves the laser head 21 attached to the main shaft 124 to an arbitrary position in the X-axis direction.

By the same motor control, the servo driver 141B moves the second slide mechanism 15 in the Y-axis direction according to the control command from the control device 101, and moves the laser head 21 attached to the spindle 124 to an arbitrary position in the Y-axis direction. Moving. By performing the same motor control, the servo driver 141C moves the removal processing head 16 in the Z-axis direction according to a control command from the control device 101, and arbitrarily moves the laser head 21 attached to the spindle 124 in the Z-axis direction. Move to the position of. By performing the same motor control, the servo driver 141D controls the rotation speed of the spindle 124 according to the control command from the control device 101.

The additional processing device 100 further includes a first drive mechanism (not shown) for driving the above-mentioned rotary table 13 (see FIG. 1) around the turning axis. The swivel axis is an axis parallel to the upper surface of the machine bed 11 (see FIG. 1). The first drive mechanism is composed of a servo driver, a servo motor, an encoder and the like. The servo driver controls the rotation angle of the rotary table 13 around the swivel axis according to a control command from the control device 101 by the same motor control as the servo driver 141A.

The additional processing device 100 further includes a second drive mechanism (not shown) for driving the above-mentioned rotary table 13 (see FIG. 1) around the rotation axis. The rotation axis is an axis orthogonal to the upper surface of the swivel table 12. The second drive mechanism includes a servo driver, a servo motor, an encoder, and the like. The servo driver controls the rotation angle around the rotation axis of the rotary table 13 according to a control command from the control device 101 by the same motor control as the servo driver 141A.

The storage device 120 is, for example, a storage medium such as a hard disk or a flash memory. The storage device 120 stores the control program 122 and the like. The control program 122 includes, for example, a program code for additional machining, a program code for removal machining, and the like. The program code for additional processing includes the above-mentioned command stacking height "LH _c ", the above-mentioned command height "H _c ", the final target height of the work by the additional processing, and the final work by the additional processing. Includes the target number of stacks.

The storage location of the control program 122 is not limited to the storage device 120, and may be stored in the storage area of the control device 101 (for example, a cache area or the like), the ROM 102, the RAM 103, an external device (for example, a server), or the like.

The control program 122 may be provided as a part of an arbitrary program, not as a single program. In this case, the feedback processing described above by the control program 122 is realized in cooperation with an arbitrary program. Even a program that does not include such a part of modules does not deviate from the purpose of the control program 122 according to the present embodiment. Further, some or all of the functions provided by the control program 122 may be realized by dedicated hardware. Further, the additional processing apparatus 100 may be configured in the form of a so-called cloud service in which at least one server executes a part of the processing of the control program 122.

<H. Control flow>
The control flow of the addition processing apparatus 100 will be described with reference to FIGS. 14 and 15. FIG. 14 is a flowchart showing the feedback process executed for the first time. FIG. 15 is a flowchart showing the feedback processing executed from the second time onward.

The processing shown in FIGS. 14 and 15 is realized by the control device 101 of the addition processing device 100 executing the above-mentioned control program 122. In other aspects, some or all of the processing may be performed by circuit elements or other hardware.

In step S110, the control device 101 initializes the total number of stacked workpieces "N" to 0.

In step S112, the control device 101 counts up the total number of stacked "N". That is, the control device 101 increases the value of the total number of stacked "N" by 1.

In step S114, the control device 101 controls the above-mentioned laser head 21 (see FIG. 1) to perform additional processing of the Nth layer.

In step S116, the control unit 101 outputs a measurement execution command to the measurement mechanism 125, obtains the actual height of the workpiece for a plurality of locations to _"H a (N)". "H _{a (N)"} shows the actual height of the workpiece surface from the reference surface 140 at the time the addition processing of the N-th layer is finished.

_{In step S118, the control device 101 calculates the actual height “LH a} (N)” of the single line for a plurality of locations in the Nth layer. More specifically, when the total number of laminated layers "N" is 1, the control device 101, the actual height measured at step S116 'H _{a (N)} "actual height of the single-line" LH _a ( Used as "N)". When the total number of laminated layers "N" is 2 or more, the control device 101, the actual height measured this time in step S116 from the "H _{a (N)",} the actual height the previously measured in step S116 'H _a (N-1) ”is differentiated, and the difference result is _{calculated as the actual height“ LH a} (N) ”of the single line.

Since the actual height of the single line is not stable in the early stage of the additional processing, the control device 101 determines in step S120 whether or not the actual height of the single line is stable. More specifically, the control device 101, the actual height of the N-th layer of a single line and _"LH a (N)", the actual height of the N-1 layer of single-line _"LH a (N- It is determined whether or not the difference from "1)" is smaller than the predetermined threshold value "th". When the control device 101 determines that the difference is smaller than the predetermined threshold value “th” (YES in step S120), the control device 101 switches the control to step S122. If not (NO in step S120), the controller 101 returns control to step S112.

In step S122, the control device 101 calculates the average value and the standard deviation _{of the actual height “LH a (N)” of the single line of the Nth layer.} The average value corresponds to the overlined “x” represented by the above equation (7). The standard deviation corresponds to "s" represented by the above formula (7).

In step S124, the control device 101 differentiates the standard deviation from the calculated average value according to the above equation (7), and sets the difference result in the additional processing device 100 as the _{command stacking height “LH c, 0”.}

In step S126, the control device 101 calculates the _{number of stacks “N f, 1} ” indicating the next measurement timing of the measurement mechanism 125 according to the above equation (9).

In step S128, the control unit 101, the actual height of the workpiece measured in the step S116 described above to _"H a (N)", and substitutes the actual height of the work _{"H a, 0".}

In step S130, the control device 101 initializes the variable “m” corresponding to the number of times the feedback process is executed to 1.

In step S140, the control device 101 _{determines whether or not the actual height “Ha, m} ” of the work is likely to exceed the target height. As an example, in the control device 101, when the difference between the current total number of layers "N" and the target number of layers is smaller than a predetermined number, the actual height "Ha _{, m} " of the work is likely to exceed the target height. Judge. When the control device 101 determines that the actual height “Ha _{, m} ” of the work is about to exceed the target height (YES in step S140), the control device 101 switches the control to step S160. If not (NO in step S140), the control device 101 switches control to step S142.

In step S142, the control device 101 controls the above-mentioned laser head 21 (see FIG. 1) to perform additional processing for the _{number of stacks “N f, 1” calculated in step S126.} After that, the control device 101 _{adds the number of layers "N f, 1} " to the total number of layers "N" and updates the total number of layers "N".

In step S146, the control device 101 outputs a measurement execution command _{to the measuring mechanism 125, and acquires the actual height “Ha, m} ” of the work from the measuring mechanism 125. At this time, the control device 101 may acquire the actual height of the work at a plurality of locations, or may acquire the actual height of the work at one location.

In step S148, the control device 101 has a command stacking height “LH _{c, m} ” _{based on the actual heights “Ha, m-1} ” and “Ha _{, m} ” of the workpiece according to the above equation (10). To update.

In step S150, the control device 101 has a height error “E _{H, m} ” _{between the actual height “Ha, m} ” of the work and the command height “H _{c, m” according to the above equation (3).} Is calculated.

In step S152, the control device 101 calculates the _{number of stacks “N f, m + 1} ” indicating the next measurement timing of the measurement mechanism 125 according to the above equation (14).

In step S154, the control device 101 corrects the focal position of the laser head 21 and the control program 122 (NC code) so that _{the height error “E H, m” becomes zero.} As an example, the controller 101 corrects the actual height of the work "H _{a, m} 'command height in accordance with the" H _{c, m} "a. Further, the control device 101 updates the target number of stacks based on _{the command stack height “LH c, m” after the update.} More specifically, the control device 101 divides the remaining height from the current actual height of the work to the target height of the work by the updated command stacking height "LH _{c, m} ", and the division is performed. Set the result as a new target stacking number.

In step S156, the control device 101 counts up the variable “m”. That is, the control device 101 increments the value of the variable "m" by 1.

In step S160, the control device 101 determines the _{number of layers "N f, f} " up to the target height according to the following equation (15).

More specifically, the control device 101 first actual height of the workpiece from the target height "TargetH _{a" "H a, m-1"} is the difference a. Next, the control device 101 divides the difference result by the command stacking height “LH _{c, m-1} ”, and sets the division result as the number of stacks “N _{f, f”.}

In step S162, the control device 101 controls the above-mentioned laser head 21 (see FIG. 1) to perform additional processing for the _{number of stacks “N f, f” calculated in step S160.}

<I. Modification 1>
Next, with reference to FIG. 16, the additional processing apparatus 100 according to the first modification will be described.

The above-mentioned additional processing apparatus 100 updates the target number of laminated layers each time feedback processing is performed. On the other hand, the addition processing apparatus 100 according to this modification does not update the target number of laminated layers when the feedback process is executed.

Hereinafter, the feedback process according to this modification will be described with reference to FIG. FIG. 16 is a graph showing the transition _{of the height error “E H} ” when the feedback processing according to this modification is executed.

In the example of FIG. 16, the measurement process by the measuring mechanism 125 _{is performed at the timing T1 when the number of layers reaches "N f, 1} " and the timing T2 when the number of layers reaches "N _{f, 1} + N _{f, 2".} It is running. At this time, the additional processing apparatus 100 according to this modification _{updates only the command stacking height “LH c} ” and does not update the command height “H _c”. As a result, at timing T1, T2 or later, the height error "E _H" remains.

In consideration of this point, the addition processing apparatus 100 calculates a _{new command stacking height error "ELH, m-1".} Specifically, the new command stacking height error " _{ELH, m-1} " is calculated based on the following equation (16).

The additional processing apparatus 100 considers the command stacking height error " _{ELH, m-1} " calculated by the above formula (16) as the above-mentioned maximum error "max | _ELH |" and is based on the following formula (17). Then, the number of layers "N _{f, m + 1} " indicating the next measurement timing is calculated.

By the above processing, the addition processing apparatus 100 can finish the addition processing processing with the target number of layers set before the start of the addition processing.

<J. Control flow according to modification 1>
Next, with reference to FIG. 17, the control flow of the addition processing apparatus 100 according to the first modification will be described. FIG. 17 is a flowchart showing a feedback process according to the first modification.

The addition processing apparatus 100 according to the first modification first executes the process shown in FIG. 14 described above. After that, the additional processing apparatus 100 executes the process shown in FIG. 17 instead of the process shown in FIG. 15 described above. Hereinafter, among the processes shown in FIG. 17, only the differences from the processes shown in FIGS. 14 and 15 will be described.

In step S152A, the control device 101 calculates the _{number of stacks “N f, m} ” indicating the next measurement timing of the measurement mechanism 125 according to the above equation (17).

In this modification, the control device 101 does not execute the process of step S154 shown in FIG. That is, the control unit 101 does not correct the command height "H _c" in accordance with the actual measured height "H _a". Further, the control device 101 does not update the target number of stacked layers.

<K. Modification 2>
Next, the additional processing apparatus 100 according to the second modification will be described.

As shown in (6) above, the number of layers "N _f " is calculated by dividing the permissible value "d" by the maximum error "max | _{ELH |".} Therefore, if the maximum error “max | _ELH |” is small, the number of layers “N _f ” becomes large, and the next measurement timing is considerably ahead. In this case, upon receiving an unexpected influence of factors such as environmental variations, height error "E _H" is likely to exceed the allowable value "d".

Therefore, in the addition processing apparatus 100 according to this modification, an upper limit value “maxN _f ” is set for the _{number of layers “N f”.} That is, when the number of layers "N _f " is equal to or greater than the predetermined upper limit value "maxN _{f ", the addition processing apparatus 100 corrects the number of layers "N f} " to the upper limit value.

The method for determining the upper limit value "maxN _f " is not particularly limited. As an example, the additional processing apparatus 100 regards the minimum value "L _{c, r} " (that is, the resolution) that _{can be set as the command stacking height "LH c " as the maximum error "max | ELH} |", and uses the following equation ( Based on 18), the upper limit value "maxN _f " is calculated.

As another example, the upper limit value "maxN _f " is determined based on the uncertainty of the height measurement of the work with reference to GUM (Guide to the Expression of Uncertainty in Measurement (ISO Guide98-3, JCGM100)). ..

Hereinafter, a method of determining the upper limit value “maxN _f ” based on the uncertainty of the height measurement of the work will be described with reference to FIG. FIG. 18 is a diagram showing factors to be considered when determining the upper limit value “maxN _f”.

As shown in the following formula (19), the upper limit value “maxN _f ” is determined based on the synthetic standard uncertainty “u _C (v)”.

The synthetic standard uncertainty "u _C (v)" is calculated based on the following formula (20).

_“Xi ” represented by the above equation (20) indicates a factor of uncertainty in the height measurement of the work. "U _{(x i)"} represents the standard uncertainty. “C _i ” represents a sensitivity coefficient. Factors "x _i", for example, repeatability of the height measurement, thermal displacement due to the temperature difference, the variation of the actual height of the workpiece N _f layer, and the like variations in the actual bed height of a single line ..

Supplements for the "thermal displacement due to the temperature difference ΔT" shown in factor "x _i". When the temperature is "T = T ₁ ", the actual height difference of the work is "H _m-1 = H ₁ (T ₁ )", and when the temperature is "T = T ₂ ", the actual height difference of the work is "H _m = H _2". When (T ₂₎ "was was that," temperature difference ΔT sensitivity coefficients "c _i in the thermal distortion" by "is calculated according to the following equation (21) and the following equation (22). The temperature difference "ΔT" is represented by _{"T 2-} T _1".

<L. Modification 3>
In the above description, the description has been made on the premise of the three-dimensional modeling technique using metal powder, but the above-mentioned technical idea for reducing the number of actual height measurements can be applied to the three-dimensional modeling technique using other powder materials.

A resin powder is an example of a material powder that replaces a metal powder. The resin powder is composed of, for example, polyamide, polyester, polyolefin, polyetherketone, polyarylketone, polyphenylene sulfide, liquid crystal polymer, polyacetal, polyimide, fluororesin and the like. The above-mentioned additional processing apparatus 100 forms an arbitrary three-dimensional model by laminating resin powder. The "three-dimensional model" here is a concept that includes the above-mentioned work made of metal and an object made of resin powder. The above-mentioned technical idea for reducing the number of actual height measurements can be applied to the addition processing apparatus 100 using the resin powder.

<M. Summary>
As described above, the addition processing apparatus 100 executes a process of measuring the actual height of the work by the measuring mechanism 125 at the first timing when the number of laminated works reaches a predetermined number (the first number of laminated works). .. Then, the additional processing device 100, the using at least the measured actual height of the workpiece to "H _a" at the first timing, the maximum error to execute a process of estimating the "max | _| E LH". After that, the addition processing apparatus 100 indicates the number of layers "2" indicating the second timing at which the measuring mechanism 125 should execute the measurement process after the first timing, based on _{the estimated maximum error "max | ELH |".} The process of determining " _{N f" is executed.}

As a result, the addition processing apparatus 100 does not execute the feedback process (that is, the work height measurement process) until the _{number of layers reaches "N f".} Further, the height error "E _H " does not exceed the permissible value "d" until the number of layers _{reaches "N f".} As a result, the additional processing apparatus 100 can reduce the number of times of measuring the height of the work while ensuring the molding accuracy.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and it is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

11 Machine bed, 12 Swivel table, 13 Swivel table, 14 1st slide mechanism, 15 2nd slide mechanism, 16 Removal processing head, 18 Magazine, 18A tool, 19 Automatic tool changer, 21 Laser head, 22 Head body, 23 slide guide, 24 third slide mechanism, 26 laser tool, 31 cable, 100 additional processing device, 101 control device, 102 ROM, 103 RAM, 120 storage device, 122 control program, 124 spindle, 125 measuring mechanism, 126 stylus , 140 Reference Plane, 141A-141D Servo Driver, 142A-142D Servo Motor, 143A-143D Encoder, 311 Laser Light, 312 Metal Powder, 313 Gas, 314 Melt Pool.

Claims (12)

It is an additional processing device that can form a three-dimensional model by melting and laminating the supplied powder material.
A laser head that supplies the powder material to the three-dimensional model that is undergoing additional processing and irradiates a laser beam.
Each time the additional processing of each layer of the three-dimensional model is completed, a drive unit for driving the laser head in the stacking direction of the three-dimensional model according to a predetermined command value,
A measuring unit for measuring the actual size of the three-dimensional model in the stacking direction,
A control device for controlling the additional processing device is provided.
The control device is
A process of causing the measuring unit to measure the actual size of the three-dimensional model at the first timing when the number of layers of the three-dimensional model reaches the first number of layers.
Using at least the actual size measured at the first timing, between the actual size and the dimension in the stacking direction of the three-dimensional model recognized by the additional processing apparatus at the first timing. And the process of estimating the error per layer in
An additional processing apparatus that executes a process of determining a second stacking number indicating a second timing at which the measuring unit should execute a measurement process after the first timing based on the error. At the first timing, the measuring unit measures the dimensions of the three-dimensional modeled object at a plurality of locations in the stacking direction.
The control device is
Based on the plurality of dimensions measured at the plurality of locations, a process of calculating the standard deviation of the dimensions per layer of the three-dimensional model is executed.
The additional processing apparatus according to claim 1, wherein the error is estimated based on the standard deviation. The control device further
A process of calculating the average value of the dimensions per layer of the three-dimensional model based on the plurality of dimensions measured at the plurality of locations, and
The additional processing apparatus according to claim 2, wherein the process of updating the command value is executed with the average value as a reference. The control device divides the difference between the dimension in the stacking direction of the three-dimensional model and the actual size recognized by the addition processing device by the first number of stacks, and calculates the division result as the error. The additional processing apparatus according to any one of claims 1 to 3. The control device further executes a process of updating the command value based on the actual size measured at the first timing and the actual size measured at the second timing. Item 4. The additional processing apparatus according to item 4. The control device further adjusts the height in the stacking direction of the three-dimensional modeled object recognized by the additional processing device at the first timing according to the actual size measured at the first timing. The additional processing apparatus according to claim 4 or 5, which executes the correction process. The fourth or fifth aspect of the present invention, wherein the control device does not correct the dimension in the stacking direction of the three-dimensional model recognized by the additional processing device at the first timing. Additional processing equipment. The control device further executes a process of correcting the number of the second stacks to the upper limit when the number of the second stacks is equal to or greater than a predetermined upper limit value, according to any one of claims 1 to 7. The additional processing apparatus according to item 1. The additional processing apparatus according to any one of claims 1 to 8, wherein the second number of layers is equal to or less than a value obtained by dividing a predetermined margin of error by the error. The addition processing apparatus according to any one of claims 1 to 9, wherein the powder material is a metal powder or a resin powder. It is a control method of an additional processing device capable of forming a three-dimensional model by melting and laminating the supplied powder material.
The additional processing device is
A laser head that supplies the powder material to the three-dimensional model that is undergoing additional processing and irradiates a laser beam.
Each time the additional processing of each layer of the three-dimensional model is completed, a drive unit for driving the laser head in the stacking direction of the three-dimensional model according to a predetermined command value,
A measuring unit for measuring the actual size of the three-dimensional model in the stacking direction is provided.
The control method is
A step of causing the measuring unit to measure the actual size of the three-dimensional model at the first timing when the number of layers of the three-dimensional model reaches the first number of layers.
Using at least the actual size measured at the first timing, between the actual size and the dimension in the stacking direction of the three-dimensional model recognized by the additional processing apparatus at the first timing. Steps to estimate the error per layer in
A control method comprising a step of determining a second stacking number indicating a second timing at which the measuring unit should execute a measurement process after the first timing based on the error. It is a control program of an additional processing device that can form a three-dimensional model by melting and laminating the supplied powder material.
The additional processing device is
A laser head that supplies the powder material to the three-dimensional model that is undergoing additional processing and irradiates a laser beam.
Each time the additional processing of each layer of the three-dimensional model is completed, a drive unit for driving the laser head in the stacking direction of the three-dimensional model according to a predetermined command value,
A measuring unit for measuring the actual size of the three-dimensional model in the stacking direction is provided.
The control program is applied to the additional processing apparatus.
A step of causing the measuring unit to measure the actual size of the three-dimensional model at the first timing when the number of layers of the three-dimensional model reaches the first number of layers.
Using at least the actual size measured at the first timing, between the actual size and the dimension in the stacking direction of the three-dimensional model recognized by the additional processing apparatus at the first timing. Steps to estimate the error per layer in
A control program that causes the measuring unit to execute a step of determining a second stacking number indicating a second timing to execute a measurement process after the first timing based on the error.

Images