April 7th, 2014
Top Ways to Reduce Wear on a VSI
When it comes to preventing wear in a vertical shaft impactor, consider these top six tips:
- No steel or metal allowed in the VSI. A metal detector or magnet is highly recommended. A metal detector attached to the feed conveyor works best as it detects stainless steel and items that a magnet will not pick up.
- Check the size. Large rocks must not exceed the mass noted in the manufacturer manual. Top size, as noted in the manual, should never be exceeded. More importantly, however, is the largest allowable mass of a single rock in the input feed. An individual rock should not weigh more than specified in the manual.
- Low feed rates. A less-than-capacity feed rate or inconsistent feed rate will cause abnormal wear and increase the risk of carbide breakage. Ideally, there will be a smooth and uninterrupted flow of rock through the crusher. Choke feeding the crusher provides a smoother flow. A low feed rate results in a higher wear cost per ton.
- Minimize water, particularly in the crusher feed. Water can create abnormal wear traits. Eliminating any free water will significantly increase the life of the wear parts of the VSI.
- Install a screen. Screening increases crushing efficiency and reduces wear costs. Screening prior to the VSI will ensure the proper feed size. In a closed-circuit system, effiecint screening after the VSI will remove sized product and decrease wear costs.
- Feed Tube Adjustment. The feed tube should be properly adjusted within 3/8” of the top of the rotor to ensure proper feed delivery into the rotor. This keeps rock from wearing the top of the rotor and improves crushing efficiency.
March 26th, 2014
Top Three Rules for Maintaining a Jaw Crusher
When it comes to maintaining a jaw crusher and securing the most uptime possible, the key is to develop a proactive preventive care program and become properly trained on the equipment.
While producers are sometimes solely focused on one specific part of an operation — like how large material can be and still be fed into a crusher — what they should be concerned about is how much production can be achieved and the best way to achieve it. That all boils down to maintenance and education. But maintenance is far more extensive than just greasing bearings and miscellaneous housekeeping.
Because of the violent nature of a jaw crusher, the equipment — regardless of application or manufacturer — will fail at some point without preventive care. But a proper maintenance program can help producers avoid costly breakdowns by repairing problems in their infancy. This could be something as minor as a loose or missing bolt, a broken weld, a loose belt, or a buildup of material that is allowed to remain. When taken care of daily, they remain small issues that can be immediately resolved to avoid downtime, but, over time, they can affect the longevity of the equipment.
While new technology can greatly enhance the efficiency of an operation, it can also add a challenge to those who have not been exposed to it. The following these guidelines can help extend the lifespan of your equipment:
- Avoid oversized feed. To establish a preventive care program that will extend the lifespan of a jaw crusher, producers must go beyond greasing bearings daily and consider the application of equipment. Because the jaw crusher is most often the primary crusher in a quarry or recycling operation, it is asked to perform the most difficult stage of product reduction. It is too often misapplied by feeding too large of material, however, which creates loss of production and the potential to damage the crusher. When an oversized rock is introduced into the jaw but is too large to fit into the chamber, it causes an interruption in crushing, which equals no production. A general rule of thumb is to keep the maximum feed size under 80 percent of the jaw opening or gap as measured from the top of the stationary die to the top of the moving die.
- Keep fines manageable. Although too large of material can cause problems for the producer, too many fines can also affect crushing performance. An excess of fine material will fill in all of the voids, which are necessary for the material that is being crushed to expand into. This creates an event called compaction. Compaction amplifies the forces in the crushing chamber, up to five times the normal crushing forces. As with any force that is generated, the energy must find a point of release, which is usually in the jaw base structure or in the shaft and bearings. Over time, this can cause damage. Excessive amounts of fine material also limit production because these fines are taking the place of otherwise crushable larger rock. Compaction can also be caused by improper use of the jaw die or plates. The corrugations of the jaw dies are crucial to the jaw performance, as the corrugations provide the expansion room needed as well as the leverage required to break the rock. Jaw dies should be flipped or replaced once the remaining corrugations get to about 20 percent of their beginning dimensions or irregular wear is detected. The wear of a jaw die should be gauged by the remaining corrugations at the bottom, not the overall weight of the jaw die itself.
- Aim for attrition crushing. If the proper feed size is introduced into the jaw and the jaw die maintenance is performed as recommended, the result will be a higher output, and true attrition crushing will take place. Attrition crushing, or rock-on-rock crushing, helps with output gradations and improves wear cost for the producer, as more of the wear takes place on the rock rather than the jaw dies.
As with all crushers, the maintenance of a crusher depends on how it is applied and taking a proactive approach to maintenance items like wear parts. Replacing wear parts before they are worn out costs less and improves the crusher’s performance, ultimately saving money, increasing uptime, and providing crusher longevity.
Although the fundamentals of jaw crusher maintenance apply to all jaw crushers, it is important to consider each scenario according to each specific producer when it comes to preventive care. Every producer needs to consider what he can do to improve his situation by adding to or developing a program that will work for his specific needs. There are no two identical applications, both in material and in people themselves. But there are similarities that can be the foundation for building a good maintenance program, so it is important to remain flexible. Keeping an open mind to suggestions may save you money and make you more profitable. It also serves as a morale booster to the employees asked to operate and maintain the equipment, and maintaining good employees will help in assuring that proper maintenance is being performed.
For more information about maintaining jaw crushers, visit Aggregates Manager's website for a detailed article. To contact KPI-JCI and Astec Mobile Screens' Field Service Representative Wade Lippert directly, e-mail him at firstname.lastname@example.org.
February 10th, 2014
Employing Fundamentals to Improve Efficiencies
Have you ever found yourself waiting impatiently at a traffic light when there were clearly no cars coming in the other direction? Do you ever find yourself looking for something that you use almost every day, such as your car keys or your cell phone? Have you ever spent a few minutes going through your closet looking for a favorite shirt, only to find yourself filling up a large bag full of clothes destined for Goodwill?
We deal with wasteful activities like these on a daily basis. And if you are engaged in mobile processing, you are acutely aware of the many challenges with which you're faced. Below are common challenges portable producers face:
- Equipment that must be highly efficient and reliable while producing maximum volumes and having the flexibility to produce an array of product specifications or adapt to any material condition;
- The loss of revenue associated with the downtime between moves to prep, clean, tear down, load, set up and wire equipment;
- Working in jobsites that are often too constrained for the footprint of the equipment spread needed; and
- Unpredictable and often volatile fuel costs and trucking expenses.
Fortunately, the same principles that lean professionals employ in equipment manufacturing can also be applied to those who manufacture a product on the run. While there is no substitute for taking advantage of a lean certification course yourself, here are just a few principles that can allow you to employ some common sense fundamentals to your operation in an effort to improve efficiencies.
- Appoint a value stream team. Identify employees from all areas of your operation, including production, maintenance, the office, safety or other non-production-related areas. The idea is to find people who have fresh ideas who are not pre-disposed. These small teams should address the needs of individual work areas in hands-on proactive workshops focusing on quick and easy ideas as opposed to groundbreaking solutions. The mindset should be continuous improvement.
- Apply the 5S's. Once the team has selected the first workstation, it is recommended that it applies a “5S” process to that workstation. This includes sorting, straightening, standardizing, shining and sustaining. It's sort of like cleaning out the pantry. Empty everything out, clean it, throw away what isn’t needed, assign everything a spot, label its place, and make sure it is returned back to that place every time and kept clean.
- Identify and analyze the system. Recognize that each component often works at a different rate, and that optimum production is achieved by balancing the system. For example, how is the jaw crusher set relative to the secondary crusher? How is the cone performing? Are there any issues? How much is it costing to operate? Is it a bottleneck? If the 5S process was thoroughly performed in step two, then this third step should be easier to address.
- Identify a focus area.The status of the 5S system and identification of bottlenecks will indicate where to improve a specific area of the system. Some common opportunities include: crusher configurations, screen configurations (throw/speed/media), conveyor flashing, transfer chutes/liners, safety/inspection reports, and calibration/controls/connections.
- Count and reduce the number of pieces. Many plants have excess processing equipment needed to fulfill their core material demand. This might create an opportunity to reduce waste by decommissioning unnecessary equipment from the plant. Ask yourself: Do you really need that extra chip screen and additional material handling equipment that was installed for the runway project back in 2003 that only produces 37 tph of a product that we could make by changing wire and flopping a chute once or twice a month?
- Accelerate flow. Accelerating flow is one of the main objectives. Just like your car burning fuel at the stoplight, material retained in your processing circuit is costing money. The quicker you can get it out of the circuit and into the stockpile, the less it will cost to produce and the more profit you will make. Ultimately, what we are really talking about here is identifying and relieving production bottlenecks. Use a stopwatch and time how long it takes from your feed material to get from the bucket to the stockpile, and then start to collaborate with your value stream about how to shorten the distance.
This systematic approach may sound complicated, but all it really takes is a group of people who are dedicated to making small, incremental changes on a daily basis in pursuit of a continuous improvement. You can help by dangling some incentives for each and every measured achievement.
While we all dream of making the large groundbreaking change, I have seen how dozens of small, quick and easy ideas tend to have a viral effect on an organization and provide even greater rewards over time through a stronger culture, improved safety and increased profits.
October 1st, 2013
The Power of the Tribe
Tribal knowledge—corporate, social, racial, etc. —is a reservoir of both written and unwritten information. It is a living energy center around which kindred minds gather and exchange ideas, traditions, protocols, inspirations, experiences, lessons learned, technology—all magnetized to a core of shared interests. A real tribe understands the inherent value of working together for its own enlightenment, growth and security.
Those of us engaged with the kinds of products that we manufacture at KPI-JCI & Astec Mobile Screens find ourselves working in a relatively small world. As such, it comes as no surprise that I am not aware of any higher education institutions offering any advanced degrees in aggregate system design. We rely on "tribal knowledge" within our industry to pass on our wisdom as well as exchange ideas and information.
I had the privilege of attending our annual National Dealer Conference (NDC) event in Eugene, OR the week of September 16. NDC is a three-day function where we get together with our dealers to unveil new products, discuss business strategies for the upcoming year, present awards to our top-performing dealers, build relationships with new associates, and strengthen relationships with old contacts.
Much of the theme in this year’s NDC centered on recognizing our past legacy as a company. A slideshow during the President’s Reception showed photos of old co-workers and mentors from years past, which really drove home the rich legacy of our company. Some of those faces shown up on the screen I still have pleasure to work with, where a few cherished others have since passed away.
I looked at those faces on the screen and it struck me as to how much knowledge and wisdom so many of us in that room – my peers and our dealers alike - gained from these legends.
It is that kind of tribal knowledge that we all rely on every day but will never find in a textbook. Like knowing at what angle a conveyor can be raised to, how to prevent shale from getting into your product pile, what kind of liners work best for crushing hard round stone in a cone crusher, or what is the best way to handle dirty material in a recycle operation.
At KPI-JCI and Astec Mobile Screens, we practice tribal knowledge by creating events like NDC to share strategic business planning information with our dealers, or PRO Training to pass on technical information to industry newcomers. And while not as glamorous, probably where this mindset pays the biggest dividend is simply through being able to provide a strong response at the answer desk.
However, the more I learn about this industry, the more I realize that I have so much more to learn. Therefore, I am grateful that my employer appreciates the value of having our associates be "out in the trenches." Therefore, in addition to our routine service and sales trips, our engineering, marketing, and product management staff routinely travel and interact with our dealers and our customers.
Even after more than 20 years of working in this industry, I still seek new information from the end-users of our products whenever I get the chance…and I find that I don’t have to look hard to find it. I find that I am far more useful to my employer when I am listening to our customers and not my own thinking!
July 9th, 2013
Don't Just Look at the Price Tag- Consider All Costs When Buying Equipment
Everybody has heard the phrase "you get what you pay for." Whether comparing automobiles, tissue paper, electronic equipment or construction machinery, the perceived value of a product is generally defined by the customer’s perception of the quality relative to the cost that has been invested.
Can someone save money by buying equipment from a smaller fabricator with a lower overhead burden as compared to a world-class manufacturing organization? Sure. But there is an inherent risk if things don’t pan out -- the biggest and costliest risk being poor or non-existent factory support, which must be absorbed by the customer in the form of downtime and costly loss of production.
Let’s do some quick math. Let’s say a customer saved $50,000 by purchasing equipment from a lower-quality manufacturer. The quick math would seem to make a strong case supporting that they made a wise choice, wouldn’t it?
Let’s put some variables to the operation: A 200tph plant produces material worth $12/ton. When the plant is up and running, it produces a revenue stream of $2,400 per hour. For a typical eight-hour shift, the system will generate just north of $19,000 per day in revenues.
Now imagine that the competitive equipment collapsed because it wasn’t properly designed by a certified engineer like that we employ at a higher wage. Now the plant is shut down and the customer’s revenue stream is suddenly at zero.
The customer calls Brand X to explain what has transpired; however, they lack a strong service department. A couple of days pass before a corrective action plan is established. By the time final repairs are implemented and the plant is back running, all of the front-end savings - and then some! - have long since been consumed by a single failure that could have been avoided.
Of course, larger, world-class manufacturers like KPI-JCI and Astec Mobile Screens go to great lengths to ensure that these types of scenarios are prevented. How, you ask? Factories like us use:
- Professional engineering systems to identify "hot spots" on paper long before anything is operated in the field;
- Industrial engineering/CNC programming to guarantee precision assembly;
- A company-wide quality and assurance culture to ensure multiple quality checks and shop-floor accountability;
- State-of-the-art manufacturing facility and tooling to provideconsistent workmanship;
- Parts inventory and service personnel on the ground to offer smooth start-ups;
- Year-round factory training schools to educate the users.
Can failures that incur downtime expenses occur? Sure. But the chances of common failures occurring are fewer, and the response time to repair them from a 24/7 global support team is far faster.
All of these activities are the norm at KPI-JCI and Astec Mobile Screens. They do add to the front-end cost of factory products. But they also contribute greatly to the value, and they ultimately will contribute to a lower cost-of-ownership on the part of the customer.