JPH042432A - Assembly order determination - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for determining the order of assembling parts when obtaining a product by assembling parts in sequence, and particularly relates to a method for determining the assembly order of parts when obtaining a product by sequentially assembling parts, and in particular, data on pre-assembly relationships of parts from the product structure. Furthermore, the present invention relates to an assembly order determining method in which the assembly order of parts is determined in an interactive manner.

[Prior Art] Conventionally, as a method for automatically performing assembly process design, for example, as described in Japanese Patent Application Laid-Open No. 63-288683,
The assembly order is automatically determined based on the rule that the parts located at the bottom are assembled first, and then the parts located at the top are placed above them based on the layout information of the sample product.

[Problems to be Solved by the Invention] However, when considering general assembly, it is almost impossible to imagine a product that can be assembled only by specific work such as the above-mentioned prior art, ie, simple building block work. In general parts assembly work, parts are connected to each other using methods such as screw tightening, press-fitting, and gluing. When determining the assembly order, it is necessary to find an assembly order that satisfies such a complicated assembly precedence relationship and that is easy to assemble or requires fewer assembly steps.

A first object of the present invention is to provide an assembly order determining method that can easily and quickly determine the assembly order of each component that constitutes a product in an interactive manner.

In addition to the first object, a second object of the present invention is to provide an assembly order determining method that allows partial assembly.

In addition to the second object, a third object of the present invention is to provide an assembly order determining method that enables simultaneous assembly of parts.

A fourth object of the present invention, in addition to the third object, is to provide an assembly order determining method that can determine the assembly order of parts with good man-machine interface.

A fifth object of the present invention, in addition to the fourth object, is to provide an assembly order determining method that makes it easy to grasp the position of each component in the entire product and to easily specify and select the components.

A sixth object of the present invention, in addition to the fifth object, is to provide an assembly order determining method that allows it to be easily known whether the assembly order of each component has already been determined or whether it can be selected next.

In addition to the sixth object, a seventh object of the present invention is to provide an assembly order determining method that can determine the assembly order of parts while easily grasping the position of each component in the entire product.

[Means for Solving the Problems] The first purpose is to specify on a parts display screen which parts are to be assembled first, based on product structure data that indicates the coupling relationships between multiple parts that make up a product. By doing this, after generating the product-specific assembly precedence relation data for restricting the parts assembly order, the precedence relation data was treated as updatable every time a part to be assembled was specified on the parts display screen. As a result, this is achieved by determining the assembly order of the parts while displaying the parts that can be assembled next on the generated upper parts display screen.

The second purpose is to improve assembly precedence relationships for groups by instructing the parts to be assembled first in product structure data for groups when multiple parts constituting a product are divided into two or more groups. This is achieved by generating data, and the preceding relationship data is generated as product-based assembly preceding relationship data.

The third purpose is to select a part that can be assembled next on the parts display screen when there are two or more parts that can be assembled next, which are generated as a result of processing the assembly precedent relationship data as updatable. This is achieved by determining the assembly order of parts while allowing simultaneous assembly.

The fourth objective is achieved by displaying necessary guidance for prompting the next operation on the display screen according to the progress of the assembly order determination process.

The fifth purpose is to display a three-dimensional model of the product on the display screen based on part-corresponding shape data stored in advance along with product structure data, and to indicate the desired part display position. Or it can be achieved by making choices.

The sixth purpose is to display each part displayed as a 3D model on the display screen according to parts whose assembly order has already been determined, parts that can be assembled next, and parts whose assembly order has not been determined. This is achieved by making the above display modes different from each other.

The seventh purpose is that the three-dimensional model of the product displayed on the display screen can be displayed in any manner, including the overall display size, display position, posture, and viewpoint direction, depending on instructions from the outside. This is achieved by allowing changes to be made.

[Function] Depending on the product structure data stored in advance, the connection relationships between the parts can be known when assembling each part.
When the first part to be assembled is specified, product-based assembly precedent relationship data is automatically generated to limit the parts assembly order, and thereafter, the precedent relationship data is updated every time a part to be assembled is specified. If it is processed as possible, the next assemblable parts will be automatically generated in sequence, and the assembly order of the parts can be determined based on this generation order. If multiple parts that make up a product are divided into two or more groups for partial assembly,
The assembly precedent relationship data is generated based on group-based product structure data. That is, by specifying the parts to be assembled first for the product structure data corresponding to the group, the assembly precedent relationship data corresponding to the group is first generated, and then the preceding relationship data is generated as the assembly precedent relationship data corresponding to the product. It is best to integrate them into one if possible. If there are two or more parts that can be assembled next, which are generated as a result of processing the assembly precedent relationship data as updatable, it is possible to assemble those parts simultaneously, but it is possible to assemble them on the parts display screen. By selecting suitable parts, the assembly order of the parts can be determined while allowing simultaneous assembly. When determining the assembly order of parts, if necessary guidance to prompt the next operation is displayed on the display screen depending on the progress of the assembly order determination process, by performing the operation according to the guidance, The assembly order determination process can be performed smoothly.

In addition, when a 3D model of a product is displayed on the display screen based on part-corresponding shape data that is stored in advance along with product structure data, the position and shape of each part can be seen with the -eye, and the display position of the part can be determined with the eye. By giving instructions, it becomes easy to specify or select parts. At that time, the display mode of each part displayed as a 3D model on the display screen changes depending on the parts whose assembly order has already been determined, the parts that can be assembled next, and the parts whose assembly order has not been determined. If they are different, the assembly order determination status for each component can be immediately known. If the 3D model of the product or its overall size, display position, posture, viewpoint direction, etc. can be changed arbitrarily due to instructions from outside, understand the 3D model in more detail. It is possible to do so.

[Example] The present invention will be explained below with reference to FIGS. 1 to 13.

First, the assembly order determining system according to the present invention will be described. FIG. 1 shows an example of its block configuration. Before explaining the system configuration, we will first explain the product structure data and assembly precedent relationship data as data to be processed in the system. Consider assembling a model airplane. As shown, the model airplane is 8
It is composed of individual parts P, -P8, and the coupling relationships among these parts P, -P are shown as product structure data in FIG. 2(b). The product structure data is obtained by taking part numbers 1 to 8 of parts P and ~P8 in rows and columns, and displaying a circle mark at the intersection of the part numbers of parts that have a connection relationship with each other. This shows the connection relationship between P8s. Based on this product structure data, assembly precedent relationship data is created, which will be described later.

Now, returning to Fig. 1 and explaining the system configuration, the system overview consists of a database 1 that stores product structure data, an assembly precedence relation generation device that creates assembly precedence relation data from the product structure data. 2,
It is constructed to include a data display device 3 for displaying the product structure data and assembly precedence relationship data, and a data input device 4 for selecting parts.

In order to determine the assembly order, first, assembly precedence relation data is created from product structure data, and then the assembly order is determined in an interactive manner using the assembly precedence relation data.

As preprocessing for determining the assembly precedence relationship, first, product structure data is sent from the database 1 to the assembly precedence relationship generation device 2 and the data display device 3, and the data display device 3 generates a part number list based on the data. At the same time, input of the parts to be assembled first is requested on the display screen. Figure 4(a) shows the display screen at that time, but if the data corresponding to the part number and part name is stored in the database 1 as shown in Figure 4(c), A display as shown in (b) is also possible. When the user inputs the part to be assembled first from the data input device 4 while the parts number list is displayed, the assembly precedence relation generation device 2 generates assembly precedence relation data based on the part selection result in the following steps. is automatically generated.

That is, assuming that part P is selected as the first part to be assembled, and to explain using FIG. All O marks in the line corresponding to , are deleted,
In addition, all the ○ marks in the column corresponding to the part P are changed to ◎ marks, so that the processing result shown in FIG. 3(b) is obtained. As you can see, the data affected by this processing is part P2. Pt, Ps
These are the objects obtained for the next processing. For each of the affected parts P, , P, , Ps, the same processing as described above is performed. That is, in the product structure data shown in FIG. 3(b), part P2. The Q marks in the rows corresponding to each of P, , Pg are all erased, and the parts P2. P? ,
All O marks in the column corresponding to each Ps are changed to ◎ marks. As a result of the above processing, Fig. 3(c)
The product structure data shown in is generated. As you can see, parts P2, P? , P * The parts affected by the processing are P a', P 4,
These are obtained as the next processing targets, and the same processing as described above is performed on each of the affected parts P3 and P4. Thereafter, by repeating the same process, the product structure data changes from the state shown in Fig. 3(c) to the state shown in Fig. 3(d).
), from the state shown in FIG. 3(d) to the state shown in FIG.
The state is updated to the state shown in e), but once the product structure data shown in Figure 3(e) is obtained, there are no longer any affected parts, so the series of processes is terminated. It becomes. The product structure data shown in FIG. 3(e) as a result of this series of final processing is obtained as the previously described assembly precedent relationship data. By the way, in the assembly precedent relationship data, ◎ is placed at the intersection of the row and column.
If there is a mark, it indicates that the part with the row number can only be assembled after the part with the column number. For example, the mark ◎ in the second row and first column indicates that the part P2 is assembled after the part P1 is assembled.

As described above, the assembly precedence relation data has been obtained, and the procedure for determining the assembly order using this assembly precedence relation data is as follows.

That is, first, the assembly precedent relationship data is searched for lines marked with ◎ or that do not exist. Taking the example of the assembly precedence relationship data shown in Fig. 5(a) (same as the data shown in Fig. 3(e)), only the row of the part P selected to be assembled first is marked with ◎. It is a line that does not work. Therefore, if you select part P1 as the first part to be assembled and then delete all ◎ marks in the column corresponding to part P in the assembly precedent relationship data, the deletion result will show that the part After P, there are parts Px,
P7. It is known that Ps can be newly assembled. The result of the processing at this time, that is, the parts (group) that can be assembled next, are displayed on the data display device 3, and display examples are shown in FIGS. 5(b) and 5(c), respectively. . These display examples correspond to the displays shown in Figures 4(a) and (b), but as shown in the figure, the parts are displayed as shaded parts or as the parts that can be assembled next. It has become. Thereafter, the user selects one of the assemblable parts displayed using the data input device 4.
New assemblable parts can be obtained by selecting one part or by performing the above-described processing in the assembly precedence relation generating device 2 based on the part selection result. Every time parts that can be assembled are obtained, one can be selected from among them and the same process can be performed. Once the assembly order for all parts has been determined,
The series of assembly order determination processing is stopped.

As described above, since the assembly precedence relationship can be generated intentionally and the next assembleable part can be clearly shown to the user, the time required for assembly process design can be significantly reduced. be.

By the way, the above example shows a method for determining the assembly order when assembling a product without subassembling it, but in actual assembly work, a product is generally assembled from several subassemblies. The reality is that Hereinafter, a method for determining the assembly order in a case including partial assembly will be described. Here, a case as shown in FIG. 6 is assumed as an example of an assembly work including partial assembly. As shown in the figure, the subassembly worker and subassembly 2 can be assembled independently of each other, and finally the subassembly (
Parts P 1. P IP 4. P7. By combining the subassembly (subassembly consisting of parts Pg, Ps and Ps) 1 and subassembly 2 (subassembly consisting of parts Pg, Ps and Ps), a model airplane as a target product can be obtained.

As a method for instructing partial assembly, Fig. 7(a) to
Consider an example of a display screen on the data display device 3 as shown in (c). First, in the example display screen shown in FIG. 7(a), the functions of each command menu on the right side are as follows.

Part assembly start Command menu for instructing the start of registering parts to a two-part assembly. Konomenu is a data input device (
For example, if selected by mouse) 4, then FIG.
A group number input instruction message as shown in is displayed. If a subassembly number is input in this state, registration of parts to the subassembly represented by the input number is started.

Registration of parts to the subassembly is performed by sequentially selecting each part displayed on the left side of the display screen example using the data input device 4.

End subassembly: Command menu for ending the registration of parts to the subassembly started in the subassembly start menu. FIG. 7(c) shows an example of the display screen at the time when the registration of parts to the partial assembler is completed. At the point when the division is instructed to end, the second
Using the product structure data shown in Figure (b), it is checked whether subassembly is possible. For example, in the display screen example shown in Fig. 7(C), in the product structure data shown in Fig. 2(b), ■ under the main wing (1) is in front of the fuselage (2).
, the strut cloth (7) and the left strut (8) are in a connection relationship, ■ The right strut (7) or the left strut (8) are connected to the top of the main wing (4), so partial assembly is possible. It turns out that there is something.

Add part: Command menu for instructing to add a part to an existing subassembly Add part: Command menu for instructing to add all parts included in another subassembly to an existing subassembly Part Delete: Command menu subassembly for deleting parts from an existing subassembly - Delete: Command menu subassembly for deleting an existing subassembly Cancel 2. To interrupt each of the above processes and return to the state before entering each command. Command menu display: Exit command menu for displaying the specified subassembly number and the names of the parts included in it. Two command menus for terminating the partial assembly instruction operation. A command menu for more than one command, by selective operations on parts. The assembly precedence relationship data creation procedure when the subassembly 12 shown in FIG. 6 is instructed will be described below with reference to FIG.

That is, in the assembly precedent relation generating device 2, the data input device 4
First, partial product structure data is created for each of subassemblies 1 and 2 based on the subassembly data from . Thereafter, the first assembled parts for each of subassemblies 1 and 2 are determined in a manner similar to that shown in FIG. 4 in the previous example. The assembly precedent relationship generating device 4 creates partial assembly precedent relationship data as explained in FIG. 3 based on the partial product structure data and the initial assembly part data for each of the partial assemblies 1. By combining these into one, assembly precedence relationship data regarding partial assemblies 1 and 2 is created. This pre-assembly related data is clearly shown in Figure 3(e).
It can be seen that there are differences as shown in the figure. Therefore, after that, the assembly order of the product including subassembly 1.2 can be determined by the same procedure as explained in FIG. 5.

By the way, in the first example, the initial component selection when determining the assembly order and further the component selection in the second and subsequent steps are performed by display/input means as shown in FIGS. 4 and 5. It is becoming more and more popular.

However, as is clear from these diagrams, if only the part numbers and names are displayed, it is difficult to immediately and intuitively understand how the product is structured by the organic relationships between the parts. ing. Because of this,
When attempting to determine the assembly order in an interactive format, in addition to these displays, it is necessary to refer to drawings that can be understood at a glance to determine the product structure, making the assembly order determination task extremely troublesome. It has become a thing. In order to solve such problems, the shape data of each part name is stored in the database 1 in advance, and the shape data is used to display the entire shape or partial shape of the product. It is conceivable that the assembly order can be determined by selecting the following. Figure 9 is the 4th
This figure shows an example of a display for initial parts selection based on a three-dimensional model of a product, corresponding to the figure. As shown in FIG. 9(a), the data display device 3 uses the shape data of the parts.
A three-dimensional model of the product (model airplane) is displayed above, and the user is asked to select the parts to be assembled first. When a three-dimensional model of a product is displayed, parts can generally be selected by using a data input device (for example, a mouse) to pick the part to be selected on the display screen. The parts selected in this way can be easily distinguished from other parts by changing their display color, brightness, etc., as shown in FIG. 9(b). It is.

Furthermore, Fig. 1O shows a display example for selecting parts in the second and subsequent steps corresponding to Fig. 5. In the display example, the definitions of the black, shaded, and white parts are as follows. It seems like.

Parts whose assembly order is determined by the two blacked out parts.

Shaded parts: parts that can be assembled next.

White areas: Parts whose assembly order has not been determined.

The functions of each command menu on the right side of the display example are as follows.

Previous: Displays the previous assembly order determination status.

Next: Display of the next assembly order determination state.

First: Display of the initial assembly order determination state.

Last: Displays the final assembly order determination status determined up to now.

End: End of assembly order determination.

The display example shown in FIG. 10(a) shows a state in which part P1 is selected as the first part to be assembled, and as a result, part P is displayed as a blackened part, and part P1 is selected as the first part to be assembled.
2. P, , P, are shaded parts, and the remaining parts ps, p4. p,, p, are displayed as white areas. FIG. 10(b) also shows a case where part P is selected as the next part to be assembled in the display state shown in FIG. 1θ(a). As shown in FIG. 10(b), part P1. If, for example, a "previous" command is input at the stage where the assembly order has been determined up to P*, the display state returns to FIG. At the stage where “
If the “next” command is input, the display state will change to Fig. 10 (b).
). In addition, apart from the above, the 10th
As shown in Figure (b), if the "first" command is input at the stage when the assembly order of parts P, P2 has been determined,
The display state returns to Fig. 9(a), and the display state returns to Fig. 9(a).
), if the "last" command is input, the display state is returned to the state shown in FIG. 10(b). Also, if the part P as shown in Fig. 1θ (b).

At the stage where the assembly order up to P has been determined (that is, at the stage where the parts assembly order 2P, → P2 has been determined), the display state is returned to FIG. 10(a) using the "Previous" command, and in this state. If a new part, for example part P7, is selected, the previously determined part assembly order: P, →P2
is canceled, and the process continues assuming that the parts assembly order: P, →P7 has been newly determined.

As mentioned above, ■Displaying a 3D model based on product part shape data, ■Determining the assembly order of each part, then displaying colors depending on whether it is possible to assemble or the assembly order has not been determined, ■Using the command menu By making it possible to display an arbitrary state within the determined order and re-execute the order determination from the arbitrary state, the usability of the interactive assembly order determination system is improved, and as a result, the order determination system is improved. The number of man-hours required for this can be significantly reduced.

In the above example, the 3D model of the product could only be displayed from a fixed state and direction, but in addition to the command menu such as "previous" mentioned above, there are also command menus such as the one shown in Figure 11. By providing a new command menu such as "enlarge", the three-dimensional model can be easily manipulated, further improving usability. By the way, the functions of the newly provided command menu can be briefly explained as follows.

<Lower command menu> Enlarge: Enlarge the entire displayed area on the display screen.

Reduction: Reduction of the entire display area on the display screen.

Movement: Parallel/rotational movement of the entire display area on the display screen.

Viewpoint: Change the viewpoint of the entire display area on the display screen.

Display: Switch display of completed product drawing/assembly drawing.

Home: Return changes such as enlargement, reduction, movement, and viewpoint to the initial state.

Command menu on the right side> Part selection Instructs the target part to perform seven rotations, etc. on two parts individually.

Movement: Parallel movement of the parts specified in “Part Selection”.

Rotation: Rotation movement of the part specified in "Part selection".

Home: Returns changes such as movement and rotation of parts specified in “Part Selection” to their initial state.

Connection: Connect any parts and use the above “move”
When performing “rotation” operations, make sure that the objects move in one block.

Detachment: Release the above connection between any parts.

Reset: Release the above connection between all parts.

By the way, on each side described above, the assembly order is determined by arbitrarily selecting one part from a group of parts that can be assembled next, but in actual assembly, Assembling is often performed in multiple processes at the same time. Now, an explanation will be given of an assembly order determining method in which simultaneous assembly of a plurality of steps can be instructed. FIG. 12 shows an example of a display on the data display device 3 in which this method can be instructed. In FIG. 12, two more command menus are added to the command menu shown in FIG. 11. These command menus have the following functions.

Start simultaneous assembly: Start instructing parts to be assembled simultaneously.

Simultaneous assembly end: End instructions for parts to be simultaneously assembled.

The parts groups for which simultaneous assembly can be instructed are the parts groups indicated by hatching in FIG. 12.

Further, instructions for simultaneous assembly are given in the following steps.

That is, first, with the command menu "Start simultaneous assembly" selected, the shaded parts on the display screen are selected by picking the displayed parts, and then the simultaneous assembly is started by selecting the command menu "End simultaneous assembly". instructions are to be given.

Now, the assembly order determined by the various methods described above is
Obviously, this will have an impact on the selection of assembly machines to perform each assembly process. Here, the relationship between assembly order and machine selection will be explained using FIG. 13.

For example, suppose there are three machines (M s , M 2.M s ) capable of assembling each part of a model airplane, and the parts are P 1. Pt, P1. P7.
Assume that the assembly order up to P s has been determined. First, when the assembly order is determined by a method that does not include simultaneous assembly, for example, the parts assembly order is P, -P2-P7-P,
-P.

The order will be determined as follows. For each assembly process, machines M, , M2. If you assign M3,
For example, the layouts shown in FIGS. 13(a) and 13(b) are modes.

However, as shown in FIG. 13(c), P, →P
After the parts P3.2 are assembled, the parts P3.2 are assembled. Assuming that the order is determined to assemble P7P8 at the same time, all machines M
1. M 2 and M a will be used.

Therefore, in selecting the machine to be used after determining the assembly order,
In order to take into account the effects of simultaneous assembly as described above, assembly order data must be in a format that can represent simultaneous assembly. For example, if we take the assembly order shown in FIG. 13(C) as an example, the output of determining the assembly order is:
Simultaneous assembly may be expressed in a format as shown in FIG. 13(d).

[Effects of the Invention] As explained above, in the case of claim 1, there is no need to consider the assembly precedence relationship while referring to separately prepared drawings, etc., and the assembly order of each part constituting the product can be determined in an interactive manner. can be determined easily and quickly. Furthermore, according to claim 2.3, partial assembly and simultaneous assembly are possible, and furthermore, according to claim 4, the assembly order of parts can be determined with good man-machine interface. .

Furthermore, according to claim 5, the order of assembling parts can be determined while easily understanding the position of each part in the entire product and making it easy to instruct and select parts. In the case according to claim 6, it is immediately and easily known whether the assembly order of each component has already been determined and whether it can be selected next, and in the case according to claim 7, the position of each component in the entire product can be easily known. can be understood more easily.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a block configuration of an example of the assembly order determination system according to the present invention, and FIGS. 2(a) and 2(b) show a model airplane as an example of a product to be assembled and its product structure data. Figures 3(a) to 3(e) are diagrams showing an example of a procedure for generating assembly precedent relationship data from the product structure data, and Figures 4(a) to (c) are diagrams showing steps for determining assembly precedent relationships. Figures 5(a) to 5(c) are diagrams for explaining an example of the selection input procedure for assembly parts in the first assembly process as pre-processing for
) is a diagram for explaining how the assembly order is determined using assembly precedence relation data, and the procedure thereof; FIG. 6 is a diagram showing a case where a model airplane is assembled including partial assembly; and FIG. Figures (a) to (c) are diagrams showing examples of display screens for instructing partial assembly, Figure 8 is a diagram showing an example of an assembly precedence relationship data generation procedure including partial assembly, and Figure 9 (a).
, (b) is a diagram for explaining an example of an input procedure for selecting assembly parts in the first assembly process using graphics;
10(a) and 10(b) are diagrams for explaining an example of an assembly order determination procedure using graphics, and FIG. 11 is an assembly order using graphics capable of various displays. FIG. 12 is a diagram for explaining an example of the determination procedure.
Figure 13 showing an example of a display screen when instructing simultaneous assembly.
Figures (a) to (d) are diagrams for explaining the relationship between the assembly order and the selection of machines used for assembly.

Claims (1)

[Claims] 1. By specifying the part to be assembled first on a parts display screen with respect to product structure data that is stored in advance and indicates the coupling relationship between a plurality of parts constituting the product. , After generating the product-specific assembly precedent relationship data for restricting the parts assembly order, the following results are generated as a result of processing the preceding relationship data as updatable each time a part to be assembled is specified on the parts display screen. An assembly order determining method that determines the assembly order of parts while displaying the generated parts on a parts display screen that can be assembled. 2. Multiple parts that make up the product to be partially assembled are 2.
If the product is divided into groups or more, the assembly precedence relation data corresponding to the group is generated by specifying the parts to be assembled first for the product structure data corresponding to the group, and the precedence relation data is the assembly precedence relation data corresponding to the product. It was created so that it was integrated into one data so that it could be generated as data.
The assembly order determining method according to claim 1. 3. If there are two or more parts that can be assembled next, which are generated as a result of processing the assembly precedent relationship data as updatable, simultaneous assembly is allowed by selecting the parts that can be assembled on the parts display screen. 3. The assembly order determining method according to claim 1, wherein the assembly order of the parts is determined while the parts are assembled. 4. The assembly order according to any one of claims 1 to 3, wherein necessary guidance for prompting the next operation is displayed on the display screen according to the progress state of the assembly order determination process. How to decide. 5. By displaying a three-dimensional model of the product on the display screen based on the part-corresponding shape data stored in advance along with the product structure data, and instructing the display position of the part,
5. The assembly order determining method according to claim 1, wherein parts are designated or selected. 6. Depending on the parts whose assembly order has already been determined, parts that can be assembled next, and parts whose assembly order has not been determined, 3 will be displayed on the display screen.
6. The assembly order determining method according to claim 5, wherein each of the parts displayed as a dimensional model is displayed in a different manner on the display. 7. The display mode of the 3D model of the product displayed on the display screen, including the overall display size, display position, posture, and viewpoint direction, can be changed arbitrarily by external instructions. 7. The assembly order determining method according to claim 5, wherein: