What are the differences between conventional PVC creasing strips and fiber creasing strips?
In the printing and packaging industry, although creasing strips are small in size, they directly affect the forming effect of packaging boxes and the smoothness of the production process. The most common materials for indentation strips in the current market are mainly PVC and fiber, and there are certain differences between the two in terms of performance and practical application.
Shenhua Printing Materials has been dedicated to the development of creasing lines for 25 years. Based on rigorous craftsmanship, it offers a wide range of creasing accessory products. This article will conduct a comparative analysis of these two types of indentation strips and, in combination with the practical application experience of Shenhua Printing Materials, provide you with a reference for selection.
I. Functional Positioning of the Indentation Strip
In the processing of packaging boxes, creasing strips, as steel components on die-cutting boards, are mainly used to press out preset crease lines on the surface of paper, cardboard or corrugated paper. It causes the material to undergo controlled deformation under pressure through a specially designed cutting edge, thereby establishing the folding position.
If the indentation is not clear or the position is inaccurate, the paper box is prone to problems such as positional deviation, surface cracking, wrinkling at the folded corners or Angle deviation when folded, which in turn affects the structural firmness, appearance regularity and subsequent assembly efficiency of the finished product.
Ii. Comparative Analysis of PVC and Fiber Creasing Strips
Material and Composition
PVC creasing strips use polyvinyl chloride as the base material, with metal creasing lines embedded in the middle and adhesive backing attached to the surface. This structure endows it with good hardness and pressure resistance, making it less prone to deformation and capable of adapting to die-cutting conditions with higher speeds and greater pressures.
Fiber creasing strips are made with multiple layers of kraft paper or fiberboard as the base, and metal creasing lines are also embedded. The back usually has self-adhesive for easy adhesion. The inherent characteristics of the fiber material make it pay more attention to economy and ease of operation. It is relatively convenient for pasting and trimming, and at the same time, it has a certain protective effect on the die-cutting knife.
Durability performance and application cycle
PVC creasing strips are usually superior to fiber products in terms of durability. Take the SEE CROCS series PVC creasing strips of Shenhua Printing Materials as an example. They can withstand a relatively large number of lamination times, which helps to reduce the replacement frequency and thereby control the comprehensive usage cost.
Fiber indentation strips, due to their relatively low hardness and limited pressure resistance, are generally suitable for pressing tasks of tens of thousands of times or less. Moreover, they may be affected by environmental humidity and are prone to deformation if not stored properly.
Comparison of applicable scenarios and economy
PVC creasing strips are more suitable for medium and long-run printing tasks, high-speed die-cutting equipment, fine corrugated paper (such as E, F, G types), and fine creasing of cardstock. They are currently a commonly used choice in industrial die-cutting.
Fiber creasing strips are mostly used in short-run printing, manual die-cutting, sample trial production, low-speed equipment or scenarios where initial costs are of great concern.
From the perspective of long-term use, although the unit price of PVC creasing strips is relatively high, their long service life and stable performance can save overall expenses for mass production enterprises.
Iii. Product Matching of Shenhua Printing Materials
Product system coverage
Based on over two decades of industry practice, Shenhua Printing Materials has developed a relatively complete product line, covering both flat die and rotary die application requirements. The main products include SEE CROCS series PVC creasing strips, economical fiber bottom mold creasing lines and resin creasing lines, etc., which can meet the diverse needs of different users.
For special process requirements, Shenhua also provides reverse creasing lines (groove bottom creasing lines), which help reduce the surface cracking problem of coated paper during creasing and support the improvement of the yield rate.
Process characteristics
The surface of the PVC creasing strips of Shenhua Printing Materials has been polished to be smooth and flat, which is conducive to reducing the risk of creasing cracking on cardboard. The adhesive attached to the product has a good bonding effect and is suitable for continuous operation. It helps maintain the stability of the pressing position and ensures production consistency.
To meet the demands of high-speed rotary die-cutting machines, Shenhua has also launched a dual-purpose creasing strip for flat dies and circular dies, enhancing the equipment's applicability and production efficiency.
Iv. Examples of Practical Applications
The cooperation situation with a certain large-scale printing enterprise
This enterprise serves multiple domestic and international brands and has high requirements for the precision, stability and environmental protection performance of printing consumables. Since 2020, Shenhua Printing Materials has established a cooperative relationship with it, continuously supplying materials such as knife plate spring pads, indentation strips, and imported backing paper.
By using the supporting consumables provided by Shenhua Printing Materials, the enterprise has achieved comprehensive cost control in the die-cutting process, improved the stability of equipment operation, and maintained a good die-cutting yield rate.
Another packaging enterprise's efficiency has been improved
In the cooperation with this enterprise, Shenhua Printing Materials provided suitable solutions for its special needs in pharmaceutical aluminum foil packaging and electronic product packaging.
By providing silicone oil backing paper suitable for food contact materials and high-precision die-cutting machine steel plates, Shenhua assisted the enterprise in raising the clean and qualified rate of pharmaceutical packaging to a better level, and the scrap rate decreased.
In terms of electronic product packaging, by providing alloy reverse pressure lines with higher hardness, the depth of the indentation is effectively controlled, the error range is small, the matching degree of product assembly is improved, and the customer return rate is reduced.
V. Suggestions for Selecting Indentation Strips
Select based on production conditions
When choosing an indentation strip, it is recommended to comprehensively evaluate the following factors:
Printing task length: For short-run tasks, fiber creasing strips can be considered; for medium and long-run tasks, PVC creasing strips are recommended to maintain stability.
The operating speed of the equipment: For high-speed die-cutting equipment, PVC creasing strips should be selected; for low-speed or manual die-cutting, fiber creasing strips can be chosen.
Paper type: For corrugated cardboard, thicker cardstock, etc., it is recommended to use PVC creasing strips. Ordinary paper can be selected as needed.
Cost budget: If the initial investment is limited, fiber creasing strips can be considered. For long-term large-scale production, PVC creasing strips are more in line with the principle of economy.
Quality requirements: For packaging products with higher requirements, it is recommended to use PVC or resin creasing strips. Fiber creasing strips can be selected for samples or products with general requirements.
Technical reference for selection
Based on the technical experience accumulated by Shenhua Printing Materials, the following calculation methods can be referred to when choosing indentation strips:
For paper boxes (such as 0.4mm thick cardstock for reverse pressure effect), a crease width of 0.71mm (i.e., 2PT) and a base height of 0.3mm can be selected.
For corrugated boxes (such as those with a thickness of 0.8mm after compaction for reverse pressure effect), a crease width of 1.05mm (i.e., 3PT) and a base height of 0.3mm can be selected.
The width of the indentation groove can generally be calculated by referring to the following empirical formula:
Board paper: Slot width b = (1.3-1.5) × c + d
Corrugated cardboard: Groove width b = (1.8-2.0) × c + d
(Where c is the compacted thickness of the cardboard and d is the thickness of the steel wire)
Contact information for Shenhua Printing Materials: Mr. Ji, 19924506937