The three-dimensional stamping technology is a combination of stamping technology and embossing technology of a composite technology, can also be seen as "stamping + embossing" combination process, is the use of etching or engraving technology will be stamping and embossing graphics into a top and bottom with the negative die gravure and positive die convex version, to achieve stamping and embossing technology to complete the process at once. process.
Printers are committed to helping printing and packaging companies achieve competitiveness through the upgrading of printing processes. Today, I will learn together with you what quality control points and defects treatment of three-dimensional stamping technology, in order to help all printing colleagues to better grasp the quality of printed products.
Hot stamping version
Compared with the ordinary hot stamping version, embossing version, three-dimensional hot stamping using the production process of the hot stamping version both the same place, but there are significant differences.
Because the three-dimensional stamping is the process of stamping or embossing at one time, so its stamping plate than simple stamping and embossing plate quality standards are higher, plate making requirements more stringent, more complex process.
For example, the ordinary stamping plate bottom die is flat, do not need special production, and three-dimensional stamping because of the formation of three-dimensional relief pattern, so its stamping plate bottom die must be corresponding with the stamping plate Yang die convex version, that is, the stamping plate concave parts on the bottom die should be raised, and the height of the raised and the stamping plate concave depth is corresponding.
High-quality stamping plate is an important basis for ensuring the quality of three-dimensional stamping products.
The hot stamping plate must be made of high quality metal material, generally made of bronze plate by laser engraving. Stainless steel is also an excellent material for the production of hot stamping plate, because its surface is very smooth, compared with the bronze plate, stainless steel hot stamping plate, hot stamping graphics gloss and clarity is higher, the effect of pressure embossing is also better.
Picture because the hot stamping plate is in high temperature and high pressure operation, in the normal state reflecting the small defects are not obvious may have a great impact on product quality. Therefore, in the quality control of the hot stamping plate must be perfect, in order to eliminate the quality of hidden dangers from the source.
Generally speaking, the hot stamping plate should be uniform thickness, patterns, text engraving clear, consistent depth; bottom mold should be flat without scratches, the same size, no cracks, toughness; hot stamping plate and bottom mold can not have the naked eye visible deformation, chipping, bubbles, burrs burrs and other defects.
Electrochemical aluminum
The quality of the electrochemical aluminum directly determines the appearance effect of the three-dimensional stamping products.
Qualified quality of the aluminum should be no obvious bright spot, dark spot or laser version of the seam, the surface protection layer is smooth and transparent, no fog and gray phenomenon. When checking the electrochemical aluminum against the light, there should be no visible quality defects such as white spots, dirty spots, glue spots and sand eyes.
Pictures in addition to the appearance of performance, aluminum carbide suitable for hot performance is also very critical. The suitable stamping performance of the aluminum carbide directly determines its adhesion, peeling force and impact resistance, which is one of the decisive factors affecting the quality of stamping.
In order to ensure that the electric aluminum can show the best hot performance, not only to carefully select the paper, ink, varnish, varnish and other chemical coatings, but also the hot stamping process temperature, speed, pressure and other parameters should be set reasonably, before mass production should also be test stamping, so as to ensure the yield of mass production.
Picture in addition to the test stamping to confirm the suitability of the electrochemical aluminum stamping performance, should also use a special instrument or tape on the electrochemical aluminum peel strength, impact resistance and other properties of the test.
If the stripping strength of the aluminum electrochemical is too small, in the process of stamping transfer may appear to drop aluminum or transfer bad problems; conversely, the aluminum electrochemical is difficult to transfer thoroughly, the quality of stamping on the failure.
If the impact resistance of the aluminum electrochemical poor, in the process of embossing will produce aluminum problems, in the finished product performance for the stamping part of the broken. Therefore, the first measure to solve the three-dimensional stamping process of aluminum, defective, blistering, leaving the layer and other quality defects is to fully grasp the various properties of aluminum carbide.
In the cigarette packet three-dimensional stamping production, the general choice of high temperature, with anti-counterfeiting holographic laser aluminum, this kind of aluminum have good peel strength and impact resistance, not easy to deformation, and suitable for hot performance is good, so can effectively ensure the quality of the finished product.
In addition, for three-dimensional positioning stamping of the aluminum plate distance must be consistent, can not exceed the set jump step parameter error (error <0.1mm). Because in the stamping step calculation, the plate distance as the laser eye tracking point, even if there is only a very small error, after repeated stamping, the cumulative error will be quite amazing, sometimes even up to tens of centimeters, resulting in a large amount of material waste, so the aluminum plate distance should be strictly controlled.
Operation points
Pictures in the three-dimensional stamping production process, from the "hot" and "pressure" two aspects of quality control, to avoid poor adhesion, ink back pull, stamping on the quality defects; to rationalize the electrochemical aluminum base adhesive hot melt and ink, varnish, varnish and affinity between relationship; also need to set up quality control points in the printing press, pay close attention to the amount of ink, ink drying effect, the impact of the amount of spray powder on the stamping process, and strict control, and timely solve the quality problems.
①Temperature regulation
To adjust the temperature as the key point of three-dimensional stamping quality control, strict control of preheating time, and ensure that the temperature rise, fall amplitude and stamping speed to maintain synchronization. The hot melt adhesive coating of the aluminum itself is very small, so if it receives a slight deviation in the heat of stamping, it will directly affect the transfer quality of the aluminum electrochemical. In addition, the electrochemical aluminum surface sprayed metal aluminum layer is also very thin (thickness of only 1 ~ 2μm), and very sensitive to temperature changes, so it must be carefully controlled stamping temperature.
Picture but the temperature adjustment is not easy to control, so in the actual production process, often due to the hot stamping temperature fluctuations and produce some quality problems. For example.
Stamping temperature is too low, the melting of aluminum hot melt glue is not sufficient, it is easy to appear stamping defect, paste plate, stamping on, flower and other quality defects;.
When the stamping temperature is too high, the surface aluminum layer of the aluminum electrochemical will melt again, the splash phenomenon, but also produce discoloration, surface fogging, no laser luster and other quality defects.
In addition, blistering, aluminum, peeling and delamination and other failures and stamping temperature control have a lot to do with the producer to adjust the stamping temperature according to the specific performance of the quality failure.
② Pressure control
In order to make the three-dimensional stamping products comparable to the pressure embossing effect of simple pressure embossing products, it is necessary to control the pressure embossing quality while ensuring the stamping effect.
Since three-dimensional stamping is the process of stamping and embossing at the same time, the pressure size not only affects the adhesion of the aluminum electrochemical, but also relates to the embossing effect, and sometimes there may be irreconcilable conflicts between the two.
For example, the pressure is set higher, can increase the adhesion of aluminum in the paper, beneficial to stamping, but in the embossing process may appear in the paper breakage problem.
Therefore, in order to achieve the best stamping effect on the basis of not breaking the paper, it is necessary to carefully set the pressure, and reasonable adjustment of the height of the stamping page, accurate calibration of the embossing bottom die, to ensure that all the stamping plate and bottom die height, flatness are consistent.
In addition, the quality of the bottom die must be checked and tracked, especially after the bottom die has continuously withstood tens of thousands, hundreds of thousands of times the impact force, pay special attention to check the degree of deformation and toughness of the bottom die, and timely replacement of worn out bottom die.
Troubleshooting
In the production process of three-dimensional stamping, quality failure may arise at any time, need to deal with in a timely manner. Among them, the main defects closely related to the suitability of the electrochemical aluminum and ink include poor adhesion of the electrochemical aluminum, ink pull back, stamping on, missing aluminum, etc.
① Bad adhesion
In the three-dimensional stamping production process, the failure of poor adhesion of the electrochemical aluminum is often manifested in the following two aspects, and the causes are different.
One is the electrochemical aluminum can not be firmly attached to the printing surface, and may even be completely stamping on, with the tape a tear on the aluminum or a large mutilation phenomenon. In the final analysis, this is due to the poor adhesion of the electrochemical aluminum caused by, at this time need to improve the electrochemical aluminum suitable for hot performance, or replace the new electrochemical aluminum.
Another is stamping after the aluminum can be firmly affixed to the printing surface, but the ink will appear to pull back the phenomenon. This phenomenon is caused by the poor adhesion of ink, and ink and paper printing suitability and ink drying is not complete and other factors, it is necessary to improve the ink and paper printing suitability, or adjust the drying speed of ink.
② stamping on
Caused by stamping on the following three main reasons.
Printed surface spray powder too much, which is the most common cause.
ink has not been completely dry on the start of stamping.
Ink surface coated with a layer of protective varnish, varnish and other resinous coatings, and thus do not have the "affinity".
Encounter stamping quality problems, must start from the actual, specific analysis of specific problems, never rashly stamping, to prevent the production of large quantities of scrap quality accidents.
With the continuous improvement of consumer demand for printing and packaging value, more and more hardcover process is sought after by the market, and three-dimensional stamping technology because of its good performance and process aesthetics, the application in the printing and packaging market is becoming more and more widespread, how to fully grasp the three-dimensional stamping technology, through the process to help print packaging products to enhance the value, is the printing and packaging enterprises must think about the problem.
