Special spring pad for circular-to-circular die-cutting: Solves the pain points of high-speed rotary die-cutting, and releases the production capacity for large-scale production.

With the explosive growth of e-commerce logistics and the fast-moving consumer goods industry, the round-to-round rotary die-cutting process, leveraging its core advantages of continuous operation, high speed and efficiency, and adaptability for wide-width and large-volume production, has become the core technology for the large-scale production of corrugated cartons, cigarette packages, pharmaceutical packages, and self-adhesive labels. Among domestic medium and large-sized packaging enterprises, the speed of over 12,000 times per hour for high-speed round-to-round die-cutting machines has reached over 60%, but the vast majority of enterprises have fallen into the predicament of "improving equipment efficiency while lagging behind in consumables" - the knife plate spring pad, as the core supporting consumable for round-to-round die-cutting, has become the core bottleneck restricting the release of equipment capacity and the improvement of production efficiency.

The round-to-round die-cutting process has essential differences in working conditions compared to the traditional flat-to-flat die-cutting process, and it places completely different and stringent requirements on the performance of the knife plate spring pad. The round-to-round die-cutting process involves the continuous rotational compression of the knife roller and the base roller in a line contact manner. The spring pad will continuously withstand high-frequency and periodic radial shear force and vertical compression force throughout the production process, while also having to cope with centrifugal force generated by high-speed rotation. These requirements for the anti-fatigue performance, shear resistance performance, dimensional stability, and back adhesive adhesion of the spring pad are far beyond those in the flat-to-flat scenario.

When the common flat-to-flat spring pads are used for round-to-round die-cutting, there are four major fatal problems: Firstly, the anti-fatigue performance is severely insufficient. Ordinary spring pads often experience elastic collapse and excessive compression deformation after tens of millions of die-cutting cycles, resulting in inconsistent die-cutting depths, inability to cut through corrugated paperboard, and labels being cut through the base paper. Enterprises have to frequently stop production to replace the spring pads, and a single stoppage can cause production losses of tens of thousands of units. Secondly, the risk of high-speed shifting and detachment of the backing adhesive is prominent. Ordinary spring pads have insufficient shear resistance for the backing adhesive, and the centrifugal force and shear force generated by high-speed rotation are likely to cause the spring pad to warp, shift, or even fall off, not only resulting in the scrapping of the entire batch of products but also potentially scratching the knife roller and causing equipment damage. Thirdly, the quality of the joint is out of control. Ordinary spring pads have a joint deviation of more than 0.1mm in the continuous rotational die-cutting process, causing skipping of the knife, uneven pressing, and the defective rate at the joint is more than 8 times that of other areas, becoming a quality shortcoming in large-scale production. Fourthly, the wear resistance is insufficient. The continuous friction in round-to-round die-cutting will rapidly wear the surface of the spring pad, causing pits and debris to fall off, which not only contaminates the printed products but also accelerates the wear of the round knife die, significantly increasing the cost of consumables for the enterprise.

For the specific working conditions of round-to-round die-cutting, the dedicated knife plate spring pad has achieved full-chain technological breakthroughs in terms of formulation, structure, and process, completely solving the industry pain points of high-speed rotary die-cutting. In the core formulation system, the dedicated spring pad for round-to-round die-cutting has broken through the limitations of traditional polyurethane formulations and created a three-dimensional network cross-linked structure of high anti-fatigue polyurethane for high-frequency shear work conditions. Through optimizing the pre-polymer synthesis process and precisely controlling the molecular chain length and cross-link density, the material's flexural fatigue performance and rebound response speed have been significantly improved. After laboratory simulation tests, high-quality round-to-round dedicated spring pads can withstand over 10 million consecutive die-cutting impacts, with an elastic retention rate of over 95%, and their service life is 6-10 times that of ordinary flat-to-flat spring pads, fundamentally solving the core pain point of frequent equipment shutdown for replacing the spring pad.

In terms of structure and process optimization, the dedicated spring pad for round-to-round die-cutting has carried out multiple customized upgrades for high-speed rotating conditions. For the problem of high-speed shifting, the product adopts a high-adhesion and strong-shear-strength backing adhesive, combined with a base coating treatment process, which can form a strong molecular-level bonding with the round roller steel plate, even in 200 meters per minute ultra-high-speed die-cutting, there will be no warping, shifting, or detachment. In response to the quality issues at the seams, leading brands in the industry have launched seamless full-circle pre-formed models and 45-degree high-precision inclined joint models. The full-circle pre-formed cushioning pads have no seams and can perfectly fit the circumference of the round-to-round die-cutting rollers, completely solving the problem of seam skipping. The inclined joint model can control the seam height difference within 0.02mm, achieving seamless connection. In terms of precision control, an imported fully automatic closed-loop foaming production line is adopted, along with an online laser thickness measurement system. The product thickness tolerance can be stably controlled within ±0.05mm, and the hardness tolerance is controlled within ±2 Shore degrees, ensuring uniform and consistent rebound force of the entire cushioning pad and guaranteeing the stability of die-cutting effects in large-scale production.

In actual production applications, the cost reduction and efficiency improvement effect of the round-to-round dedicated knife plate cushioning pads is very significant.