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Zhejiang Wenchen Packaging Technology Co., Ltd.

About Us

Zhejiang Wenchen Packaging Technology Co., Ltd. was established on December 24, 2004. As Cardboard Mailer Boxes Manufacturers in China, Corrugated Mailer Boxes Compnay, the company integrates R&D, manufacturing, export and domestic sales. It mainly deals in color boxes, corrugated boxes, corrugated cardboard, industrial cartons, Taobao Tmall and various e-commerce platforms postal express cartons, various specifications of customized printing and other carton products. With 15 years of carton production capacity, the company has rich product experience. The production of cardboard and carton is completed by the company, which guarantees the quality of the product from the source, focuses on automation and large-scale production, and responds quickly to customer requirements; vertical integration can bring better costs to customers.


The company covers an area of ​​61,111 square meters, with a plant area of ​​35,000 square meters, an annual output of 150 million square meters of cardboard, and a monthly output of 80 million cartons. Offer Custom Printed Corrugated Mailer Boxes. In 2018, the company's annual output value was 260 million yuan.


At present, the company's annual production capacity of paper containers is 300 million square meters, with a fully automatic 2500 door width high-speed cardboard production line, a fully automatic 5-color carton linkage production line, a fully automatic digital printer, 8 three-color printing machines, 2 fully automatic four-color printing machines, 3 1500 die-cutting machines, 1 1450 fully automatic die-cutting machine and other production equipment. As Custom Cardboard Mailer Boxes Compnay, the total investment is about 200 million, and the annual sales are about 500 million.


The company has a sound organizational structure and adheres to the principle of "people-oriented, integrity first, customer first, quality first". Friends from all walks of life are welcome to visit, guide and discuss business.

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Corrugated Mailer Boxes

What Actually Separates a Mailer Box from a Regular Shipping Carton

A mailer box is usually die-cut and creased as a single flat blank that folds and locks into shape without tape or glue at the point of packing. That one difference changes a lot: packing speed goes up, the box opens flat again for easy return labeling, and the tolerances have to be tighter, since a self-locking tab only works if the die line is accurate to a millimeter or two. We keep separate die sets for mailer-style boxes rather than adapting standard carton tooling, precisely because that tolerance matters.

Flute Choice: Why Most Mailer Boxes Use B or E Flute

Mailer boxes are usually shipping lighter goods and doubling as the brand's first physical touchpoint, so the priority shifts from raw stacking strength toward clean folds and print clarity.

  • B flute — thinner wall, holds tight folds and self-locking tabs well, standard for most mailer boxes
  • E flute — even thinner, best print resolution, suited to cosmetics, jewelry, or small subscription items
  • C flute — only worth using on mailers if the contents are heavier or have sharp edges that risk puncturing a thinner wall

Closure Styles and What Each One Trades Off

Common mailer box closure styles and their practical trade-offs
Closure Style Packing Speed Best Suited For
Auto-Lock Bottom Fastest High-volume fulfillment, repetitive packing
Tuck-Top Fast Retail-style presentation, tamper-evident options
Roll-End Tray Moderate Reusable packaging, easy open-and-reseal for returns

We can build any of these as a one-piece structure with no separate lid to lose or misalign during packing, which is usually the detail that matters most once a warehouse team is packing at volume.

Sizing for Mailbox and Locker Fit, Not Just the Product

Beyond dimensional-weight pricing, mailer boxes have a second sizing constraint: many carriers offer a discounted flat or letter-mail rate only if the box fits their specific thickness limit, often somewhere around 3–4 cm. A box that's a centimeter too thick loses that rate entirely and defaults to standard parcel pricing. If low-cost mail delivery is part of the plan, it's worth confirming the target carrier's exact threshold before finalizing a die line rather than after.

Interior Color and Print Contrast for the Unboxing Moment

Because a mailer box is opened by the end customer rather than a warehouse worker, the inside surface is part of the design, not just the outside. A white or contrasting-color interior against a kraft or dark exterior is a common way to create that reveal moment without paying for full interior printing. We offer white, kraft, and printed interior linings on the same mailer structure, so the finish can be adjusted per SKU without changing the box's structural tooling.