In order to attract more consumers’ attention, more and more corrugated box manufacturers choose offset printing or preprint (flexographic printing, gravure printing) to make corrugated boxes.Purchase Instructions for Corrugated Base Paper
However, due to the purchase of “sick” paper, the printing equipment was shut down, the corrugated box scrap rate increased and the customer complaint rate increased, which made the corrugated box production enterprises pay a painful price. Purchase Instructions for Corrugated Base Paper
Then, what are the paper diseases of the face paper making corrugated boxes (mainly gray background whiteboard, coated kraft cardboard, etc.).Purchase Instructions for Corrugated Base Paper
7 What are the causes of these paper diseases? 7. What will be the impact on the printing process if you buy these diseased “paper”. Purchase Instructions for Corrugated Base Paper
7 in this paper, the author analyzes the common causes of corrugated base paper one by one, hoping to help corrugated box manufacturers identify the advantages and disadvantages when purchasing base paper.Purchase Instructions for Corrugated Base Paper
Diagnosis of common diseases of corrugated paper
Symptom 1: static electricity:Purchase Instructions for Corrugated Base Paper
Causes:Purchase Instructions for Corrugated Base Paper
(1) In the process of paper making, the content of rosin is too much, while electrolytes such as aluminum sulfate and fillers such as kaolin are less. High voltage static electricity is generated after drying and high temperature and high pressure treatment.Purchase Instructions for Corrugated Base Paper
(2) In the printing process, if the paper itself contains less water, static electricity will also be generated in the process of mutual friction.Purchase Instructions for Corrugated Base Paper
(3) The paper is full in the paper warehouse. And the time is short, and the water content in the paper has no time to reach balance.Purchase Instructions for Corrugated Base Paper
(4) The paper temperature (related to the ambient temperature of the paper warehouse) is quite different from the temperature of the printing workshop. Causes the paper to shrink. Generate physical static electricity.Purchase Instructions for Corrugated Base Paper
harm:Purchase Instructions for Corrugated Base Paper
Paper with static electricity will be difficult to separate, and multiple sheets of paper will be formed during offset printing and enter the printing press at the same time.Purchase Instructions for Corrugated Base Paper
In web printing, the same charges repel each other. There will be printing drift, overprint inaccuracy, uneven paper receiving or difficult paper pouring.Purchase Instructions for Corrugated Base Paper
In addition, paper with static electricity is also easy to absorb dust and paper scraps in the air, so that it adheres to the printed matter and directly pollutes the printed matter. Sparks will be generated when static electricity accumulates to a certain intensity.Purchase Instructions for Corrugated Base Paper
Bury fire hazards. When it is dry in winter. Such accidents are particularly likely to occur.Purchase Instructions for Corrugated Base Paper
Symptom 2: hair loss. Powder dropping
Causes:Purchase Instructions for Corrugated Base Paper
(1) Improper slurry ratio or filling amount will weaken the fiber adhesion.Purchase Instructions for Corrugated Base Paper
(2) Beating degree can not meet the requirements.Purchase Instructions for Corrugated Base Paper
(3) Internet paper leaves fluctuate greatly and the uniformity is not good.Purchase Instructions for Corrugated Base Paper
(4) The set pressure of the press drum is not enough.Purchase Instructions for Corrugated Base Paper
(5) There are attachments on the surface of the drying cylinder.Purchase Instructions for Corrugated Base Paper
(6) The temperature of the drying section is too high.Purchase Instructions for Corrugated Base Paper
(7) The paper cutter has dust. The cutter is too blunt.Purchase Instructions for Corrugated Base Paper
(8) The moisture content of the finished paper is too low.Purchase Instructions for Corrugated Base Paper
harm:Purchase Instructions for Corrugated Base Paper
Paper wool and filler block the printing plate and affect the normal production of the printing press.Purchase Instructions for Corrugated Base Paper
Symptom 3: fluctuation of paper quantity and uneven web quantity
The paper quantitative fluctuation includes the paper longitudinal quantitative fluctuation and the paper web direction quantitative fluctuation. These fluctuations can be divided into periodic fluctuations and irregular fluctuations.Purchase Instructions for Corrugated Base Paper
Main reasons for cyclical fluctuations:Purchase Instructions for Corrugated Base Paper
(1) Because the conveying system of paper material to headbox is subject to periodic
Vibration.Purchase Instructions for Corrugated Base Paper
(2) Vibration of rotor screen or slurry pump in front of headbox.Purchase Instructions for Corrugated Base Paper
Main reasons for irregular fluctuation:Purchase Instructions for Corrugated Base Paper
(1) Caused by unreasonable production process or improper operation.Purchase Instructions for Corrugated Base Paper
(2) The change of raw pulp concentration causes the fluctuation of pulp concentration.Purchase Instructions for Corrugated Base Paper
(3) Improper discharge operation of the beater resulted in poor mixing in the slurry tank.Purchase Instructions for Corrugated Base Paper
(4) The air mixed in the pulp withstands the paper material.Purchase Instructions for Corrugated Base Paper
(5) The speed of the paper machine has changed.Purchase Instructions for Corrugated Base Paper
Uneven paper web direction refers to the inconsistent quantification along the width of the paper machine, that is, the thickness of half of the paper web. Purchase Instructions for Corrugated Base Paper
Half thin or one thick. A thin layer.Purchase Instructions for Corrugated Base Paper
main cause:Purchase Instructions for Corrugated Base Paper
(1) The paper material is in the whole width of the headbox. The flow velocity at each point is different
agreement.Purchase Instructions for Corrugated Base Paper
(2) Uneven opening of sizing lip or defect of lip.Purchase Instructions for Corrugated Base Paper
(3) The edge setter causes the paper material on the web to break.Purchase Instructions for Corrugated Base Paper
(4) There are “ditch beams” in the longitudinal direction of the copper mesh.Purchase Instructions for Corrugated Base Paper
harm:
Uneven web sizing will lead to uneven printing pressure, resulting in uneven inking and inconsistent dot reduction.Purchase Instructions for Corrugated Base Paper
In addition to the above hazards, the uneven longitudinal quantification may also cause the collision between the printing cylinder and the embossing cylinder, shortening the service life of the machine and the printing plate.Purchase Instructions for Corrugated Base Paper
When carton manufacturers purchase base paper. A simple method to check whether the paper quantity is uniform can be adopted: observe whether the wet water line of the paper is neat. If the wet waterline is very neat, it means that the paper quantity is relatively uniform.Purchase Instructions for Corrugated Base Paper
If the wet waterline is seriously uneven, it means that the paper quantity may change greatly. Generally, the quantity of wet waterline elongation is higher. The quantification of the shortened wet waterline was low.Purchase Instructions for Corrugated Base Paper
Symptom 4: dust spots and hard blocks:Purchase Instructions for Corrugated Base Paper
(1) Dust: refers to exposure to the surface of paperboard or paper. Various impurities with obvious color difference from other parts can be seen from any angle. It is divided into black dust and other dust.Purchase Instructions for Corrugated Base Paper
(2) Spots: there is little difference between spots and dust. The main reason is that the gloss of the paper is inconsistent with the light and reflection. According to the characteristics of spots, they can be divided into wet spots. Cylinder spot. Purchase Instructions for Corrugated Base Paper
Calendering dark spots, slurry spots and bubble spots, filler spots, paint spots, bright spots and white spots. Where there are spots on the paper, the inking is poor. Purchase Instructions for Corrugated Base Paper
The ink is not easy to absorb the printing color or the handwriting is inconsistent with other parts.Purchase Instructions for Corrugated Base Paper
(3) Hard block: hard block refers to the hard block material and coarse-grained material occasionally appearing on the paper, such as wood knot, grass knot, pulp block, raw material block, etc. Purchase Instructions for Corrugated Base Paper
Hard block is very harmful to printing. It will crush the printing plate and blanket, and even cause serious damage to the printing press. Once a large hard block appears on the paper, it may lead to serious printing failure.Purchase Instructions for Corrugated Base Paper
Symptom 5: poor evenness
main cause:Purchase Instructions for Corrugated Base Paper
(1) In the beating process, the beating of long fiber slurry is insufficient, and less cutting occurs in the beating process, so that the slurry in the fiber is intertwined into a mass.Purchase Instructions for Corrugated Base Paper
(2) The vibration of the net front box and net table of the paper machine will also lead to poor uniformity due to insufficient dispersion of the fiber.Purchase Instructions for Corrugated Base Paper
(3) In the printing process, the paper with poor uniformity will produce stress concentration under the tension of the printing press, especially the roll paper printing press, resulting in a high end breakage rate.Purchase Instructions for Corrugated Base Paper
A simple way to check for poor uniformity is to point the paper against a strong light source. Evenness
Poor paper will have flocculent clusters.Purchase Instructions for Corrugated Base Paper
Symptom 6: crack:Purchase Instructions for Corrugated Base Paper
A crack is a crack or break in the middle or edge of a paper. These cracks or breaks 1:3 are easy to expand or be broken during the printing process, resulting in paper breakage and shutdown. Affect production efficiency. Increase paper loss.Purchase Instructions for Corrugated Base Paper
Symptom 7: inconsistent tone
In the same batch of paper or even the same color, the whiteness and tone are inconsistent in the paper
The phenomenon of.Purchase Instructions for Corrugated Base Paper
This phenomenon often occurs in some small and medium-sized paper enterprises. Due to the different whiteness of paper. Purchase Instructions for Corrugated Base Paper
There is an obvious difference between the depth and shade of the printed pattern. It’s easy for customers to refuse.Purchase Instructions for Corrugated Base Paper
Symptom 8: Ruffle:Purchase Instructions for Corrugated Base Paper
Ruffle refers to the edge of the paper. In particular, the paper loses its original straight state longitudinally. Purchase Instructions for Corrugated Base Paper
Through the observation of the side of the paper, it is easy to find that the side of the paper with lotus leaf edge has irregular pores similar to honeycomb. Purchase Instructions for Corrugated Base Paper
When printing paper with ruffled edges. There will be inaccurate overprint and wrinkles. Fine folding phenomenon. Paper with severe ruffles cannot be printed on the machine. Purchase Instructions for Corrugated Base Paper
The above 8 kinds of paper diseases are the problems that corrugated box manufacturers may encounter in the base paper procurement process. Purchase Instructions for Corrugated Base Paper
If we can understand the causes and identification methods of paper defects, we can identify them in the procurement process and reduce unnecessary losses.Purchase Instructions for Corrugated Base Paper