Conveyors and Secondary Forming: Adding Flattening, Stamping, and Pleating After the Encrusting Machine

The Encrusting Machine Only "Wraps"; Shape Is Left to Downstream Equipment

What comes out of the encrusting machine's shutter is mostly round balls or short cylinders; see Three Product Shapes. But products on the market come in endless shapes: sun cakes (太陽餅) are flat, chive boxes (韭菜盒) are half-moon shaped, steamed buns have pleats on top, and mooncakes have patterns. Most of these shapes are created after encrusting, by "secondary forming" devices connected downstream.

How Are Filled Balls Pressed into Cakes?

The most common method uses rollers or press plates to flatten the balls from above or from the sides:

• Roller flattening: One or more sets of rollers are mounted above the conveyor, gradually flattening the balls as they pass. RHEON's forming conveyor can be fitted with up to three "longitudinal and transverse rollers," which press products into ovals using rollers arranged lengthwise and crosswise, with the speed of each set controlled individually. The example on its website is making hamburger patties downstream of a KASEIJIN (火星人).
• Staged pressing: Pressing too flat in one go tends to tear the dough and expose the filling, so pressing is often done gradually in two or three stages.
• Anti-stick: The rollers come with drip tubes and scrapers to keep products from sticking.

Dong-Yih Machinery also offers flatbread pressing machines. If you want to press filled balls into cakes, call us to discuss how to set them up together.

Stamping, Embossing, and Half-Moon Shapes

• Stamping: A patterned die is pressed down from above to imprint patterns or lettering like those on mooncakes and pineapple cakes. The list of peripherals on RHEON's U.S. website includes a "Heat Stamper" for stamping and shaping.
• Half-moon pressing: Balls are clamped from both sides with special dies and pressed into half-moons, suitable for products such as stuffed pancakes (餡餅), curry puffs, and chive boxes. RHEON's Half Moon Stamper uses sensors to detect each product and press it one at a time, at up to 3,000 pieces/hour; dies can be custom-made for the customer's products and changed quickly.
• Guillotine cutting: RHEON's forming unit conveyor consists of two belts; with a guillotine fitted, it uses the speed difference between the two belts to separate the products.

How Are the Pleats on Steamed Buns Made?

The ring of pleats on top of a steamed bun is what many customers care about most: "Can a machine make it look handmade?" There are two approaches:

Form pleats during sealing: As the shutter seals, the blade shape or a twisting motion creates a pattern on top.

Pleat after encrusting: RHEON's pleating machine for Chinese-style steamed buns is connected downstream of a KASEIJIN. According to the manufacturer, it uses curved blades to create pleats like those made by hand, and another version can also pinch and twist the top. Pleats can number 9, 12, 18, or up to 24. There are two ways to change the number of pleats: swap the entire pleating unit, or remove some of the blades from the unit. There are also dedicated parts suited to xiaolongbao (小籠包), for small products of about 50 g or less that are hard to twist.

Dong-Yih Machinery's DY-201 Automatic Steamed Bun and Mantou Machine is built around "a traditional technique that does not break down the dough structure" and can produce meat buns, vegetable buns, red bean buns, xiaolongbao, longevity peach buns (壽桃), and more. For the complete bun forming process, see How a Steamed Bun Machine Works.

Can Stamping Dies Be Added? How to Arrange the Conveyors

Yes, but keep a few things in mind:

• Speed matching: The pace of secondary forming must keep up with the encrusting machine's output, or products will pile up on the conveyor.
• Spacing and number of rows: Products from multi-row encrusting machines come out closely packed, and some downstream equipment needs the row spacing adjusted. RHEON has a "narrowing conveyor" whose left and right belt speeds can each be adjusted between 2 and 20 meters per minute.
• Panning: The last stage is often an automatic panning machine that places finished products onto baking trays or steamer racks, reducing hand contact.
• Cleaning: Belts, rollers, and scrapers that contact the product must be removable for washing.

Safety Reminder

Secondary forming equipment has many rollers, press plates, and belts, all of which are places where hands can easily be caught or pinched. Before cleaning, adjusting, or changing dies, always stop the machine, cut the power, apply lockout/tagout according to factory rules, and confirm that all moving parts are completely still before reaching in.

FAQ

Q: How are filled balls pressed into cakes?
A: A forming conveyor is connected after the encrusting machine, using rollers or press plates to flatten the balls in stages; to stamp patterns, add a stamping die.

Q: How are the pleats on steamed buns made?
A: They can be formed during sealing, or a pleating machine can create them with curved blades after encrusting. RHEON's pleating machine can make 9 to 24 pleats and can also add a twist.

Q: Can stamping dies be connected to an encrusting machine?
A: Yes. Common options include pattern stamps, half-moon pressing dies, and guillotines. The key is matching speed and row spacing to the encrusting machine.

Q: What should I do if the dough keeps tearing during flattening?
A: Press in stages with less compression per stage, and check the dough's extensibility and the dough-to-filling ratio. Thin dough is especially prone to tearing when flattened.