In glass fiber production, "stability" is the main focus
In glass fiber production, "stability" is the core principle to ensure product quality, production efficiency and economy. The production process of glass fiber is complex, involving multiple key links such as high-temperature melting, high-speed drawing, and impregnation agent coating. Fluctuations in any link may affect the mechanical properties, uniformity and yield of the fiber. The following is the specific connotation and implementation path of "stability" from multiple dimensions:
I. Raw material stability: the basis of production
1. Accurate raw material ratio
The main raw materials of glass fiber (quartz powder, pyrophyllite, limestone, quicklime, soda ash, etc.) need to be mixed in strict proportions. Fluctuations in composition will cause changes in the viscosity and melting temperature of the glass liquid, which will directly affect the stability of the drawing process. For example, insufficient aluminum content affects strength.
2. Raw material purity control
Impurities (such as metal oxides such as iron and titanium) will introduce defects, resulting in microcracks inside the fiber or surface defects. The raw materials need to be pre-treated by magnetic separation, flotation, etc. to ensure that the purity meets the standard (usually SiO₂ purity must be ≥99.5%).
3. Particle size uniformity
The particle size distribution of raw material particles affects the melting speed and homogenization degree. The use of particle size classification technology (such as vibration screening) can avoid local unevenness of glass liquid caused by incomplete melting of coarse particles.
2. Process parameter stability: core control point
1. Melting temperature control
Temperature uniformity: The temperature in the kiln needs to be controlled within ±5℃. Uneven temperature gradient will cause turbulent convection of glass liquid and form bubbles or stones. The use of multi-zone electric melting + closed-loop PID control can optimize the temperature field.
Melting efficiency: Too low temperature will prolong the melting time (increase energy consumption), and too high temperature will aggravate the erosion of refractory materials (shorten the life of the kiln).
2. Wire drawing process stability
Leakage plate temperature: The temperature of the leakage plate also affects the viscosity of the glass liquid. Temperature fluctuations of ±1℃ may cause fiber diameter deviations ≥5%. Thermocouples are required for temperature detection to achieve real-time adjustment of the leakage plate power by temperature control.
Wire drawing speed: High-speed wire drawing needs to be precisely matched with the glass liquid flow rate. Speed fluctuations can cause wire breakage or uneven diameter. Servo motors can be used with tension sensors to achieve dynamic compensation.
3. Wetting agent coating consistency
Coating amount control: The solid content and coating thickness of the wetting agent (such as epoxy resin emulsion, silane coupling agent) affect the fiber bundling and antistatic properties. Real-time monitoring of oil temperature and regular measurement of oil coating speed.
Curing process: The curing temperature (200-300℃) and time must be precisely matched with the resin cross-linking reaction kinetics to avoid under-curing (adhesion) or over-curing (embrittlement).
III. Equipment stability: guarantee of efficient operation
1. Key equipment maintenance
Kiln life management: Refractory materials will continue to erode during high temperature. Regularly check the erosion degree of the inner wall of the kiln to avoid the risk of leakage.
Leakage plate maintenance: Leakage plates are constantly aging during use, and they should be replaced regularly. Leakage plates are used with coolers. Coolers are easily oxidized in high temperature environments, reducing the cooling effect, and the sheets should be washed regularly.
Regular maintenance of wire drawing machines: During high-speed operation, some parts of the wire drawing machine are severely worn, which affects the operation of the wire drawing machine. Regular maintenance of the wire drawing machine and replacement of some parts should be performed to ensure the stability of the wire drawing machine.
IV. Quality management system: systematic stability control
1. Application of SPC (Statistical Process Control)
CPK (Process Capability Index) analysis is performed on key parameters (such as glass liquid viscosity and fiber diameter), and CPK ≥ 1.33 is considered a stable state.
2. Six Sigma method
Reduce process fluctuations through DMAIC (Define, Measure, Analyze, Improve, and Control)
V. Personnel operation specifications: Human factor noise reduction
1. Standardized operation (SOP)
Develop a detailed operation manual to standardize the wire drawing and loading actions, and other standard data related to regular operations.
2. Skill training and assessment
Operators need to pass the melting process simulation system assessment to ensure emergency response capabilities for abnormal working conditions (such as sudden temperature drop).
VI. Environment and energy management: external interference suppression
1. Ambient temperature and humidity control
The wire drawing workshop needs to maintain a constant temperature (20±2℃) and humidity ≥70% to avoid static electricity adsorption of dust on the fiber and suspended particle size requirements at the air outlet of the air conditioner.
2. Stable energy supply
A dual-circuit power supply + backup gas system is used to prevent power outages from causing a sudden drop in kiln temperature (risk of glass liquid solidification).