Liquor Class Filling Production Quality Control Technology

Crown caps are widely used in the field of alcoholic or soda-flavored or non-gasified glass bottled beverages. Compared with the rotary lid, tinplate, and three-piece cans, the sealing structure and process are different, but there are many similarities in the quality problems that occur in the actual production process, such as poor sealing performance and poor adhesion of the coated surface of the printing surface. Wait. Here only a few superficial understandings and opinions on the problems that often occur in the production and use of white wine filling crown caps.

The quality defects of the crown cap during production and use are mainly manifested in: poor sealing, prone to irregular sealing, glass bottle breaking, cracking, and other anomalies; crown cover coating surface paint falls off, poor adhesion, Affects the appearance of the cover; Adhesion of paint debris on the inner liner can easily stray into the wine and affect the intrinsic quality of the contents; Corrugated liners (PVC pellets) Cushioning pad detachment, lack of material, affect Sealing of filling seals can cause leakage or chronic air leakage.

Tinplate materials, printing materials to meet the performance requirements Crown is a stamped type tinplate cover, generally according to the actual needs of the general choice of thickness 0.23mm, hardness T3 or T4, tin layer 1.1 ° / 2.8g/m2 Tinplate (SPTE) or Chrome Plated Iron (TFS). The tinplate material must meet the MR standard, and the imported iron should meet the Japanese JISG3303 standard, which must have a certain strength and hardness, and must have a certain impact resistance.

The performance of ink or paint raw materials for printing and coating must meet the actual requirements of crown caps. It is best to use the same manufacturer's matching products with good quality and reputation as the ink and coating. Otherwise, the product can be put into mass production only after passing the managerial test.

Tinplate materials and printing materials are the basic materials for product quality assurance. In many cases, poor product quality is caused by unstable or unsatisfactory raw material properties, which should also be given enough attention by people.

Crown cap size specifications to meet process and practical use requirements

The technical dimensions of the crown cap are mainly: the crown cap outer diameter D, the cap height H basic dimensions and their deviations, the cap corner radius r, the cap top radius R, and the tooth number Z are determined by the stamping die.

During the production process of the bluff cover, the crown cover shall be randomly sampled and measured with a special gauge. The basic dimensional deviation shall not exceed the given value. In particular, when the machine is re-installed after polishing machine or die grinding, the crowns punched out by each row of die must be checked one by one, mainly the outer diameter D, the cover height H and the appearance quality inspection. When adjusting the machine parts, it is necessary to pay attention to the dimensional and process requirements of the crown cap, and also to meet the sealing and appearance requirements of the glass bottle mouth.

Paint surface coating film adhesion is better, to resist stamping

Crown cover in the red cap, injection molding process prone to paint film off, flash and other phenomena, mainly due to paint film adhesion and resistance to poor stamping caused. Here are some reasons to look for the following reasons: Material properties of the tinplate and paint itself are poor or do not meet the actual requirements; after the tinplate is passivated, the surface is coated with a layer of oil or dioxin, etc. to prevent storage. Rusty and friction between the iron sheets during transportation. If the oil layer is too large or unevenly applied, it will cause poor adhesion of the coating film. Before the production, the iron skin will be baked once, and then the coating film will be produced.

The oven itself has poor performance. The unstable furnace temperature or the poor temperature uniformity is also an important factor that causes the poor adhesion of coating film. Generally, it should be checked every six months or one year depending on the actual production conditions. When testing the furnace temperature performance, it is easy to see from the temperature control curve: The well-behaved temperature rise zone should be 2-3 minutes, the uniform temperature zone should be 12-13 minutes, and the change curve should be relatively stable, with high and low temperature difference of 3°C-5. °C. When coating film production must strictly refer to the process of construction, the production process must be fully mixed after adding paint or thinner, and to ensure the uniformity of coating viscosity, coating film is too large, too small or uneven will cause adhesion bad. Whether the process arrangement is reasonable and correct is also an objective factor that affects the film adhesion. For example, the current color printing surface design of the crown cap is generally relatively simple, clear, personalized, the printing plate is also more monochrome, two-color printing, printing process more complex coating film adhesion problems occur more.

The ink adhesion is better. For the case of no-primary coating or direct coating after color printing, the staff must carry out physical and chemical inspection; at the same time, it should be noted that the coating process is generally thinner in the primer coating and thicker in the outer wall, which depends on the performance of the coating itself and actual production. The situation is flexible. In addition, the crown cap's cut-to-finish product is recommended for use after 24 hours of storage to ensure that the paint and ink layers on the surface of the print are fully cured. Poor film adhesion or poor impact resistance is a key factor affecting product quality, and it is also the most common quality defect. Therefore, each link in the printing process must be strictly controlled.

PVC adhesive and cap inner coating adhesive adhesion is better

Injection molding temperature instability, poor adhesive properties, poor performance of PVC raw materials are the three main factors affecting whether the injection mat is cushioned; in addition, lack of injection molding will seriously affect the sealing of the bottle mouth. According to the process requirements, the weight of a normal single pad must be strictly controlled (0.35±0.2g) during the production operation. During the inspection of quality control, the staff can arbitrarily select 10 to 20 sample caps for weighing, and carefully detach the rubber pads after they are peeled off with bamboo sticks, and then take the average of the difference between the cover weights twice to the nearest 0.1 g.

In short, the crown cap in the stamping production process should pay attention to several technical indicators are: the appearance of quality can not have obvious paint off, skirt burr, etc.; process dimensions to meet the cap size requirements and use requirements; PVC pad Injection molding should be complete and good adhesion; pad weight should be the same. Operators only have a comprehensive understanding and understanding of the crown coating technology and the stamping process. Only in the event of different quality defects can they find the causes for each link and make corresponding adjustments to ensure product quality.