Learning Forum

[Tnancy]

Hey, I'm confused. Do we have to increase the velocity of the object in the explicit analysis? For a milling simulation, our bulk's velocity is 50 mm/s going to endmill and endmill have 16000 rpm. So if I give 50 mm/s velocity to bulk I can't see any movement with 0.001 end time. Because displacement is 0.05mm.On the other hand, I can not increase the end time. Its take weeks or months. (for example, end time is 1s for 50 mm displacement).If I increase velocity(5000 mm/s with 0.001s end time for 5 mm displacement), will the results really be accurate for my main simulation? Is there any other way for real end time simulation?

 
 


 

[peteroznewman]

You understand Explicit Dynamics model duration perfectly.

No, you can't "speed up" the velocity, that would change the physics of what you are simulating. If you increased the feed velocity 10 times, then the chip would be 10 times thicker. That is not the same problem.  If you sped up the feed and the tool velocity 100 times, now there is a huge rotational velocity that is not the same.

Ask yourself what is different in the last 10 mm compared with the first 10 mm. What new information will you obtain in the last 10 mm of travel that you didn't already see in the first 10 mm of travel?  The key to Explicit Dynamics models is to define a problem that only lasts milliseconds.

[Tnancy]

Thank you, Peter. I understood better. Explicit dynamics analysis focus on the instantaneous problem. Well for a longwinded simulation what kind analysis Should I prefer?

 

[peteroznewman]

You still want Explicit Dyanamics, you just have to clearly define what you want the model to predict.  If you create a workpiece that has a cut that is a full diameter of the tool for half the length of the workpiece, pre-cut if you will, and you have the tool touching the end of that cut, in just a few turns of the tool, you will be cutting as if it had been cutting all that way.  One turn of the tool is 3.75 ms, so a few turns is a feasible end-time.