High-Speed Double Channel T-Shirt Bag Making Machine

Technical Specifications

Applications

The DCM-400 double-channel T-shirt bag making machine converts HDPE and LLDPE blown film into finished T-shirt bags — shopping bags with punched-out handles for supermarkets, convenience stores, and retail chains. Its dual-track design runs two independent bag lines simultaneously, producing up to 400 pcs/min in 30% less floor space than two single-channel machines side by side.

• Supermarket checkout bags — 350–400 pcs/min to supply chain stores with daily bag consumption in the tens of thousands. Hot-knife sealing delivers consistent bottom-seal strength so bags hold 5–8 kg without splitting.

• Branded retail carry bags — Printed logo bags for clothing stores, pharmacies, electronics retailers. The photoelectric sensor tracks registration marks on pre-printed film, keeping logos centered on every bag ±1 mm.

• Fruit & produce bags — Lightweight HDPE bags on-the-roll or stacked flat for wet-market and grocery sections. The DCM-400 punches clean handle cutouts at speed without tearing 0.008–0.012 mm film.

• Promotional event bags — Short-run branded bags for exhibitions, store openings, seasonal campaigns. Quick film changeover — line switches from blank to printed film in under 10 minutes.

Who This Machine Is For

• Dedicated bag converters running 500,000+ bags/day — Shops where output-per-square-meter determines profit. Dual-channel gives two lines of output from one machine: one operator, one power drop, two finished streams.

• Supermarket and retail chain packaging suppliers — Monthly bag contracts where late delivery means lost orders. The DCM-400's 400 pcs/min ceiling covers daily volumes that would otherwise need two single-channel lines.

• Printing houses expanding into bag converting — Flexo printers who want the converting margin. PLC recipe storage — select a stored job and the machine auto-sets seal time, cut length, and punch position.

• Export bag producers shipping container-loads — At 400 pcs/min, 20 hours/day, the DCM-400 fills a 40-foot container in under 8 production days — critical when shipping deadlines don't move.

Who Should NOT Buy This Machine

• Shops producing under 100,000 bags/day — If daily output fits on a single-channel machine running one shift, the DCM-400 goes underutilized. A single-channel T-shirt bag machine costs roughly 55% less and produces 180–220 pcs/min — enough for most small converters.

• Producers needing garbage bags or flat bags — The DCM-400 is configured for T-shirt bag geometry (bottom seal + handle punch). For flat bags, garbage bags on roll, or C-fold bags, you need a different machine configuration — the sealing and punching stations are specific to T-shirt bag tooling.

• Biodegradable bag startups — PLA and PBAT films seal at a narrower temperature window than HDPE. The hot-knife sealing on the DCM-400 was calibrated for polyolefin melt behavior — running biodegradable films risks inconsistent seal strength and higher reject rates. See our biodegradable film blowing line.

Technical Advantages

Hot-Knife Seal with Independent Temperature Zones Per Channel

Independent PID temperature control per channel — no compromise when two bag sizes run simultaneously. Standard dual-channel machines share one temperature controller across both lanes: thinner-gauge channel runs hot, thicker channel runs cold. The DCM-400 gives each lane independent PID hot-knife control — Channel A seals 0.012 mm HDPE at 165°C while Channel B seals 0.03 mm LLDPE at 185°C. Unlike shared-thermal machines where operators split the difference and accept higher reject rates, this keeps seal-strength variation under 8% across 100,000 bags.

Servo-Driven Registration with Auto-Correction at Speed

Photoelectric eye + servo loop corrects cut position within 0.5 mm at full 400 pcs/min. On pneumatic registration systems, correction lag means 3–5 bags print off-center before the fix lands — acceptable for blank bags, a batch rejection for branded retail. The DCM-400 servo recalculates between consecutive cycles: registration drift caught on bag #247 is fixed by bag #248. On printed film where a single misregistered roll wastes ¥3,000–5,000 in material, this is the difference between profitable and scrap.

Punch-and-Stack Integration Without Handle Tear-Out

Hardened tool-steel punch with air-eject assist — clean handle cutouts at speed without tearing thin film. At 400 pcs/min, a poorly engineered punch leaves micro-tears radiating from handle cutouts — the bag holds 3 kg at checkout but tears when the customer swings it walking home. The DCM-400 punch retracts cleanly without dragging, and a compressed-air puff clears the punched slug so it never sticks to the next bag. The auto stacker collates finished bags in counted batches (adjustable stack height to 300 mm), so the operator pulls completed stacks without slowing the line.

Real Production Issues It Solves

• Weak bottom seals on Monday morning startup — After weekend cooldown, the hot knife needs 15–20 minutes to saturate. Operators running full speed immediately get cold seals that split under load. The PID locks out high-speed mode until the knife reaches setpoint ±3°C — first bag off the line has the same seal strength as the 10,000th.

• Misaligned prints after film-roll change — New roll, different unwind tension, registration creeps 2–3 mm over the first 500 bags — waste the operator doesn't notice until the stacker fills. The servo loop samples the eye every bag cycle and adjusts immediately, not every 10–20 cycles like stepper-based systems.

• Handle punch jamming on thin-gauge film — At 0.008 mm HDPE, the punched slug clings to the die, then fuses onto the next bag as a plastic blob — a reject. The air-eject punch clears the die on every stroke, eliminating slug carryover even on the thinnest grades.

• Uneven stack counts — Mechanical counters drift when sensors miss thin bags. The PLC counts from the servo encoder — one pulse = one bag, zero missed counts — and ejects stacks at the exact preset quantity. A stack labeled "500 bags" contains 500 bags, not 497 or 503.

Production Scenarios

How It Works

1. Film unwinding: A roll of HDPE or LLDPE tubular film is mounted on the unwinding stand. The optional auto unwinder maintains constant tension via dancer-arm feedback as roll diameter decreases.

2. Film feeding & registration: Servo-driven feed rollers pull film into the machine. A photoelectric eye scans for printed registration marks; the servo adjusts feed length per cycle to keep cut position aligned.

3. Bottom sealing: The heated hot knife descends and seals at the programmed bag length. Each channel has independent temperature control — knife temperature, dwell time, and pressure set per channel via PLC touch screen.

4. Handle punching: The punch die stamps the T-shirt handle profile after sealing. Air-eject clears slugs instantly. Punch position relative to seal line is servo-controlled.

5. Cutting & separation: The hot knife cuts through the sealed section, separating finished bags from the continuous film. Cut bags drop onto the stacker table.

6. Automatic stacking & counting: The PLC counts bags via servo encoder pulses and ejects completed stacks at the preset quantity. The operator removes stacks without stopping the machine.

Optional Configurations

Customer Case

Location: Nairobi, Kenya — retail packaging supplier
Machine: DCM-400 double-channel T-shirt bag making machine
Product: Printed HDPE supermarket checkout bags, 0.018 mm, 400×550 mm
Before: Two single-channel machines at 180 pcs/min each — 360 pcs/min total, two operators, two power drops, 9.6 m². Film waste 4.2% from registration drift and bad seals.
After: One DCM-400 at 380 pcs/min, one operator, one power drop, 6.7 m². Waste down to 1.8%. Labor cost per 1,000 bags fell from $0.31 to $0.12. Payback in 14 months.

Why Choose MINGYANG

• 15+ years building bag converting equipment — Mingyang Packaging Machinery Co., Ltd. manufactures in Guangdong, China, with machines in 40+ countries. We build both film blowing and bag converting — so we know how upstream film quality affects downstream bag production.

• CE-certified, export-ready — Every DCM machine meets CE safety and electrical standards. PLC is Siemens or Delta; documentation includes wiring diagrams and spare parts list in English.

• Factory acceptance testing with your film — Send us a roll of your production film. We run it on your DCM-400, record seal strength, cycle time, and registration accuracy, and send you the video before it ships.

• Installation and on-site training — One engineer travels to your site for setup and operator training (5–7 days). Covers recipe programming, hot-knife profiling, registration alignment, and troubleshooting.

• 12-month warranty with fast spare parts — Covers hot knife, punch die, servo motors, PLC, and all mechanical assemblies. Common wear items ship from stock within 48 hours.

Frequently Asked Questions

Performance and Material Compatibility

What film materials and thicknesses can the DCM-400 run?

HDPE and LLDPE tubular film from 0.008–0.06 mm. It handles blank, single-color printed, and multi-color printed film. It is not designed for LDPE flat film that requires side-sealing — T-shirt bags need tubular film (blown film tube).

What's the real production speed, not the maximum?

Rated max is 400 pcs/min. Sustained production: 320–380 pcs/min depending on bag size, thickness, and printing. Thin blank HDPE at standard supermarket size reliably hits 370–390 pcs/min. Printed film with registration tracking runs 300–350 pcs/min — the servo needs slightly more time to verify registration between cycles.

Can both channels run different bag sizes simultaneously?

Yes. Each channel has independent seal temperature, bag length, and punch-position settings — Channel A can run 350×450 mm while Channel B runs 400×550 mm, useful for mixed-SKU orders. Both channels share the same film feed, so gauge and material must match on both sides.

Purchasing and Delivery

What's the lead time?

Standard-configuration DCM-400 ships in 30–40 days. Custom voltage or optional modules (auto unwinder, printing unit) add 7–10 days. Sea freight: 15–25 days to East/West Africa, 10–18 days to Southeast Asia, 25–35 days to South America.

What utilities do I need to prepare?

A level concrete pad (footprint + 1.5 m clearance), a power supply matching your order voltage with a dedicated breaker, and a compressed air line (0.6–0.8 MPa) for punch air-eject. We send the utility checklist and installation drawing 2 weeks before shipment.

Can I visit the factory before ordering?

Yes. Visit our Guangdong factory and we'll run your film on the DCM-400 at your target bag size. Bring your own film roll — we match your actual production conditions.

Installation and Maintenance

How long does installation and training take?

Mechanical setup: 2–3 days with your crew. Electrical & commissioning: 1–2 days. Operator training: 4–5 days covering recipe programming, hot-knife setup, registration, and daily maintenance. Most operators run independently by day 5.

What wears out and how often?

Hot-knife blade dulls after 3–6 months — first sign is incomplete cuts. Punch die lasts 8–12 months on HDPE. Silicone sealing pads: every 2–4 months. All user-replaceable; we stock and ship within 48 hours.

What's the daily maintenance routine?

Each shift: clean burnt-on polymer from hot knife, check punch die for slug buildup, wipe photoelectric eye lens. Weekly: check film-path rollers rotate freely, verify air pressure at punch eject, inspect wiring terminals for vibration loosening.

Get Your DCM-400 Quote

Tell us about your bag production:

• Bag type & size: T-shirt bag dimensions (width × length in mm) and handle style

• Film material & thickness: HDPE or LLDPE? Gauge in mm or micron? Blank or printed?

• Daily output target: How many bags per day or per month?

• Power supply: Voltage, frequency, and phase at your factory

• Optional modules needed: Auto unwinder? Printing unit? Dual stacker? Perforation?

• Destination port: For freight quotation