Experts talk about carton supplies procurement - printing supplies

It is well known that it directly affects the quality of the carton. Consumables account for a very important part in the purchase of cartons, but in the face of uneven conditions such as brands and grades currently on the market, how should carton manufacturers cope with and how to purchase the most suitable products for them? The columns in this issue will be answered for you.

We will be long-term concerned with the procurement needs of the carton factory. If you have purchasing experience and procurement advice, welcome to your contribution to share with us. The magazine will launch "builing lines", "printers", "cross cutting machines", "inks" and "adhesives" and other procurement topics. Welcome your attention.

Experts talk about purchasing - overall consideration and reasonable purchase

Corrugated box supplies are mainly divided into four categories: India Deputy supplies, accessories, die-cutting supplies and equipment bristle. The printing consumables mainly include printing plates, water-based inks, double-sided adhesive tapes, and printing pads; the sub-facilities mainly include corn starch and flat yarns; the die-cutting consumables include roller boards or plates, blade liners, and die cutters; and the equipment consumables mainly Including thin knife and grinding wheel, slotting tool.

For the purchase of corrugated paperboard consumables, we must adhere to the principles of open tendering and comparison of the three principles of storage and storage, and establish a stable supply relationship with suppliers with good reputation, stable quality, and strong strength. However, many corrugated boxes are in the actual procurement process. China and Hong Kong often lag in form and are only operated by the purchasing department alone. They do not achieve the effect of genuine comparison of goods. This requires the participation of relevant departments. It is advisable that the quality department, the manufacturing department and the finance department jointly conduct the assessment. Quality and price will eventually be confirmed.

When purchasing inks, tapes, corn starch, it must require the presence of six hazardous substances: lead and its compounds, cadmium and its compounds, mercury and its compounds, hexavalent chromium compounds, and brominated combustion enhancers (PBDE and PBB). The content must be guaranteed to fully comply with EU Day. (a) The maximum limit of the S directive; Suppliers need to provide internationally recognized institutional laboratory reports, such as SGS, to ensure that products are environmentally friendly, safe, and healthy, and that they do not promise to use hazardous chemicals in their products.

This article focuses on the matters needing attention and procurement requirements for the main consumables of corrugated boxes in the procurement process.

a printing consumable

Corrugated box companies use printing plates generally two kinds of rubber plate and resin plate, in which the rubber plate is divided into natural rubber plate, synthetic rubber plate, natural rubber + synthetic rubber plate three types; resin plate is divided into liquid photosensitive resin plate and Two types of solid photosensitive resin plate.

In order to ensure the uniform use of printing plates, the rubber plates and resin plates purchased by corrugated cartons are required to have the same thickness, which is generally 3.94 mm. The hardness requirements of the printing plate should be selected according to the specific conditions of the printing. For the printing dots and extremely small texts, the plate with high hardness should be used. In flexo printing, it is best to separate and print the same color dot and field. The hard printing plate outlets have a small expansion, and the printing continuously adjusts the light part to perform well. The soft printing plate has good flexibility and can completely fit with the printing material, so the printing field is even and thick. In addition to the printing factors, it depends on the working environment. If ozone is concentrated in the production plant, plates with strong ozone resistance should be selected. In this way, the printing plate is not easily cracked during printing, and the printing life is long.

Ideal for carton printing is to use a natural rubber + synthetic rubber version of the combined rubber plate, its two-sided surface treatment is particularly important, requiring two-sided fine grinding processing, the surface smooth and no scar or glue phenomenon, in order to achieve uniform ink transfer And stickers are solid and convenient. The rubber plate is generally hand-carved. The current laser-engraved rubber plate has also been adopted in some corrugated boxes, but it has not achieved the expected results.

Since DuPont invented the solid photosensitive resin plate in the early 1970s, the resin plate has grown from the original single variety, thickness and size to several varieties and thicknesses and sizes today. Domestic commonly used flexible solid-state photosensitive resin plates include DuPont's Cyrel (CYREL), BASF (Germany), GS (China), Poly Co., Ltd. of USA, and Co-prosperity of Japan. At present, there are a large number of professional plate-making companies with high-quality flexographic plates in China, such as Yingjie platemaking and Foley plate-making companies. These companies have been able to provide high-quality and relatively inexpensive plates.

The printing plate storage environment is between 4°C and 32°C. It should be placed in a dry, dark, cool place away from heat sources and ozone (such as motors). Safe light sources should be installed in the platemaking room to avoid sunlight and UV light irradiation. dust. Because the unexposed resin plate is still a single-molecule molecular structure and is easy to flow, it must be stored flat and must not stand firm. Do not stack more than 10 boxes when stacked. Do not step on or press on heavy objects.

Water-based ink

First of all, understand the situation of various environmental protection water-based ink products and manufacturers on the market, select suppliers with stable product quality and reasonable price, and have a good reputation in the market.

Corrugated carton enterprises are more successful approach is to use water-based ink supplier in-service mode, allowing ink suppliers to participate in the management of ink, provide technical services, help corrugated box companies improve print quality, improve print management, in order to achieve a win-win situation.

double-sided tape

The double-sided tape currently used in China is basically manufactured by 3M. These double-sided tapes are generally composed of a protective paper, a substrate, and a pressure-sensitive adhesive. The compressibility and recovery of the tape will have a direct impact. The type of printing and the quality of printing. The factors that affect print quality are usually:

Adhesiveness: The double-sided tape must have good conformability and be properly applied to the printing plate and the platen roller. Too hard to attach and have bubbles. Too soft is not easy to use, and there are wrinkles and air bubbles.

Tackiness: It depends mainly on the glue system. The type of substrate for double-sided adhesive tapes will play a role. As far as printing quality is concerned, proper selection of double-sided tape will improve the print quality. Density can be considered as an important indicator of elastic double-sided tape. 3M company after testing and based on actual production needs, determine the hard vinyl tape suitable for full version of the field, bar code printing; high-density elastic tape for full version of the field, bar code printing; medium density tape is more suitable for bar code lines, gradient mesh printing; Low-density elastic tape is more suitable for primary color plate printing.

Printed liner

The printing lining plate must have excellent compressibility, can be slowed down; neutralize the printing pressure, absorb the printing distortion caused by the printing pressure over the ambassador plate, and effectively control the dot expansion; the printing lining plate is several times higher than the flexibility of the corrugated cardboard. When the amount of compression is too large, the printing lining plate can absorb a large amount of compression to avoid pressure loss of the cardboard. For printing machines with eccentric rollers, worn bearings, and excessive runout, the use of a printing lining plate can make up for the shortage of equipment and increase the printing speed. Printing grade; the thickness of the printing lining should be selected according to the gap between the plate roller and the embossing roller of the corrugating press and the thickness of the printing plate; the lining plate with the PE film should be used as far as possible; the lining plate of the leading film can prevent the lining plate from being deformed and not It is damaged, has a long service life, and has a significant use effect. Finger pressure and nib can be used to test the elasticity of the lining plate. The lining plate that can quickly rebound to the original shape can significantly improve the printing quality; the surface of the lining plate can be inspected with vision and feel. Flatness and thickness uniformity, the lining plate with PE film evenness, on the contrary, the effect is not obvious, the service life is very short.

The most representative print lining is R/bak air-cushion lining, which is a product of Rogers Inc., and is a world-renowned manufacturer and industry leader of compressible substrate materials. The material is made of a unique formulation of a number of uniformly open-celled microcellular polyurethane materials. This open-cell interconnected microporous structure does not block air when compressed and absorbs the applied pressure. When the pressure is relieved, it will spontaneously spring back to the original state. Use an air-cushioned lining plate to provide consistent printing pressure for corrugated printing.

Non-professional lining plate is generally made of polyethylene closed-pored rough angular structure, will be closed when the air pressure, can not rebound to the original state, or even cause structural damage, can not play a role in air cushion, printing pressure can not be stable.

(to be continued)