Suppliers Offer Tips and Advice For Adding Grinding Operations
Grinding Machinery Purchase Tips: Suppliers of grinding systems offer advice on key issues to consider when selecting a wood grinding or shredding solution for your operation.
Date Posted: 9/4/2018
Pallet and sawmill companies have to deal with wood scrap material generated by their operations. Whether the business is processing logs, remanufacturing cants or rough lumber, producing pallet cut stock, recycling pallets, or any combination of those operations, scrap wood is a byproduct.
A sawmill may be dealing with bark, slabs, edgings and trim ends while another company may generate mainly cant and lumber trim ends. Some pallet companies may have to dispose of whole scrap pallets, and recyclers certainly deal with scrap material from pallet dismantling operations.
Grinding may be a solution for disposing of scrap wood material in any of these scenarios, and processing byproducts into wood grindings may be an opportunity to supply markets for the material — for products like animal bedding, mulch or boiler fuel. Although a grinder represents a significant capital investment as well as ongoing operational costs, it can also become critical to your operations to improve wood waste utilization.
In the space that follows, suppliers of grinding or chipping equipment discuss some of the factors a business should consider in a decision to invest in a machine to process wood waste material. These include the type of wood material that will be processed, the desired end product, where the machine may be located, what kind of maintenance to expect and other factors.
The Enterprise also lists the website for each supplier, the city and state where they are located, a contact phone number, and email address. Questions for any supplier should be directed to them.
Cresswood Shredding Machinery
Cresswood Shredding Machinery uses low-speed technology in its grinders, noted Jack Cress, owner of the company. Because they operate at lower speed, the machines use less electricity and produce less noise and dust. “That allows you to put it in close proximity to where your scrap is actually produced,” he said.
It is a critical consideration, noted Cress, because locating the grinder close to where the residuals are actually produced can significantly reduce unnecessary material handling and its associated costs. Those efforts include time spent by an employee operating a forklift to travel around a plant to pick up hoppers of debris, plus those forklift costs.
“You need to take a good look at your layout and material flow,” suggested Cress, whether it is a pallet recycling company that is generating scrap from dismantling used pallets or some other wood product business that generates offal.
One of the biggest challenges of grinding is handling the material after it has been reduced and, for pallet recyclers, removing fragments of steel fasteners. Nail fragments have to be removed for most residual products.
“One of the key elements for producing a quality residual product is having a cross-belt magnetic separator and also a secondary magnet pulley head or a hump magnet,” said Cress. “It’s very difficult to take all the metal out with one magnet, and this combination is very effective.”
What we’re finding,” said Cress, is that a lot of new pallet manufacturers now are having to deal with used pallets. “Customers are telling them, ‘If you want the new pallet business, you have to take our scrap pallets.’ So, having the capability to grind scrap pallets is a necessity if you want to grow your business.”
After the metal has been removed, options for moving the grindings include an air lock system to blow them into a truck or a top-loading, leveling auger system. If the grindings are simply conveyed to an area to be formed and stored in piles, eventually the material will have to be handled a second time with some type of equipment to be loaded into a truck or container.
“What most companies want is to eliminate that costly second material handling,” said Cress. “After they grind it they want to efficiently get it into a truck and never touch it again.”
Low-speed grinders typically require routine preventive maintenance, keeping cutting tools sharp, and rotating teeth periodically, noted Cress.
Cresswood grinders use indexable cutters and anvils that can be rotated two to four times. The amount of metal in the wood will impact how frequently tooling must be rotated and eventually changed out. Customers in the pallet industry typically get 200-350 hours before having to index their cutters, he said.
In calculating what is the most cost-effective application for a company, consider power usage, maintenance, tooling, and other costs, and determine the overall cost to produce a unit, such as a cubic yard of wood grindings, suggested Cress. Low-speed grinding is very efficient, he added. “It does it with a lot less horsepower.”
Material handling also should be considered in grinding operations, said Cress, with the goal of minimizing handling and its associated costs. Grinders fed by conveyor systems eliminate the costs associated with a forklift and hoppers. With some type of automated feeding system, “What we’ve found,” said Cress, “is we can actually produce more product with less people because we’re not spending time on material handling.”
Cresswood’s large hopper-fed grinder, the XR2400, is equipped with a 24-inch diameter cutter head and features a new hydraulic screen carriage for easy access and tooling changes.
Cresswood grinders feature ‘Ever-New’ technologies that allow easy, efficient replacement of all key wear items.
“We typically start by asking for three things,” said Yuri Chocholko, sales manager for Vecoplan, when a company is considering investing in a grinder. One is the size of the material to be reduced by grinding — the dimensions. Another is the volume of material, and the third thing is what size the material will be reduced to.
It is hard for some companies to quantify how much material they have to grind, he said. They may know they fill a trailer a day with debris or know how many containers of waste material have been sent to a landfill on a regular basis, but Vecoplan calculates the pounds per hour in order to properly size the motor for a grinder.
The size of the particles of the reduced material will depend on the company’s markets for the material, and whether it will be sold or supplied for boiler fuel, mulch, animal bedding, feed stock for particle board manufacturing or some other wood-based product, or simply going to a landfill.
One of the most important considerations is the size of the grinder. “Do not cut corners with the size of the machine,” said Chocholko. “Make sure the machine is large enough to handle the biggest piece of material you want to process.”
“One thing we point out,” added Chocholko, particularly for pallet companies, is that while a standard pallet may be 40x48, if the pallet is turned sideways at an angle — catty-cornered — when it goes through the grinder, it is 62-63 inches wide. If a company is grinding skids that are 48 inches wide, the grinder infeed needs to be considerably wider, he noted, in case the skid gets turned at an angle. “If a grinder is too small, that becomes a big issue because it gets easily plugged up.”
Most of Vecoplan’s customers in the pallet industry are using their grinders for processing scrap material that is a byproduct of pallet recycling operations. They typically use some type of infeed conveyor to move scrap into the grinder or else collect scrap in hoppers that are dumped into the grinder.
In order for wood grindings of used pallet parts to be of value, nail fragments and other ferrous metal components need to be removed, noted Chocholko. “It’s part of the standard package,” he added, that is offered to pallet recyclers for grinding. There are various styles of self-cleaning magnets available that will remove virtually all the steel, giving the customer a clean and marketable product, he said.
Like any other machine, a grinder will require regular maintenance and service and replacing some wear components, noted Chocholko. “You’re probably looking at, weekly, 15 minutes looking it over to make sure it’s running as good as it should, nothing leaking.” Routine maintenance would take a “couple of hours” a month or every two months, he said.
Employee turnover can be high, and the pallet industry is not immune to this. To guard against this, Vecoplan developed an industry-first intuitive touch-screen control panel that contains maintenance procedures, troubleshooting guides, and the operating manual.
“We use photographs of the machine and its components on the screen itself,” said Chocholko, “not diagrams and drawings in a hard copy of the manual that often goes missing. This allows a new employee to be able to operate the machine very easily with little or no technical training. Everyone knows how to use a tablet or a smart phone, so we built on this trend with our control panel.”
Customers typically install the machines next to a loading dock but below the loading dock level. Material is fed into the grinder in hoppers or via a conveyor. Hopper-fed grinders are typical of most pallet recyclers, who have two or three hoppers throughout the plant to collect debris. Larger companies with automated facilities tend to use conveyors to move waste to grinders.
The grinder is located outside in about 80% of installations for the pallet industry, estimated Chocholko.
West Salem Machinery
One of the most important things to consider is the type of ground wood product you want to produce, such as boiler fuel or mulch, noted Mark Lyman, president of West Salem Machinery, and that requires market research. “Understand what your market is and what you are going to produce so you can properly size the grinder and select the right type of grinder for your product,” he said.
Another factor is the volume of wood material that will be processed by grinding. Consider the company’s future growth to properly size the machine, he suggested.
Pallet companies that have a revenue source for their grindings are in a position to expand their operations and services, suggested Lyman. They can source more cores and other pallet material, for example. Some pallet companies have added drop container service to take and grind industrial wood waste. “It gives you the ability to provide a broader range of services,” said Lyman.
While some pallet companies focus only on grinding to dispose of their waste material, others treat it as a separate business. The day he was interviewed for this article, Lyman had visited a pallet company that also had a mulch business co-located on the same property. “They turned their waste processing into a business opportunity.”
A small pallet recycling company or other wood product business may find a hopper-fed, high torque grinder is a good application for grinding low volumes of material — from 5-15 tons per day, suggested Lyman. Larger companies may need to grind that much by the hour; for large volume producers, horizontal-fed grinders are a common application in the pallet and sawmill industry.
There are two approaches to type of grinders and where to locate them, observed Lyman. A hopper-fed grinder works well if the waste material is going to be collected from various work stations throughout a plant. These are low-speed grinders that generate less noise and dust and can be located inside or outside.
On the other hand, some businesses want to reduce their material handling costs and are looking at simple automation to reduce handling and the number of people required to ‘touch’ the material. Horizontal-fed grinders are a good application for this scenario; they can be fed via waste conveyor. “You process your waste continuously as it’s generated,” said Lyman. Larger businesses tend to go with more automated solutions for moving and handling material.
Grinders are a “tough application,” noted Lyman. Routine wear occurs, and the machines require regular maintenance. Some components have to be greased regularly. Hammers or cutters, screens and anvils are items that wear with normal operation. For example, hammers or cutters should be inspected every 2-4 weeks to determine if they need to be rotated.
A lot of wood material contains metal contaminants, said Lyman. “Do the best you can to protect the machine.” West Salem offers a new ‘flex’ tooth design that allows the grinder to be more tolerant of tramp metal, which can increase maintenance costs.
“A standard set-up for us is to grind the material,” said Lyman, “and configure the grinder with magnets to remove metal like nails, bolts, and pallet repair plates. Normally we have an overhead self-cleaning magnet and a magnet head pulley. It pulls metal off the top and bottom.” For some ground wood products, like animal bedding, additional magnets may be required to ensure the grindings are free of metal. “You can’t over-do on magnets,” said Lyman.
“Ideally, with grinders you buy a little bit bigger and heavier machine than you think you might need,” said Lyman, “because it’s going to deliver the best long-term service. Look for heavy-duty gear. Look for proven gear. Do your due diligence.”
Stationary electric grinders are a much lower cost solution, he said. “Understand what all your costs are going to be.”
West Salem offers a broad range of grinders to handle either small volumes or large. The company also manufactures a complete line of screening equipment. “We know how to match grinding and screening into a processing system to maximize the return of your wood fiber material,” said Lyman.
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Grinding Machinery Purchase Tips