Horizontal Grinders vs Whole Tree Chippers
Chippers and grinders each have unique advantages for different fiber sizing applications. Which is right for your wood waste processing needs?
In this equipment selection guide, we will give you an overview of whole tree chippers, horizontal grinders and horizontal grinders with conversion packages. For easy comparison between the two options you will also find a selection matrix to help you make your decision.
| Whole Tree Chipper | Horizontal Grinder | |
| Raw Materials | Logs, small round wood. | Logs, whole trees, brush, forestry residue, sorted C & D, pallets, waste, agricultural products, and shingles. |
| Efficiencies | Processes clean round wood quickly. | Takes more horsepower to turn waste wood into chips. |
| Versatility | Only used for chipping clean round wood. | Use for a variety of applications by switching teeth & screens. |
| End-Product Control | Product size controlled by the number knives in/on the chipper drum. Less knives = less control over product size & more knives = more control over product size. | Product size controlled by screens & teeth. |
| End Products | Chips, micro-chips, sawdust. | Chips, mulch, colored mulch, playground cushion, fine-texture fiber, compost. |
| Uptime & Maintenance | High wear costs & frequent down-time. Raw material must be clean to insure consistent uptime. Contaminants quickly damage the chipper knives. Need to swap rotors to change applications. | Replaceable mounts can be switched by a single operator. Indexable knives can be reversed when they become dull on one side. No specialized tools required to switch applications. |
Whole Tree Chippers
If you have a steady stream of clean round wood, nothing beats the efficiency of a whole tree chipper. Disc chippers and drum chippers are designed for a single purpose—to very quickly process solid round wood—and they do it better than any other machines on the market.
Types of Wood Chippers
Wood chippers are not a new technology and have been around since 1884. There are two kinds of whole tree chippers. Disc chippers consist of a disc with steel knives that cut the wood perpendicular when it comes into the chamber. Alternatively, a drum chipper, utilizes a drum with knives on it that cuts the wood down when the wood is fed into the chamber.
Uses for Wood Chips
Many industries need chips that are produced by a whole tree chipper, such as paper manufacturers, companies that use chips in particle board and certain fuel applications. Some chippers can produce highly uniform chips. Some can even produce short fiber chips for pellet fuel production and other applications. The chipper might even have a screen that the chips pass through before they are blown out through the shoot.
A disc chipper can make a more precise sized chip that is good for pulp and paper but does not produce chips at a high volume. Drum chippers are better for making chips that will be used for pellets or fuel. Typically, controlling the size of the chip is done by the thickness of the knives and number of knives.
Maintenance & Wear Costs
Unfortunately, as knives become dull or damaged, particle size will usually increase and become inconsistent. Knife dullness may occur within a few hours—or instantly if the knives encounter rocks or steel. Additionally, if pliable or small-diameter branches bend or twist in the throat opening, they can pass through a chipper as long spears, rather than chips.
Chippers can often involve high wear costs and frequent downtime, especially in environments where operators have less control over contaminants. Sand and dirt can quickly cause expensive damage that may be time consuming and costly to repair. Rocks and steel can instantly ruin a set of chipper knives, requiring immediate maintenance.
Chippers also generally have difficulty feeding and chipping material of mixed dimensions, including tangled piles of tree trunks and branches. Many chippers lack a feed system aggressive enough to process whole trees with rigid limbs.
Once you move outside a wood chipper’s design purpose, its advantages quickly disappear in favor of a wood grinder.
Horizontal Grinders
Whereas chippers are highly specialized, horizontal grinders can be versatile and allow you to easily switch between applications by swapping the rotor or mounts and teeth. This offers you the flexibility to switch between processing logs, whole trees, bark, slab wood, and other solid materials in addition to the flexibility in controlling your end product. Horizontal grinders will efficiently process green wood, seasoned timber, or kiln-dried lumber, including pallet waste and sorted C & D.
Horizontal grinders also have an advantage when it comes to particle size control within many industries and applications. If you need to make multiple fiber products, you need the grinding precision of a horizontal grinder.
Horizontal Grinder Chipping Options
Just as there are options for a disc and drum chipper there are also a couple of different ways to convert your horizontal grinder into a chipper. First is a chipper conversion package. This option would require you to change the mounts and teeth on your current rotor. The second possibility is by switching the entire rotor to a chipping rotor for horizontal grinders.
Horizontal Grinder with Conversion Package
A horizontal grinder with a chipper conversion package will reduce wear costs and maximize uptime by allowing fast, convenient access to teeth and screens.
If you want to be able to perform across multiple applications, utilizing a horizontal grinder is the way to go, but if you’re only looking to make wood chips, a whole tree chipper will always outperform a horizontal grinder with higher production rates and higher efficiency.
Unique Rotochopper Advantage
A Rotochopper horizontal grinder has many unique features that can make chipping and grinding easy. One of its most valuable qualities is its versatility across use cases, feed stocks and preferred end products. The available chipper conversion package creates an efficient system to switch between grinding and chipping applications. With the Rotochopper replaceable mount rotor you can easily swap your grinder mounts for the chipper mounts and knives. In addition, the chipper knives are indexable and you can flip them to utilize both sides of the knife, increasing the life span of the part and decreasing wear costs.
Rotochopper horizontal grinders are known for their superior particle size control, allowing operators to create a finished product in just one pass. This advantage provides consistency in your end product that is not possible with alternative solutions and creates efficiencies throughout the resizing process.
Finally, as with all Rotochopper equipment, the factory direct service and support provided from our team of experts is invaluable to minimizing downtime, maximizing productivity and ensuring continued success.