What are the differences in usage between creasing lines and reverse creasing lines?
In the field of packaging printing, exquisite finished product effects cannot be achieved without a meticulous grasp of process details. The quality of creasing and die-cutting directly affects the final form and brand presentation of the packaging box. Creasing lines and reverse creasing lines, as two commonly used types of consumables, their functions and differences are often overlooked. With 25 years of industry experience, "SEE CROCS" will combine years of practical accumulation, real data and cases to analyze the differences and key points of use between the two for you.
I. Concept Analysis: Function determines purpose
To understand the differences between creasing lines and reverse creasing lines, it is first necessary to clarify their positions and functions in the process flow.
Creasing line: Active forming tool
Function: Installed between the knife strips of the die-cutting plate, it forms easily foldable grooves by applying downward pressure on the paper.
Function: Ensure accurate folding position and clear edges to prevent paper cracking.
Metaphor: Just like a carpenter pre-marking lines on wood to prepare for the subsequent fine folding.
Reverse pressure line: Auxiliary forming structure
Function: Installed on the bottom mold directly below the indentation line, with a raised "ridge" at the top, corresponding to the upper and lower parts of the indentation line.
Function: When pressing under the creasing line, it supports the paper upwards, guiding the paper fibers and coating to extend to both sides to prevent surface damage.
Metaphor: Just like the anvil below when forging iron, it cooperates with the hammer above to complete the shaping.
In simple terms: The indentation line is the "force-applying party", responsible for creating creases. The reverse creasing line serves as the "supporting side" to prevent color cracking or breakage on the paper surface during the creasing process.
Ii. Data Comparison: Distinguish the Two from Multiple Dimensions
To facilitate understanding, we compare the two from multiple dimensions:
It is recommended that the table content be presented in two columns. The left column should be the "comparison dimension", and the right column should be the specific description of the "indentation line/reverse indentation line", such as: location, function, applicable materials, etc.
Industry observations show that according to the sampling survey in the "2023 China Packaging and Printing Industry Quality White Paper", in the production of cosmetic packaging boxes, surface damage caused by improper indentation accounts for approximately 5% to 8% of the scrap rate. After using the reverse voltage line in combination, such problems can be controlled within 1%. For production lines with a large daily output, this means that a significant amount of unnecessary losses can be reduced every day.
Iii. Case Sharing: The Application of SEE CROCS in Actual Production
Case background
The health care product color boxes of a certain pharmaceutical enterprise have undergone a technological upgrade, using grey board paper with UV coating as the material. During the initial production stage, fine white cracks frequently occurred at the indentation positions, with a product qualification rate of 92%, which affected normal delivery.
Problem analysis
After on-site assessment by the technicians of "Shenhua Printing Materials", it was pointed out that the main problem lies in the weak ductility of the UV coating itself. The unidirectional pressure applied by the indentation line is prone to cause the coating to break.
Solution
Selection of creasing line: SEE CROCS PVC creasing line is adopted. Its surface treatment is smooth, which helps to reduce the initial stress on the paper.
Reverse pressure line coordination: The SEE CROCS reverse pressure line is used in conjunction. Through its raised structure, it supports upwards during pressing, allowing the coating to extend synchronously with the paper.
Implementation effect
After adjusting the process and replacing the materials, the problem of creasing and color bursting on the color boxes of this enterprise was effectively solved, and the product qualification rate increased to over 99.5%. Meanwhile, SEE CROCS PVC creasing lines perform well in terms of durability. Their service life is superior to that of ordinary products, reducing equipment downtime and achieving a certain degree of reduction in overall production costs.
Iv. Selection Suggestions: How to Use Them Reasonably in Combination?
Based on years of technical practice of Shenhua Printing Materials, we have summarized the following selection suggestions:
Is a reverse voltage line used? It depends on the surface characteristics of the paper
It is recommended to use: all coated paper (such as glossy, matte, UV), laminated paper, gold and silver card paper, transfer laser paper and other materials with more surface treatments.
It is recommended to use: cardstock with a higher grammage, which helps to make the creases more full.
Materials with relatively loose fiber structures such as ordinary offset paper and uncoated grey board paper may not be used.
How to choose an indentation line? -- According to business requirements and equipment types
For small batch production and sampling: You can choose the Shenhua Printing Material fiber base mold creasing line. It is easy to operate and suitable for samples and short orders.
For regular and medium to long-term orders: We recommend Shenhua Printing Materials PVC creasing lines. They have good precision and durability, are compatible with various die-cutting equipment, and can be used as a feasible alternative to imported products.
Large-scale and high-speed production: Suitable for Shenhua Printing Materials' resin-based creasing lines, with a long service life, meeting the requirements of stable production for long-run orders.
Usage and matching suggestions
Model correspondence: The height and width of the creasing line must match the specifications of the reverse creasing line. Shenhua Printing Materials can provide process consultation and sample testing to assist in achieving a good coordination effect.
Synchronous maintenance: When replacing worn creasing lines, it is recommended to check or replace the corresponding reverse creasing lines at the same time to avoid new process problems caused by inconsistent accessory conditions.
Contact information for Shenhua Printing Materials: Mr. Ji, 19924506937