Common problems and countermeasures in the process of cutting white cardboard
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First, trimming
The most common method of printing on flat sheets is offset printing, so paper dust and other particles must be prevented from entering the press with the paper as much as possible. An important aspect of the quality of the cutboard is to ensure that there are no paper dust on the cut edges. The following measures can reduce paper dust to a minimum:
According to the cut cardboard, choose the most suitable paper cutter material and angle; the paper cutter should be replaced on time; adjust the base of the paper cutter (clip edge, inclination, knife edge overlap, knife pressure, etc.), cut The paper knife base should be maintained on time.
During the entire paper cutting process, the pressure of the conveyor belt should be suitable and as stable as possible.
Install the trimming tube correctly so that the force of the pulling when trimming is as small as possible.
The volume that needs to be slit is as round as possible to ensure that the tension does not change after the cardboard is pulled out.
When replacing a new roll for slitting, make sure that all four sides are centered.
When cleaning the machine, pay special attention to the dust-free cleaning of the slitting knife. Treat static electricity.
The cutting workshop should be air conditioned.
Good slitting machines usually have the function of trimming, so that the cardboard can get clean and clean sides and can be neatly beautiful on the pallet. But sometimes customers will ask not to trim, in order to reduce waste. However, in general, the paperboard is trimmed at the time of slitting, and the side of the roll is likely to be slightly damaged during transportation. Only by trimming can it be ensured that the printing machine is not damaged by the unevenness of the cardboard.
Second, the indentation
Indentation is mainly caused by inconsistent speeds of conveyor belts, rafts, belts, straighteners, and the like. Therefore, all transmissions should conform to the rotational speed of the conveyor belt (whether in contact with the upper surface of the paper or with the lower surface). At the same time, the slip of the drive wheels should be avoided as they may also cause a change in the shape of the cardboard. In addition, when adjusting the pitch of the rotating wheel, the factor of the thickness of the cardboard should be considered.
When smashing paper, use an air damper to reduce the indentation. The use of mechanical brakes must be properly adjusted to the shape and structure of the jaws. The material of the conveyor belt must be suitable for the matt board (the material is resistant to slipping), especially when the speed is inconsistent, the surface layer of the board is the most sensitive.
In places where it is not connected, such as the paper tray behind the drive wheel, where the paper is being fed and the paper is being fed, a blower should be used to reduce friction. If the traces left by the brakes at the crepe paper are carefully observed, they can be seen with the naked eye, and proper adjustment of the cut paper can reduce the influence.
Third, the surface rupture
The closer the cardboard is to the portion of the core, the greater the degree of bending. It is important that the paper cutter has anti-bending equipment and that the cardboard portion closest to the core cannot be used. The thicker the cardboard or the smaller the diameter of the core, the more cardboard is discarded at the core. A 12-inch (306 mm) diameter core minimizes surface rupture and other related issues.
The anti-bending 轳 should be equipped with bearings and have a large enough diameter to prevent the surface from rupturing. From the empirical point of view, the diameter of the anti-bending cymbal should reach 60mm-70mm, in order to avoid the surface rupture of the FBB with a thickness of 6001xm. Of course, if the cut white card is low, you can also use a smaller anti-bending 轳. Alternatively, the reverse bend can be used in several different places.
Special care must be taken when bending thick or long-stocked cardboard.
In addition, special attention should be paid when a whole roll is to be cut.
To avoid the use of a transmission wheel with a large bending force, the minimum diameter of the drive cymbal should not be less than 100 mm.
There are various types of slitting machines on the market, which are specially used for the slitting of cardboard, and are used for slitting a variety of materials. When slitting different materials, the slitter needs to be properly adjusted to ensure the best quality of the cut paper. In the event of customer complaints about slitting paperboard, in addition to the basic information, the most important thing is to correctly sample and send it to the paper mill. Generally speaking, the following information must be provided: full-printed paper to show the problem; When the problem occurs, use the tape to stick the residue on the relevant equipment of the printing press, and put the tape into the plastic bag and send it together with the paper; there is no printed flat sheet (cut into strips) to show the paper dust. The side; avoid feeding the paper in a roll-up manner, preferably in a folded manner.