Postpress Expo: Hot Stamping FAQs

Hot stamping process can greatly increase the added value of packaging products. It is widely used in the production process of printing companies. For some of the technical problems of this process, this article was sorted out through an interview with the printing factory, hoping to provide reference for packaging and printing companies.

1. Q: The bronzing can be divided into round and flat bronzing. What is the difference between the two?

A: The difference between round-hot round hot stamping and flat-press flat hot stamping is that the general round-press hot stamping method can be applied to large-area hot stamping and small-area hot stamping because the round hot stamping is a kind of line contact. Stamping method, and hot stamping speed. The flattened hot stamping is a surface contact and it is not easy to discharge the air. It is prone to false printing failures. The flattening and stamping method is suitable for hot stamping small area patterns, lines or text, and has a low hot stamping speed.

2. Q: What is the difference between hot stamping on composite card paper and hot stamping on white card paper?

A: The main difference is adhesion. The adhesive layer of anodized aluminum is related to the affinity of the stamped material, and the hot stamping effect on the white card paper is better than the composite card paper because the surface tension on the white card paper is large.

White cardboard usually uses ordinary inks and UV inks. Compound paperboard generally use composite printing inks (such as Hanghua Ink Chemical Co., Ltd. Offset JP series inks) or UV inks. The surface of the composite paperboard is smooth and dense. The hot stamping method is not easy to remove the air. Circular pressure line contact hot stamping machine.

3, Q: What should be paid attention to when printing on hot stamping foil?

A: It should be noted that it is best not to polish, so that the ink will not transfer. When printing, make sure to try it first, and do a careful study of the properties of the material and the ink.

(1) The first printing after stamping should pay attention to the affinity of the aluminum and ink, if allowed, the hot stamping parts can be hollowed out.

(2) Select the surface tension in the (4.0 ~ 4.6) × 10-2N / M of aluminum, to ensure that the ink has a good adhesion.

4. Q: What problems should be noticed in the aluminum foil hot stamping on UV varnish?

A: General solvent-based and waterborne varnish products are not prone to problems. UV is the most problematic. This is mainly related to the affinity and inseparable with the surface tension of the substrate.

(1) Ordinary aluminum foil on UV Varnish, there will be a false impression of hot stamping, it is necessary to ensure that the surface tension of the aluminum is greater than the UV Varnish surface tension;

(2) If allowed, the hot stamping part can be hollowed out, or it can be coated with UV varnish after hot stamping;

(3) It is best to try and print first, and then determine the hot stamping process and hot stamping material.

5, Q: What are the reasons for not allowing stamping? What is the solution?

answer:

(1) The paper is deformed. Solution: Reduce the drying temperature or UV curing temperature during printing (excessive temperature will shrink the paper).

(2) The bronzing plate is thermally expanded. Solution: Make sure that several hot stamping points are on a hot stamping plate, and grasp the inflation rule of the hot stamping plate with temperature change, and compensate before making.

(3) The hot stamping pattern, text, or lines were not scaled during platemaking.

(4) The previous process. Solution: For the problem of the previous process, ensure that the front gauge and side gauge (the distance from the paper edge to the finished product line) are the same.

In addition, the inconsistency of the ambient temperature, human factors, and the accuracy of the equipment can also lead to overprinting and inaccurate printing. Therefore, the influence of these factors must be considered in the production process.