Thank you very much for your answers. They are very helpful!

>>What is controlling the timestep? I assume the SPG particles were, but maybe it is the deformable body of the drill? The first step would be to make sure you have a uniform size mesh and you don't have small elements here and there. If you have small elements, try to remesh to get a more uniform mesh. The small elements will control the timestep.

all is clear, thank you

>>What are you interested in the drill? Could you model the drill as fully rigid and calculate the wear using the contact?

This is one of the best pieces of advice right now. I'd like to do that too. Using CONTACT_ADD_WEAR contact and calculating wear. But will it be enough? This will be wear in the contact and not on the drill.

My task is this: there are attachments on the drill, my goal is to examine these attachments for wear and temperature after drilling a certain interval. When we model drills, we distribute the nozzles on its surface and do not immediately understand which of the nozzles will be loaded more heavily and which less, our goal is for all the nozzles to be loaded with sharp rock.

Using the calculation, I want to find out which nozzles have worn out and heated up faster, after which I will change their location and size and run the calculation, etc.

Tell me, will it be enough to examine the contact for wear using attachments in the form of a rigid body? That would be great! Will I be able to track the temperature on the surface of the nozzles?

>> We usually increase the density of the SPG material only, which is initially at rest. We have to be careful when increasing the density of the deformable components of the drill. This will increase the kinetic energy of the system and may affect the results. You can do some tests and change the density and see if it affects the results you are interested in.

all is clear, thank you

>> It is a best practice to extend the *DEFINE_CURVE beyond the termination time. Here, the value is constant and it does not make any difference if the last point on the curve is 10 000, 1000, or 100, or even 10 ms. As long as the last point on the curve is beyond the termination time of 7.5ms. 

If you don't extend the curve beyond 7.5ms, you might run into issues. You can try it. Because, the LS-DYNA calculation will almost always go beyond the termination time. How far beyond the termination time depends on the timestep. And, for the calculation happening beyond the termination time, the LS-DYNA solver will not know what value to use and it will be reset to zero.

Now everything is clear to me.

Thank you. My tool rotates at 26 rad/s and the feed speed is 40 mm/s. I want to test my speeds on this task from LSTK. Can I leave the solution time at 7.5, set the rotation speed to 26 (at a time of 10,000), and set the feed to 40 (at a time of 10,000). Will this be logical for the program?