Resin Sand Mixing Machine Safety Precautions
A. Personnel and Safety Protection
Operators must undergo specialized training to familiarize themselves with the equipment structure, electrical control, metering pumps, and emergency stop buttons. Unlicensed personnel are prohibited from operating.
Complete personal protective equipment: dust masks, protective glasses, solvent-resistant gloves, protective clothing. Mandatory ventilation in the area. Resin and curing agent volatilize toxic substances, avoid inhalation and prolonged skin contact.
During operation of the resin sand mixing machine, do not extend hands or tools into the mixing tank, agitator cage, or feeding/outlet ports; for maintenance and cleaning, power must be cut off, and a dedicated person must supervise.
No open flames or smoking on site. Resin and curing agent are flammable chemicals. Equip with dry powder fire extinguishers.
B. Pre-check before starting the resin sand mixing machine
1. Mechanical body inspection
Tighten all bolts: large arm, agitator cage, blades, liners, shock-absorbing springs. No loosening, cracking, or deformation.
Clean the accumulated sand and residual sand on the inner walls of the mixing tank and agitator cage; replace blades with excessive wear or excessive gap immediately; otherwise, the mixing will be uneven and the strength will be insufficient.
Check the opening and closing of the discharge door and the sand valve smoothly, without sand sticking or getting stuck.
Lubrication: Add lubricating grease to bearings and reducers. Add oil to the vibration motor every 15 days. Regular maintenance of the high-speed agitator bearings.
2. Air system
Drain the air tank first, then stabilize the air source pressure at 0.4-0.6 MPa. Check for no air leakage in the pipelines and no leakage at the joints; ensure the atomization nozzles are unobstructed and free of resin blockages.
3. Liquid material metering system (core, directly affecting the sand performance)
Check the liquid levels of resin and curing agent tanks are sufficient, verify the model, and ensure there is no stratification, sedimentation, or deterioration; seal the opened containers to prevent moisture absorption and contamination.
Check for no leakage in the gear pumps (resin) and diaphragm pumps (curing agent) and no blockages in the pipelines; perform liquid material return and exhaust every morning to ensure accurate metering.
Regularly calibrate the metering flow rate, and prohibit production if the error exceeds the process range; ensure the nozzles have good atomization, no dripping, and no uneven spraying.
4. Electrical and auxiliary equipment
Check for no damage to the cables and reliable grounding of the equipment; test the emergency stop, sand supply, and overload alarm functions.
Start the dust removal, sand conveying, magnetic separation, and other supporting equipment first, run at no-load for 1-2 minutes without abnormal sounds, shaking, or odors before feeding.
5. Raw sand inspection
The sand bin should have no stones, metal debris, or wet sand; control the moisture and temperature of the raw sand. Hot sand needs to be cooled; otherwise, the usable time will be significantly reduced and the hardening will be out of control.
C. Operating Specifications during the operation of the resin sand mixing machine
Starting sequence of the resin sand mixing machine: dust removal → air source → main motor of the mixing machine → sand supply → first spray curing agent, then spray resin (in the process standard sequence); reverse operation for shutdown: stop the supply of liquid → stop sand supply → idle rotation to remove the remaining sand → stop the main machine → turn off the air source, dust removal, and the main power supply.
Do not force start under load; the interval between two starts should be ≥ 5 minutes to prevent burnout of the motor and frequency converter.
Supply sand evenly and continuously, do not stop the sand supply or add sand suddenly; always observe the sand discharge status: the sand should be loose, without dry sand clumps, and without localized dampened and compacted blocks.
Monitor the liquid material ratio, sand temperature, and environmental temperature: shorten the usable time in hot weather, complete the casting as soon as possible after each discharge, and do not reuse the sand that has exceeded the time limit.
During the initial stage of operation, the sand ratio of the first sand is unstable; it cannot be used as surface sand, but can only be used as back sand.
Any abnormal noise, severe vibration, liquid leakage, blockage of materials, or overheating of the motor should be immediately stopped, power cut for inspection, and prohibited from running with faults.
Do not arbitrarily adjust the flow rate of the metering pump, the speed of the motor, or the angle of the blades. Changes to parameters must be confirmed by the process personnel and recorded.
Continuously monitor the accumulation of dust in the dust collector, and clean it in time. Stop the machine if the dust exceeds the limit.
D. Cleaning and maintenance after shutdown (daily must be done)
After stopping the supply of sand, let the agitator cage idle to remove all the sand from the tank before shutting down.
Turn off the power supply, lock the machine, thoroughly clean the residual resin sand clumps in the mixing tank, blades, nozzles, and pipelines; do not use hard objects to strike the accumulated sand blocks on the inner wall of the tank to avoid deformation of the liners and blades.
After cleaning, apply a thin layer of demolding agent on the inner wall, blade rods, and blades to prevent sand clumps from sticking and blocking the next day.
Short-term shutdown of liquid pipeline: Rinse the nozzle and pump body with the matching diluent to prevent resin from solidifying and blocking the pipeline; for long-term shutdown, empty all liquid materials and clean the entire liquid pipeline.
Clean the machine body and surrounding areas, classify and collect sand and waste liquid, and do not allow them to flow randomly and pollute the ground.
Daily check the wear of the blades and liners of the resin sand mixing machine; conduct comprehensive lubrication of moving parts once a week; calibrate the metering pump and tighten all connecting parts once a month; replace the reducer and bearing lubricating grease every six months.
E. Key points of process control for resin sand mixing machine
Add resin and curing agent according to the process ratio; do not add them randomly based on experience; an imbalance in the ratio may result in non-hardening, brittle, mold adhesion, and sanding defects.
Control the temperature of the raw sand between 20-35℃; for temperatures above 40℃, the usable time will sharply decrease; adjust the proportion of the curing agent appropriately in winter due to low temperatures.
Separate and test the moisture content of new and recycled sands from different batches; unqualified sands must not be mixed.
Expired, stratified, or deteriorated resin / curing agent must not be used; to avoid batch waste of sand.
F. Emergency response and prohibited behaviors for resin sand mixing machine failures
Do not open the cover, clean with hands, or cross over moving parts while the machine is running;
Do not work without ventilation or protection for a long time;
Do not frequently jog, forcibly start with materials;
Do not disassemble the electrical control, metering pump, or pneumatic components without being an electrician;
Do not bring open flames close to the liquid material storage tank or the sand mixing area.
Common fault handling
Uneven mixing, local dry clumps: Check for nozzle blockage, pump leakage, blade wear, and inconsistent sand supply;
No liquid material output / low flow rate: Pipe crystallization blockage, immediately stop the machine to clean the pump and nozzle;
Overload trip of the motor: Accumulated sand and blockage in the trough, blade jammed with foreign objects, power off for sand cleaning before retesting;
Fast sand hardening, too short usable time: High sand temperature, excessive curing agent, high environmental temperature, reduce temperature and lower the curing agent ratio.
G. Precautions for long-term shutdown storage
Empty the sand tank completely, clean all liquid pipeline and metering pump;
Apply anti-rust oil to metal parts, seal the nozzle;
Turn off the main gas source and main power supply, cover the equipment to prevent dust;
Run the equipment at short intervals once a month to prevent rust and jamming of bearings and pump body.