What Determines Disc Chipper Production?
One of the common questions we hear when someone is considering a used disc chipper is:
“How much will it produce?”
The answer isn't as simple as looking at the horsepower or the diameter of the chipper disc. Several factors work together to determine both how fast material can be fed into a chipper and how much material it can process.
Number of Knives and Feed Rate
One of the primary factors determining the feed rate of a disc chipper is the number of knives in the disc.
As the disc rotates, each knife takes a cut from the material being fed into the chipper. The number of knives, combined with disc speed and the chip length being produced, largely determines how fast the stock can advance into the machine.
This is why two chippers with similar disc diameters and horsepower can have very different feed rates.
Throat Opening and Material Size
Feed rate isn't the same thing as production volume.
The size of the chipper's throat opening determines the physical size and amount of material that can enter the machine. A larger throat can accept larger logs, slabs or a greater volume of material, while a smaller opening can become the limiting factor even if the chipper itself is capable of a high feed rate.
How the Chipper Is Fed
The feeding system can also have a major effect on actual production.
A chipper that is continuously and evenly supplied with material will generally produce more than the same machine being fed intermittently. Infeed conveyors, rolls, chutes and other feeding arrangements can all affect how consistently material reaches the knives.
A high-capacity chipper doesn't accomplish much if the feeding system can't keep it full.
What Are You Chipping?
The stock being fed matters too.
Logs, slabs, edgings and other wood waste don't feed or pack into the throat in the same way. Species, diameter, length, moisture content and the shape of the material can all affect how efficiently a chipper can process it.
That's why a production figure based on one application may not accurately predict production in another.
Horsepower Still Matters
Of course, the chipper has to have enough horsepower to do the work.
The motor must be properly sized for the chipper, the feed rate and the material being processed. Insufficient horsepower can prevent an otherwise capable chipper from maintaining its intended production under load.
But horsepower by itself doesn't tell you a chipper's capacity.
Look at the Entire Application
When evaluating a disc chipper, don't ask only:
“How much horsepower does it have?”
or
“How big is the disc?”
Instead, consider the entire system:
- Number of knives
- Disc speed
- Chip length
- Throat opening
- Feeding method
- Type and size of material being chipped
- Available horsepower
Ultimately, chipper production is the result of all of these factors working together.
When evaluating a used chipper, understanding the application is just as important as understanding the machine. A chipper that performs well in one operation may have very different production in another.
Ben Jones Machinery has worked with chippers and other sawmill and wood-processing equipment since 1976. If you're evaluating a used chipper, we can help you determine whether a particular machine is a good match for your application.
https://www.benjones.com/chippers/