Die-Cutting Problems Are Frequent? These Four Methods Should Be Mastered!

01

CNC cutting machine



From the perspective of cost saving, flat die cutting and CNC cutting machine are the most cost-saving material costs, especially CNC cutting machines, their consumables cost is not only low, but also fast and convenient, no need to prepare a physical knife plate, an electronic knife layout, through the computer or mobile APP can execute cutting commands, one or more special cutter bits start working at the same time, along the set line of the knife diagram or the camera to automatically find the edge for cutting work. The cutting depth of the cutter head is carried out according to the thickness of the material and the pre-set process requirements of the label, and the cutter head can be slightly adjusted according to the actual cutting situation during the cutting process.







In addition, the working area of CNC cutting machine tools varies from 300mm~2000mm or more, and the larger the cutting width, the lower the positioning accuracy and repeatability; The cutting speed range of CNC cutting machine is 400mm/s~2000mm/s, and the more cutter heads, the faster the paper feeding speed. Due to the low price of CNC cutting machine, it is suitable for small label printing enterprises, printing agencies or proofing. However, the die-cutting efficiency and die-cutting accuracy of CNC cutting machine are lower than those of the other three die-cutting methods, making it more suitable for manual labeling.



02

Flatten flat die-cut



Compared with CNC cutting machines, the flat die-cutting method is the earliest and most used die-cutting method by label printing companies. The knife making cost of flat die-cutting is low and the knife making speed is fast (depending on the complexity of the graphics). The cutter plate of flat die-cutting is generally manually rowed or laser cutting, that is, the CNC automatic cutlass and row knives install the blade on the medium-density wooden board, and finally the blade plate is installed on the knife holder of the die-cutting machine.

The die-cutting efficiency of flat die-cutting is much higher than that of CNC cutting machine, with a paper feeding speed of 20m/s~100m/s, and the price of flat die-cutting machine ranges from tens of thousands of yuan to hundreds of thousands of yuan, which is suitable for small orders, urgent orders, proofing, relatively narrow printing formats, non-high-speed automatic labeling, and orders with not strict requirements for bottom paper cuts.



03

Circular pressing and circular die-cutting



Circular die-cutting, also known as circular knife die-cutting, was first used in the field of post-press processing, and was later widely used by daily chemical, electronics, pharmaceutical and other industries. In recent years, with the rapid development of flexographic printing technology and the higher requirements of label printing enterprises for production efficiency, this die-cutting method has gradually been used as the main die-cutting method.



From the perspective of online methods, circular die-cutting can be divided into in-line die-cutting and offline die-cutting. In-line die-cutting mainly occurs on flexographic printing machines with its own circular knife die-cutting unit, which can complete the die-cutting requirements simultaneously while completing label printing. In the customer group served by the author, in-line die-cutting accounts for about two-thirds, and the in-line die-cutting speed ranges from tens of m/min to 200m/min, in-line die-cutting can greatly improve production efficiency. Offline die-cutting is convenient for offset printing, gravure, flexo printing and other offline die-cutting requirements after pressing.

At present, circular die cutting is the most efficient, the best die-cutting accuracy control (±0.0025mm, that is, the die-cutting knife should cut through the glue layer, but not damage the silicone oil layer), for high-speed automatic labeling, ultra-thin bottom paper (less than 40g glassine, less than 0.030mm PET) trace-free requirements, special surface material knife angle control (40°~60°), special cutting edge treatment such as adding wear-resistant coating (5~10μm dense chromium salt oxide), anti-stick coating, etc., circular die-cutting has very obvious advantages.



The knives used in circular die cutting are divided into two types: engraving knife and flexible blade, and the circular die cutting method of flexible blade is used, which increasingly replaces the die cutting method of circular engraving knife and flattening.



The circular engraving knife is a kind of blade that is directly milled out of the tip (cutter line) by computer-controlled three-axis or multi-axis (CNC) on a 45# steel roller and then made the hardness of the tip and other treatments. The circular engraving knife is integrated with the blade roller, the flatness is controlled by the precision of CNC, the flatness is high, the operation is simple, and the knife roller can be put into the chute to pressurize. The disadvantage is that the price is more expensive, inconvenient to replace, the tip needs to be sent back to the supplier to repair and polish the new tip after wearing, the maintenance time and logistics cost are larger, and generally printing companies will spare multiple knife rollers to achieve the cycle of grinding, transportation and use to ensure continuous production.

Because domestic label printing enterprises use domestic engraving knives, the wear resistance of the tip is uneven, and the loss of the tip of the knife with poor wear resistance is very fast, and the operator mostly adopts the pressure method of pressurizing the die-cutting effect is not good, but often ignores a problem, that is, the deformation rate and hardness of the bottom roller shoulder iron position under the die-cutting unit, how much pressure the bottom roller bearing or support roller bearing can withstand so that it will not be damaged. The author suggests that the pressurization refers to the technical guide of the die-cutting seat to operate the pressure.



Circular flexible blade is a kind of blade that is generally made of European high-quality, high-hardness spring steel, and is engraved by computer program control equipment (CNC) after a strictly controlled chemical etching process. The accuracy of circular flexible blades can be controlled within the range of ±2.5μm~±5μm with the same design height difference to ensure the uniformity of die-cutting, and the higher the accuracy and life requirements of the blade, the higher the price, the price is composed of the combined process, the length of the cutter line, and label printing enterprises need to customize different process requirements according to the needs of the actual product.



Compared with the circular engraving knife, the dimensional accuracy between the blade and the blade of the circular flexible blade is more accurate, and various process requirements can be customized, especially when the wear-resistant coating of the blade is only 5μm~10μm, but the hardness can reach 73°~75°, which can not only meet the life requirements, but also protect the equipment well and reduce the occurrence of damage from heavy pressure. In addition, the delivery time of the circular flexible blade is shorter, it can be completed within 4~5 days, the cost is relatively low, and it is more convenient to replace and replace. However, the circular flexible blade needs to purchase a magnetic roller with high precision, and when pasting the blade, you need to pay attention to cleaning the surface of the magnetic roller and the blade adhesion surface to avoid dust and other debris adhering between the blade and the magnetic roller, destroying the flatness of the blade and uneven cutting marks on the bottom paper.



04

Laser die cutting



Laser die-cutting is a die-cutting method that uses a laser beam to focus on the printed material according to the designed knife line shape, and cut evenly, and the cut can reach the micron level.



Laser die cutting does not need to make a physical knife plate, can realize the rapid switching of different order graphics, can complete the cutting graphic design on the computer, various graphics, material parameter setting, automatically generate the depth of the cutting trace required, and can be repeatedly processed, the computer can start production immediately by retrieving the previously processed, compiled cutting program, saving the time of traditional die-cutting knife die replacement and adjustment.

At present, the speed of laser die-cutting is slower than that of traditional die-cutting machines, the price is high, the cutting edge has a cauterization phenomenon, and there is a problem of the minimum line width of the cutting line, which is more suitable for invitations, greeting cards, candy boxes, cake boxes, paper carving artworks, paper-cutting, gift packaging boxes, etc., and the application of self-adhesive labels is less.



In short, considering cost control, the order quantity is small, you can choose CNC cutting machine and low-speed flat die-cutting; The product structure tends to low-speed automatic labeling, manual labeling, and the order quantity is large, you can choose high-speed flattening and low-speed circular die-cutting; The order is large, the product process and materials are changeable, the requirements for the cutting mark are demanding, and most of them are high-speed automatic labeling order structures, it is recommended to choose circular die-cutting, which is cost-effective; Laser die-cutting is still a die-cutting method that everyone uses more cautiously in the field of label printing, and you can choose a suitable die-cutting method according to the product structure. The above only represents a personal opinion, I hope it will be helpful to you.