MODIFICATION THE PARAMETERS OF THE SHOE LAST USING CRISPIN DYNAMICS - LASTMAKER

In this paper we present methods for creating and modification a shoe last using the application LastMaker. The last type can also be changed to a type that allows the entire last surface to be used for creating the design of footwear product using the module of Crispin Dynamics CAD SUITE product.

INTRODUCTION

Computer-aided manufacturing (CAM) system is widely used in shoe last manufacturing, which has realized the digitalization of the machining program from the free-form surface detection method to produce numerical control (NC) requirement by the shoe last CAM software system automatically. In this type of free-form surface NC machining, it is common to digitalize the shape of the entity through the three dimensional (3D) measuring system after obtaining the scanning data and the process of the natural pattern; the next step is the rebuilding of the surface model. There are two steps involved in remodeling the discrete data, which has become an entity shape in recent years: the first is the sequencing of the measurement data, the second is the generating for creating the design.  In this work on discuses for measurement data technique and creating format solid corps of the shoe last technique.

1. Registration the format of the shoe last

After digitize the surface outside, inside and optional foot and the optional points result the shape of the last, see figure 1.

The shape on save in fishier with extension .dat. This can be imported and process to become a fishier with extension .v3e for use in Last Maker for analyzing and adjusted the shape of the shoe last.

2. Last Information

The shape on save in fishier with extension .dat. This can be imported and process to become a fishier with extension .v3e for use in Last Maker for analyzing and adjusted the shape of the shoe last. 

Information about the last can be displayed in a dialog box using the menu:

Information > Last Info

function from the main menu. Once the Last Info option is selected, a dialog is displayed and the system prompts you to specify the Operator name and displays information over the current last.

The field of the window are:

File name: file name of the current last with its destination path

Operator: Name of the operator

Gender: Current gender (or grading system) assigned to the last for grading purposes

Size index: The corresponding size index number in the gender being used

Width index: The corresponding size index number in the gender being used

Toe Spring: System-calculated distance from the toe point to the ground when the last is in standard orientation

Heel Height: Operator-entered value for the heel height (or pitch)

If any of the above last information is changed in the program (e.g. the toe spring is changed), the information displayed in the Last Info option is automatically changed accordingly.

3. Adjusting Last Parameter

Using the menu: Edit>Last>Adjust on visualized and modified the parameters for shoe last. This is centralized in Table no 1. Each parameters on modified using a specify window.

Table 1

4. Comparing and analyzing the new Shoe Lasts

Comparing function brings possibility to compare two different lasts; the result can be measured or displayed as a solid lasts. First open the last you want to compare; it is possible to have open a number of lasts and any of them can be compared. You can easily check them if you select cascade view using function: Window > Cascade

Now from the main menu select: Verify > Compare > Alignment and the list of all the open files names is bringing up. Select desired last and the last is opened and positioned similary as the original last. Last Positioning: The next steps are the various translations and rotations required in order to properly position the toe with the back part.

5. Swapping Toes

Toe swapping function permits to bring toes from different lasts and positioning. First you can cut the last and keep the back part selecting option: Toe Swap > Cut Back > Cut Bottom. This option will cut the whole toe part of the toe. It is also possible to cut the toe while the bottom is entirely kept, which can facilitate better positioning of the back part and a to

To use this possibility select:

Toe Swap > Cut Back > Keep Bottom

Now you can open another lasts and cut them to keep only their toes. To provide this option select function:

Toe Swap > Cut Toe and the active last will be cut so that the toe is kept.

In Fig. 5 is modified the toe of the shoe last using menus of Last Maker.

6. Blending the section

After swapping the toe of the shoe last on blending the section for creating a new last.

7. Proportional Grading

Select the last you want to grade. From the main menu select:

Grade > Proportional

and select the requested .GRF file.

In the following dialog box select Gender you want use for grading and size and width parameters of the current last.

Once defined click OK and the system will prompts you to select the same .GRF file once again. Now in similar box the parameters of the Original (current) last are already displayed with selected gender. In this dialog select all the Sizes and all the widths to be graded. (Use the standard windows selection functions: Shift + left mouse click, Ctrl + left mouse click).

The system will grade all the combinations of sizes and widths as defined.

All the graded lasts will be graded and place into separate files so they can be easily saved separately. For better control of the graded files use the Window > Cascade function.

8. Last Surface Flattening

The surface of the last can be flattened, so that the flatten forms will be created. These forms can afterwards be exported to 2D system for engineering of the upper components. It is recommended to use the V3E last data structure for the flatten function. This ensures, that the last is flattened properly. To flatten the current last select from the main menu: Verify > Flatten and the surface of the last is flattened. The inside, outside and the bottom of the last is flattened and all these flattened forms are displayed in the flatten window. There are 3 windows 2D with the flattened forms and one window with the original 3D last.

Conclusion

Models for surface modeling of free-form surface and massive data points are becoming an important feature in commercial computer aided design/computer-aided manufacturing software. However, there are many problems to be solved in this area, especially for closed free-form surface modeling. This article presents an effective method for cloud data closed surface modeling from asynchronous profile modeling measurement.

Acknowledgements: The paper is within the research activities of the CNMP programme INOSOC and BIOTECH, ctr. 106/006 and 41064/2007.

REFERENCES

Bend Itski, A. A. (2003), A mathematical model of a measuring multimicrophone acoustic antenna, Measurement Techniques, Vol. 46, No. 5.

Driscu M., Mihai, A. (2008), Shoes Design Using the Crispin Dynamics CAD Suite Engineer System, Ed. Performantica, Iasi.

Dubrovin, B. A., Novikov, S. P., Fomenko, A. T., (2001), Modern Geometry: Methods and Applications [in Russian], Editorial URSS, Moscow.