Frequent cold perm defects? 9 Common Faults Completely Solved at Once!

Frequent cold perm defects? 9 Common Faults Completely Solved at Once!

In the actual production process of label flexographic cold stamping, multiple factors such as equipment parameters, consumable quality, substrate performance, and operating processes can easily lead to various foil stamping quality failures, directly affecting the appearance, texture, adhesion, and durability of the finished label, leading to product rework and scrapping, and increasing production costs. To precisely solve production problems and stabilize product quality, the following is a summary of common typical faults, core causes, and corresponding standardized solutions in cold stamping processes, making it easier for production personnel to quickly identify and rectify issues.



Irregular transfer of cold stamping foil is poor



This fault mostly arises from insufficient hardness of the foil lamination roller or insufficient foil lamination pressure. During production, it is possible to replace the harder laminating roller and appropriately increase the foil overlay pressure to improve the foil transfer effect.



The cold stamping pattern is irregular and incomplete



Fault causes often include uneven or damaged foil lamination roller surfaces, or dirt spots or damage on the printing plate or anilox roller. During handling, adjust or replace the laminating roller to increase foil coating pressure; At the same time, clean or replace the damaged printing plate and anilox roller.



Paste plate



There are two main reasons for the formation of glue plates: first, excessive adhesive application; second, insufficient hardness of the foil lamination roller. Suitable analox rollers can be replaced to reduce the glue application amount; Simultaneously replace with laminating rollers with higher hardness.



Cold stamping foil must not be transferred



If the adhesive quality is abnormal, expired, or the substrate's surface energy is too low, the cold stamping foil will not transfer at all. Check the adhesive's shelf life and replace with qualified adhesives; Apply corona treatment to the substrate to improve its surface energy.



The adhesive does not adhere to the substrate



This is mostly due to low UV lamp power and incomplete curing of the adhesive. UV lamp power can be increased, and if necessary, a corona treatment step may be added to the substrate.



The stamping pattern has crack patterns



If the tension between winding and unwinding cold stamping foil is too high, or if the foil sticks to the pressing roller, cracks in the pattern may occur. The tension of winding and unwinding the cold stamping foil should be adjusted, the pressing roller should be cleaned, and if damaged, the roller should be replaced directly.



The stamping pattern shows jagged rough edges



Improper setting of printing pressure and foil cover pressure can cause serrated burrs. Separately adjust the printing pressure between the plate roller and the impression roller, as well as the foil lamination pressure between the lamination and lamination rollers, to eliminate burr defects.



The stamping pattern has pinholes



Insufficient adhesive application, low foil coating pressure, and rough substrate surface all cause pinholes. Replace the anilox roller to increase glue application and increase the pressure of the foil lamination roller; If the substrate surface is rough, add a primer step and pre-apply primer.



The embossed pattern is not scratch-resistant



The main reason is poor curing of adhesives. UV lamp power can be enhanced to enhance curing effect, and varnish coating can also be used to improve scratch resistance of finished products.



In summary, most quality failures in the cold stamping process stem from improper parameter matching, incorrect consumable selection, inadequate equipment maintenance, and non-standard substrate pretreatment. In actual production, operators can follow the investigation logic of "first inspecting equipment parameters, then verifying consumable quality, and finally optimizing substrate processes," making targeted adjustments and rectifications. At the same time, daily equipment cleaning and maintenance, standardized debugging of process parameters, and quality inspection of consumables during storage can reduce cold stamping quality issues at the source, effectively improving the yield rate and production stability of label cold stamping products.