Automatic Pulp Molding Machines

Automatic Pulp Molding Machines

Several typical automatic pulp molding machines are introduced below:

1. Cold and Hot Pressing No Transfer Molding Machine

Structural Principle: This machine, as shown in Figure 4-23, uses a quantitative pulping and suction filtration molding process. It follows with cold pressing to remove excess water and uses minimal energy for drying and shaping. The transmission system employs a dual-proportion hydraulic control for pressure and flow, allowing variable speeds and smooth operation, with mold forces reaching 300-400KN.

(1) Working Process:

• Suction Filtration Molding: Pulp at 0.4% to 0.7% concentration is injected into the mold tank. Vacuum suction forms a wet paper mold with 33% to 36% dryness. Cold pressing further dehydrates it. The cold pressing upper mold moves quickly, slowing down as it nears the mold to ensure a smooth closure. Maximum pressure reaches 400kN, forcing out water and reducing energy needs for hot pressing. Post-cold pressing, dryness exceeds 50%. The mold opens, transferring the wet paper mold.
• Hot Pressing Shaping: The cold pressing upper mold rises, and the hot pressing lower mold moves beneath it. They close, transferring the wet paper mold. The upper mold rises, and the lower mold returns to its initial position. The hot pressing upper mold descends, closing with the lower mold to dry and shape the mold.
• Product Output: Products either fall from the hot pressing upper mold to the transfer position or are lifted by a mechanical hand and placed on a conveyor for further processing.

(2) Structural Features:

Compact and small-footprint, this machine saves energy with its cold pressing process and hydraulic system. It pairs one suction filtration molding and cold pressing set with two hot pressing sets, optimizing time allocation between processes.

2. Single Hot Press Transfer Molding Machine

Working Process:

• Suction Filtration Molding: Pulp is injected into the tank, forming a wet paper mold after vacuum suction. The mold closes with the transfer mold, adsorbing the wet paper mold. It then moves to position 2, transferring the mold to the hot pressing lower mold.
• Hot Pressing Shaping: At position 3, the hot pressing upper mold presses down for shaping. After completion, the product remains in the lower mold.
• Product Output: A mechanical hand with a suction cup moves to position 3, picks up the product, and places it on a conveyor belt.

Structural Features:

Despite its compact design, this machine has limitations. It lacks effective cold pressing and sufficient hot pressing force. The mismatch between molding and shaping cycles causes inefficiency. An improved version adds an extra hot press position to enhance efficiency.

3. Combined Hot Press Transfer Molding Machine

Working Principle:

This machine forms wet paper molds by scooping pulp from a pool. The suction filtration mold sinks and forms a mold through vacuum suction. It then transfers the mold to a hot pressing shaping position, where the process repeats.

Structural Features:

Large and scattered, this machine combines individual units, leading to higher energy consumption. Its fluctuating pulp concentration and lower mold closing force result in inconsistent product weight and quality.