The single-faced corrugating machine is the heart of the corrugated board production line. How to ensure that the single-face corrugated board meets the quality requirements has been widely concerned.
The quality problems of single-sided corrugated board are mainly:
Corrugated cardboard warping is a very headache problem, which seriously affects the quality of the next printing and slitting process. Due to the warpage of the cardboard, it is impossible to accurately position when entering the printing and grooving machine, resulting in inaccurate overprinting, inconsistent depth of the grooved chamfering position and inability to fine-tune, and sometimes wrinkles and creases on the surface of the cardboard. The reason for the warpage of the single-faced corrugated board is very simple, that is, the water content of the inner (core) tile is inconsistent or the thickness is inconsistent. Of course, to prevent the warpage of the cardboard, you must have a definition of "warping". Our understanding of the meaning of "warping" is that one-sided (see pit) cardboard is determined by corrugation, and the arc is bent downward (bending in the direction of the paper). On the contrary, it is regarded as a downward warp.
If the single-sided (see pit) paperboard is upturned, the reason is that the corrugated paper has more water than the core paper. If it is tilted down, the reason is: the corrugated paper has less water than the core paper or the core paper is higher than the corrugated paper. After determining the cause of the warpage of the cardboard, it must be separately resolved for the direction of the warpage of the cardboard.
Single-sided corrugating machine single-sided (see pit) paperboard can open the heat source of the corrugated paper preheating roller on the single-face corrugating machine while closing the heat source of one or two inner paper preheating rollers, correspondingly reduce the speed of the vehicle, and there is still warpage. Should increase the heat source of the paper preheating roller (increasing the electric heating tube, increase the air pressure, etc.) or increase the wrap angle of the corrugated paper on the preheating roller (take the method of increasing the tensioning shaft or adjusting the position of the tensioning shaft) When warping, you need to apply spray humidification to the paper. Make the paper and corrugated paper nearly the same.
When the single-sided corrugating machine has a single-sided (see pit) cardboard to be turned down, the heat source of the corrugated paper preheating roller on the single-face corrugating machine should be turned off, and one or two inner paper preheating roller heat sources should be turned on, and the heat source can be raised without degumming. Speed. If there is still warpage, it is necessary to increase the heat source of the paper preheating roller or increase the wrap angle on the preheating roller of the inner paper. When there is warpage, the corrugated base paper must be treated by spray humidification to make the paper moisture and The water in the paper is close to the same. S-type warpage of single-sided cardboard is generally caused by uneven distribution of moisture in the base paper. According to the warpage condition, the amount of glue applied or the partial paper with too low moisture is spray-humidified according to the above-mentioned warpage. It is best to measure the moisture content of the inner (core) and the corrugated paper separately by using a moisture tester before starting the machine, and then control the temperature of each roller separately for different moisture contents. In general, when the cardboard is off the machine, let it keep the micro-up (tile) warp, and take the positive and negative stacking method. After about one hour, the cardboard will completely return to the flat state.
If the cardboard is degummed in a large area, the reason is roughly as follows:
When the temperature of each roller is less than required, the vehicle speed is increased. (Open the paper, you can see the glue watermark that is not dry)
The viscosity of the adhesive is too low or the water ratio is too high, or the adhesive has expired and the adhesive has no viscosity.
The pressure of the pinch roller is too low to press the liner and the paper.
The viscosity of the adhesive is too high and becomes a paste at high temperatures.
The rubber roller and the lower corrugating roller are not parallel, and the gap is large and small. The big one can be degummed without applying glue. At this time, the rubber roller can be loosened first, and then the adjusting screw at the bottom is adjusted to the two ends in parallel to lock the adjusting nut. Tighten the rubberized roller, measure the gap between the two ends with a thickness gauge, or observe whether the amount of glue applied to both ends of the cardboard is uniform.
The amount of glue applied is too small. (The starch solid content per square meter is not less than 4 grams)
The temperature is too high and the speed is low. This phenomenon is a fake stick. When the paper is opened, only the glue mark is seen, and the paper will be peeled off without destroying the paper fiber.
Some of the paper guides are not aligned with the rubber roller, causing the rubber roller to fail to pass, and the glue cannot be applied to the corrugated peak. At this point, stop the paper and re-adjust the paper guide.
The reason for the degumming of the two ends of the cardboard is that the gap between the rubberizing roller and the lower corrugating roller is too small. In severe cases, the corrugated will break. If the cardboard is partially foamed, the cause may be:
The gap between the paper guide and the lower corrugating roller is too small, and the glue cannot be applied to the corrugated paper.
There is a foreign matter on the pinch roller and the lower corrugating roller drive gear, so that the pinch roller cannot press the corrugating roller.
The gap between the rubberized roller and the lower corrugating roller is too large, and the partial coating is not applied.
Corrugated rolls, rubberized rolls, and pinch rolls are partially worn or eccentric. The glue roller can be driven in while the machine is running, (the rubber roller must be in contact with the glue) to be close to the lower corrugating roller, and idling a few turns, and in detail, check whether the corrugating roller tip is completely stained with glue, such as partial no. Glue, check the corrugated roller and rubber roller for partial wear or eccentricity.
In short, no matter which kind of foaming or degumming, first check the degumming site with or without glue, and then analyze and eliminate according to the situation. Periodic partial degumming, especially when starting up. The reason for this is that the wall thickness of the pressure roller is not uniform, the wall of the degumming site is too thick, and the temperature rises slowly. If this situation is not serious, you can slow down the speed at the beginning and accelerate after the temperature of the wall thickness rises and reaches equilibrium. If the situation is serious, the pressure roller should be repaired.