Calculation of Film
1. Packaging Paper Length
The length of the packaging paper is equal to the paper feeding length for one end seal and the distance between two color blocks, which is determined by the operation principle of the packaging equipment and the positioning requirements of the film. The paper feeding length for one end seal directly determines the packaging length of a single product, and the distance between two color blocks, as the positioning mark of the film, must be consistent with the paper feeding length to ensure the accurate identification of the light sensor, realize the accurate positioning and heat-sealing of the film, and avoid problems such as packaging misalignment and sealing deviation.
The specific calculation formula for length is: Length (mm)＝A + C + 30, where A represents the actual length of the packaged contents, C represents the reserved sealing edge length required during the packaging process, and the additional 30mm is a redundancy to compensate for minor errors during equipment operation, film stretching deformation and subsequent trimming allowance, ensuring that the size of the packaged finished product meets the requirements and avoiding problems such as insecure sealing and packaging damage due to insufficient size.
2. Packaging Paper Width
The width of the packaging paper needs to be calculated according to the width of the packaged contents and the reserved sealing edge length to ensure that it can completely wrap the contents and achieve effective sealing. The specific calculation formula for width is: Width (mm)＝2×(B + C) + 30, where B represents the actual width of the packaged contents, C is the reserved sealing edge length on one side. Multiplying by 2 is because the film needs to wrap and seal from both sides of the contents. The additional 30mm redundancy is used to cope with film stretching, equipment positioning errors and losses during the sealing process, ensuring that the packaging width is sufficient and avoiding situations such as incomplete wrapping and sealing gaps.
3. Color Block Size
Position: The color blocks must be printed on both side edges of the film, and the specific position must correspond to the light sensor of the equipment to ensure that the sensor can accurately identify the color blocks, realize the accurate positioning of the film, avoid problems such as misalignment and deviation during packaging, and ensure the consistency of the packaged finished products.
Size: The standard size of the color block is 10～15mm in length and 5mm in width. This size has been verified through multiple equipment debugging, which can not only meet the identification needs of the light sensor, but also not affect the packaging appearance due to too large color blocks, or cause sensor identification failure due to too small color blocks. In actual production, it can be appropriately adjusted within this range according to the film width, equipment accuracy and other conditions, but the size must be uniform and standardized.
Color: The color blocks must be selected from dark color series such as black, blue and dark brown, and light color series such as light green, light yellow, pink and gold are strictly prohibited. This is because the contrast between dark color blocks and the film itself is higher, so the light sensor can identify more clearly and quickly, reducing identification errors; while the contrast of light color blocks is low, which is easily affected by light and film color, leading to sensor identification failure, thereby affecting packaging efficiency and finished product quality.
4. Notes
Due to the differences in surface gloss, color and material characteristics of different types and thicknesses of films, which will affect the identification effect of the light sensor, it is necessary to readjust the sensitivity of the light sensor after replacing the film type and specification. During adjustment, it is necessary to combine the characteristics of the new film and gradually debug the sensor parameters to ensure that it can stably and accurately identify the color blocks, avoid problems such as packaging misalignment and abnormal sealing due to improper sensitivity, and ensure the smooth progress of packaging production.
Note: The above size calculations are all theoretical values. In the actual production process, due to the influence of various factors such as the stretching characteristics of the film material, the operation accuracy of the equipment, and the operation level of the operator, there may be a slight deviation between the theoretical size and the actual packaging size. Therefore, before mass production, it is necessary to carry out actual test packaging operation, adjust the size slightly according to the test packaging results to ensure that the packaged finished product meets the quality requirements, and finally take the actual test packaging size as the standard.
