In the fiber materials course, the manual copying machine is the core equipment for preparing uniform wet fiber sheets (hand copied sheets), which is used for subsequent physical performance testing. To ensure the accuracy and reproducibility of experimental results, strict operating procedures must be followed and effective data optimization must be carried out.

1、 Operating standards

Preparation stage:

Preparation of fiber suspension: Accurately weigh the dry fibers and fully disperse them in a standard disperser until there are no fiber bundles. The concentration needs to be calculated and recorded, which is the basis for subsequent quantitative calculations.

Pre copying inspection: Ensure that the mesh of the copying machine is clean and free of residue, the upper and lower forming meshes are aligned, and the vacuum system and waterway are unobstructed.

Copying process:

Quantitative control: Based on the target, accurately measure the calculated volume of fiber suspension, pour it into a slicer filled with an appropriate amount of water, and stir thoroughly to evenly distribute the fibers.

Forming and dehydration: Open the drainage valve smoothly and quickly to ensure even water flow through the mesh, avoiding turbulence and uneven fiber distribution. Then turn on the vacuum pump and dehydrate under the set negative pressure until there is no visible water, ensuring that the fiber web is completely transferred to the woolen cloth.

Squeezing and drying:

Squeeze under standard pressure and time to further dehydrate and enhance fiber bonding.

Transfer the wet paper sheet to a dryer and dry it to a constant weight at a specific temperature. Avoid excessive temperature that can cause fiber keratinization and affect performance.

2、 Data optimization

Accurate recording and correlation of process parameters:

Record in detail all variables such as fiber type, beating degree, suspension concentration, tapping volume, vacuum degree, pressing pressure and time, drying temperature, etc.

Perform correlation analysis between process parameters and performance indicators such as quantification, thickness, tightness, tensile strength, and burst resistance of finished products. For example, analyzing the relationship between beating degree and tensile strength, or quantifying the relationship between opacity.

Statistical analysis and repeated experiments:

Prepare at least 3-5 parallel samples for each experimental condition to eliminate accidental errors.

Calculate the average and standard deviation of performance data, evaluate the repeatability of experiments and the reliability of data. If the standard deviation is too large, it indicates unstable operation or uneven fiber dispersion, and the operation process needs to be traced back.

Result correction and standardization:

All strength performance data should be calibrated to standard quantification (such as 80g/m ²) for comparison to eliminate bias caused by quantitative differences.

Compare and test with standard samples or commercial paper with known properties to verify the accuracy of the experimental system and operating methods.

By strictly adhering to operational standards and systematically recording, analyzing, and standardizing data throughout the entire process, students can not only successfully prepare qualified hand-made sheets, but also gain a deeper understanding of the impact mechanism of various process parameters on fiber network structure and final product performance, thus achieving a sublimation from "knowing how to operate" to "understanding principles".