Research on the Design System of Folding Carton Based on AutoCAD (Part Two)

3.3 variable naming and coding

For carton design, the variables used for almost every carton are the length, width, height, and thickness of the carton. In the development process, use the common method in the design of folding carton structure. The length, width and height are expressed as L, B, H, and T. When writing code, variables are named in lowercase letters according to custom: l, b, h, t. For the base point of the carton diagram, Pt is used.

The system adopts the same coordinate specification method as AutoCAD: the two-dimensional plane where the screen is located is the x-y plane, and the Cartesian-plane rectangular coordinate system is adopted. The origin of the coordinate is located in the lower left corner of the screen.

According to the parametric design concept, after the carton design in Fig. 2 is completed, the user only needs to input different parameter values ​​to obtain a series of structural drawings with similar shapes and different sizes.

4 System Operation Example

For example, a general tray folding carton having a length of 100 mm, a width of 80 mm, and a height of 50 mm is to be designed, and the thickness of the cardboard is set to 1 mm, and there is no requirement for other structures.

Run the system, you can see the menu bar more than a "carton" menu, click on the menu pop-up five sub-menu, select the "disc box" sub-menu or toolbar "disc box" icon, enter the disc box drawing Module.

4.1 Box type selection

Select the “Tray” menu in the “Tray” menu or the “Tray” toolbar as shown in Figure 3, and pop up the image menu of the “Disc Enclosure” module as shown in Figure 4, and select the name of the appropriate tray-type folding tray. Or on the right side of the stereo preview (in this case, select a general disc cartridge), click the "OK" button to enter the "general disc box" in the drawing process.

4.2 Parameter input

After entering the “General Disc Cartridge” drawing program, the Disc Cartridge Parameter Design Dialog Box will pop up, as shown in Figure 5.

In the base point part on the left, you can directly input the value of vertical and horizontal coordinates in the input box, or click “Pickup Point<” to hide the dialog box. When the user selects an appropriate base point on the screen with the mouse, the dialog box will automatically pop up. Allows the user to set and modify other parameters.

The dialog box just opened shows the default value of the carton size. The user can modify the basic parameters such as the length, width, height, and the thickness of the paper according to needs (in this case, there are special parameters, such as the upper end of the carton. The size of the longitudinal direction and the height of the middle part of the carton).

During the writing process, the system fully considered the various problems that may be encountered in the user's design process and possible errors, and added error handling during the design process. For example, if the user sets the parameter value to a negative value in Figure 5, the system displays an error message at the bottom of the dialog box. The user can modify it according to the error message. After confirming the correct input, the flat development of the paper box can be output.

4.3 Cartridge Plan Drawing

After confirming that all the parameters in the dialog box in Figure 5 are appropriate, the user clicks the "OK" button and the system automatically draws a plan view of the folding carton at the user-selected base point, as shown in Figure 6. If this diagram differs from the user's needs, the user can use AutoCAD's drawing and editing functions to continue to modify the output map.

5 Conclusion

(1) The folding carton system adopts a parametric design method. The carton's length, width, height, board thickness, base point coordinates, etc. are set as the basic parameters of the carton. They are used to represent the vertices in the structure chart, and then connected with a suitable line type to draw a carton structure diagram. The parameters are set to different values ​​and some structural drawings with similar shapes and different sizes can be obtained.

(2) The system uses AutoCAD as a platform for secondary development, mainly based on box-type library technology, combined with partial box library technology, which not only realizes the rapid and accurate drawing of carton structure floor plan, but also increases the number of box type, which greatly saves Design costs and design time.

(3) Taking into account the trend of packaging CAD/CAM integration and digital work flow, it is required that the folding carton structure diagram system improve the interface with packaging CAM equipment in the future development, and provide conditions for its wide application in the packaging industry.

The grim situation of international competition requires that we must develop a packaging CAD system with independent intellectual property rights, effectively improve the production efficiency of our country's packaging industry and the competitiveness of enterprises, and make our packaging companies invincible.

Author: Rui Xia segment, into Shijie, Sun Cheng
1. Zhengzhou University 2. Qingdao University of Science and Technology 3. Tianjin University of Science and Technology,

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Source: Packaging Engineering