What are the quality inspection standards for blow molded products in Dalian?

The blow molding process in Dalian, as an efficient, flexible, and cost-effective manufacturing technology, occupies an important position in the production of plastic products. With the continuous advancement of technology and the diversification of market demand, blow molding products will be applied in more fields and develop towards green environmental protection, intelligence, and high performance. In the future, blow molding technology will continue to provide innovative solutions for the plastic products industry and promote sustainable development of the industry.

Blow molded products are usually made of lightweight plastics such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), which have excellent mechanical properties and durability. Blow molding technology is simple, highly efficient, suitable for large-scale production, and can effectively reduce product costs. Blow molding technology can produce hollow products of various shapes and sizes to meet the needs of different application scenarios.

What are the quality inspection standards for blow molded products in Dalian?

Appearance quality standards

Surface smoothness: The product surface should be smooth, without obvious defects such as unevenness, bubbles, scratches, burrs, etc. Slight unevenness may affect the appearance of the product, while severe unevenness may cause inconvenience in use or problems in subsequent processing.

Color uniformity: The product color should be uniform and consistent, with no obvious color difference. Excessive color differences in different parts can affect the overall aesthetics and brand image of the product.

Color: The product should have the normal color that the material and process should have, without discoloration, yellowing, darkening, or other phenomena. Abnormal color may be caused by quality issues with raw materials or improper production processes.

Impurities and foreign objects: There should be no visible impurities or foreign objects, such as particles, fibers, etc., on the surface and inside of the product. Impurities may reduce the performance of the product and even cause harm to the user.

Dimensional accuracy standard

Overall dimensions: The main dimensions of the product, such as length, width, height, and diameter, should comply with the design drawings or customer requirements, and dimensional deviations should be within the specified tolerance range. Sizes that are too large or too small may affect the functionality of the product and its compatibility with other components.

Wall thickness: The wall thickness of the product should be uniform, and the average wall thickness should meet the design requirements. The deviation of local wall thickness should not exceed the specified range. Uneven wall thickness may lead to inconsistent product strength and may cause problems such as cracking during use.

Bottle mouth or opening size: For blow molded products with bottle mouth or opening, such as plastic bottles, the diameter and thread size of the bottle mouth should meet the standards to ensure that the bottle cap or other sealing components can fit well and achieve sealing function.

Physical performance standards

Tensile strength: refers to the ability of a product to resist tensile failure, which should reach the minimum tensile strength value specified by the material and product type to ensure that the product does not break when subjected to tensile force during use.

Impact strength: reflects the ability of a product to resist impact damage, determined through impact testing. The product should be able to withstand a certain degree of impact without breaking, in order to adapt to collisions and other situations during transportation and use.

Hardness: According to the product's usage requirements, its hardness should be within a reasonable range. Insufficient hardness may cause the product to deform easily, affecting its use; If the hardness is too high, it may make the product brittle and prone to cracking.

Transparency: For some blow molded products that require transparency, such as transparent plastic bottles, they should have certain transparency and haze indicators to meet the needs of product display and content observation.

Sealing: Blow molded products used for packaging liquids or gases, such as plastic bottles, plastic buckets, etc., must have good sealing. Through sealing tests, the product should not leak under certain pressure and time.

Chemical performance standards

Chemical corrosion resistance: Test the corrosion resistance of the product in different chemical media according to its usage environment. The product should not show obvious deformation, discoloration, dissolution, cracking, or other phenomena after contact with specific chemical substances.

Mobility: Detect whether harmful substances in the product will migrate to the substances it comes into contact with, such as blow molded products for food packaging. It is necessary to test whether harmful chemicals will migrate to the food, and the migration amount should comply with relevant food safety standards.

Odor: Products should not have a pungent or unpleasant odor, especially blow molded products used for packaging food, medicine, etc. Excessive odor can affect product quality and user experience.

Other performance standards

Hygiene performance: For blow molded products used in the fields of food, medicine, etc., strict hygiene standards must be met, including the total number of bacteria, mold and yeast, Escherichia coli, pathogenic bacteria and other microbial indicators that should comply with relevant regulations.

Aging performance: By accelerating aging tests and other methods, the stability of product performance under long-term use or specific environmental conditions is tested. After a certain period of aging, the performance indicators of the product should not decrease beyond the specified range.

The basic principle of blow molding technology is to place a plastic preform in a molten state in the mold cavity, and then introduce compressed air into the preform to expand and adhere to the mold cavity wall under air pressure. After cooling and shaping, a plastic product with a certain shape and size is obtained. According to different manufacturing methods of preforms, blow molding can be divided into extrusion blow molding, injection blow molding, and stretch blow molding.

The injection blow molding process is divided into two steps: first, the preform is produced through injection molding, and then the preform is placed into a blow molding mold for blow molding. This process is suitable for producing high-precision and high transparency products, such as pharmaceutical bottles, cosmetic bottles, etc. The advantage of injection blow molding technology lies in the uniform wall thickness and high dimensional accuracy of the product, but the equipment cost is relatively high.