The calculation of carton box dimensions

When we put a product into the carton box, the box must be larger than the product, else it can not be put inside, but which sizes of the carton box template are appropriate? The length and width of the box template should be slightly larger than the product size plus one caliper of the cardboard is enough while the depth (height) of the box template should be slightly larger than product size plus twice caliper of the cardbard. For example, a carton box with size 10cm x 10cm x 15cm, its inner size is less than 10cm × 10cm × 15cm once it is folded, if the product size is 10cm × 10cm × 15cm box, the unfolded size of the box template should be 10.1cm × 10.1cm × 15.2cm, because the lid and bottom of the carton box have two dust flaps, so the depth of the box template need to increase twice calipers of the cardboard. Thus, the structural design of the box template is just like wearing cheongsam the size have to be completely fit for products so the structure can be safe and reliable.

1. Internal size calculation

The internal dimensions of the carton box is calculated as follows: Xi = Xmax + Kxi.

In the formula, Xi is the internal dimensions of the carton box, the Xmax is product Dimensions. Kxi is the correction factor of the internal dementions of the carton box. For folding cartons, take in the direction of the length, width with 3mm-5mm; 1mm-3mm in height direction. If the product is elastic objects such as clothing, you should take a small value; if the product is rigid objects such as instruments, then take the large value.

2. Manufacturing dimensions

The manufacturing size of the carton box is according to the following formula: X = Xi + (n-1) t + Kx.

In the formula, X is the manufacturing size of the carton box, Xi is internal dimonsion of the carton box, n is the cardboard layers in a certain direction, t is the caliper of the carton box, Kx is the correction factor.

3. Correction factor of Manufacturing dimensions

The manufacture of carton box are subject to many aspects of factors, in addition to the product external dimensions, caliper and number of layers, in determining the manufacturing size of carton box, should plus the specific size of correction factor. It is related to the following aspects of the impact.

(1) Cardboard humidity changes. Cardboard is absorbent, humidity causes the cardboard size increases, dry will make the cardboard size shrink.

(2) Process. Mechanical machining accuracy and process conditions would be affected on changes in the paperboard.

(3) Vertical and horizontal fibers of cardboard. The differences in the vertical and horizontal fibers of cardboard, will cause the cardboard size in the vertical and horizontal changes in ambient humidity environment.

(4) Size of the direction difference. Owing to the forming features of the folding carton and consider packaging products loading direction, there is a difference between the size of change in the length, wideth, heigth direction on the cardboard.

Considering all the above factors, manufacturing size correction factor is generally taken in the direction of length and width, and cardboard humidity and processing in the vertical direction is negligible.