The vacuum packaging machine is a key equipment for the storage and
transportation of quartz sand products, responsible for sealing and packaging
the dried quartz sand (with a sealing peel strength of ≥ 3N/15mm and a
measurement error of ≤± 2%). If the seal is not firmly sealed (prone to cracking
during transportation) and the measurement deviation is large (exceeding ± 5%),
it will cause the material to become damp, agglomerate, and increase losses.
Based on practical experience, summarize a three-step troubleshooting method to
quickly restore stable packaging performance.
Step 1: Check the sealing system and vacuum degree - prevent leakage of the
sealing core
Abnormal heat sealing structure and vacuum parameters are the main causes of
loose sealing.
Improper heat sealing temperature or pressure: If the temperature is below
160 ℃, the composite film may not be fully heat sealed; Beyond 200 ℃, the film
material is prone to burning, pasting, and brittleness; The pressure is below
0.3MPa, and the sealing is not tightly adhered. Use a temperature tester to test
and adjust the heat sealing temperature to 170-190 ℃ (select the low range for
PE film and the high range for PP film); Calibrate the cylinder pressure to
0.4-0.5MPa to ensure even sealing pressure.
Insufficient vacuum degree or short heat sealing time: Vacuum degree below
-0.09MPa, residual air in the bag causing moisture; Heat sealing time<1.5
seconds, incomplete heat sealing. Adjust the parameters of the vacuum pump to
stabilize the vacuum degree at -0.092~-0.095MPa; Extend the heat sealing time to
2-3 seconds and install a cooling fan to prevent immediate stress cracking after
heat sealing.
Sealing strip wear or foreign object attachment: Scratches on the sealing
strip exceeding 0.5mm, uneven heat transfer; Quartz sand fine powder adheres to
the sealing strip, resulting in a sealing gap. Replace the PTFE coated sealing
strip and clean the surface dust with a brush before each startup; Install dust
barriers at the sealing area to reduce fine powder pollution.
Step 2: Calibrate the measuring device and feed control - precise feeding is
key
Abnormal measuring institutions and feeding speeds can lead to measurement
deviations.
Inaccurate weighing sensor or blocked hopper: sensor zero drift (empty hopper
display exceeds ± 0.1kg), measurement benchmark deviation; Powder accumulation
at the discharge port of the hopper (thickness exceeding 5mm) and uneven feeding
speed. Calibrate the sensor with standard weights and control the zero point
error within ± 0.05kg; Install PTFE lining plate on the inner wall of the
hopper, clean the powder accumulation at the discharge port every week to ensure
smooth discharge.
Excessive feeding speed or gate failure: feeding speed exceeding 5kg/s,
material impact causing weighing fluctuations; Electromagnetic gate closing
delay (exceeding 0.2 seconds), causing deviation due to excessive feeding.
Adjust the speed of the spiral feeder through a frequency converter to control
the feeding speed at 3-4kg/s; Inspect the electromagnetic gate, replace the
aging electromagnetic valve, and ensure that the closing response time is ≤ 0.1
seconds.
Quantitative cup volume mismatch: The deviation between the quantitative cup
volume and the packaging specifications exceeds 3%, directly leading to
inaccurate measurement. According to packaging requirements (such as 25kg/bag),
replace the matching quantitative cup or adjust the height of the adjustment
plate inside the cup, and calibrate the volume error to within ± 1%.
Step 3: Adapt material characteristics and packaging parameters - source
optimization to improve stability
Improper material status and packaging parameters can exacerbate the
problem.
High moisture content or uneven particle size of materials: if the moisture
content exceeds 5%, the fine powder will stick together, resulting in poor
feeding; Coarse particles (>3mm) are mixed with fine powder, and the bulk
density fluctuates greatly. Ensure that the material is dried to a moisture
content of ≤ 3%. If there is a large difference in particle size, install a pre
homogenization bin to ensure uniform material density; Install a vibrator at the
feed inlet to prevent clogging of the fine powder bridge.
Inappropriate packaging bag specifications or materials: deviation between
bag opening width and sealing strip exceeds 10mm, incomplete heat sealing; The
thickness of the packaging bag is less than 8 threads, which is easily punctured
by the edges and corners of quartz sand. Select wear-resistant composite bags
with a thickness of 10-12 threads to ensure that the width of the bag mouth
matches the sealing strip; Add inner lining film inside the bag to enhance
puncture resistance.
Daily maintenance should pay attention to: cleaning the vacuum pump filter
element and checking the sealing strip status every day; Calibrate the weighing
sensor and vacuum level weekly; Monthly maintenance of electromagnetic gate and
cylinder sealing. By taking the above measures, the sealing peel strength can be
increased to 4N/15mm or more, and the measurement error can be controlled within
± 1.5% to ensure stable storage of quartz sand packaging. If there are still
problems, it is recommended to contact the manufacturer to test the
compatibility between the heat sealing parameters and the packaging bag, and
optimize the measurement control program.