How to Produce 1200*600mm Terrazzo Slabs Using a Fully Automatic Terrazzo Tile Production Line

In the field of architectural decorative materials, the demand for 1200*600mm terrazzo slabs has been increasing due to their regular dimensions and excellent decorative effects. Their production relies on the efficient operation of fully automatic Terrazzo Tile Production Lines. However, the large size of the slabs makes them prone to quality issues such as cracking, uneven surfaces, and color inconsistency during production. Combining the process characteristics of automatic production lines, this article analyzes quality risk points from a full-process perspective and proposes targeted preventive measures to help enterprises stably produce high-quality products.

I. Raw Material Stage: Laying a Solid Foundation for Quality and Preventing Risks from the Source

The quality of raw materials directly determines the final quality of terrazzo slabs. The standardized operation of automatic production lines has higher requirements for the consistency of raw materials, and the following key points must be focused on:

1. Aggregate Screening and Pretreatment

1. Select marble or granite aggregates with uniform particle size (recommended 2-5mm, suitable for the structure of 1200*600mm slabs) and qualified hardness (Mohs hardness ≥ 6), and avoid aggregates containing impurities or weathered particles. Before automatic feeding, conduct graded screening using a vibrating screen, and simultaneously use magnetic separation equipment to remove metal impurities, preventing equipment damage or scratch formation during subsequent grinding.

1. For aggregates with high water absorption (such as some limestone), conduct pre-drying treatment (control moisture content within 3%) to prevent uneven hydration of the cement matrix caused by water absorption of aggregates, which would lead to concentrated internal stress in the slabs and subsequent cracking.

2. Control of Cementitious Materials and Additives

1. Use 42.5-grade ordinary Portland cement to ensure qualified strength and good stability. For each batch of cement, test the initial setting time (≥45min) and final setting time (≤600min) to avoid insufficient slab strength or shrinkage cracking caused by fluctuations in cement quality.

1. Select inorganic pigments with strong weather resistance and good dispersibility, and control the mixing ratio error with cement within ±0.1%. Before automatic batching, pre-mix the pigments with a small amount of cement to make color powder, then add it through the precise batching system of the production line, preventing color inconsistency on the slab surface caused by pigment agglomeration.

3. Precise Setting of Water-Cement Ratio

According to the dimensional characteristics of 1200*600mm slabs, the water-cement ratio must be strictly controlled between 0.32 and 0.35. An excessively high water-cement ratio may increase the shrinkage rate of slabs, leading to surface sanding and cracking; an excessively low ratio will reduce the fluidity of the mixture, making it difficult to fill the corners of the mold during automatic material distribution and forming voids. Use the intelligent water supply system of the production line to monitor the humidity of the mixture in real time and dynamically adjust the water addition amount to ensure stable mixture conditions.

II. Core Stages of the Automatic Production Line: Standardizing Operation Processes and Eliminating Process Hazards

The fully automatic Terrazzo Tile Production Line includes key processes such as batching, mixing, material distribution, compression molding, curing, and grinding/polishing. Parameter deviations in any process may cause quality issues, requiring targeted optimization:

1. Precise Batching and Uniform Mixing

1. Adopt an automatic batching system equipped with load cells to dynamically weigh raw materials such as aggregates, cement, pigments, and water, controlling the batching error of each batch within ±0.5%. Calibrate the load cells with standard weights regularly (recommended once a week) to avoid uneven mixture ratio caused by inaccurate weighing, which would affect slab strength or color.

1. Use a twin-shaft forced mixer for the mixing process, and set the mixing time to 3-5 minutes (adjust according to the dryness/wetness of the mixture) to ensure uniform material mixing. During mixing, monitor the mixture status in real time through the observation window. If agglomeration or segregation occurs, promptly adjust the mixing speed (recommended 300-400r/min) or add a small amount of dispersant to prevent local density differences during material distribution, which would lead to uneven slab surfaces.

2. Uniform Material Distribution and Precise Compression Molding

1. Due to the large area of 1200*600mm slabs, a combined method of "layered material distribution + spiral material distribution" must be adopted for automatic material distribution: first, evenly spread the mixture on the bottom of the mold through a conveyor belt (thickness approximately 1/3 of the total slab thickness), then complete the remaining material distribution using a spiral distributor. At the same time, turn on the mold vibration device (vibration frequency 50-60Hz) to discharge air bubbles inside the mixture, avoiding voids or loose areas after molding.

1. Use a fully automatic hydraulic press for compression molding, set the pressure to 25-30MPa, and the pressure holding time to 15-20s. Before molding, check the flatness of the mold (error ≤0.2mm/m); if the mold is deformed, replace or repair it promptly to prevent slab warping after molding. During the compression process, monitor pressure changes in real time through the press's pressure sensor; if the pressure fluctuation exceeds ±1MPa, stop the machine immediately for inspection to avoid insufficient local strength of the slab caused by uneven pressure.

3. Constant Temperature and Humidity Curing: Controlling Shrinkage and Preventing Cracking

1. After molding, immediately transfer the slabs to a fully automatic curing kiln for curing, with a curing period of no less than 7 days. Control the temperature inside the curing kiln at 20-25℃ and the relative humidity at ≥90%, avoiding sudden temperature changes (temperature difference ≤5℃/h) or insufficient humidity, which would cause rapid evaporation of surface moisture and generate shrinkage cracks.

1. During curing, adopt a layered stacking method, and place elastic cushioning pads (such as rubber pads) between each layer of slabs to avoid edge/corner damage caused by mutual extrusion between slabs. Meanwhile, check the surface condition of the slabs regularly (every 24 hours); if fine cracks are found, promptly spray curing agents (such as silane-based curing agents) to prevent crack expansion.

4. Refined Grinding and Polishing: Ensuring Surface Quality

1. After curing, the slabs enter the automatic grinding and polishing production line, adopting a four-stage process of "rough grinding - medium grinding - fine grinding - polishing":
   1. Rough grinding: Use 60-80 mesh diamond grinding pads, control the grinding depth at 1-2mm to remove surface laitance of the slabs, expose the original appearance of aggregates, and correct the flatness of the slabs (error ≤0.3mm/m);
   1. Medium grinding: Use 150-200 mesh grinding pads to further refine the surface and eliminate rough grinding marks;
   1. Fine grinding: Use 400-600 mesh grinding pads to reduce the surface roughness to Ra ≤1.6μm;
   1. Polishing: Use 800-1200 mesh polishing pads, combined with polishing agents (such as resin-based polishing agents), to make the surface gloss of the slabs ≥80 gloss units.

1. During grinding, ensure that the grinding heads are closely attached to the slab surface, control the grinding speed at 1-1.5m/min (adjust according to the mesh size of the grinding pads), and simultaneously use the cooling water system for continuous cooling to avoid surface spalling caused by differences in thermal expansion and contraction between aggregates and the cement matrix due to excessive grinding temperature.

III. Equipment Maintenance and Quality Inspection: Building a Full-Cycle Guarantee System

1. Regular Equipment Maintenance: Ensuring Stable Operation of the Production Line

1. Inspect key components of the automatic production line weekly: clean residual materials in the silos of the batching system to prevent material agglomeration and blockage; check the sealing rings of the hydraulic press to avoid insufficient pressure caused by hydraulic oil leakage; calibrate the grinding head position of the grinding machine to ensure uniform grinding trajectory.

1. Conduct comprehensive equipment maintenance monthly: replace the mixing blades of the mixer (if the wear amount exceeds 5mm); check the temperature and humidity sensors of the curing kiln to ensure accurate data; lubricate the transmission components of the production line (such as conveyor rollers and gears) to avoid equipment jamming that affects production rhythm.

2. Comprehensive Finished Product Inspection: Preventing Unqualified Products from Leaving the Factory

1. Appearance inspection: Use a visual inspection system to inspect the surface color, flatness, cracks, and corner defects of 1200*600mm slabs. The area with color inconsistency shall be ≤5%, the surface flatness error shall be ≤0.5mm/m, there shall be no cracks longer than 5mm, and the depth of corner defects shall be ≤2mm.

1. Physical performance inspection: Randomly select 3 slabs from each batch to test compressive strength (≥60MPa), flexural strength (≥8MPa), and water absorption (≤0.5%). If the inspection fails, expand the sampling range, identify the problematic processes, rectify them, and then restart production.

1. Dimensional deviation inspection: Use a laser length measuring instrument to inspect the length and width deviations (≤±1mm) and thickness deviation (≤±0.5mm) of the slabs to ensure the dimensions meet customer requirements.