Why Your Pellet Machine Won't Form Pellets & How to Fix It

There's nothing more frustrating than running your pellet machine only to find a stream of loose powder instead of solid, formed pellets. When your machine fails to form pellets properly, production stops, material is wasted, and downtime costs you money. This common issue, often called "failing to pelletize," can happen with both brand-new machines and equipment that was previously working perfectly.

The good news is that the cause is rarely mysterious. It usually points to a specific imbalance between your material, your machine settings, or a worn component. The troubleshooting approach differs slightly depending on whether the machine is new or has been in operation. Let's diagnose the reasons why pellets won't form and get your production line back on track.

If You Have a Brand-New Pellet Machine...

When a fresh-out-of-the-box machine won't form pellets, the issue is almost always related to setup and material preparation, not immediate wear and tear.

Start by checking the two most critical foundational factors: raw material moisture and die compression ratio. Your biomass must be within the optimal moisture range (typically 10-15%). Material that is too dry lacks the natural binding agents; material that is too wet turns to paste. Secondly, verify that the compression ratio of your die is suited to your specific material's density. A mismatch here means the machine cannot generate the right pressure to form a pellet from the start.

If Your Working Machine Suddenly Stops Forming Pellets...

For a machine that was running well but suddenly starts producing only powder, you need to check for mechanical failure first.

The primary suspects are severely worn or damaged dies and rollers. Over time, the critical working surfaces of the die and rollers wear down smooth. When they lose their grip and compression ability, they simply polish the material instead of pressing it. Inspect them closely; if they are worn out, replacement is the only fix. If the tooling looks acceptable, your next step is to immediately test the moisture content of your raw material. A sudden batch of material that is too dry or too wet is a very common culprit for a sudden stop in pellet formation.

The Gap Between Die and Rollers Has Shifted

The precise gap between the die and rollers is a key setting that can drift over time or through improper adjustment. If this gap becomes too large, the rollers cannot effectively grab the material and press it into the die holes—the material just rolls around. Conversely, if the gap is too small, it creates excessive friction and heat without allowing enough material into the compression zone. In both cases, the result is poor or no pellet formation. Regular checks and adjustments to maintain the manufacturer-specified gap are essential.

Uneven Pelletization: Top vs. Bottom Die Holes

This is a more specific but telling issue. If the holes on the top half of your die produce normal pellets while the holes on the bottom half output only powder, the problem is usually internal material distribution.

The cause is often the angle of the distributor blades (or "feeder knives") inside the pellet chamber. If their angle is incorrect, they fail to spread the raw material evenly across the entire face of the die. The top holes receive material while the bottom holes are starved. Adjusting these blades to ensure a uniform material layer across the entire die surface will solve this uneven pelletizing problem.

Get Back to Making Perfect Pellets

Pellet formation failure is a solvable problem. For a new machine, focus on moisture and die specification. For a machine that has stopped working suddenly, inspect for worn tooling and check material moisture. Always keep an eye on your roller gap and the internal distribution of material. By systematically checking these areas, you can quickly identify the root cause, apply the correct fix, and return to producing high-quality, consistent biomass pellets without costly delays.