The full name of the manual color wheel metal anilox roller is the anilox roller, which is a very fine and very important part of the ink transfer part of the flexographic plate. What is the specific function of the anilox roller and what are the parameters of the anilox roller? , and how to use and maintain the anilox roller.
1. Describe the parameters of the anilox roller
The function of the anilox roller is to transfer ink quantitatively and evenly to the graphic part of the printing plate. Whether the anilox roller can transfer ink quantitatively, uniformly and accurately depends on the parameters of the anilox roller.
1. Number of texture lines
The number of anilox lines is different from the number of dot lines. It is defined as the number of cells per unit length along the axial direction of the anilox roller, and the unit is line/inch or line/cm. The number of anilox lines is different from the number of dot lines. Another point is that there is no direct correspondence between the number of screen lines and the clarity of printed graphics, but it affects the quality of printed graphics.
2. Cell shape
The shapes of the cells are quadrangular pyramid, quadrangular truss, hexagonal truss, spiral, etc. At present, most of the quadrangular pyramidal cells exist on metal anilox rollers, which are completed by electronic engraving technology; most of the hexagonal truss cells are It exists on the ceramic anilox roller and is made by laser engraving. Compared with the quadrangular pyramid-shaped mesh, it has the characteristics of more ink storage and better ink transfer and ink release performance.
3. Mesh hole opening, depth, opening degree
The opening of the mesh cell refers to the width of the opening on the surface of the cell, usually expressed by b; the depth of the cell refers to the depth of the cell, usually represented by H; the opening of the cell refers to the depth (H) of the cell and the opening of the cell The percentage of (b) is usually between 23% and 33%, preferably 28%.
4. Angle of texture
Anilox rollers made by electronic engraving can carve out 30°, 45°, and 60° cells due to the different angles of the engraving knife. Laser engraving usually engraves 60° positive hexamorphic cells.
5. Cell volume
Cell volume refers to the total amount of ink that can be accommodated per unit surface area of the anilox roller. The unit is BCM (Billion Cubic Micro). It is a parameter that reflects the ink storage capacity of the anilox roller. Converted to domestic units, 1BCM=1.55cm3/m2.
2. Structure and type of anilox roller
From the perspective of the surface structure of the anilox roller body, it is mainly composed of two parts: the cell and the mesh wall; from the perspective of the structure of the anilox roller, it is mainly composed of the roller core, the base material and the surface coating. The commonly used material for the base material is electroplated copper. It is the basis for making anilox roller cells and mesh walls; the surface coating is made of metal chromium or ceramics, which mainly improves the wear resistance of the anilox roller and prevents the corrosion of the base copper layer by solvents.
According to网纹辊表面镀层的不同可分为金属镀铬网纹辊和陶瓷网纹辊,从雕刻精度、耐印力、传墨释墨性能对比,由于陶瓷网纹辊具有更多的优点,所以企业更多使用的是陶瓷网纹辊.
金属辊基→涂布陶瓷材料→抛光→激光雕刻
因为先雕刻后镀铬或喷涂陶瓷会导致网纹辊网穴容积的减小,而采用先喷涂陶瓷再激光雕刻的方法更能保证网纹辊网穴精度,这也是陶瓷网纹辊使用更为广泛的原因之一.
金属网纹辊加工工艺流程:金属辊基→镀铜→雕刻→镀铬
陶瓷网纹辊加工工艺流程:金属辊基→镀铜→雕刻→喷砂处理→陶瓷材料喷涂→抛光
三、网纹辊使用时考虑的因素
1.选择合适的网穴形状
①与供墨形式相配合
柔性版印刷的供墨形式主要分为双辊式和刮刀式两种,其中刮刀式又可分为正向刮刀、反向刮刀、全封闭双刮刀三种.在相同线数的条件下,四棱锥形网穴的容积会因刮刀磨损而迅速减小,因此,四棱锥形网穴大多数情况下配合双辊式供墨形式使用.而四棱台、六棱台则可应用于刮刀式中.
②与油墨类型相配合
斜线形网穴因为可进而保证油墨的流动性,提高网纹辊的传墨性.所以针对粘度较高的油墨,或光油、涂料等,可采用斜线形网纹辊供墨.
2.选择合适的网穴容积
容积的大小直接决定了网纹辊的供墨量的大小,不同精细程度的印品需要不同的供墨量,因此选择网纹辊时要充分考虑到网穴容积.
3.选择合适的网纹角度
通常大多数的情况下,选择60°、正六边形陶瓷网纹辊供墨,只有特殊的情况下采用其他角度网纹辊.
4.选择合适的网纹线数
一般来讲,网纹辊的供墨量随网纹线数的增加而下降,网纹线数越高,供墨量越小,相对均匀性越好.对于单个网穴而言,因为网穴形状决定了网穴内部存在棱角,也正因为网穴棱角的存在,所以导致了网穴对油墨传递的阻碍作用,即"边角效应".网纹线数越高,那么单位长度内网穴个数越多,同时考虑到每两个网穴之间存在网墙的因素,因此在相同容积的情况下,网纹线数越高网穴开口度越大,即相对深度越大,边角效应也更为严重,从而导致传墨量的减少.因此在选择网纹线数时也应该充分考虑供墨量.
①考虑印刷品的精细程度
相对而言,实地、线条、文字等需要油墨量大,选网纹线数选择较低的;彩色网线图案需要油墨量小,选网纹线数较高的(如表1所示).除了供墨量的因素之外,同时要考虑印版上的网点线数.印刷品的精细程度取决于网点线数的高低,在印版上,网点尺寸确定后,如果采用较低线数的网纹辊,此时每个网穴的面积会大于印版上某些网点的面积,这样印刷时,网点由于没有隔墙的支撑,网点会浸入到网穴中,不仅网点表面被着墨,而且侧壁也会着墨,从而导致网点增大,例如对于80%网点面积率大小的色块就会导致糊死,印刷成实地,同时导致边缘重影的故障.实践证明,要获得品质优越的印刷,网纹辊的网纹线数与印版的网点线数保持4:1左右的比例关系较好.
②考虑承印材料及印刷要求
不同的承印材料吸墨性不同,不同的承印材料油墨干燥方式不同,所以应该充分考虑到承印材料需求墨量的因素,一般吸墨性大的,选网纹线数低的,吸墨性小的,选网纹线数高的.
四、网纹辊的保养
网纹辊是柔性版印刷机上最精密的部件,切实注意日常使用过程中的保养是延长网纹辊使用寿命的重要一环.
1.使用网孔显微镜定期检查网穴
使用网孔显微镜定期检查网穴,如发现网纹辊出现划痕、堵塞等问题,及时采取措施处理.
2.检测油墨粘度、及时清洗网纹辊
The reason for the clogging of the anilox roller is, on the one hand, caused by the nature of the ink itself, such as drying too fast; on the other hand, it is the reason for cleaning, such as ineffective cleaning or untimely cleaning. Therefore, attention should be paid to maintaining the viscosity of the ink during the printing process. When cleaning the anilox roller, the cleaning method with less damage to the anilox roller and the importance of timely cleaning need not be repeated.
3. Use the anilox roller protective sleeve when storing the anilox roller
Using the anilox roller protective cover, on the one hand, it plays a better role in buffering and absorbing vibration, and on the other hand, it can keep the surface of the anilox roller clean.
4. Use good scraper and magnetic filter
Use a good scraper and control the pressure between the scraper and the anilox roller. If conditions permit, put a magnetic filter in the ink tank to reduce the impurity particles in the ink, reduce the wear of the anilox roller, and prolong its life. service life.
