Hi, how are you kalman?
There's a free software on https://www.microchip.com/ it's a simulator for robots, I downloaded it before, and read about it, and I think it is good one, although i never use it before
You use it, and tell us
I personaly use the Fanuc simulation software for Fanuc robots.
It works very well since it's not only a simulator, but it's a real translate of a complete robot controler to run on a PC.
All simulator other than the robots company's are limited in programming option and compatibility.
Actually, Simulator of industrial robots must be professonally made by Robotic company, for example ABB so it is hard to find freesoft that is good enough to demonstrate aspects of industrial robot. If you have good background on robotics, you can code a simulator using C++ and OpelGL.