How to Calculate the Litho-lamination Cost Accurately ?

This section shows cost breakdown for producing a standard-size box for different batch uantities using the litho-lamination process. Similar to flexo post-sheet, costs are indicated as Price per unit” which includes profit and the cost of manufacturing one box. The cost was alculated for 1, 10, 50, 100, 500, 1500, 20,000 and 100,000 rint orders. Table 6 shows the esults with all the direct and indirect cost and profit included. Litho-lamination cost estimation for different print quantities The cost estimation format is quite similar to the flexo post-sheet cost estimation. Total ost is the sum of direct cost and indirect cost. In the direct cost, instead of ink and printing plates, printed linerboard is included. Litho-lamination uses a lithographically printed linerboard pasted to a single face corrugated blank. Therefore the linerboard cost estimate includes cost of the lithographically printed linerboard. It is assumed that the linerboard is printed independent of the facility that combines the corrugated board. It is added as a separate cost in the software. Likewise the “paper board” is the estimated cost of single-face corrugated sheet.Production and labor costs are almost similar to flexo post-sheet as calculated by the Amtech software. The difference is that set-up cost doubles at higher runs of 100,000 for litholamination. The reason for doubling the set-up cost includes operator shift change and/or machine cleaning. The machines assumed for production were an Automatan laminating machine, a one-cut auto-platen die-cutting machine, and a unitized banding machine. The costs of these machines were already loaded in the software library. Overhead costs are lower than the flexo post-sheet as printing is done independent of the lamination facility. Similar to set-up cost, overhead costs are assumed to double at 100,000 prints. With a big print order, more overhead is associated. Table 7 and figure 10 below show the magnitude of direct, indirect and total cost per unit for different batch sizes for the litho-lamination process. Price/unit cost for direct, indirect and total cost for different print quantities for flexo post-sheet Like flexo post-print, the direct cost is a big part of total cost. Fixed direct costs are prominent up to 500-1,500 units, and for higher quantities variable direct cost becomes moreprominent. Direct cost is a big part of total cost and independent corrugated companies have no control over the prices of direct costs for example paperboard. Independent corrugatedcompanies only control indirect costs. Hence, independent corrugators strive to run manufacturing plants very effectively and efficiently to reduce total indirect cost and offer low prices to the customer.  Closer view of the price/unit cost for direct, indirect and total cost for 500 units or higher for litho-lamination The price to a customer was calculated the same way as flexo post-sheet. Figure 11 shows a closer view of the costs. A standard 10% profit margin is added to the cost up to 1500 prints, and the profit margin is reduced to 6% for bulk orders of 20,000 or higher. Price per unit is calculated by dividing the “Price to customer’ by number of units produced.The unprinted paperboard price assumptions were same as flexo post-sheet and were 10% and 15% for bulk orders of 20,000 and 100,000 quantities respectively. A 10% labor discount is applied and as mentioned earlier, the set-up and overhead cost is assumed to double for 100,000 quantity increments.The cost per unit decreases with the increase in the number of print orders. The cost of printed linerboard remains constant up to 250-300 sheets because all run jobs are not prevalent in the lithographic printing industry. At 1,500 units, the estimated cost per unit is $4.79 compared to flexo post-sheet where the estimated cost per unit was $2.45. Although the price is higher, litho-lamination offers great printing quality. The results also show that litho-lamination is most cost efficient at print quantities of 20,000 prints or higher. However, results indicate that flexo post-print is a substantially less expensive option for the same volume if quality is not a concern. Another process that offers a high print quality is litho-labeling, which is discussed in the next section.

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How to Solve the Problem of Cardboard Bending?

1.Relevant Factors, Parameters Testing and Qualitative AnalysisHow to improve the flatness of cardboard. We have tested and qualitatively analyzed the physical properties, process equipment and other related factors and parameters of several commonly used paper.The test results show that the shrinkage rate is different with the paper, quantitative and moisture content. This is an important physical property of paper. The same material of linerboard and inner linerboard, cardboard easy to achieve a better flatness. On the contrary, it needs to take into account the changes of major factors and make appropriate adjustments. Good or bad flatness depends on the shrinkage rate of each layer of paper, to make the paperboard has a good flatness, the shrinkage rate of each layer of paper must be basically the same, the most important is the linerboard and inner linerboard. The shrinkage of the linerboard is less than the inner linerboard is positive arch, otherwise negative arch, the shrinkage of the linerboard and inner linerboard uneven is positive and negative arch. From the production line cardboard forming process, shrinkage size controlling can be divided into two stages. 1). Corrugating Forming Stage. That is, the raw paper feeding to the second glue coating before each process, is the key stage to control the shrinkage rate. According to the Characteristics of each layer of paper, steam pressure of each layer, the actual situation of the environment temperature and humidity, respectivelyto adjust good preheating temperature, heating surface (Angle) length, ventilation means of releasing moisture, steam spray, the gluing quantity, production speed and other technical parameters, making each layer of paper by appropriate effective process control to free shrinking, so as to keep shrinkage rate basically same. 2).Cardboard Forming Stage. That is, the second coating of glue to the next process of adhesion, drying and ironing. At this point, each layer of paper can’t free shrinking, each layer after being glued to the cardboard is restricted by each other, the adhesive point can be said to be the beginning of the cardboard arch. Choose and adjust the amount of glue, drying temperature, production line speed and other technical parameters, to minimize the shrinkage rate difference, and iron the cardboard produced arch. 2.Improved Methods on Board FlatnessImprovement ideas on corrugated board flatness : one is to require the supplier to provide the raw paper with qualified and stable quantitative, moisture content, transportation and loading and unloading to avoid rain. Store in the factory to maintain the basic constant environmental humidity. Second, the material of linerboard and inner linerboard should be the same, or quantitative, moisture content, grade is basically the same. Third, the paper with a large moisture content through the pre-heater heating surface (Angle) length increase, fan ventilation, increase the time of water loss, slow down the speed of the production line, paper with a all moisture content through the pre-heater (Angle) heating surface length decrease, natural ventilation, steam spray, speed up the production line. Four is the adhesive amount of each layer of paper to maintain the same, along the corrugated direction of the width of the whole width of the adhesive amount uniform moderate. Fifth, air pressure stability, traps and other pipe accessories to maintain normal .There are many factors that affect the flatness of corrugated board, flatness changes with the change of each factor, improvement must be adapted to local conditions,  grasp the main contradiction and strive to solve. In terms of the common problems in producing single and double corrugated board, I would like to take some examples to discuss.A . The cardboard is arched horizontally. Known: linerboard is 250 g / ㎡ import A grade kraft paper, moisture content of 7.7%, (clip) tile paper is 150 g / ㎡ domestic high-strength corrugated paper. Moisture content of 10%, inner linerboard is 250 g / ㎡ B grade kraft paper, moisture content is 14%, atmospheric pressure of 1.1 MPa/cm squared, line speed of 60 m/min. Improved method: (1) Inner(clip)flute paper through the preh-eater (wrap Angle) heating surface length increased by 1 to 1.6, respectively. 0.5 to 1.1 times. (2) in (clip) tile paper in the production line bridge moving place using 0.9KW fan medium speed ventilation. Open Windows in the workshop for natural ventilation.(3) Small amount of steam spray evenly on liner board. The speed of the production line was reduced to 50m/min or so. The original transverse arch can disappear by adjusting the above selected parameters.B. Cardboard is arched length wise. Improved method: (1) Linerboard in front of the three-layer pre-heater to increase the motion resistance, increase the cylinder rotating brake force.(2)Inner linerboard in front of the three-layer pre-heater guide wheel, tensioning wheel and so on to reduce the movement resistance. Proper adjustment of the original longitudinal arch can disappear; C . Cardboard transverse negative arch. Known: Liner board is 200 g / ㎡ B grade kraft paper, moisture content is 13%, (clip) tile of 150 g / ㎡ high-strength corrugated paper, paper moisture content is 10%, inner linerboard with 200 g / ㎡ B grade imitation kraft paper, moisture content is 8%, atmospheric pressure 1.0 MPa/cm squared, line speed of 50 m/min. Improved method: (1) surface (clip) tile paper through the preheater heating surface length increased 0.9 to 1.4, 0.6 to 1.1 times.(2) Inner linerboard to reduce the pre-heater heating surface length or a all amount of steam spray.(3)The production line speed increased to about 60m/min. D .The cardboard is negatively arched longitudinally. Improved method: (1) Linerboard in front of the three-layer pre-heater to reduce the motion resistance, reduce the cylinder rotating braking force.(2)Inner(flute) linerboard in front of the three-layer heater guide wheel, tensioning wheel and so on to increase the movement resistance. E .Cardboard arched positive and negative. Because there are two kinds of positive and negative arch, the improved methods are varied, only the common transverse positive and negative arch is explained here. Known: Linerboard is 180 g / ㎡ A grade kraft paper, 7 to 12.6% moisture content, middle paper of 125 g / ㎡ high-strength corrugated paper, moisture content is 12%. Inner linerboard is 180 g / ㎡ in 8 to I4 % C grade kraft paper, moisture content, pressure is 1.1 MPa/cm squared, production speed 70 m/min, improved methods: (1) Use steam spray in transverse arch area .(2) Use steam spray in the transverse negative arch area .(3) the production line speed is reduced to about 60m/min.(4) adjust paper barrel 180 ° in the direction.In addition, there is a way to make up, that is use the cardboard with a larger arch just made from the production line , to put a pressure plate on a stack, usually about 10 pieces for a stack, and let cardboard in the semi-finished product storage process by positive and negative pressure of the external force. After a few hours (according to the ventilation and heat dissipation conditions of the workshop), a good flatness can be achieved. 3.Ideas and Suggestions1) . In the technical requirements of corrugated cardboard, there is the regulations of flatness."Corrugated cardboard has a ooth surface..." At present, as the level enhancement in the packaging industry automatic production, multial machine work and machine packing production line are being widely used, such as paperboard printing, die-cutting, slotting corner cutting, gluing, binding, strapping. Flatness requirements are getting higher and higher, those which can not meet the requirements of the cardboard will be automatically stopped or exit by machine packaging production line. We think corrugated board flatness regulation is necessary, it is convenient for operators and quality inspectors to work in accordance with the chapter inspection, and is conducive to the control of process quality. Corrugated flatness must be measured after placed in the horizontal without any external force, with the string height as the value. Flatness is divided into three levels.Grade 1 precision is suitable for the production of multi- machines such as cutting groove and angle of printing die, which is used for machines with high precision.Grade 2 precision is suitable for the production of die cutting machine in printing, used for high precision packaging cartons.Grade 3 precision is suitable for single-machine production of printing, slitting indentation, slotting and cutting angle, etc., and is used for packing cartons with general precision. 2) . Improve corrugated board production line equipment.(1) The preheater for each layer of paper tape, especially for linerboard and inner linerboard, should be able to make the length of the paper heating surface (wrapping angle) arbitrary adjustment;(2) There should be enough space for each paper to give off water after passing through the preheater, especially the insufficient space for the linerboard to give off water ;(3) electric fan ventilation device shall be installed in the area where moisture is distributed after each paper is preheated;(4) Each paper must be equipped with a steam spray device, and along the corrugated direction of any steam volume adjustment. 

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