What material should be used for the gap between the two knives of the die-cutting mold?
In the field of die-cutting processing, the clearance treatment between the two cutting lines on the die is a seemingly minor but far-reaching process step, directly related to the service life of molds worth tens of thousands or even hundreds of thousands of yuan and the final product effect.
During the die-cutting process, if the gap between the knife lines is not properly handled, it can easily cause the blade to loosen, shift or even fall off. At the same time, the generated waste chips may also remain in the knife gap, thereby interfering with the production rhythm and product consistency. At this point, the application of sealant becomes particularly important - it can not only stabilize the blade but also absorb the vibration caused by die-cutting, thereby extending the service life of the die.
01 Key Functions of Caulking glue
In the die-cutting process, sealant plays a significant role in the production and maintenance of die-cutting molds, mainly reflected in the following three aspects:
Stabilize the blade position: By providing reliable adhesion, prevent the blade from shifting or popping out under continuous pressure, ensuring the consistency of die-cutting dimensions.
Mitigating impact: During die-cutting operations, the caulking compound can disperse the force acting on the blade, protecting the blade structure while reducing damage to the die-cutting base plate and lowering the possibility of cutting through it.
Auxiliary chip removal: Prevent small waste materials from getting stuck in the blade gap, thereby maintaining a stable die-cutting effect and reducing product defects caused by chip accumulation.
02 The supporting materials provided by Shenhua Printing Materials
Shenzhen Shenhua Printing Equipment Technology Co., LTD. (hereinafter referred to as "Shenhua Printing Materials") was established in 2000 and has long been committed to the research and development and supply of various equipment required for the post-processing of printing and packaging.
The company has accumulated over twenty years of practical experience in this field, and its service scope covers both domestic and international markets.
For the filling requirements of die-cutting molds, Shenhua Printing Materials can provide a variety of supporting materials, including die-cutting plate spring pads, backing paper, explosion-proof rubber strips, rebound glue, acrylic glue, elastic glue, sponge glue and EVA sponge glue, etc.
These materials jointly construct a set of caulking solutions suitable for different die-cutting and process requirements.
Through systematic operation management, a complete product portfolio and continuous service support, Shenhua Printing Materials has established stable cooperation with many industry enterprises, including Yutong Group, Baoshen Group, Yatushi Printing, Hongxing Group, etc.
These collaborations also reflect the market's recognition of the applicability and stability of its products.
03 Classification and Application of Grouting Adhesive Materials
According to the type of die-cutting molds (mainly laser die-cutting molds and etching die-cutting molds) and specific application conditions, caulking adhesives can be classified into the following categories:
Epoxy resin-based grouting adhesive
As A relatively common type at present, epoxy resin grouting adhesive is usually a two-component configuration (A adhesive and B adhesive), which cures through a chemical reaction after being mixed.
This type of colloid has excellent structural strength and durability. After curing, it has a relatively high hardness, can effectively lock the position of the blade, and can withstand pressure, wear and impact, with a long service life.
However, when in use, it needs to be mixed in proportion and a certain curing time must be waited for, so it cannot be put into production immediately.
It is suitable for most laser die-cutting dies and etching die-cutting dies, especially for working environments with high die-cutting frequency and high pressure.
Silicone-based grout sealant
Silicone sealant has good elasticity, flexibility and cushioning properties, providing good protection for blades. At the same time, it can withstand high temperatures and is suitable for scenarios where heat generation is significant during die-cutting.
If local blades need to be replaced, silicone materials are also relatively easy to clean. However, its fixing strength for blades is generally lower than that of epoxy resin types.
It is mainly used in precision die-cutting where high elasticity is required, or in situations where the knife lines are densely arranged and enhanced buffering is needed.
Polyurethane grouting adhesive
Polyurethane-based grout sealants strike a certain balance between strength and elasticity and can be used as an intermediate choice between epoxy resin and silicone.
04 Industry Trends and Selection References
According to the research and statistics of QYResearch, the global market size of die steel was approximately 102 million US dollars in 2024 and is expected to reach 149 million US dollars by 2031, with a compound annual growth rate of about 5.7% from 2025 to 2031.
This data reflects the continuous development of the die-cutting mold and its supporting materials market, and also highlights the significance of caulking as a key auxiliary material.
When choosing grout sealant, multiple factors need to be comprehensively considered. The following are the recommended types of caulking agents for different die-cutting materials:
(Here, tables or diagrams can be provided to explain the recommended grouting adhesives for different materials.)
In addition, die-cutting accuracy also affects the selection of caulking compound. If the dimensional accuracy of the product needs to be controlled within ±0.05mm, etching molds, engraving molds or metal molds can be selected, and epoxy resin caulking glue can be used in combination.
If the precision requirement is within ±0.1mm, wooden molds or rubber board molds can be selected, and the corresponding type of grouting glue should be used in combination.
05 Practical Experience and Case References
An experienced die-cutting technician emphasized the importance of matching the die-cutting die with the material in his sharing: "Foam is squeezed during the die-cutting process and will rebound after demolding. Its deformation range is greater than that of most other materials."
When the foam is relatively thick (for example, 2mm), it is prone to bevel or serpentine bending after die-cutting, resulting in dimensional deviations. Therefore, dimensional compensation must be carried out before the die-cutting is made.
He also pointed out: "The distance between the two knife lines should not be less than the thickness of the foam; otherwise, the foam will deform due to excessive squeezing." For instance, when the foam thickness is 2mm, the spacing between the knife lines must be greater than 2mm."
This reflects the close connection between the selection of caulking compound and the design of the die.
In practical applications, for die-cutting of high-density materials such as automotive interiors and electronic boards, it is usually necessary to select die-cutting dies with higher hardness and the corresponding sealant.
For instance, the hardness of the blade of a common laser knife is approximately 39HRC, and that of the cutting edge is about 57HRC. When die-cutting hard rubber sheets, it is recommended to use a die with a blade hardness of 47HRC and a cutting edge hardness of 59HRC, and to pair it with the appropriate filling compound.
Contact information for Shenhua Printing Materials: Mr. Ji, 19924506937