Terrazzo Press Machine Machine Working Process

I. Terrazzo Production Process with Full-Automatic Terrazzo Press Machine

The core advantages of the full-automatic Terrazzo Press Machine lie in "precise measurement, automatic linkage, and efficient pressing". The entire production process relies on the coordinated operation of the equipment's hydraulic system, PLC control system, and automatic conveying system, with specific steps as follows:

(I) Pre-Production Preparation Stage

1. Raw Material Proportioning and Pretreatment
   1. Aggregates: Marble/granite chips with a particle size of 5-15mm (clean and free of impurities) are selected, accounting for 60%-70%. For colored terrazzo, 1%-3% inorganic pigments (such as iron o
   2. xide red, chromium oxide green) are added and mixed evenly with the aggregates.
   3. Cementitious Materials: P.O 42.5 ordinary Portland cement (meeting strength requirements) is used, accounting for 25%-30%. A 0.5%-1% water-reducing agent (e.g., naphthalene-based water-reducing agent) can be added to reduce the water-cement ratio to 0.3-0.35 and improve compactness.
   4. Pretreatment: Aggregates must be cleaned by a vibrating screen to remove impurities and dried in a dryer (at 60-80℃) until the moisture content is ≤3% to avoid air bubbles during pressing. Cement should be stored in a dry silo to prevent moisture absorption and caking.

1. Pre-Production Equipment Inspection
   1. Mold Inspection: Clean the steel molds (common sizes: 600×600mm, 800×800mm) of the full-automatic press to remove residual slurry. Check the sealing performance of the mold edges (to prevent slurry leakage); replace the mold if wear exceeds 0.2mm.
   2. Equipment Calibration: Set parameters via the PLC system—pressing pressure (15-25MPa, adjusted according to slab thickness: 15-18MPa for 20mm-thick slabs, 20-25MPa for 30mm-thick slabs), pressing time (10-15 seconds), demolding speed (50mm/s). Calibrate the hydraulic system oil level (must reach 80% of the oil tank scale) and the metering accuracy of the automatic feeding system (error ≤1%).
   3. Auxiliary System Testing: Start the automatic conveying roller table, dust collection system (for grinding dust collection), and curing area temperature-humidity control system to ensure no jamming or malfunctions.

 

(II) Automatic Feeding and Mixing Process

1. Precise Automatic Batching

Raw materials enter the automatic metering device through compartmentalized hoppers (aggregate hopper, cement hopper, pigment hopper). The PLC system controls the screw conveyor to feed materials according to the preset proportion (e.g., 65% aggregates, 28% cement, 2% pigments, 5% water). After metering, the materials are sent to the full-automatic mixing tank via a chute.

2. High-Speed Uniform Mixing

The mixing tank adopts a double-helix mixing structure, with a rotation speed set to 60-80r/min and a mixing time of 3-5 minutes (observe the slurry state: no caking and uniform color indicate completion). During mixing, the equipment automatically adds water to adjust consistency (qualified slurry should form a ball when held and disperse when dropped) to avoid slab deformation due to excessive thinness or poor compactness due to excessive dryness.

(III) Automatic Material Distribution and Hydraulic Pressing

1. Uniform Material Distribution

The mixed slurry is evenly spread into the steel mold by an automatic material distribution trolley (equipped with infrared positioning). The material distribution thickness is 5-8mm higher than the finished slab thickness (to reserve for pressing shrinkage). During distribution, the trolley moves reciprocally along the mold's diagonal, and the vibration motor (frequency: 50-60Hz) under the mold vibrates slightly to help the slurry fill the mold corners and reduce voids.

2. Full-Automatic Hydraulic Pressing

After material distribution, the mold enters the pressing station along the conveying roller table. The upper mold of the press descends automatically and presses according to the preset pressure and time:

1. Initial Stage: Low-pressure pre-pressing (5-8MPa) for 3 seconds to expel air on the slurry surface;
2. Middle Stage: High-pressure pressing (15-25MPa) for 8-12 seconds to compact the slurry (compactness ≥95%);
3. Late Stage: Pressure holding for 2 seconds to stabilize the slab structure.

During pressing, the PLC system monitors the pressure curve in real time. If pressure is abnormal (e.g., 10% lower than the set value), the equipment automatically shuts down and alarms to check for slurry leakage from the mold or insufficient slurry volume.

(IV) Automatic Demolding and Semi-Finished Product Conveying

1. Non-Destructive Demolding

After pressing, the mold enters the demolding station. The equipment lifts the terrazzo semi-finished product uniformly from the mold bottom via hydraulic ejector rods (ejector force: 8-10kN). Meanwhile, the side demolding push plate gently pushes the semi-finished product onto the conveying roller table (to avoid edge damage caused by direct falling).

2. Semi-Finished Product Pre-Inspection and Conveying

During conveying, the visual inspection system equipped with the equipment automatically checks the semi-finished product surface: if there are obvious cracks or corner defects (area >2cm²), the system marks and diverts them to the waste area. Qualified semi-finished products are sent to the constant temperature and humidity curing area via a closed roller table to avoid moisture loss due to exposure to the external environment.

II. Curing Process of Terrazzo Semi-Finished Products

Curing is crucial for ensuring terrazzo strength (compressive strength ≥50MPa, flexural strength ≥5MPa) and surface quality. It is divided into three stages—"initial curing, mid-term strengthening, late-stage stabilization"—and completed by the full-automatic curing system:

(I) Initial Curing (1-2 Days): Ensure Initial Setting Strength

1. Curing Environment Control

Place the semi-finished products in a full-automatic curing kiln, set the temperature to 20-25℃ (temperature difference ≤±2℃) and relative humidity ≥90%. The curing kiln maintains humidity via a steam humidifier and controls temperature via electric heating, automatically recording temperature and humidity data every hour (if humidity is lower than 85%, the system automatically sprays water to replenish moisture).

2. Initial Protection

Cover the semi-finished product surface with breathable non-woven fabric before curing (to prevent excessive moisture evaporation), and avoid moving them within the first 24 hours. After 24 hours, the products can be slightly turned over (via a full-automatic turnover machine to avoid surface scratches caused by manual contact) to check for moisture regain or cracks on the bottom. If there is slight moisture regain, reduce humidity to 85%-90% appropriately.

(II) Mid-Term Strengthening Curing (3-5 Days): Improve Structural Strength

1. Steam Curing (Optional, for Rush Orders)

To shorten the curing cycle, the steam curing mode can be activated: introduce saturated steam of 0.1-0.15MPa into the curing kiln, raise the temperature to 80-90℃, and perform constant temperature curing for 3 days. Ventilate three times a day (10 minutes each time) to expel condensed water in the kiln and prevent water spots on the slab surface.

1. Note: The heating rate ≤10℃/h and cooling rate ≤5℃/h to avoid slab cracking due to excessive temperature difference.

1. Natural Curing (Routine Choice)

For natural curing, maintain the curing kiln temperature at 20-28℃ and humidity at 80%-85% for 5 days. Keep the surface moist via the full-automatic sprinkler system (sprinkling once every 2 hours, water volume: 0.5L/m²) and regularly test the slab strength (sample test compressive strength on the 3rd day, which should be ≥30MPa; extend curing by 1 day if it fails to meet the standard).

(III) Late-Stage Stabilization Curing (2-3 Days): Adapt to Environment

1. Temperature and Humidity Transition

After mid-term curing, gradually reduce the curing kiln humidity (5%-10% per day) and temperature (2-3℃ per day) until they match the external environment (to avoid surface shrinkage and cracking caused by direct exposure), with a transition period of 2 days.

2. Finished Product Strength Testing and Handling

After curing, conduct sample testing:

1. Appearance: No cracks, color difference (color difference of the same batch ≤ΔE2.0), or corner defects on the surface;
2. Physical Properties: Compressive strength ≥50MPa, surface flatness error ≤0.2mm/m;

Qualified finished products are sent to the next process (e.g., full-automatic grinding and polishing). Unqualified products (e.g., insufficient strength) are crushed and recycled as aggregates to avoid waste.