From Mixer to Moulder: Optimizing Dough Feeding Systems in Biscuit Production

In our previous article, we explored the science of mixing raw materials. However, once the dough is perfected, it must be transported to the forming unit without compromising its structure or the line's efficiency.

The method of transport depends heavily on the factory layout. For facilities with horizontal mixers installed on a mezzanine level, gravity allows the dough to be automatically unloaded directly into a feeding system below. However, for floor-level setups or vertical mixers, specialized handling equipment is required.

1. The Dough Lift and Tilt Machine

Vertical mixers typically utilize detachable, movable mixing tubs. Because the dough cannot simply be dropped out of the bottom, it requires mechanical assistance to move from the mixing area to the production line.

A Dough Lift and Tilt Machine is the standard solution here. The operator wheels the mixing tub into the unit, which locks it securely. The machine then hydraulically lifts the heavy tub and tilts it, tipping the bulk dough into the hopper of the feeding system. This eliminates manual handling and ensures a rapid transfer of large batches.

2. Dough Feeding Systems for Hard Biscuits

Hard doughs (for crackers and semi-sweet biscuits) possess a developed gluten network, making them elastic and tough. They cannot be fed as a single massive block; they must be portioned.

The feeding system for hard biscuits typically comprises a dough tipping unit, a feeding hopper with a vertical guillotine, and a transfer conveyor.

• The Process: After the dough is tipped into the hopper, a conveyor belt at the base moves the dough mass forward. 
• The Guillotine: As the dough advances, a pneumatically controlled vertical guillotine slices the dough into manageable chunks or sheets. 
• Conveyance: These cut pieces drop onto a secondary feed conveyor, which delivers them to the Laminator or the Gauge Roll Sheeter. 
• Safety & Quality Control: Crucially, the conveyor should be equipped with a metal detector. This is a vital critical control point (CCP) to prevent metal contaminants from entering the food stream and to protect the expensive rollers of the sheeter from damage.

3. Dough Kibblers for Soft Biscuits

Soft biscuit doughs (short doughs) have high fat content and little gluten development. If dumped in a large mass, they can bridge or compact, leading to uneven feeding.

For these doughs, a Dough Kibbler is essential. The kibbler uses rotating blades or fingers to break the dough block into small, loose granules or "kibbles." This ensures the dough flows evenly into the hopper of the Rotary Moulder.

To maintain weight accuracy in the final biscuit, the rotary moulder’s hopper is equipped with sensors that monitor the dough level. The control system automatically adjusts the feeder speed based on this data, ensuring a constant pressure and consistent product weight.

4. Batter Feeding for Cookies

Cookie doughs and batters are often relatively liquid or semi-solid. For these products, heavy mechanical chunking is unnecessary.

• Pump Systems: The batter is often pumped directly from the mixer to the hopper of the forming machine (Depositor or Wire-cut machine).
• Gravity Feed: Alternatively, batter can be poured from overhead hoppers.
• Flow Control: The hopper is typically fitted with a valve or a variable speed pump to precisely control the volume of batter entering the forming head, preventing overflow and ensuring consistent depositing.

The dough feeding system is the "artery" of the biscuit production line, connecting the heart (the mixer) to the body (the forming equipment). Whether utilizing a high-impact guillotine for tough cracker doughs or a precision kibbler for delicate soft doughs, selecting the right feeding mechanism is essential. A well-designed system not only reduces manual labor but also ensures a consistent feed rate, which is the prerequisite for uniform biscuit weight, shape, and baking quality.