Pressing force does not equal output (Baling myth 2)
So, you want a 100-tonne baler? Sure, we can help you with that. But I must ask: Is it really a baler with a pressing force of 100 tonnes you want? Or is it a baler with a high output? Pressing force and output are not the same thing but it’s easy to get the two concepts confused. That mistake can cost a lot of money.
Let’s start with some definitions. Pressing force is the amount of force (calculated in tonnes) that a baler can apply to the material being compressed. Output is the amount of material that a baler can compress during a specific amount of time (usually measured in tonnes per hour).
Not created equal
Ok, let’s get back to the 100-tonne baler you want. Let me explain why a 100-tonne baler not always is needed, even if you may think that is what you need. It’s because all balers are not created equal:
While there is a link between pressing force and output the relationship is not linear. For example, if one baler has a pressing force of 100 tonnes and can output 25 tonnes of corrugated cardboard per hour, it does not mean that other balers must have a pressing force of 100 tonnes to reach the same output. It all depends on how the baler is designed.
Prepress and shear
Simply speaking there are two kinds of horizontal balers being used today: shear balers and prepress balers. Shear balers use a shear, a kind of knife blade, to cut the material that can’t fit in the press chamber. This cutting process uses up some of the pressing force.
Prepress balers apply pressing force from above (by means of the prepress) and thereby closing the press chamber and eliminating the need for a shear. All pressing force from the main press of a prepress baler is used for compressing the material, unlike the shear baler where some pressing force is lost to the cutting process. This means that prepress balers can achieve the same amount of output as a shear baler, but with a lower pressing force for its main press.
…so that’s why pressing force not does not equal output.
Does this mean that it’s wrong to buy a 100-tonne baler? No, not at all. Just remember that depending on what kind of baler you are buying you may not need 100 tonnes of pressing force.