Dong-Yih Machinery Co., Ltd.

Food Machinery Knowledge

What Is an Encrusting Machine? Structure, Uses, and How It Differs from a Forming Machine

An encrusting machine feeds the outer dough and the filling into the machine at the same time, extrudes them through a concentric nozzle, and cuts and seals them with a shutter. It can make everything from red bean buns, mooncakes, and mochi to croquettes and tangyuan, and it plays a different role from a forming machine, which only shapes the product.

The Co-Extrusion Principle: How Dough Wraps Filling in a Continuous Flow

An encrusting machine meters the dough and the filling separately, brings them together in a concentric double-layer nozzle, and extrudes a continuous rope with filling in the center and dough around the outside, which a shutter then cuts. Feeding them separately is what makes the ratio adjustable and the weight consistent.

Feeding Mechanisms: Screws, Vane Pumps, and Roller Feeding Compared

An encrusting machine pushes the dough and filling into the nozzle, most commonly with twin screws plus a vane pump for metering, though roller feeding and cycloid flow regulators are also used. Different feeding methods suit materials of different hardness and elasticity, and the quality of the design directly affects gluten and weight.

Cutting and Sealing: How a Shutter Turns a Filled Rope into Individual Pieces

After the filled rope is extruded from the nozzle, a shutter made of several blades arranged in a ring closes like a camera iris, pinching off the rope and gathering the dough to cover the cut. The conveyor below moves up and down in sync to support the bottom, so the product comes out round without leaking filling.

How to Adjust the Ratio of Dough to Filling (Encrusting Ratio)

The dough-to-filling ratio on an encrusting machine is adjusted through the speed ratio of the two feed systems for dough and filling. RHEON's KASEIJIN series lists a ratio from 1:0 to 0:1, but extremely thin dough and very high filling content are still limited by the dough's extensibility, the firmness of the filling, and sealing conditions.

Weight Control: How Does an Encrusting Machine Keep Every Piece the Same Weight?

Whether each piece from an encrusting machine weighs the same depends on whether the feeding mechanism fills completely every time, whether the ingredients are uniform, and whether the control system can compensate. Microcomputer control turns speed and timing into stored numbers, making it easier to reproduce the same conditions than with mechanical adjustment.

Three Encrusted Product Shapes: Balls, Bars, and Continuous Cylinders

Encrusting machines most often make balls; lengthening the shutter interval produces tawara (bale) shapes and bars, and skipping the cut produces a continuous cylinder. Changing shapes usually starts with adjusting settings, then changing nozzles or adding peripherals as needed; two-color and three-layer products rely on special nozzles and triple-encrusting units.

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