In the automated packaging lines of industries such as food, daily chemicals, and hardware, the seam-type wrapping machine (commonly known as the pillow-shaped packaging machine) is one of the most widely used and highly automated wrapping equipment. It wraps the product with flexible film and seals the film seams through a heat pressing process. It can continuously and automatically complete the entire process of forming, feeding, longitudinal sealing, and cross-sealing cutting, and is suitable for the batch packaging of most block-shaped and regular products. This article comprehensively explains the core knowledge of the seam-type wrapping machine from the definitions of the equipment, mainstream classifications, working characteristics, and the distinction of supporting equipment.
I. Basic Definition of the Equipment
The core principle of the seam-type wrapping machine is: using flexible packaging materials such as film to wrap the product, and sealing the overlapping and protruding parts of the film through heat pressing to form a shape. The entire machine relies on continuous feeding of the roll of film, and is folded into a cylindrical shape by the forming device. The longitudinal seal is made on the film seam, and then the cross-sealing is completed through the cross-sealing mechanism to cut and produce independent pillow-shaped packaging bags. It can be combined with manual or mechanical feeding mechanisms and can be used to place seasoning packets, instructions, and small accessories as auxiliary materials. The equipment is compatible with various packaging materials such as color-printed composite films, PE, and PVC heat shrink films, and is suitable for continuous production on standardized assembly lines.
| Project | Standard Pillow-Type Packaging Machine | Gusseted Pillow Packaging Machine | Finless Pillow Packaging Machine |
| Vertical edge sealing | Overlap back seal with raised ribs | Retains overlap back seal | Butt-joint seal; no protruding fin; completely flat back |
| The corners at both ends | Right-angled, loose corners; no special finishing | Corners folded inward and heat-sealed; creates a square, box-like shape | Straight end seals; no corner gussets |
| Core institution | Basic forming + longitudinal sealing + transverse sealing | Standard version + servo-driven corner-folding/pressing mold | Butt-joint forming unit + flat sealing jaw; no overlap seal |
| Bag-shaped characteristics | Standard pillow bag with a back ridge | Squared, three-dimensional pillow bag | Flat, smooth pillow bag; no back fin |
| Printing effect | Back center obscured by the sealing fin | Back center features a sealing fin | Unobstructed full-surface printing on front and back |
| Production speed | Highest speed (180–220 bags/min) | Moderate (120–180 bags/min) | Medium-high (130–190 packs/min) |
| Equipment cost | Lowest | Mid-range | Highest |
| Primary purpose | High-volume, general-purpose mass production | Premium products + automated case packing lines | Premium packaging with full-surface color printing |
II. Classify equipment based on the overall film feeding layout
The position of the film feed directly determines the size, weight and shape of the products that the equipment is suitable for. It can be divided into two structures: top-fed film and bottom-fed film:
Top-mounted film feeding pillow-type packaging machine
The film roll is installed above the equipment and is transported to the forming device at a constant speed through traction and heat sealing components to form a cylindrical shape. The forming device supports wide range of width adjustment and the internal body is designed with a dedicated overbridge guiding structure to ensure that the materials enter the film cylinder smoothly and accurately. The overall load-bearing capacity of the machine is relatively small, suitable for small-sized products with compact volume, light weight and regular shape, such as candies, small baked snacks, and disposable daily necessities.
Bottom-mounted film feeding pillow-type packaging machine
The film is fed upward from the bottom of the equipment. The forming device has a fixed specification and a small adjustable range. Different width products require replacement of matching molds. The equipment has stronger load-bearing performance and can handle large-sized, heavy and irregular-shaped goods, often used for packaging bread, large-sized daily necessities and small hardware accessories.
III. Core Differences between Seam-Type Wrapping Machines and Knot-Type Wrapping Machines
Wrapping equipment is mainly divided into two categories: seam-type and knot-type. Their sealing principles are completely different: The knot-type wrapping machine seals the opening by twisting the film ends, and it is divided into single-end twisting and double-end twisting forms. The mainstream in the domestic market is the intermittent double-end twisting type, which is mostly used for simple candy packaging; while the seam-type relies on high-temperature heat pressing to seal the film seams, achieving a tight seal, with better dust-proof, moisture-proof and preservation effects. The finished product has a regular and beautiful shape, and is suitable for a wider range of products. It is the preferred equipment for large-scale food processing enterprises for automated packaging.
IV. Comprehensive application advantages of the equipment
The seam-type wrapping machine has a complete range of sub-models, including independent packaging of single items, multi-piece combination packaging, and transparent body shrink packaging. The automated continuous production significantly reduces labor costs. The heat press sealing has stable sealing performance and can meet multiple packaging requirements such as food preservation, dust-proof for daily necessities, rust prevention for hardware, etc. The equipment is simple to debug, easy to switch products, has strong flexibility in production, and is the main equipment for automated packaging in the food, daily necessities, small hardware, and medical device industries.