How to Choose the Right PP Woven Bag Printing Machine: 5 Types Compared

Introduction

Printing transforms a plain woven sack into a branded, market-ready product. It conveys your customer's brand identity, product information, and quality promise at a single glance. But with multiple machine types available—each with distinct capabilities, costs, and limitations—choosing the wrong equipment can lead to wasted investment, compromised print quality, and ongoing production inefficiencies.

This guide compares the five main types of PP woven bag printing machines available today. For each type, we explain how it works, its key features, limitations, and ideal application scenarios. Whether you are a small factory printing finished sacks for local orders or a high-volume producer requiring precision registration for export packaging, this article will help you make an informed decision.

1. Bag-to-Bag Printing Machine (Finished Sack Printer)

How it works: Prints directly on finished sewn sacks—not roll fabric. Printing and bag-making are separate processes.

Key features:

1. Flexible job change—bag size adjusted by mechanical stopper, no need to change plate cylinder circumference.

2. Low capital cost—much cheaper than roll-fed stack-type / CI flexo press. Small footprint, no special requirements for workshop height and floor load-bearing.

3. Single-side & double-side printing available in one pass.

4. Simple operation & low maintenance cost—compatible with water-based and solvent-based ink.

5. No fabric stretching trouble—prints on rigid finished sacks, avoids mis-registration caused by PP woven web elongation.

6. Optional automatic bag feeding & stacking—high-end version with auto-feeder.

Best for: Small to medium factories, frequent small-batch orders and sampling, stock sack reprinting, limited floor space, and budget.

Not for: high-volume continuous production, extremely high precision requirements.

2. Stack-Type Flexo Printing Machine

How it works: Printing units stacked vertically, each with independent impression cylinder. Double-side printing (2+2, 3+1, 4+0) via turning bar mechanism.

Key features:

1. Occupies relatively little floor space.

2. Printing plate cylinders must be changed for different print repeat lengths.

3. Printing precision (±0.25 mm) higher than horizontal unit-type flexo presses.

Best for: Limited floor space, medium-precision work, moderate job-change frequency, and double-sided printing needs.

Not for: Frequent repeat-length changes, ultra-high-speed production,  premium color-critical work.

3. In-Line / Unit-Type Flexo Printing Machine

How it works: Each printing unit independently controlled by dedicated servo motor. Printing across different repeat lengths possible without changing print cylinders.

Key features:

1. No cylinder change for different repeat lengths.

2. Independent servo drive per unit.

3. Very long web travel path—PP woven fabric prone to stretching; registration depends heavily on tension; registration precision (±2 mm) is worse than CI press.

4. Huge floor space—requires long workshop length.

Best for: Very frequent repeat-length changes, factories with ample workshop length.

Not for: High-precision work, limited floor space, stretch-sensitive fabrics. 

Note: Requires the longest workshop length among all types.

4. CI (Central-Impression) Flexo Printing Machine

How it works: All printing stations surround one large central impression drum. PP woven web wraps tightly on drum surface with short web path, minimizing fabric stretching and distortion. Designed for high-accuracy, high-speed mass production.

Key features:

1. Excellent register accuracy (±0.1–0.15 mm)—color alignment stable during high-speed running, capable of fine patterns, logos, and gradient effects.

2. High-speed for large-volume orders—max printing speed 120–180 m/min; material waste decreases with larger batch size.

3. Uniform & stable ink output—even ink laydown on rough woven surface with consistent batch-to-batch color; corona treatment for strong and scuff-resistant ink adhesion.

4. Wide substrate compatibility—suitable for plain PP woven fabric and laminated and coated woven material; low-tension web handling prevents wrinkles on thin & soft woven cloth.

Best for: High-volume long-run production, fine patterns and gradient effects, and export-oriented quality standards.

Not for: Very small batches (setup waste significant), limited budget, frequent job changes.

5. Gravure Printing Machine (for BOPP/PE Film, Laminated with PP Woven Fabric)

How it works: Rotogravure printing machine is the mainstream equipment for BOPP color-film printing. It adopts engraved metal gravure cylinders for roll-to-roll continuous production. The printed film is then laminated with PP woven fabric.

Key features:

1. Equipped with unwinder, corona treatment, multi-color printing units, independent drying ovens, automatic register control, tension control, web video inspection, and rewinder.

2. Compatible with BOPP, PET, CPP, metallized film, and other substrates.

3. Thick & rich ink layer, high-saturation color, fine dot reproduction—suitable for premium food packaging film, laminated film, and large-volume long-run orders.

Best for: Premium food packaging film, laminated film, large-volume long-run orders, photo-quality graphics, and multi-layer barrier sacks.

Not for: Direct printing on woven fabric, short runs (cylinder engraving cost), and factories without lamination capability.

Quick Comparison Table

How to Choose — A Decision Framework

Common Selection Mistakes to Avoid

Mistake 1: Buying a high-speed CI flexo press for small-batch work

The setup waste and plate change time make CI presses uneconomical for short runs.

Mistake 2: Choosing a unit-type flexo press without checking workshop length

Unit-type presses require significantly more floor space than other types.

Mistake 3: Assuming all flexo presses deliver the same print quality

Register accuracy varies widely—from ±2 mm (unit-type) to ±0.15 mm (CI press).

Mistake 4: Overlooking substrate compatibility

Not all printing machines handle laminated, coated, or lightweight fabrics equally.