The production process of a backpack
From the design drawing to the finished product, a backpack needs to go through five major stages: "design → cutting → sewing → assembly → inspection", and each stage is further divided into more than ten procedures. Process-oriented and data-driven approach is the guarantee of stable quality and also the key to understanding the superiority or inferiority of backpacks.
I. Design and prototyping
First, use CAD to draw the backplate and the unfolding diagram of the storage bag, and output a 1:1 paper grid. Set the fabric weight per gram and the density of the stitching according to the capacity and load. After the sample bag is completed, it should be carried by a 5-kilometer dummy to confirm the center of gravity and the position of the pick-up port. Only after making the necessary modifications can it be stacked.
Ii. Cutting and material preparation
The main material is mostly 210D - 500D nylon, which is cut layer by layer using an automatic cutting machine, with an error of no more than 0.5mm. Foam, mesh fabric and other auxiliary materials should be cut simultaneously and numbered according to "piece number + color" to avoid mixed pieces.
Iii. Sewing and Splicing
Sew small items first: zipper Windows, mesh bags;
Re-assembly of the main warehouse: Five-thread overlock and sewing are completed in one go, with 10 stitches per 3cm, tensile strength ≥80N.
Back plate reinforcement: Apply the needle back three times at the root of the shoulder strap to form a "cross" force-bearing point to prevent tearing.
Iv. Assembly System
Insert the 2mm carbon fiber rod frame and rivet the chest strap and belt buckle. For the swivel wheel model, install the wheel seat first and then rivet it, with a torque of 12N·m. Finally, attach reflective strips with a position error of less than 2mm to ensure visibility at night.
V. Inspection before leaving the factory
The finished products first pass through the needle detector, and then are statically lifted and pulled for 10 minutes at 120% of the nominal value. If the seam slippage is ≤2mm, it is considered qualified. Finally, a 1.5-meter drop test and 5,000 zipper pull and close tests will be conducted. Only after all tests are passed can the labels be affixed and the boxes be packed.
From the paper grid to the fabric, from the needle and thread to the buckle, the backpack is verified layer by layer in more than thirty procedures. Understanding the production process enables you to grasp the quality significance behind details such as "stitch length, line type, and return stitch" when making a purchase: Only backpacks that have been evaluated by data are worth accompanying on a long journey.
