T-shirt bag making:
speed, size, cost

What the machine actually does

A bag making machine takes blown film from a roll and turns it into finished bags: it unwinds the film, seals the bottom, cuts the handles, punches the T-shirt holes and stacks the finished bags for packing. Modern machines run on servo drives with photocell registration, so the seal lands on the same spot every cycle.

The production rate is quoted in cycles per minute (c/min). A 4-line machine cuts four bags per cycle — a 200 c/min machine therefore produces 800 bags per minute. That is why multi-line machines dominate high-volume shops.

Speed is not the same as output

Real output is cycles × lines × efficiency. A single-line machine running 200 c/min makes 12,000 bags an hour. A 4-line machine at the same cycle speed makes 48,000. But bags are only counted when they are stacked correctly — jams, misaligned seals and film gauge variation all eat into the real number.

Buyers should ask for three figures: cycle speed, lines, and a realistic bags-per-day figure at typical efficiency. If a quote only gives you cycles per minute, the rest of the calculation is being left to you.

Bag size range is a product decision

Your bag width is limited by the machine's cutting width and your bag length by the film feed path. If your product range spans small pharmacy bags and large shopping bags, check that the machine's adjustment range covers both without changeover pain — servo-driven width adjustment is worth paying for if you change sizes often.

Film quality matters as much as the machine: consistent gauge from the blown film line keeps sealing temperatures and cutting accurate. Buyers who pair their bag maker with a good film line report far fewer stoppages.

Heat seal vs cold cut

Heat sealing is the standard for T-shirt bags: the seal bar melts the film closed while cutting. Cold-cut machines (used for certain garment and speciality bags) cut without sealing, so they depend on the film's own properties at the cut line. Choose by your product: if you sell handled bags, heat seal is the workhorse; if you make bags from pre-sealed or heavier films, check which configuration your supplier recommends for that material.

What to send us

Tell us your target bags per day, your bag width and length range, and the film material you run (LDPE, HDPE, LLDPE, recycled content). We will match you to a machine — from single-line entry models to 4-line high-speed machines — and confirm the configuration in a written proposal within 4 hours on business days.