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MJ-350A High Speed Center Seal Pouch Making Machine | Automatic Bag Maker for Food Packaging
Description
Center Seal Pouch Making Machine
MJ-350A High Speed Center Seal Pouch Making Machine
for BOPP 50 Micron Back & Bottom Seal Bags
The MJ-350A is a fully automatic, servo-driven pouch-making machine designed to convert BOPP, CPP, and OPP film rolls into pillow-style center seal bags — the same construction used in chips, snacks, and dry food packaging. 80–200 bags/min. CE certified. Factory direct.
200max bags/min
50µmBOPP compatible
350mmmax film width
CEcertified
Product Overview
What Does the MJ-350A Actually Make?
Before evaluating any machine, buyers need to understand the exact bag construction. The MJ-350A produces center seal pillow pouches — the format you see on virtually every bag of chips, popcorn, or puffed snack on supermarket shelves worldwide.
Key distinction: The MJ-350A is a bag-making machine, not a form-fill-seal (FFS) machine. It outputs finished, open-top bags ready for a filling line. This makes it ideal for bag converters, flexible packaging plants, and contract packagers who supply pre-made bags to food brands.
Machine Process
How the MJ-350A Center Seal Process Works — Step by Step
Understanding the production sequence helps buyers assess whether the MJ-350A fits their line layout and whether 50 micron BOPP film is the right substrate choice.
Film Specification
Why 50 Micron BOPP Is the Industry Standard for Snack Bag Packaging
Most buyers arrive with the spec "50 micron BOPP" — but few suppliers explain why that gauge exists and what it means for machine compatibility. Here is the full picture.
50µm
0.05mm — standard snack packaging gauge
~46
gsm film weight (grams per square metre)
120–160°C
optimal sealing jaw temperature on MJ-350A
Why Thin Film Requires a Servo-Driven Machine
50 micron BOPP is significantly thinner than laminated films and is highly sensitive to heat and tension. On a standard stepper-motor machine, inconsistent film speed causes micro-stretching that leads to wavy seals, film distortion, and bag rejection rates above 3–5%. The MJ-350A's closed-loop servo system maintains film tension to ±0.1N — keeping defect rates below 0.5% even at 180 bags/min.
Procurement note: Always request a COF (coefficient of friction) test report alongside the film spec. BOPP film with COF above 0.35 (kinetic) will cause stacking issues on the MJ-350A output belt. Optimal COF for this machine is 0.15–0.30.
Technical Specifications
MJ-350A Full Technical Specification
All specifications are for the standard MJ-350A configuration. Custom configurations (wider film, dual-lane, nitrogen purge) are available — request a technical datasheet for non-standard requirements.
| Parameter | MJ-350A Specification |
|---|---|
| Machine model | MJ-350A |
| Bag type | Center seal / Back seal / Pillow pouch (fin seal construction) |
| Compatible film | BOPP, CPP, PE, OPP, VMPET laminate, heat-seal coated film |
| Film width (max) | 350 mm |
| Bag width range | 60 – 180 mm |
| Bag length range | 80 – 350 mm |
| Production speed | 80 – 200 bags/min (size-dependent) |
| Sealing method | Heat seal — longitudinal fin seal + transverse cross seal |
| Sealing temperature | 120 – 220°C (independently adjustable per seal jaw) |
| Drive system | Servo motor — closed-loop tension control |
| Control system | PLC + 7-inch touchscreen HMI (recipe memory, fault log) |
| Counting system | Automatic electronic bag counter + batch stacker |
| Power supply | 220V / 380V, single or 3-phase, 50/60 Hz (specify on order) |
| Machine dimensions | Approx. 3,500 × 800 × 1,500 mm (L×W×H) |
| Machine weight | Approx. 800 kg |
| Certification | CE (EU machinery directive) |
| Warranty | 12 months on mechanical parts |
How It Compares
MJ-350A vs. Competing Center Seal Machine Configurations
Most buyers shortlist 3 machine types before committing. Here is how the MJ-350A compares to the alternatives on the criteria that matter most for BOPP snack bag production.
| Criteria | MJ-350A Servo Center Seal | Stepper Motor Budget Center Seal | VFFS Machine Form-Fill-Seal |
|---|---|---|---|
| 50µm BOPP compatibility | ✓ Excellent | ✗ Risk of stretch | ✓ Yes (inline) |
| Speed (bags/min) | 80–200 | 40–100 | 60–150 |
| Seal consistency | High — servo control | Medium | High |
| Bag-only output (no filling) | ✓ Yes | ✓ Yes | ✗ Fills inline only |
| Product variety / bag size flexibility | High (60–180mm W) | Medium | Medium |
| Setup / changeover time | ~20 min (recipe memory) | 30–60 min | 60–90 min |
| Price range (USD) | $8,000–$18,000 | $3,000–$8,000 | $15,000–$60,000 |
| CE certification | ✓ Yes | Often not | ✓ Yes |
Table reflects typical market specifications. Verify with individual machine suppliers before purchase.
Applications
Who Uses BOPP Center Seal Bags — and Why the MJ-350A Serves Them
🥔
Potato Chips & Extruded Snacks
The pillow bag format maximises the volume-to-film ratio for low-density snack products. Nitrogen-flushed BOPP bags keep chips crisp for 4–6 months. The MJ-350A's output rate of 150–200 bags/min suits high-volume snack lines.
chipspuffspretzels
🥜
Nuts, Seeds & Dried Fruit
50µm BOPP provides the moisture barrier these products require. Bags in the 80–120g range (100–160mm wide) run efficiently on the MJ-350A. Gravure-printed BOPP gives these premium products shelf-ready visual quality.
almondscashewsraisins
🍿
Popcorn & Puffed Grains
Large pillow bags (160–180mm wide × 280–350mm long) for bulky popcorn packs are within the MJ-350A's range. The servo tension system prevents the thin BOPP from tearing at maximum film width on fast runs.
popcornrice crackers
🐾
Pet Treats & Animal Feed
Food-grade BOPP is approved for animal food contact. Small treat bags (60–90mm wide) run at near-maximum speed on the MJ-350A, making it highly cost-efficient for high-volume pet snack converters.
dog treatscat snacks
Procurement Guide
Sourcing Checklist: What to Verify Before You Order
This checklist is drawn from common procurement errors that result in machine commissioning failures or film compatibility issues. Work through every point before placing an order.
For the MJ-350A Machine
Confirm voltage/phase (220V or 380V) matches your factory supply
Verify achievable speed at your specific bag dimensions — not the rated maximum
Check servo brand (Mitsubishi, Panasonic, Delta) — affects parts availability in your country
Request CE certificate document (not just a label claim)
Confirm spare sealing jaw availability and lead time
Agree on-site commissioning and operator training in writing
Clarify film width range vs. your narrowest and widest bag requirement
For 50µm BOPP Film
Confirm gauge at 50µm ±2µm — request QC test report per roll
Specify heat-seal coating side (inside face of finished bag)
Request COF test report — kinetic COF must be 0.15–0.30 for MJ-350A
Confirm seal strength ≥4 N/15mm (peel test, T-peel method)
Request food contact compliance (FDA 21 CFR or EU 10/2011)
Specify roll OD and core ID compatible with machine unwind spindle
Confirm print method (gravure/flexo) and colour gamut before artwork sign-off
Frequently Asked Questions
MJ-350A & BOPP Center Seal Bags — Expert Q&A
Questions answered by Ruian Xuanhai machine engineers. These cover the points most buyers ask before purchase.
What exactly is a center seal pouch making machine?
A center seal pouch making machine takes a flat roll of film, folds it lengthwise along its center, and seals it along the back spine (the "fin seal") and across the bottom. The result is a pillow-shaped bag open at the top — the standard format for chips, popcorn, and dry snack packaging worldwide. The MJ-350A automates this entire sequence at 80–200 bags per minute.
Is the MJ-350A compatible with 50 micron BOPP film specifically?
Yes — 50µm BOPP is the primary design target for the MJ-350A. The machine's servo-driven film transport maintains consistent tension on thin heat-seal BOPP, and the independently adjustable jaw temperature (120–160°C is typical for 50µm BOPP) prevents burn-through or under-sealing. On stepper-motor machines, 50µm BOPP frequently causes film stretch and seal defects at higher speeds.
What is the MJ-350A price? Is it negotiable?
The MJ-350A is typically priced between $8,000 and $18,000 USD ex-factory, depending on servo motor brand, HMI specification, and any optional accessories (automatic film splicer, nitrogen purge port, IoT monitoring). Factory pricing is available for direct buyers. Contact us with your bag dimensions and target output to receive an accurate quotation.
Does the MJ-350A fill the bags, or only make them?
The MJ-350A is a pouch-making machine only — it produces open-top bags ready for a filling line. It does not fill or top-seal. If you need an integrated fill-seal system, you would need a vertical form-fill-seal (VFFS) machine instead. The MJ-350A is the right choice for bag converters, flexible packaging plants, or brands that want to pre-make bags and fill on a separate system.
Can the MJ-350A run BOPP/VMPET laminated film as well as mono BOPP?
Yes. The MJ-350A is compatible with BOPP/VMPET (metallised polyester) laminate, BOPP/CPP, and other heat-sealable laminated structures. Laminated films are thicker and require a higher sealing temperature — typically 160–200°C for the cross seal jaw. The MJ-350A's independent temperature control for each jaw makes this adjustment straightforward. Laminated films also improve oxygen barrier performance for products requiring extended shelf life.
What is the difference between a center seal bag and a side seal bag?
In a center seal bag, the back seam runs along the vertical center spine of the bag — visible as a fin on the back. In a side seal bag, the seam runs along one edge. Center seal is more material-efficient for high-speed production (the fold eliminates one seam), which is why it dominates chip and snack packaging globally. The MJ-350A is designed exclusively for center seal construction.
How long does machine changeover take when switching bag sizes?
With recipe memory stored in the PLC, the MJ-350A can switch between saved bag sizes in approximately 15–25 minutes — mainly mechanical adjustment of the cross-seal jaw position and bag length setting. First-time setup for a new bag size requires more time (45–60 min) for fine-tuning seal temperature and tension for the new dimensions. Training significantly reduces changeover time.
Production Overview
The Complete BOPP Snack Bag Supply Chain — Where the MJ-350A Fits
Ready to Source the MJ-350A?
Send us your bag dimensions, target output speed, and film specification. We'll confirm compatibility and provide a factory-direct quotation within 24 hours.
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