1. Caliper /厚度
Caliper: means the thickness of the paper. it is very important that the caliper of the paper is even over the full width, as it may cause wrinkling, bad gluing, warp and twist on the sheets. /保证原纸在整个幅宽范围内厚度均匀是非常重要的，否则，可能会导致起皱，粘合不好和瓦楞纸板的弯翘。
2. Humidity / 湿度
Humidity: means the moisture contentsofthe paper. It is essential that the moisture content is even, and within a restricted percentage. the moisture content of liners and fluting are different, usually liners should contain between 6 and 10%, and fluting between 4 and 8%. It is however essential that the papers are in "blance", meaning that when your top-liner has a humidity of 5%, and your bottom-liner 10%, you will have the greatest problems to run flat board. From this, it is obvious that the moisteure content of your paper will greatly decide the flatness of your board. /湿度就是原纸的含水量。原纸的水份均匀，并在一定的范围内是至关重要的。箱板纸和瓦楞芯纸的湿度是不同的， 通常箱板纸的水份在6%~10%之间，瓦楞芯纸的水份在4%～8%之间。 所使用的原纸的水份相互间“均衡”是至关重要的。如果所使用的面纸水份为5%，而里纸的水份为10%，我们将会遇难到生产平整纸板的最大问题。很明显，所使用原纸的水份将极大决定你所生产出瓦楞纸板的平整度。
Important Note: There are many different types of moisture meters, but most of them give a rather inaccurate moisture content of the paper. To check the humidity over the width, these meters are very useful, but to determine the moisture content, the best way is to use a proper moisture analyzer. whereby the paper is put on a balance and by first weighing the paper, drying the paper out by means of heating, weighing the paper again, the moisture content can be properly obtained. This method is also useful to check the humidity content of the board. The most commonly used moisture meter is the Doser P12. Remember that these meters have to be calibrated regularly to maintain a trustful read out.
3. Even structure /均匀的组织结构
Even structure, without steaks, caused by the paper machine. When the paper runs into the machine, it should be straight, evenly tensioned. when not, the steaks will be loer in temperature, due to bad contact with the pre-heaters, therefore will cause bad gluing at higher speed and cause warp./
4. Winding /
Winding of the paper is very important too, plus the general condition of the reel. Badly wounded reels can cause problems at higher speeds, due to the "jumping" of the paper going into the machine.
Most liners have a smooth and a ruff side, especially the Kraft qulity. This depends on the calendring of the paper. Therefore, most rolls have direction indicators on the sides of the reel. it is essential to follow these indications, as sever peeling might occur at the finishing machines, or even at the hotplates if these instructions are not fllowed.
5. Weight or Grammage /克重
Weight煌grammage. Wrong or uneven weitht will cause trouble at a further stage of the boxmaking, as the demands for strength of your finished box will mainly depend on the grammage of your paper. Extrme big grammage differences will show up on the board as weak spots. due to the fact that is mostly combined with caliper loss.
Note: it is an important part of the foreman job to keep a close check at the paper at all times, and keep a record of all defects and or abnormality which occurs during the production. it is a good habit to do this, even if in most cases you have to run the bad reel anyway. when it comes to the point where heavy production losses occurs due to the paper, it is always handy to have these records.
6. Shrinkage /
Shrinkage of paper is always present, due to the fact that paper is heated when used on the corrugator. Heating means reducing the moisture content of the paper, and by doing so, the peper "shrinks", i.O.W. the width of the paper is reduced.
The misalignment of the fibre in the paper can also cause extreme schrinkage, but this is a very rare phenmena, as this is usually a serious paper machine fault, therefore mostly cured on the paper machine afte detection! this fault can also be detected by observing the even structure of the paper, very large, loose bands over the paper width with no higher moisture content will indicate this problem.
From the above remark, it is easily deducted, that fluting paper has less schrinkage due to the fact that the fibre is much shorter, thus less risks of unaligned fibres!.
The amount of sch
7. Aging.
Paper freshly produced on the paper machine can cause trouble on the corrugator.
8. Specifications.
Conditions for good quality and high speed. These specifications are recommended by FEFCO for Liner and Fluting medium.
Paper humidity:
Drop test:
Runability conditions to ensure good flute formation and acceptable gluing, at the same time running flat board.
