How to effectively balance a jaw crusher: Insights needed

Question:

Greetings, friends! I need your expertise on a pressing issue I'm dealing with. Recently, I conducted vibration measurements on a jaw crusher and discovered that the vibrations are likely due to imbalance. If you have experience working with such machinery, I would greatly appreciate any insights on how to effectively balance this equipment. Is dynamic balancing a viable option, or are there specialized techniques needed for this type of machinery? Is it normal for this equipment to operate with some level of imbalance? I am unsure if balancing is necessary or if a certain degree of imbalance is to be expected. Any thoughts or advice you can offer would be immensely valuable. Just a heads up, the crusher underwent repairs where bearings were replaced and the foundation was reconstructed. It is likely that the same issue existed previously, resulting in the deterioration of the foundation and bearings. Now, due to the perceived imbalance, there is mechanical looseness in the area where the frame is attached to the foundation. Thank you in advance for your insights and assistance. - Christian Petroniu

Top Replies

Christian, the vibrations observed in the jaw crusher during your measurements are likely due to imbalance, which is common in reciprocating machines like this one. The rotating crank shaft may have compensating weights to reduce vibration in one plane, but they can create an unbalanced force in another plane. Typically, these machines are designed with compensating weights to achieve a moderate level of vibration. If there are compensating weights on the crank, attempting to balance the shaft is not recommended. To address high vibration levels, a sturdy foundation or an isolation base is required. If you have experience with such equipment, your insights on balancing techniques for the jaw crusher would be valuable. It is important to ensure that the machine is properly balanced to prevent damage to the foundation and bearings. Your expertise and suggestions are appreciated. - Eugene Vogel

When it comes to the jaw crusher's vibration issue, the options of resizing, rebuilding the foundation, or installing vibration dampers are currently not feasible, as previously suggested. However, during a recent conversation with a jaw crusher manufacturer, I learned about the importance of balance in equipment operation. Interestingly, after a repair by the manufacturer's representatives, the balancing weights on the crusher pulley were adjusted without proper measurements or analysis. Now, the equipment owner is requesting dynamic balancing for the crusher. I am unsure about the process and its suitability for this specific equipment. If anyone has expertise in balancing such machinery, I would appreciate your advice. This situation raises questions about the necessity of balancing and the correct approach for balancing this type of equipment. Your insights are valuable.

Hello, Christian! This forum is an invaluable resource for all our endeavors, wouldn't you agree? Let's delve into the workings of a jaw crusher. The jaw crusher operates on a unique mechanism where the jaw is connected to the main shaft through an eccentric, while the upper part remains relatively stable. This configuration allows for the crushing of rocks into smaller pieces through a "chewing" motion. The gap between the jaw and the back plate can be adjusted to ensure the output rock size is suitable for further crushing in secondary crushers such as cone or hammer crushers. It's normal for the jaw crusher to exhibit large 1xTS and 2xTS vibrations. To ensure smooth operation, the jaw shaft drive pulley must undergo dynamic balancing, typically done in a specialized repair facility with the necessary equipment. The frequency of vibration during operation can provide insights into the machine's structural integrity. If you suspect imbalance issues, it's crucial to address them promptly. Feel free to contact me for more guidance and assistance. Jim Carrel, CRL-BB, ISO Cat. III COO, Reliability Coach. For reliable insights, visit www.forumreliability.com.

Dear Christian and Jim, the discussion around what constitutes a reciprocating machine is intriguing. The key point is that the moving jaw's mass has both a linear and circular component to its motion. The linear component generates a 1xRPM force in a specific plane. Check out this informative animation at https://www.youtube.com/watch?v=3np_Ipw3R-A. Take note of the compensating weight on the pulley, which should not be balanced independently of the crank (eccentric) shaft. Gene ------------------------------ Eugene Vogel ------------------------------ Dear Jim Carrel, It's fantastic to see this forum aiding our efforts. While the jaw crusher is not a reciprocating machine, the jaw's linkage to the main shaft via an eccentric allows for a 'chewing' action as the space between the jaw and back plate adjusts with each shaft rotation, crushing rocks into smaller pieces. This adjustable space ensures the output rock dimensions suit other crushers. Vibration is normal, and balancing the pulley is crucial for smooth operation. If you need help understanding vibration patterns or balancing techniques, feel free to reach out. Jim Carrel, CRL-BB, ISO Cat. III COO, Reliability Coach 206-892-8074 Reliability into Every Company www.forumreliability.com Christian, in a reciprocating machine like the jaw crusher, the 1xRPM vibration is often attributed to the reciprocating motion. Compensating weights on the crankshaft can help reduce this vibration but may introduce an unbalanced 1xRPM force in the perpendicular plane. Balancing the crankshaft in these scenarios is not recommended. Consider reinforcing the foundation or using an isolation base to address excessive vibration. Gene ------------------------------ Eugene Vogel ------------------------------ If you're experiencing imbalance-related vibrations in your jaw crusher, exploring dynamic balancing techniques may offer a solution. Understanding the possibility of imbalance in this type of equipment is crucial for maintenance and operational efficiency. Seeking professional advice on balancing methods and the significance of imbalance in equipment operation can provide valuable insights for effective maintenance strategies. Additionally, investigating the root causes of imbalance, such as mechanical looseness, can help in addressing issues before they escalate. Your input and experiences are highly appreciated. ------------------------------ Christian Petroniu ------------------------------

Thank you, Gene, for the informative video. This is not just about balancing, but about minimizing the natural effects of the main shaft force caused by the eccentricity. The compensating weights are specifically designed to reduce directional vibrations caused by the eccentric motion. It may not be necessary to alter the size of the weights, but their positioning and potential mishandling during reassembly could be the issue. Considering the mounting aspect, I suggest using motion amplification or an operating deflection shape analysis to pinpoint the source of excessive movement or incorrect force angles. If the issue stems from improper repair or reassembly, it should be addressed as a warranty concern by the contractors. Feel free to contact me with any queries. Jim Carrel, CRL-BB, ISO Cat. III COO, Reliability Coach 206-892-8074 Reliability into Every Company www.forumreliability.com In response to Eugene's discussion, it's important to understand that the jaw crusher operates with both a linear and circular motion due to the mass of the moving jaw. The compensating weight on the pulley is critical in this mechanism, as it should not be balanced independently of the eccentric shaft. Watch this animation for a better visualization: https://www.youtube.com/watch?v=3np_Ipw3R-A. Eugene Vogel Regarding the jaw crusher balancing issue you raised, it's worth noting that the vibrations could be stemming from imbalance. It’s essential to consider the possibility of dynamically balancing the equipment, just like with other machinery, to address any potential issues with operational imbalance. Additionally, a thorough assessment of the vibration frequencies and phases throughout the machine and its base can help pinpoint the source of the problem. If the issue persists, it may be related to mounting integrity or operational factors. For more assistance, feel free to reach out to me. Jim Carrel, CRL-BB, ISO Cat. III COO, Reliability Coach 206-892-8074 Reliability into Every Company www.forumreliability.com When it comes to balancing a reciprocating machine like a jaw crusher, understanding the unique vibration patterns is crucial. Compensating weights on the crankshaft should be considered to mitigate vibration, but balancing them independently can lead to unbalanced forces. Ensuring the foundation is solid or utilizing an isolation base can help manage high vibration levels effectively. Gene If you’re dealing with vibration issues on a jaw crusher and suspect imbalance, it’s imperative to consider dynamic balancing to address potential operational challenges. Proper diagnosis through vibration analysis can help determine the root cause of the imbalance and guide you towards the right solution. Feel free to share more details for personalized assistance.

Hey Christian, indeed jaw crushers, like any rotating machinery, can face imbalance issues. The severity and approach to fixing the problem will largely depend on how out-of-balance the equipment is. While a slight imbalance due to wear and tear is somewhat normal, excessive levels could lead to bigger issues, such as what you're facing with the loose frame. Dynamic balancing could indeed be a possible solution, but I'd also strongly recommend getting a professional to conduct a thorough machine diagnosis, paying attention to things like operating speed, alignment, and even revisiting the replaced bearings. Sometimes, incorrect installations after repairs can unknowingly create new headaches. If you're noticing symptoms of high vibration levels, it's usually a signal to rectify the balance before it causes any further complications. It's always better to tackle these issues before they escalate. Best of luck!

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Frequently Asked Questions (FAQ)

FAQ: 1. Is dynamic balancing a suitable method for balancing a jaw crusher?

Answer: Answer: Dynamic balancing can be a viable option for balancing a jaw crusher, but specialized techniques may also be required depending on the specific machinery and circumstances.

FAQ: 2. Is it normal for a jaw crusher to operate with some level of imbalance?

Answer: Answer: While some degree of imbalance may be expected in machinery like a jaw crusher, excessive imbalance can lead to issues such as mechanical looseness and vibrations.

FAQ: 3. What are the potential consequences of operating a jaw crusher with imbalance?

Answer: Answer: Operating a jaw crusher with imbalance can lead to mechanical issues like looseness in the frame attachment to the foundation, which can result in further deterioration of components like bearings and the foundation itself.

FAQ: 4. How can repairs such as bearing replacements and foundation reconstruction impact the balance of a jaw crusher?

Answer: Answer: Repairs like bearing replacements and foundation reconstruction can uncover existing imbalance issues in a jaw crusher, which, if not addressed, can lead to mechanical problems and further damage.

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