At present, domestic corrugated paperboard has foaming in varying degrees, which greatly affects the quality of corrugated board. If the sum of the area of degumming parts per square meter is greater than 500px-2, the board is unqualified. Effectively control and eliminate degumming and blistering defects, it is necessary for manufacturers to improve product quality and reduce costs!
There are four main reasons for the foaming of corrugated cardboard. If the correctness is solved in a targeted manner, there will be no such troubles.
Situation one
When the single-sided machine is running at high speed, a continuous, usually spherical, unbonded zone appears in the center of the single-sided web or on a portion of the web across a substantial portion of the web.
Cause Analysis
1. Insufficient heat leads to white paste line
2, inaccurate pressure roller high
3, wet lines on the paper
4. The tension of the paper or core paper on the whole paper is inconsistent
5, the gelatinization temperature is too high
6. Crystalline paste line appears when the heat is excessive
7, the pressure roller position is not accurate
Improve strategy
1. Check the steam pressure in all pressure pipes, siphon and steam quality
2. Check the high pressure of the pressure roller and adjust according to the equipment manufacturer's standard.
3, increase the tension or wrap angle to increase the temperature of the paper and core paper
4, check for unaligned equipment parts
5. Check the rollers for improper wear and use an adjustable tension roller to ensure uniform tension.
6. Check the gelatinization temperature and adjust to the appropriate standard
7. Reduce the wrap angle on the paper preheater and core paper preprocessor
8. Retract the pressure roller frame and check the hydraulic and pneumatic roller drive system for normal operation.
Situation two
Although there is a phenomenon of scraping the adhesive on the top of the corrugated board, the corrugated medium has a slack phenomenon before entering the nip point of the lower corrugating roll.
Corrugated roll
Cause Analysis
1. Vacuum or insufficient pressure
2, vacuum hole or corrugated roller gap blockage
3, there is dirt on the corrugated roller
4, corrugated roller occlusion pressure is insufficient
5, corrugated roller bearing wear
6, corrugated roller heat is insufficient
7, high pressure wear in the pressure roller
8. The rubber roller hits the corrugating roller tip
9, the position of the guide dog is not properly adjusted
Improve strategy
1. Adjust the clearance between the guide pawl and the lower corrugating roller, and the clearance between the guide pawl and the pressure roller.
2, increase vacuum and pressure
3, remove the dirt between the hole and the gap
4, remove the dirt on the corrugated roller
5, improve the occlusion pressure
6, replace the bearing
7. Check the siphon and see if there is condensation on the steam drum.
8, replace the pressure roller
9. Increase the gap between the top roller and the corrugating roller
Situation three
There is no paste on the paper.
Cause Analysis
1. The gap between the rubber roller and the corrugating roller is too large.
2. The gap between the rubberizing roller and the metering roller is too small
3. The steam condensate drops on the rubber roller
4. The cooling device on the rubber roller leaks
5, the gelatin on the paste anti-spray baffle wipe off the paste on the core paper
6, the paste liquid level in the paste plate is too low
7. Poor or no contact with corrugating rolls and pressure rolls
8, the pressure roller in the middle is not correct
9, the pressure roller position is not correct
Improve strategy
1. Reduce the gap between the top roller and the corrugating roller
2. Increase the gap between the top roller and the metering roller
3. Repair the steam condensate drain
4. After disconnecting the flow of water to the cooling jacket, observe whether the problem is solved and repair the cooling jacket.
5, remove the paste on the anti-splash baffle
6, improve the paste level
7, check the pressure roller pressure load
8. Adjust the medium and high according to the equipment supplier's standard specifications.
9. Retract the pressure roller to stop the moving parts, check the hydraulic and pneumatic rollers, and drive the system to make it run normally.
Situation four
When the single-sided machine starts, the cardboard foams, but the machine stops running for a while and then restarts, and the foaming phenomenon disappears.
Cause Analysis
1. Condensate is deposited in the lower corrugated or pressure roller
2. When the lower corrugating roller is not heated in the vacuum system, or the vacuum chamber on the lower corrugating roller is used to obtain the vacuum effect, the deformation of the lower corrugating roller is caused.
Improve strategy
1. Check the siphon and see if there is condensate deposit in the steam roller.
2. Check the pressure difference between the steam input pipe and the return pipe. The minimum pressure difference during normal operation must not be less than 5 psi.
3. Consider disengaging the upper corrugating roller and the lower corrugating roller and let it idle after stopping the operation. If possible, reinstall the heated corrugating roller. If the consumption of the following method is less than the consumption when the corrugating roller is started under cooling, it can be considered: cutting the core paper and idling the single-sided machine until the temperature is reached, then reinstalling the core paper and starting, so that it can be solved.
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