A jaw crusher is a device that reduces the size of various solid materials in many applications, including underground mining and mobile crushing applications mainly using the compressive force of the two jaws, one of which is stationary and the other is moving. The jaw crusher’s moving jaw undergoes two main types of motion, one resulting from the eccentric shaft movement, and the second from the toggle plate and the tension rod.
Using simulation and the Discrete Element Method (DEM) it is possible to model the complex crushing process in order to optimize the operation and design of the machine. In this post we look at a jaw crusher model that was set up in EDEM in order to show the type of analysis that can be performed with the software. The simulation focused on the options enabling a jaw crusher’s optimization using EDEM’s Breakage Model (based on Tavares, UFRJ).
A continuous feed-rate was simulated in EDEM, which is crucial in analyzing the crushing of the ore, as the jaw crusher usually operates with uniform feeding and its crushing performance is dynamically affected by the fill level. [Video at the end of the post]
Users can choose which approach to follow for simulating a jaw crusher in EDEM:
- The software allows the option of combining pre-defined sinusoidal motions to replicate the complex motion of the moving jaw. This simpler approach was used for the creation of the example shown here.
- Users interested in the dynamic motion and loads experienced by the equipment, could couple EDEM with a Multi-Body Dynamics (MBD) software for further optimization. EDEM provides coupling solutions with a range of MBD software including Adams, RecurDyn and LMS Virtual.Lab Motion.
Additionally, EDEM provides two options for simulating the crushing process:
- The first involves using EDEM’s Breakage Model (based on Tavares, UFRJ) which is built utilizing EDEM’s Application Programming Interface. This breakage model is able to address the different mechanisms of breakage including both surface damage and fragmentation and it provides key data including size distribution and mass loss.
- The second option uses the Bonded Particle Model, as shown in the Cone Crusher simulation video below. In this model the breakage occurs at the bond and not the particle itself, allowing for more complex multi-spherical shapes to be created. More information about that method and example can be found in this published paper from Chalmers University of Technology.
Video: Cone crusher simulation using the Bonded Particle Model (Courtesy of Chalmers University of Technology)
As you can see, EDEM provides different modelling options and flexibility for the simulation and performance analysis of jaw crushers and other crushing equipment, enabling design and process optimization and minimizing the need for physical prototyping.
Specifically, by using the resources and academic literature available for EDEM’s Breakage Model (available to EDEM customers from the EDEM Forum) users can accurately simulate the crushing behavior of different materials such as iron ore, limestone and granulite of varying size according to their requirements.
EDEM provides the user with valuable information regarding the Diameter of the simulated crushed material at different locations inside the crusher during the simulation. A very useful feature of the EDEM Analyst is plotting the particle size data before and after crushing and obtaining the maximum particle size for each simulation, minimizing the need for sieve analysis.
The pressure and compressive forces experienced as well as the wear on the jaw crusher’s plates can also be obtained using EDEM. This allows optimization for the pitman’s design and crushing angle, and better prediction and planning for each crusher’s maintenance.
By using a sensor in the EDEM Analyst, the discharge flow rate from the orifice can be measured, for varying parameters such as material type and discharge orifice width, providing useful data for the jaw crusher’s designers and operators.
Here is a video showing the jaw crusher simulation and the analysis discussed in this post:
Video: Jaw crusher simulation using EDEM’s Breakage Model (based on Tavares, UFRJ)
IN SUMMARY EDEM provides a range of benefits for simulating and optimizing Jaw Crushers:
- EDEM’s Breakage Model and Bonded Model provide two different options for modelling the crushing process.
- EDEM-MBD coupling allows detailed data to be obtained regarding the dynamic motion and forces experienced by the pitman.
- Particle size data can easily be obtained and analyzed in EDEM, minimizing the need for sieve analysis.
- The jaw crushing process parameters such as the eccentric shaft’s RPM and fill level can be simulated and optimized.
- The jaw crusher’s crushing plates can be optimized, as well as the toggle plate’s motion for different applications.
- An overall decrease in a plant’s operating costs including electricity consumption and replacement parts can be achieved as a result of optimized jaw crusher operation and design.