Abstract:
A model producing means for modeling a chip model at an edge of a solid model of a nozzle through a predetermined space in a three-dimensional virtual space, and a trace machining propriety judging means for watching a state of an interference between the chip model and the solid model of a workpiece at the time of simulation of laser beam machining program and outputting a predetermined signal when releasing the state of the interference are provided. If an inconvenient instruction wherein the nozzle and the workpiece do not face each other is included in the laser beam machining program, the chip model departs from the solid model of the workpiece and the trace machining propriety judging means outputs a predetermined signal, through which program error can be properly detected with no visual observation of an operator.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a machining simulation machine for inspecting a program error by simulating a laser beam machining program. Especially, the invention relates to a machining simulation machine for judging propriety of contents of trace machining in the laser beam machining program wherein trace machining is instructed. 
   In a conventional machining simulation machine for simulating machining program of machining with laser beam, various kinds of functions for inspecting a program error have been developed. But, most part of this inspection still depends on visual observation of an operator, and then automation of such inspection is desired. 
   In the trace machining wherein a torch for emitting laser beam is moved, keeping a constant distance from a surface of a workpiece, a state of moving the torch, keeping a constant distance with respect to the surface of the workpiece which is designated in the machining program is computed at the time of simulation, and the state can be simulated on a display. But, an inspection as to whether or not an instruction of trace movement of the torch with respect to the workpiece to be machined is proper depends on visual observation of an operator. 
   Applicant does not know prior art for disclosing inspection as to whether or not an instruction of trace movement of the torch with respect to the workpiece to be machined is proper at the time of simulation of the trace machining in the laser beam machining program. 
   Under these circumstances, an operator is required to have a high level of knowledge of the trace machining when inspecting machining program, and in addition, to watch a state of moving the torch displayed on a display with high level of attention. That is, an operator is required to shoulder excessive burden. 
   Then, developments of the machining simulation machine for inspecting as to whether or not an instruction of trace movement of the torch with respect to the workpiece to be machined is proper in the laser beam machining program including trace machining on a machine side without depending visual observation of an operator are still desired. 
   SUMMARY OF THE INVENTION 
   One aspect of the invention is machining simulation machine for displaying a state of movement of a nozzle with respect to a workpiece which is instructed by a laser beam machining program on a display means by simulating said laser beam machining program, comprising:
         a modeling means for modeling solid models of said workpiece and said nozzle to be used for machining with laser beam in a three-dimensional virtual space;   said modeling means having a chip model producing means for modeling a chip model at an edge of said solid model of said nozzle produced in said three-dimensional virtual space through a predetermined space;   a simulation execution means for controlling to move said solid model of said nozzle with respect to said solid model of said workpiece together with said chip model in said three-dimensional virtual space according to an instruction of said laser beam machining program; and   a trace machining propriety judging means for watching a state of an interference between said chip model and said solid model of said workpiece, and outputting a predetermined signal when said state of said interference being released.       

   According to this aspect of the invention, the chip model producing means produces the chip model at an edge of the solid model of the nozzle through a predetermined space, and the trace machining propriety judging means watches the state of the interference between the chip model and the solid model of the workpiece at the time of simulation by the simulation execution means and outputs a predetermined signal when releasing the interference state. Even if a instruction inconvenient for the trace machining wherein the nozzle and the workpiece do not face each other is included in the laser beam machining program, the chip model departs from the solid model of the workpiece at the time of simulation and the trace machining propriety judging means detects this inconvenient state and outputs a predetermined signal, so that the program error can be properly detected with no visual observation of an operator. 
   Another aspect of the invention is the machining simulation machine, wherein a trace machining instruction judging means for judging whether or not trace machining is instructed in said laser beam machining program is provided, and said trace machining propriety judging means watches said state of said interference between said chip model and said solid model of said workpiece only when said trace machining instruction judging means judges that said trace machining is instructed in said laser beam machining program. 
   According to this aspect of the invention, the trace machining propriety judging means watches the state of the interference between the chip model and the solid model of the workpiece only when the trace machining instruction judging means judges that the trace machining is instructed in the laser beam machining program, so that it is possible to execute an operation of detecting the propriety of the instruction of the trace machining in the laser beam machining program only in the case where the trace machining is judged to be instructed in the laser beam machining program, thereby effectively simulating with no vain computation. 
   Another aspect of the invention is the machining simulation machine, wherein said chip model producing means models a virtual object for connecting said solid model of said nozzle and said chip model therebetween. 
   According to this aspect of the invention, an operator can easily understand the relation between the chip model and the solid model of the nozzle by modeling this virtual object. 
   Another aspect of the invention is the machining simulation machine, wherein said virtual object is modeled in the shape of an elongate bar. 
   According to this aspect of the invention, the virtual object is modeled in the shape of an elongate bar, so that the virtual object can be modeled so as to have the shape different from the chip model and the solid model of the nozzle, thereby the chip model and the solid model of the nozzle which are connected with each other through the virtual object can be easily visually differentiated from each other. 
   Another aspect of the invention is the machining simulation machine, wherein said chip model producing means forms said virtual object such that a space between said solid model of said nozzle and said chip model has a dimension corresponding to a space to be kept between said workpiece and said nozzle in said trace machining which is instructed in said laser beam machining program. 
   According to this aspect of the invention, the virtual object is formed such that the distance between the solid model of the nozzle and the chip model has a dimension corresponding to the space between the workpiece and the nozzle to be kept in the trace machining which is instructed in the laser beam machining program, so that the space between the workpiece and the nozzle to be kept in the trace machining can be visually perceived at the time of simulation. 
   Another aspect of the invention is the machining simulation machine, wherein a warning means for warning that said instruction of said trace machining in said laser beam machining program is improper when said trace machining propriety judging means outputs said predetermined signal is provided. 
   According to this aspect of the invention, the warning means warns that the instruction of the trace machining in the laser beam machining program is improper, so that an operator can immediately perceive the propriety of the laser beam machining program through the display means. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a control block diagram showing a machining simulation machine; 
       FIG. 2  is a flow chart showing simulation control program; 
       FIG. 3  is a view showing a positional relation between a machining torch and a workpiece in a three-dimensional virtual space constructed by a simulation execution portion, the positional relation being computed according to simulation control program, and is a view showing a normal trace control state; and 
       FIG. 4  is a view showing the positional relation between the machining torch and the workpiece in the three-dimensional virtual space constructed by the simulation execution portion, the positional relation being computed according to the simulation control program, and is a typical view showing a state wherein an instruction of trace movement of the torch with respect to the workpiece to be machined is improper. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  is a control block diagram showing a machining simulation machine,  FIG. 2  is a flow chart showing simulation control program,  FIG. 3  is a view showing a positional relation between a machining torch and a workpiece in a three-dimensional virtual space constructed by a simulation execution portion, the positional relation being computed according to simulation control program, and is a view showing a normal trace control state, and  FIG. 4  is a view showing the positional relation between the machining torch and the workpiece in the three-dimensional virtual space constructed by the simulation execution portion, the positional relation being computed according to the simulation control program, and is a typical view showing a state wherein an instruction of trace movement of the torch with respect to the workpiece to be machined is improper. 
   A machining simulation machine  1  has a main control portion  2 , as shown in  FIG. 1 . A communication control portion  5 , a program memory  6 , a simulation execution portion  7 , a nozzle interference judging portion  9 , a trace machining propriety judging portion  10 , a trace model producing portion  11 , an input portion  12 , a display portion  13 , and a machining parameter memory  15  are connected with the main control portion  2  through a bus line  3 . 
   The machining simulation machine  1  has the above-mentioned structure, and a laser beam machining program PRO which is composed outside is on-line inputted in the communication control portion  5  of the machining simulation machine  1  through a communication line, such as the LAN. The method of inputting the laser beam machining program PRO is not only through the communication line, but may be that the laser beam machining program PRO is stored in a proper storage medium, such as a magnetic disc, and the storage medium storing the laser beam machining program PRO therein is set on an outside data input portion which is connected with the machining simulation machine  1  so as to read out the program PRO. 
   The laser beam machining program PRO thus inputted is stored in the program memory  6 . When an operator inputs an instruction of execution of simulation through the input portion  12 , the main control portion  2  instructs the trace model producing portion  11  to produce trace models of a workpiece  20  and a nozzle  21 . 
   Receiving this instruction, the trace model producing portion  11  produces a solid model SD 1  of the workpiece having a predetermined thickness in a three-dimensional virtual space according to a shape of a material of the worpiece which is designated in the laser beam machining program PRO, and reads a three-dimensional shape of the nozzle  21  which is used at the time of machining on the workpiece  20  out of the machining parameter memory  15  and produces a solid model SD 2  of the nozzle  21  in the three-dimensional virtual space in a similar way, as shown in  FIG. 3 . 
   When producing the solid model SD 2  of the nozzle  21 , the trace model producing portion  11  produces the solid model SD 2  having a dimensional shape suitable for the shape of the nozzle  21  to be used for an actual machining, and a chip model SD 4 , a predetermined space GP 1  away from the solid model SD 2  in the lower hand of the nozzle  21  in  FIG. 3 , that is, in a direction where the nozzle  21  emits laser beam, through a connecting bar model SD 3  which is a virtual object so as to move together with the solid model SD 2  of the nozzle  21 . The size of the chip model SD 4  is optional, but preferably, the connecting bar model SD 3  has the shape different from the chip model SD 4  and the solid model SD 2  of the nozzle so that both models SD 4  and SD 2  can be differentiated from each other. In a case of  FIG. 3 , the connecting bar model SD 3  has an elongate bar shape having a small diameter. 
   After thus producing the solid models SD 1 , SD 2  of the workpiece and the nozzle and the connecting bar model SD 3  and the chip model SD 4  in the three-dimensional virtual space, the main control portion  2  instructs the simulation execution portion  7  to execute simulation according to the laser beam machining program PRO. Receiving this instruction, the simulation execution portion  7  executes a machining instruction stored in the laser beam machining program PRO so that the solid models SD 1 , SD 2  of the workpiece and the nozzle which were produced in the three-dimensional virtual space are objects to be controlled, and then, simulation of moving the solid model SD 2  of the nozzle to the solid model SD 1  of the workpiece is executed in the three-dimensional virtual space. At this time, the connecting bar model SD 3  and the chip model SD 4  are also controlled to be moved in the three-dimensional virtual space together with movement of the solid model SD 2  of the nozzle. 
   The positional relation between the nozzle and the workpiece in the three-dimensional virtual space after executing the laser beam machining program PRO is represented by rendering the solid models SD 1 , SD 2  from predetermined positions in the three-dimensional virtual space, and displaying the rendered on the display portion  13 . This representation is displayed as an image in such a manner that the solid model SD 2  of the nozzle is moved, for the solid model SD 1  of the workpiece together with the connecting bar model SD 3  and the chip model SD 4  in a direction of a movement instructed by the laser beam machining program PRO, such as an arrow A direction as shown in  FIG. 3 . 
   Keeping an eye on a state of the image displayed on the display portion  13 , an operator watches as to whether or not there is an error in the laser beam machining program PRO. The simulation execution portion  7  thus executes simulation of the laser beam machining program PRO. At the time of the simulation of the laser beam machining program PRO, the simulation execution portion  7  reads a simulation control program SPR as shown in  FIG. 2  out of the program memory  6 , and controls the simulation in the three-dimensional virtual space according to the simulation control program SPR. 
   That is, the main control portion  2  judges as to whether or not trace machining is instructed in the laser beam machining program PRO during the simulation by interpreting contents of respective instructions of the laser beam machining program PRO in Step S 1  of the simulation control program SPR. If no trace machining is judged to be instructed, the program SPR enters in Step S 2 , and a first operation of judging an interference of the nozzle is executed, putting the operation of judging the interference between the solid model SD 2  of the nozzle and the solid model SD 1  of the workpiece ON and the operation of judging the interference between the chip model SD 4  and the solid model SD 1  of the workpiece OFF. 
   The first operation of judging an interference of the nozzle is one of judging only interference between the workpiece and the nozzle. The simulation execution portion  7  gets the nozzle interference judging portion  9  to judge only as to whether or not the solid model SD 2  of the nozzle interferes with the solid model SD 1  of the workpiece in Step S 3  of the simulation control program SPR. 
   The solid model SD 2  of the nozzle is controlled to be moved in the three-dimensional virtual space according to the laser beam machining program PRO. If there is an error in the laser beam machining program PRO and the nozzle and the workpiece interfere with each other in the instruction in the program PRO, the solid models SD 1 , SD 2  of the workpiece and the nozzle interfere with each other in the three-dimensional virtual space, so that a program error is judged by checking this interference. When the interference between the solid models SD 1 , SD 2  of the workpiece and the nozzle in the three-dimensional virtual space is judged in Step S 3 , the nozzle interference judging portion  9  outputs a nozzle interference signal SG 1  to the main control portion  2 . Receiving this signal, program enters in Step S 4 , and the main control portion  2  informs an operator that the workpiece and the nozzle will interfere with the contents of the instruction of the present laser beam machining program PRO through the display portion  13 . 
   If the main control portion  2  judges that the trace machining has been instructed in the laser beam machining program PRO during the simulation according to Step S 1  of the simulation control program SPR, the program enters in Step S 5 , and a second operation of judging an interference of the nozzle is executed, putting the operation of judging the interference between the solid model SD 2  of the nozzle and the solid model SD 1  of the workpiece ON and also the operation of judging the interference between the chip model SD 4  and the solid model SD 1  of the workpiece ON. 
   In this second operation of judging the interference of the nozzle, the trace model producing portion  11  sets the length L of the connecting bar model SD 3 , that is, the distance between the solid model SD 2  of the nozzle and the chip model SD 4  so as to have a dimension corresponding to a space GP 1  to be kept between the workpiece and the nozzle in the trace machining instructed in the laser beam machining program PRO in the three-dimensional virtual space. 
   The second operation of judging the interference of the nozzle is one of judging as to whether or not the trace machining of the workpiece is properly programmed in addition to judgment of the interference between the workpiece and the nozzle. Then, the simulation execution portion  7  gets the nozzle interference judging portion  9  to judge as to whether or not the solid model SD 2  of the nozzle interferes with the solid model SD 1  of the workpiece in Step S 6  of the simulation control program SPR. At the same time, the simulation execution portion  7  gets the trace machining propriety judging portion  10  to watch and judge whether or not an interference state between the chip model SD 4  and the solid model SD 1  of the workpiece is maintained in Step S 7  of the simulation control program SPR. 
   That is, the solid model SD 2  of the nozzle is controlled to be moved in the three-dimensional virtual space according to the laser beam machining program PRO. If there is an error in the laser beam machining program PRO and interference between the nozzle and the workpiece is instructed, the solid models SD 1 , SD 2  of the workpiece and the nozzle are interfered in the three-dimensional virtual space, thereby judging the program error by checking this interference. 
   If the interference between the solid models SD 1  and SD 2  of the workpiece and the nozzle in the three-dimensional virtual space is judged in Step S 6 , the nozzle interference control portion  9  outputs the nozzle interference signal SG 1  to the main control portion  2 . Receiving this signal, the program enters in Step S 8 , and the main control portion  2  executes error processing of informing an operator through the display portion  13  that the workpiece and the nozzle interfere with each other with the contents of the present laser beam machining program PRO. 
   The nozzle interference judging portion  7  judges the interference between the nozzle and the workpiece, and simultaneously, the trace machining propriety judging portion  10  judges whether or not the instruction of the trace machining is proper with the simulation. If the trace machining has been also instructed to a position outside the workpiece in the laser beam machining program PRO, the solid model SD 2  of the nozzle departs from the upper portion of the solid model SD 1  of the workpiece as shown in  FIG. 4  and goes to a right hand of  FIG. 4 , and at the same time, the chip model SD 4  connected through the connecting bar model SD 3  also departs from the solid model SD 1  of the workpiece, so as to release the interference state between the solid model SD 1  of the workpiece and the chip model SD 3 . 
   If the trace machining in the laser beam machining program PRO has been improperly instructed to the position outside the workpiece  20  also, the nozzle  21  is unlimitedly moved and driven in the lower hand of  FIG. 4  for catching the workpiece in an actual machining on the basis of a property of the trace machining control wherein the distance between the nozzle and the workpiece to be in the lower hand of  FIG. 4  (that is, a direction where the nozzle  21  emits laser beam) is constantly maintained, so that an inconvenient accident, such as collision between the nozzle  21  and the other mechanical portion, such as the workpiece  20  and a table of the laser beam machine, may occur. 
   Then, the trace machining propriety judging portion  10  always checks the interference between the solid model SD 1  of the workpiece and the chip model SD 4  in Step S 7  if the trace machining is instructed in the laser beam machining program PRO. When keeping the interference, the trace machining propriety judging portion  10  judges that the nozzle is moved with respect to the workpiece through the proper space GP 1  determined by the connecting bar model SD 3  in the instruction. When judging release of the interference between the solid model SD 1  of the workpiece and the chip model SD 4  in Step S 7 , that is, no interference between the solid model SD 1  of the workpiece and the chip model SD 4  as shown in  FIG. 4 , on the contrary, the nozzle is judged to lose the workpiece for continuing trace machining, and the trace machining propriety judging portion  10  outputs a predetermined trace fail signal SG 2  to the main control portion  2 . Receiving this signal, the program enters in Step S 9 , and the main control portion  2  executes error processing by informing an operator through the display portion  13  that the present instruction of the trace machining in the laser beam machining program PRO is improper, so the nozzle is moved to the position outside the workpiece with the contents of the present instruction, so that the proper trace machining is impossible. 
   An operator thus properly perceives whether or not the trace machining is properly instructed in the laser beam machining program PRO by the simulation. 
   It is not always necessary to display the connecting bar model SD 3  and the chip model SD 4  on the display portion  13  during the simulation. But, the interference between the chip model SD 4  and the solid model SD 1  of the workpice may be internally watched without displaying the connecting bar model SD 3  and the chip model SD 4  on the display portion  13 , and the trace machining propriety judging portion  10  may output the predetermined trace fail signal SG 2  to the main control portion  2  when no interference between the solid model SD 1  of the workpiece and the chip model SD 4  being judged as shown in  FIG. 4 , and receiving this signal, the main control portion  2  may inform an operator through the display portion  13  that the present instruction of the trace machining in the laser beam machining program PRO is improper, so the nozzle is moved to the position outside the workpiece with the contents of the present instruction, so that the proper trace machining is impossible. 
   Furthermore, the connecting bar model SD 3  having an optional shape can be adopted. But, preferably, the connecting bar model SD 3  has a dimensional shape different from the solid model SD 2  of the nozzle and the chip model SD 4  so as to differentiate the solid model SD 2  and the chip model SD 4  from each other when displaying the image of the simulation on the display portion  13  during the simulation. 
   The present invention has been explained on the basis of the example embodiments discussed. Although some variations have been mentioned, the embodiments which are described in the specification are illustrative and not limiting. The scope of the invention is designated by the accompanying claims and is not restricted by the descriptions of the specific embodiments. Accordingly, all the transformations and changes within the scope of the claims are to be construed as included in the scope of the present invention.