Plastic Pelletizing Equipment Guide
By Meadoworks | April 2026 | 11 min read
Key Takeaways
- Strand pelletizing is mechanically simpler and lower-cost; ideal for engineering thermoplastics and smaller throughputs
- Underwater pelletizing dominates compounding and masterbatch — uniform spherical pellets at high throughput
- Top brands: Gala (underwater), Maag (both), Coperion and Berstorff (integrated lines), NGR (reclaim/PCR)
- Used pricing: small strand $8k; large underwater $250k; complete lines $150k–$1.5M+
- Critical inspection: die plate condition, cutter blades, water system, and centrifugal dryer rotor
Pelletizing is the final and arguably most demanding step in any compounding or recycling line — the point where molten polymer becomes a free-flowing pellet ready for downstream processing. The right pelletizing system can run unattended for shifts; the wrong one drowns operators in start-up problems and off-spec material. This guide compares strand and underwater pelletizing, explains the components of a complete line, profiles the top Gala, Maag, and Coperion systems on the used market, and walks through the inspection points that matter most.
Three Types of Pelletizing
Strand Pelletizing
Polymer is extruded as continuous strands, water-cooled in a bath, then fed into a rotating knife pelletizer that cuts the cooled strands into pellets.
Best for: Engineering thermoplastics, smaller volumes, lower capital cost, and start-up flexibility. Common in PA, PBT, PET, and styrenic compounding.
Underwater Pelletizing
Polymer is extruded directly into a water-filled cutting chamber where rotating blades shear off pellets that are immediately quenched and conveyed.
Best for: High-volume compounding, masterbatch, polyolefins, and any application requiring spherical pellets, high throughput, or unattended operation.
Water-Ring (Eccentric)
A specialized form between strand and underwater. Polymer exits a die into a circulating water ring where a rotating cutter shears pellets from the die face.
Best for: Polypropylene, polyethylene, and polystyrene compounds at moderate throughputs. Simpler than full underwater and less dependent on die-plate precision.
Strand vs Underwater: Side-by-Side
| Factor | Strand | Underwater |
|---|---|---|
| Capital Cost | Lower | 2-4x higher |
| Pellet Geometry | Cylindrical (length-to-diameter ratio) | Spherical / lentil-shaped |
| Throughput | 200-5,000 lb/hr typical | 200-25,000+ lb/hr |
| Start-up Forgiveness | Good — strand handling is mechanical | Lower — die plate must be hot and primed |
| Operator Attention | Moderate — strand breaks require intervention | Low — runs unattended for shifts |
| Best Polymers | PA, PBT, PET, PC, ABS | PE, PP, masterbatch, filled compounds |
Components of a Pelletizing Line
Extruder
Twin-screw for compounding (Coperion ZSK, Berstorff ZE), single-screw for clean resin reclaim. Sized in pounds per hour at typical viscosity.
Melt Pump & Screen Changer
Gear pump stabilizes pressure to the die. Screen changer (manual, slide-plate, or continuous) filters out gels and contamination. Critical for pellet quality.
Die Plate
Heated die with precision-drilled or laser-cut holes. Holes range from 0.5mm to 5mm depending on pellet target size. Die plates are the most expensive consumable.
Water System
Pellet water is filtered, cooled (typically 130-150°F), and recirculated. Cooling tower or chiller capacity must match throughput. Water quality affects pellet quality.
Centrifugal Dryer
Spin dryer removes surface moisture from pellets after the water system. Internal screens classify out fines and oversize pellets. Critical for dry-pellet specs.
Pellet Classification
Vibrating screens or rotary classifiers separate on-spec pellets from fines, longs, doubles, and tails. Reject material returns to the extruder or recycling stream.
Top Pelletizer Brands on the Used Market
Gala Industries
Models: A-Series (compact), SLC, EAC, NextGen
American leader in underwater pelletizing systems. Gala A-series is the most widely installed compact underwater pelletizer; SLC scales to thousands of pounds per hour. Now part of Maag Group, Gala remains the reference brand for underwater pelletizing in North America.
Maag
Models: Pearlo, Primo, Sphero, M-USG
Swiss-engineered pelletizing systems with global reach. Pearlo strand pelletizers and Sphero underwater systems are known for precision and repeatability. Maag also makes the gear pumps and screen changers used in many competitors' lines.
Coperion
Models: Pelletizing dies and cutters integrated with ZSK extruders
While best known for ZSK twin-screw extruders, Coperion also supplies integrated underwater pelletizing systems matched to the extruder for complete compounding lines. Tight integration with ZSK reduces start-up issues.
Berstorff
Models: Underwater pelletizers integrated with ZE/KE extruders
Now part of KraussMaffei. Strong installed base of compounding lines with matched pelletizer/extruder packages. Often paired with ZE-series twin-screws and Maag screen changers.
NGR
Models: P:GRAN strand pelletizers, A:GRAN integrated reclaim lines
Austrian builder specializing in plastics recycling and reclaim — full lines integrating shredding, plasticizing, devolatilization, and pelletizing. Strong fit for in-house scrap reclaim and PCR processing.
Used Pelletizing Equipment Pricing
| Configuration | Price Range |
|---|---|
| Small strand pelletizer (200-1,000 lb/hr) | $8,000 – $40,000 |
| Mid-size strand pelletizer (1,000-5,000 lb/hr) | $25,000 – $100,000 |
| Compact underwater pelletizer (Gala A6/A8) | $40,000 – $120,000 |
| Mid-size underwater (Gala EAC, Maag Sphero) | $80,000 – $250,000 |
| Large underwater (Gala SLC, Berstorff CPM) | $150,000 – $500,000+ |
| Complete used compounding line w/ pelletizer | $150,000 – $1,500,000+ |
Die Plate: The Hidden Cost
The die plate is the most expensive consumable on an underwater pelletizing system and the most-overlooked item during a used purchase. Plate damage from inadequate filtration, die freeze-off, or wrong start-up procedure can require a $5,000-$40,000 replacement. Always inspect die holes individually under magnification, and ask for the plate's service history.
What to Inspect on a Used Pelletizer
Die Plate Condition
Inspect every die hole for erosion, plugging, and edge damage. Visible tail-shaped pellets in the dryer screen indicate die-plate problems. Replacement plates run $5,000-$40,000 depending on size and metallurgy.
Cutter Blades & Hub (Underwater)
Check for blade chipping, uneven wear, and hub balance. Worn blades produce irregular pellets, longs, and tails. Blade replacements are routine ($1,000-$5,000) but a damaged hub is expensive.
Pelletizer Knife Roll (Strand)
Inspect knife roll for chipping and wear. Verify gap setting between knife roll and bedplate is correct. Misalignment causes inconsistent cuts and pellet length variation.
Water System & Filtration
Examine water filtration screens, pump condition, and heat exchanger. Stagnant water indicates flow problems; cloudy water indicates fines accumulation. Verify water temperature and flow rate at the cutter chamber.
Centrifugal Dryer
Inspect the rotor for wear, broken pins, and screen condition. Worn screens allow good pellets to escape with fines. Excess moisture downstream usually traces back to the dryer.
Screen Changer & Melt Pump
Verify screen changer operation (slide plate or continuous), pump bearings, and pressure gauges. Failed screen changers cause unfiltered melt to reach the die — fast track to die-plate damage.
Frequently Asked Questions
What is the difference between strand and underwater pelletizing?
Strand pelletizing extrudes molten polymer through a die plate as continuous strands, which pass through a water bath to cool and solidify, then enter a strand pelletizer where rotating knives cut the solid strands into pellets. It's mechanically simple, low-cost, and forgiving — but it requires consistent strand handling and is sensitive to start-up problems. Underwater pelletizing extrudes molten polymer through a die plate directly into a water-filled cutting chamber where rotating blades shear off pellets the instant they exit the die. The pellets are immediately quenched by the water and conveyed to a centrifugal dryer. Underwater systems produce uniformly spherical pellets, handle higher throughputs, and run unattended — but capital cost, die-plate complexity, and start-up procedures are more demanding.
How much does a used pelletizer cost?
Used pelletizer pricing depends heavily on type and throughput. Small strand pelletizers (200-1,000 lb/hr) range from $8,000 to $40,000. Mid-size strand pelletizers (1,000-5,000 lb/hr) run $25,000 to $100,000. Underwater pelletizers start around $40,000 for small systems (Gala A6/A8) and scale to $250,000+ for large production systems (Gala SLC, Maag M-USG, Berstorff CPM). Complete used pelletizing lines including extruder, die-face cutter, water system, and dryer can range from $150,000 to over $1,000,000.
What are the components of a pelletizing line?
A complete pelletizing line includes: (1) the extruder (typically twin-screw for compounding, single-screw for resin reclaim); (2) a melt pump for pressure stabilization; (3) a screen changer for melt filtration; (4) a die plate; (5) the pelletizer itself — strand or underwater cutter; (6) a water system with cooling, filtration, and recycling; (7) a centrifugal dryer or vibrating screen; (8) classification screens for pellet sizing; (9) bulk bag or silo packaging. Add-on equipment can include side-feeders for fillers, vacuum vent systems for devolatilization, and online viscometers.
Which pelletizing system is best for compounding?
Underwater pelletizing is the dominant choice for high-volume compounding because it produces uniform spherical pellets, handles wide viscosity ranges, runs unattended, and is more forgiving of formulation changes. Strand pelletizing is preferred for engineering thermoplastics with specific pellet aspect ratios, lower-volume specialty compounding, and applications where the die-plate complexity of underwater systems is undesirable. Most large-scale compounders (Coperion ZSK, Berstorff ZE) feed underwater pelletizers. Most small to mid-size compounders use strand pelletizing for flexibility.
What can go wrong with a used underwater pelletizer?
The most common failure modes are die-plate damage (clogged or eroded holes producing tail-shaped pellets), worn cutter blades (irregular pellet sizes and tails), water system contamination (poor pellet quality and dryer fouling), centrifugal dryer rotor wear (broken pellets and excessive moisture), and seal failures on the cutting head. Always inspect die plates carefully — replacement plates can run $5,000 to $40,000 depending on size and material.
Looking for Used Pelletizing Equipment?
Meadoworks regularly sources strand and underwater pelletizers, complete compounding lines, and reclaim systems. Whether you need a single Gala A8 or a turnkey production line, we can help.
Browse extrusion equipment or contact our team. Call 800-323-0307.
