What Is a Circular Loom?
A circular loom is a weaving machine that produces tubular polypropylene (PP) woven fabric used for making cement bags, fertilizer bags, and other industrial packaging. The loom weaves PP tapes (flat yarns) in a circular pattern to create a continuous tube of woven fabric that is then cut and converted into bags.
Circular looms are the heart of any PP woven bag factory. A typical medium-scale factory operates 6–12 circular looms running 24/7 to produce enough fabric for their bag production targets.
Circular Loom Weaving Process
How Circular Looms Work
- Warp Yarn Setup — Hundreds of PP tapes are loaded onto the creel (holder) and threaded through the loom
- Shuttle Insertion — Shuttles carry weft (cross-direction) tapes through the warp tapes
- Weaving — The circular motion interlaces warp and weft to create tubular fabric
- Take-Up — Finished fabric is wound onto rolls for the next process
- Auto-Stop — Built-in sensors stop the loom if a tape breaks
Types of Circular Looms
By Number of Shuttles
| Type | Shuttles | Speed | Fabric Width | Price Range |
|---|---|---|---|---|
| 4-Shuttle | 4 | Standard | 350–800mm | $15,000–$35,000 |
| 6-Shuttle | 6 | 50% faster | 350–1000mm | $25,000–$55,000 |
| 8-Shuttle | 8 | Fastest | 500–1200mm | $40,000–$80,000 |
By Fabric Type
- Standard Mesh — For open-weave bags (lower cost, lighter weight)
- Dense Mesh — For heavy-duty bags (higher GSM, better strength)
- Coated-Ready — Tighter weave for lamination compatibility
By Technology Level
- Cam-Drive — Traditional mechanical drive, lower cost, more maintenance
- Gear-Drive — Smoother operation, less vibration, mid-range price
- Electronic Let-Off — Computer-controlled tension, best fabric quality, premium price
Key Specifications
- Number of Shuttles — 4, 6, or 8 (determines speed and fabric density)
- Fabric Width Range — 350–1200mm flat width (tubular circumference = 2× flat width)
- Mesh Density — Warp × weft tapes per 10cm (e.g., 10×10, 12×12, 14×14)
- Tape Count — Number of warp tapes the loom can handle (300–1200+)
- Weaving Speed — Measured in picks/min (revolutions per minute)
- Fabric GSM Range — 55–120 GSM typical for cement bags
- Power Consumption — 15–22 kW per loom
- Auto-Stop Systems — Warp break, weft break, fabric fault detection
Machines Compared
4-Shuttle Circular Loom (CL-4S)
- Shuttles: 4
- Width: 350–800mm
- Features: Auto stop on breakage, high-density weaving
- Price: $15,000–$35,000
- Best for: Standard cement bag fabric, small to medium factories
6-Shuttle Circular Loom (CL-6S)
- Shuttles: 6
- Width: 350–1000mm
- Features: Electronic let-off, wider fabric, higher speed
- Price: $25,000–$55,000
- Best for: Large factories, wide bag production, premium fabric
8-Shuttle Circular Loom
- Shuttles: 8
- Width: 500–1200mm
- Features: Highest speed, computerized control, auto tension
- Price: $40,000–$80,000
- Best for: Very large factories, jumbo bags, FIBC (bulk bags)
How Many Looms Do You Need?
Production Capacity Calculator
A single 4-shuttle loom produces approximately:
- 4,000–6,000 meters of fabric per day (24 hours)
- Enough for 2,000–3,000 bags per day (depending on bag size)
- Approximately 60,000–90,000 bags per month
| Monthly Target | Looms Needed (4-shuttle) | Total Investment |
|---|---|---|
| 200,000 bags | 3–4 looms | $45,000–$140,000 |
| 500,000 bags | 6–8 looms | $90,000–$280,000 |
| 1,000,000 bags | 12–15 looms | $180,000–$525,000 |
| 2,000,000 bags | 24–30 looms | $360,000–$1,050,000 |
Note: 6-shuttle looms produce ~50% more fabric per loom than 4-shuttle, so you need fewer units.
Pricing Guide
| Category | Price Range (USD) | Key Feature |
|---|---|---|
| Economy 4-shuttle | $15,000–$22,000 | Cam drive, basic controls |
| Standard 4-shuttle | $22,000–$35,000 | Gear drive, auto-stop |
| Standard 6-shuttle | $25,000–$40,000 | Wider fabric, higher speed |
| Premium 6-shuttle | $40,000–$55,000 | Electronic let-off |
| Premium 8-shuttle | $40,000–$80,000 | Computerized, widest fabric |
What Affects Loom Price
- Shuttle count: Each additional pair of shuttles adds 30–50% to the price
- Drive type: Electronic > gear > cam (each step ~20–30% more)
- Width range: Wider-capable looms cost more due to larger frame and more warp positions
- Brand/origin: Chinese looms are 40–60% cheaper than European equivalents while offering comparable quality for standard applications
Maintenance Tips
- Every Shift: Check tape tension, inspect shuttles for wear, clean fabric sensors
- Daily: Lubricate shuttle tracks, inspect drives and gears, clean yarn dust
- Weekly: Full shuttle replacement rotation, inspect warp beam tension, check auto-stop sensors
- Monthly: Bearing inspection, drive belt/chain tension, full cleaning
- Annually: Frame alignment check, complete bearing replacement cycle, electronic system calibration
Frequently Asked Questions
How long does it take to set up (beam) a circular loom? Initial beam setup takes 4–8 hours for experienced operators. Once beamed, the loom runs continuously until the warp yarn is depleted (typically 3–7 days), requiring only roll changes.
What is the lifespan of a circular loom? 10–15 years with proper maintenance. Shuttles are the primary wear part and should be replaced or refurbished every 1–2 years.
Can circular looms make non-cement products? Absolutely. The same looms produce fabric for fertilizer bags, grain bags, sandbags, geotextiles, and other woven products. Changing the product only requires adjusting weave density and fabric width.
What is the power consumption per loom? Typically 15–22 kW. Running 8 looms for 24 hours uses approximately 2,880–4,224 kWh per day. At $0.10/kWh, that’s $288–$422 per day in electricity.
Learn about the complete PP woven bag production process in our PP Woven Bag Machine Guide or explore all machines in the machine directory.