Sunday, August 22, 2010

How to use Unigraphics NX4 Motion Simulation in Timing Diagram Design Process - Part 4

In [How to use Unigraphics NX4 Motion Simulation in Timing Diagram Design Process - Part 3], we've already set all the links and joints with drivers for links included in Motion Simulation using UG NX4 Motion simulation module. But the driver functions for both indexing mill and punch die are not as per the timing diagram yet. Now it's time to set them according to the timing diagram and see the simulation results in 3D movement.

1. Select "Graphing" command. The graphing command will export the value of displacement of all driving joints (have "driver"). By default, the displacement values of other driven joints will not be exported.

2. Select "Spreadsheet". This is to specify that we need to get the data in excel.
3. Click Ok to confirm.

UG NX4 will then open excel spreadsheet and put the data as shown in the above picture. You can see that the displacement of drv J_Mill and drv J_Die are linear as we specified earlier. Therefore, we will modify it by replacing all of these values with our preferred timing diagram.

4. Save the excel file as new name. This is to have another excel for formula entering. I use to try putting all formula in the original excel file exported from UG, but somehow with Excel 2007, it has an error (no problem with excel 2003). So I often make another excel file with all formula, and paste special only "values" into the original excel file.
5. Click Save to confirm new file name.

6. Enter formula into the column of drv J_Mill, revoulute
As we know from this example, the indexing mill has 16 heads (positions). So the angular displacement of the indexing mill in each cycle is 360/16 = 22.5 degress. So this is our hm. You can see how I enter the formula of cycloid in the above picture.

7. Open the excel file from [Polynomial Cam Function (Fifth-degree polynomial Example) - Part 4]. Copy the displacement values from column h(mm) as shown above.
It contains several displacement cam profiles such as fifth-degree polynomial and linear. It's too difficult to enter all of these formula in the excel file that we created in step 5. The easiest way is just copy it.

8. Paste special > Values into the column of drv J_Die, slider. Make sure that you paste only values, otherwise you may have the wrong values. Now we have all required data in the new file. It's time to paste them back to the original excel file exported from UG NX4 Motion Simulation Module.

9. Select all cells by clicking at the top-left corner of excel and click Copy.

10. Now switch back to original excel file exported from UG. The file name will be something like "Worksheet in motion_1" as shown above. Then select cell A1 and paste all value replacing all original values. After that Click at the top-left of excel software (Microsoft Office logo) and click "Update" (not shown in the above picture). This is to update values of this table into UG.

11. Switch windows back to UG NX4 Motion Simulation Environment. Then select "Spreadsheet Run".

12. There will be a pop-up windows as shown above. Select "Attached". This is to let UG uses data in the attached excel file (Attached excel file is the file "Worksheet in motion_1").

13. Click at the "Loop" play mode to see the motion simulation in several cycles.
14. Click "Play" button to start simulation.

You will see the results of timing timing diagram calculation in 3D motion. You can then see any interference that may exist, change the timing diagram, paste the values back again and see the simulation results until you satisfy with the results.

Quite a long post already. I'll put the video clip of the motion simulation result in the next post.

Further reading:

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