Precautions for die cutting indentation of packaging boxes the application of die cutting indentation technology in corrugated boxes
die cutting indentation is an indispensable process in the processing of corrugated boxes. After die cutting and indentation, the appearance quality and market competitiveness of cartons have been greatly improved. The main technological process of die cutting indentation is: product design → die cutting tool processing → typesetting → loading and pad → die cutting indentation → finishing → finished products
1. Product design
when designing corrugated boxes, it is necessary to accurately calculate the internal dimensions of the packaging, and try to use rounded corners at the corners of the lines to prevent sharp corners, which is conducive to knife arrangement; Avoid connecting multiple adjacent narrow edges to facilitate waste removal
after the specifications of each part of the corrugated box are determined, the method of proofing and trial molding is adopted to check the rationality of the specifications and the artistry of the appearance, and then formal plate making is carried out
2. Tool selection and processing
the tools used for die cutting are called die cutting knives, also known as steel knives, beer knives, etc; The tool used for indentation is called indentation line, also known as steel wire, beer wire, etc. Die cutting knives and indentation lines are made by professional factories. Users only need to select them according to requirements. The height of the commonly used die cutter is 23.8
mm, and the thickness is 0.7 mm
thickness D and height h of corrugated box indentation line: D ≥ C h=h-c
c - thickness of corrugated board after compaction H - height of die cutter. The cutting edge of the die-cutting indentation tool should have a certain hardness, and the tool should be specific to toughness, which can be bent into any complex shape to meet the needs of the complex shape of the die-cutting indentation product. The thicker the blade, the harder it is to bend; The higher the blade, the greater the force required to bend. For products with extremely precise and complex shapes, thinner blades can bring many conveniences
according to the requirements of the product, select tools with different hardness and shapes, and bend the tools into the required shape with bending machine and other equipment. The die of the bending machine with good design can avoid incorrect pressure on the deformation of the blade. The blade should have a certain degree of bending plasticity. The blade can neither be like a spring nor deform under a little pressure. Good plasticity should be that the blade bends into a certain shape and rebounds slightly
when installing the blade into the slotted formwork, it should be properly tightened. The blade can be embedded by gently tapping with a plate making hammer. The thickness of the blade and the width of the sawing gap should be controlled within a certain tolerance range. The knife back with an inclined plane allows the blade to be easily installed into the template. The die of the blade cutting machine should have precise perpendicularity, which can ensure that each cutting end is perpendicular to the blade. Drum type die cutting indentation tools are divided into assembly type and integral type. The assembly type die cutting tool and indentation line are assembled on the die cutting indentation drum, and the integral die cutting tool and indentation line are integrated with the drum
the assembled die-cutting indentation roller is easy to assemble and flexible to replace products: the manufacturing of the integral die-cutting indentation roller is complex, and the whole roller should be replaced when replacing products, but this method has high die-cutting indentation precision and fast speed
3. Typesetting is also known as knife arrangement. Before typesetting, bend the cutter into the required shape according to the shape of the die-cutting indentation product, and fix the cutter in the frame with blank lining material to make a die-cutting indentation plate. The lining materials include lead, wood, fiber plastic board and steel board. Lead lining materials include lead blocks and lead bars. Die cutting indentation plates made of lead blocks and lead bars have low dimensional accuracy and are easy to scatter. Wood board lining material 2. To remove the antirust grease on the exposed surface, multilayer plywood is generally used, with a thickness of about 18mm. This material is greatly affected by the changes of ambient temperature and humidity, which is prone to deformation, unstable size, and affects the accuracy of die-cutting indentation. Fiber plastic board is not affected by temperature and humidity changes, and has good dimensional stability. It is a good die-cutting indentation plate, which requires special equipment for processing, and the cost is high. Steel die cutting indentation plate has high precision, no deformation and complex processing
when typesetting, first design the die cutting layout according to the product. The size of the layout should match the specification and working capacity of the selected equipment; The position of the die-cutting plate should be consistent with the printing position; The working part should be in the center of the die-cutting plate; The cutting lines of the layout should be straight, and the vertical and horizontal cutting lines should be at right angles to each other and parallel to the side of the die-cutting plate
the outline drawing of the die-cutting plate is the unfolding drawing of the whole plate product. If the printing adopts the whole page assembly system, the outline drawing of the die-cutting plate can be directly output in the printing and plate making process. In order to ensure that the die-cutting plate does not scatter during the plate making process, several "bridges" should be left in the large-area closed graphic part. The bridge width can be designed as 3 ~ 6 mm for small plates and 8 ~ 9 mm for large plates. When designing the layout, the cutting line of slotting and opening should be the whole line as far as possible, and the corner of the line should be rounded to prevent the splicing of mutually perpendicular steel knives; Sharp corners shall be prevented at the joint of two lines; Avoid the connection of multiple adjacent narrow waste edges, and increase the connection part to make it connected into a piece, which is convenient for waste removal; Prevent continuous multiple sharp corners. Sharp corners without functional requirements can be changed into rounded corners; Prevent the sharp corner line from cutting off the middle section of another straight line, which will make it difficult to fix the knife, the steel knife is easy to loosen, and reduce the die cutting suitability. It should be changed to arc or increase the included angle
in the process of plate making, it is also necessary to open the connection point. The connection point is to open a small opening with a certain width at the edge of the die-cutting knife. During the die-cutting process, the waste edge is still partially connected to the whole print sheet after die-cutting without spreading, which is convenient for paper feeding. The connection point is opened with a knife line punch, which is ground with a grinding wheel. Do not open the connection point with a hammer and chisel, otherwise the knife line will be damaged and burrs will be generated in the connection part. The connection point is usually placed in the concealed place of the formed product to avoid affecting the appearance of the finished product. Do not open the connection point at the bridge crossing position, and try to avoid opening the connection point at the gluing position. Generally speaking, the width of the connection point of corrugated board is corrugated paper, and the actual thickness of the board plus 0.2mm is about 1 ~ 3mm
(1) manual typesetting
manual typesetting is to manually fix the steel knife and steel wire with hollow lining materials according to the design size of the corrugated box to form a die-cutting indentation plate. For manual typesetting, lead or wood can be used as lining material. Using lead lining material is to fix the steel knife and wire with lead blocks, empty lead and lead bars. The size of the die-cutting indentation plate made by this method is inaccurate, and the lining material is easy to scatter. The use of wood board lining material is to use a hand saw to saw the multi-layer plywood according to the product specifications, and embed the steel knife and steel wire into the sawing seam for fixation. The size of the die-cutting indentation plate made by this method is inaccurate, and the wood board is easy to deform when wet. The manual typesetting process is simple, but it is not strong, easy to scatter, and the graphics are easy to deform and inaccurate. It can only process simple graphics
(2) mechanical typesetting
mechanical typesetting is to use a sawing machine and other equipment to saw the base board out of the sawing seam according to the layout specification, and insert the formed die-cutting indentation cutter into the sawing seam to make a die-cutting indentation plate. The sawing seam of the layout cannot be completely penetrated to ensure the integrity of the plate after sawing. Before sawing, first drill holes at the starting and ending points of the steel knife and steel wire bridge position (notch) of each line on the plate, so that the saw blade can enter the plate smoothly. The plate position corresponding to the steel knife and steel wire bridge position is not sawed through, leaving an interval equivalent to the width of the bridge position
mechanical typesetting is semi-automatic typesetting, with less equipment investment and high production efficiency. The direction of sawing line is manually controlled, which is highly dependent on workers' technology. The sawing seam is not too straight, and the repeatability is not good. The multilayer plywood used is easy to deform when wet
mechanical typesetting is the leading method of making die cutting and indentation plates in China at present
(3) laser typesetting
laser typesetting is to use computer to draw CAD graphics of product specifications, shapes and other parameters that need die-cutting indentation, or use scanner to input, compile die-cutting indentation program, and use laser cutting machine to cut plates to make die-cutting indentation plates
the laser cutting machine is controlled by the computer, and uses the laser as the energy to cut the substrate material through the high temperature generated by the laser. Laser typesetting can control a single graphic design. When cutting plates, it will automatically become the partner and bridge of the igauto project, and output laser cutting graphics. The computer-controlled laser cutting machine can cut any complex cutting seam of the plate, while maintaining the integrity of the plate. The matched computer scissor machine scissor is accurate. The cutting seam cut by the laser cutting machine is smooth, straight and accurate
the accuracy of laser typesetting and plate making is high, but the plate base still uses multilayer plywood, which is easy to deform when wet
there are many parameters needed in the cutting process, such as material quality parameters, plate thickness, laser output power, type and pressure of auxiliary gas, diameter and caliber of nozzle, distance and gap between material and nozzle, focal length of lens, position of focus and cutting speed, etc. The main disadvantage of laser cutting is that the laser cutting machine is expensive and the cutting cost is high, which makes the production cost of die-cutting plate higher. Therefore, this kind of die-cutting plate is generally produced by professional manufacturers and directly customized by users
(4) high pressure water jet cutting typesetting
high pressure water jet cutting is used for cutting fiber plastic boards. If laser cutting machine is used to cut fiber plastic board, toxic gas and smoke will be produced. Cutting fiber plastic board with saw machine is easy to wear the saw blade and produce a lot of dust, both of which pollute the environment
high pressure water jet cutting uses computer to draw CAD graphics, or scan input, compile die cutting indentation program, and use high pressure water jet cutting machine to cut plates to make die cutting indentation plates. High pressure water jet typesetting can control a single graphic design, and automatically add a bridge position when cutting the plate, which can cut the plate into any complex cutting seam, while maintaining the integrity of the plate, and the matched computer scissor machine scissor is accurate. The cutting seam cut by the laser cutting machine is smooth, straight and accurate
there is no pollution when cutting fiber plastic board with high-pressure water jet. High pressure water beam is similar to laser beam, which can be accurately controlled by computer. The cutting seam is smooth, straight, accurate and high-quality. Fiber plastic board does not deform when wet, with high dimensional accuracy. The equipment cost is high
4. After the die-cutting indentation plate is arranged, it is loaded into the plate frame and fixed, and then loaded into the die-cutting indentation machine for processing
(1) stick a rubber strip
after the die-cutting indentation plate is arranged, stick a rubber strip on the plate base on both sides of the die-cutting knife, and use the elastic effect of the rubber strip to assemble, test and push the die-cutting printing material from the knife edge to Jinan new era Gold Testing Instrument Co., Ltd., so as to prevent the steel knife from being embedded firmly and affecting the operation
rubber strips for die cutting are generally divided into hard and soft ones. Hard rubber is used for thicker printing materials, and soft rubber is used for thinner printing materials, which are produced by professional manufacturers. Generally speaking, the rubber strip should be 3 ~ 5mm higher than the die-cutting blade, and the distance between the rubber strip and the knife line is 1 ~ 2mm
if the distance between the die-cutting knives is less than 8mm, the rubber strip with hardness of hs600 should be selected; If the distance between die-cutting knives is greater than 10mm, rubber strips with hardness of hs250 should be selected. If the distance between the die cutter and the steel wire is less than 10mm, the arch rubber strip with hardness of hs700 should be selected; If it is greater than 10mm, the rubber strip with hardness of hs350 shall be selected. The punching position of the die-cutting knife uses an arch rubber strip with a hardness of hs700 to protect the connection point from being broken
(2) backing plate
backing plate is to pad one or more layers of paper or paperboard under the die-cutting indentation plate to make the height of the plate steel knife or steel wire consistent and the pressure uniform
the die-cutting indentation plate can be obtained from the stamping mechanism of the die-cutting indentation machine
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