Plastic Shredder Buying Guide: Types of Shredders and Which Machine to Buy
Four questions decide the right machine: what material, in what form, at what throughput, to what output size. Answer them in order and the choice usually makes itself. This guide walks you through each step with the same decision tables our own technical team uses, and explains the types of shredders, how a plastic shredder works and which shredder blade suits which material.
The four-step decision flow
- What material? PET, HDPE, PP, PVC, FRP, film, thermocol…
- What form? Bottles, film, lumps, pipes, mixed scrap
- What throughput? kg per hour you must actually process
- Match the machine Shredder, grinder, or both in line
How does a plastic shredder work?
A plastic shredder cuts rather than crushes. Material drops from the hopper into the cutting chamber, where blades on a slowly turning shaft grip it, pull it down and cut it against fixed blades or against the cutters of a second shaft. Low speed and high torque let the machine bite through thick, tough pieces instead of throwing them back.
On a single shaft shredder, a hydraulic pusher presses the material onto one rotor carrying many small blades. The rotors of our S3 range turn at 60 to 80 rpm, and on the S3-600 and S3-1000 a screen holds pieces in the chamber until they are small enough to pass. If a piece jams, the S3-600 senses the overload and reverses.
On a dual shaft shredder, two shafts turn towards each other and pull bulky, hollow and flexible items in rather than bouncing them, and the uneven shred falls out below.
A grinder (granulator) then finishes the job. Its rotor turns faster, its knives cut the shredded pieces against fixed knives in a scissor action, and a screen sets the final granule size. That is how a recycling line turns bulky scrap into uniform regrind: shredder first, grinder second.
Types of shredders, and what each one is for
Most plastic plants use one or more of three types of shredder machine, and a few special machines exist for particular duties. Here is what each one does, and our range in each.
- Single shaft shredder. For thick, dense and solid scrap: lumps, purgings, pipes, FRP and wood. Our single shaft shredder range is the S3-600, S3-800 and S3-1000.
- Dual shaft shredder, also called a double shaft or twin shaft shredder. For bulky, hollow, mixed and flexible waste: drums, crates, bags, film and rejects. Our double shaft shredder range runs to 13 models, from the DS4005 to the DS1080.
- Grinder or granulator. For secondary size reduction of clean or pre-shredded plastic into uniform regrind. Our plastic grinder machine range is 14 RE models, from the RE8 to the RE40, with and without a cyclone blower.
- Machines for special duties. A liquid pouch recovery machine squeezes and shreds sealed pouches in a single pass and recovers the contents of FMCG, cosmetic, pharma and food rejects.
Four shaft shredders also exist, used where a finer primary shred is needed in one pass. Our range does not include them: single shaft and dual shaft shredders and RE grinders cover the plastic scrap in this guide.
Step 1: What material are you processing?
Material decides blade type, motor load and what the shredded output is worth. Soft polyolefins like LDPE film tear differently from glass-filled nylon or FRP, which blunt blades fast. Start by identifying your dominant material. If your stream is mixed, plan around the toughest component, not the easiest.
Two honest exceptions up front. Thermocol (EPS) is light and bulky, so it needs its own route, set out on our thermocol grinding machine page. And heavily contaminated post-consumer waste should be pre-sorted before any machine touches it.
Material → machine matrix
Find your material in the left column. Capacities are from our standard specification sheets. Actual output depends on material density and feed rate.
| Your material | Recommended machine | Capacity (kg/hr) | Why this machine |
|---|---|---|---|
| PET bottles (up to 1 L) | RE12CB Grinder with Blower | 45 | Semi-automatic crushing with blower discharge, built for bottle volumes |
| Plastic bottles, jars (larger/mixed) | RE16 Plastic Grinder | 150–250 | 16″×16″ throat takes jars and containers up to 10 litres |
| HDPE / LDPE bottles & containers | RE Series CB Grinders with Blower (RE8CB–RE40CB) | 20 to 700 | Seven sizes, cyclone blower conveys regrind straight into collection bags |
| Moulding scrap, runners, rejects | Plastic Grinder Machine (RE8–RE40) | 35–1,200 | Uniform regrind through a customisable mesh, ready for reuse |
| Plastic lumps, purgings, blocks | S3-600 Single Shaft Shredder | 300–500 | Single rotor with 26 hardened blades handles thick, tough lumps |
| FRP / fibreglass waste | S3-600 Single Shaft Shredder | 300–500 | Hardened blades and a heavy-plate chamber for abrasive FRP |
| Mixed plastic waste, drums, crates | Dual-Shaft Shredder | Per spec | Counter-rotating shafts grip bulky and irregular items |
| General plastic scrap (high volume) | RE20 Plastic Grinder (20″) | 250–400 | 20″×20″ throat, 15 HP, the workhorse for plant scrap |
| Laminates, lamitubes, pouches | Laminate Shredder | Per spec | Built for multi-layer packaging waste |
| Cement bags / PP woven sacks | DS5007 Dual-Shaft Shredder | Per spec | Dual shaft action prevents woven bags wrapping the shafts |
| Non-woven bags & fabric | DS5007 Dual-Shaft Shredder (non-woven config) | Per spec | Dual shaft shredder configured for PP non-wovens |
| Thermocol / EPS | Thermocol and EPS grinding | Per spec | Light, bulky foam needs its own route, and we advise on it case by case |
Step 2: What form is the waste in?
Form matters as much as material. The same HDPE arrives as bottles, drums or purged lumps, and each needs a different cutting action:
- Bottles, containers, moulding scrap → a grinder/granulator. Thin walls cut cleanly through a screen into uniform regrind.
- Thick lumps, purgings, pipes, FRP sheets → a single shaft shredder first. Slow rotor, high torque, no jamming on solid sections.
- Bulky, irregular or mixed items (drums, crates, bags, film bales) → a dual shaft shredder. The counter-rotating blades pull material in instead of bouncing it.
- Film, woven sacks, non-wovens → dual shaft, configured so flexible material cannot wrap the shafts.
Step 3: What plastic shredder capacity do you need?
Work from your real waste generation: kilograms per day ÷ planned running hours. Then add 25–30% headroom, because machines should not run at their ceiling all shift. Buying one size larger is almost always cheaper than replacing an undersized machine in year two.
| Throughput needed | Machines to consider |
|---|---|
| Up to 50 kg/hr | RE8 grinder · RE12CB Grinder with Blower |
| 60–250 kg/hr | RE12–RE16 grinders · RE16 Plastic Grinder |
| 250–600 kg/hr | RE20 Plastic Grinder · RE25 grinder · S3-600 single shaft · S3-800 single shaft · dual shaft models from the DS4005 (250-350 kg/hr) |
| 600 kg/hr and above | RE30 (600–800 kg/hr) and RE40 (1,000–1,200 kg/hr) grinders · S3-1000 single shaft (600–800 kg/hr) · larger dual shaft models up to the DS1080 (2600-3000 kg/hr) · custom configurations, talk to us |
Shredder vs grinder: which do you actually need?
The two machines do different jobs. A shredder is primary size reduction: it makes big things small. A grinder (granulator) is secondary: it makes small things uniform, sized by the screen you fit.
| Shredder | Grinder / Granulator | |
|---|---|---|
| Job | Primary reduction of bulky waste | Uniform regrind for reuse or sale |
| Output | Uneven shred (strips/chunks) | Even granules through a mesh |
| Handles | Lumps, drums, crates, FRP, mixed waste | Bottles, runners, rejects, pre-shredded material |
| Speed/torque | Low speed, high torque | Higher speed rotor with fixed + rotating blades |
| Buy it when | Waste is too big or tough to grind directly | You want regrind that goes straight back into production |
Many recycling lines need both: a shredder to break down lumps or bales, feeding a grinder that produces saleable regrind. If your waste is already small and clean (moulding rejects, runners, bottles) a grinder alone is usually enough.
Single shaft vs dual shaft shredder
| Single shaft (S3 line) | Dual shaft (DS series) | |
|---|---|---|
| Suits | Thick, hard, dense waste: lumps, purgings, FRP, pipes, wood | Bulky, mixed, flexible waste: drums, crates, bags, film |
| Cutting action | One rotor (26 to 42 blades) against 2 fixed blades, fed by a hydraulic pusher | Two counter-rotating shafts with interlocking blades |
| Output size | More controlled, suits onward grinding | Uneven shred |
| Feeding | Side hopper (600 x 1000 mm) on the S3-600, 1800 x 1600 mm opening on the S3-800 and S3-1000 | Top feeding, gravity pulls material into the shafts |
| Typical capacity | 300–800 kg/hr across three models | 250-350 to 2600-3000 kg/hr across 13 models |
| Start here if | Your problem is toughness | Your problem is bulk and variety |
Still between two machines? That is normal, and the deciding factor is usually a trial. Bring a sack of your actual waste to our Andheri East works and watch both run. Our guide to choosing a single shaft vs double shaft shredder goes through the trade-offs in more depth.
Types of shredder blades, and which material each suits
The blade for a shredder is chosen with the machine, because the cutting action decides the blade. Three kinds cover most plastic work.
Interlocking cutters on dual shaft shredders
Cutters with hooked teeth sit side by side on two shafts and mesh as the shafts turn towards each other. The hooks grip the material and pull it in, and the cutters shear it into an uneven shred. They suit bulky, hollow and flexible waste: drums, crates, bags and film.
Rotor blades on single shaft shredders
Many small blades are fixed around one rotor and cut against stationary blades as it turns, a little at a time, while the pusher feeds the material in. The S3-800 carries 33 square-type rotary blades and the S3-1000 carries 42, and the S3-600 carries 26 welded roto-type blades, each against 2 fixed blades. They suit thick, dense and solid scrap such as lumps, purgings and pipes.
Granulator knives on grinders
Long rotating knives sweep past fixed knives in a fast scissor cut, and a screen holds the material until it is small enough to pass. RE grinders carry 3 rotating and 2 fixed blades from the RE8 to the RE25, 6 + 4 on the RE30 and 9 + 6 on the RE40. They suit bottles, sprues, runners and pre-shredded pieces.
Choosing plastic shredder blades for your material
Let the material decide. Abrasive scrap such as FRP and glass-filled plastics wears edges fastest and needs hardened blades. Film, woven sacks and non-wovens need cutters set so the material cannot wrap the shafts. Clean, rigid scrap is the easiest on any shredder machine blade. Whatever the type, keep metal, stones and sand out of the feed, and sharpen or replace blades before the cut turns into tearing: a blunt blade draws more power and gives a ragged shred.
Applications and industries: which machine each plant uses
The four questions play out differently by industry. These are typical set-ups, with the material as it arrives and what comes out.
- Injection and blow moulding. Sprues, runners, rejects, flash and tails arrive small and clean. A grinder beside the press (the RE8, RE12 or RE20 to RE30, or a CB model that bags the regrind) turns them into regrind that goes straight back into production. See the injection moulding scrap grinder.
- Bottle and container recycling. PET, HDPE and LDPE bottles and jars arrive baled or loose. The RE12CB, RE16, RE20 or a CB model grinds them into flakes and regrind for sale or reuse. See the PET bottle recycling machine.
- Extrusion, rotomoulding and FRP. Purge lumps, off-spec pipe, reject tanks and FRP sheets arrive thick and solid. The S3-600 single shaft shredder breaks them down, and a grinder follows where regrind is wanted. See the plastic lumps shredder.
- Packaging, bags and textiles. Film bales, woven cement bags, jumbo bags, non-woven offcuts and fabric rolls would wrap a fast rotor, so a dual shaft shredder such as the DS5007 takes them. See the cement bag shredder.
- FMCG, pharma and medical. Expired stock, blister packs and disinfected biomedical plastics are destroyed in house on a dual shaft shredder, and filled pouches go to a liquid pouch recovery machine that recovers the contents. See the product destruction shredder.
- Automotive and electronics. Bumpers, dashboards, trims and appliance housings are shredded on an S3-600 or a dual shaft shredder, then ground on an RE grinder. See the automobile plastic shredder.
Not sure which machine fits your material?
Talk to our technical team for a free recommendation based on your material, volume and output size, and a trial with your own waste.
Selection FAQs
What type of machine is used for shredding plastic?
Three types do most of the work. A single shaft shredder handles thick, solid scrap such as lumps, purgings, pipes and FRP. A dual shaft shredder handles bulky, mixed and flexible waste such as drums, crates, bags and film. A grinder (granulator) cuts clean or pre-shredded plastic into uniform regrind, and many lines run a shredder followed by a grinder. Which one you need depends on your material, its form and your volume, and a trial on your own material settles it.
What is the purpose of a shredder machine?
A shredder machine reduces bulky or tough waste to smaller pieces. For a plant that means scrap that takes less floor space and costs less to move, material a grinder can then turn into reusable regrind, and secure destruction of branded rejects, expired stock or data media that must not reach the market. Shredded material is easier to store, sell, recycle or dispose of.
What is the size of a shredder machine?
It depends on the type and the largest piece it must take. Our smallest grinder, the RE8, has an 8″ × 8″ throat and weighs about 150 kg, and the RE40 has a 40″ × 40″ throat and weighs about 4,700 kg. Most of our dual shaft shredders stand 1930 mm high, and they weigh from 750 kg for the DS4005 to about 7000 kg for the DS1080. The S3-600 single shaft shredder takes material through a 600 x 1000 mm feed opening and weighs about 2,300 kg. Size the opening to your largest piece, and the capacity to your volume.
What is the difference between a plastic shredder and a plastic grinder?
A shredder does primary size reduction: low-speed, high-torque shafts tear bulky or tough waste into uneven strips and chunks. A grinder (granulator) does secondary reduction: a bladed rotor cuts material against fixed blades until it passes through a screen, giving uniform granules sized by that screen. If your end goal is regrind you can reuse or sell, the grinder produces it. The shredder exists to make material small enough to grind. See our grinders & granulators range for screen and capacity options.
Do I need both a shredder and a grinder?
Only if your input is too big or too tough to grind directly. Plastic lumps, purgings, FRP sheets, drums and bales need a shredder first. The shredded output then feeds a grinder for uniform regrind. But if your waste is already small (bottles, moulding runners, thin-wall rejects) a single grinder of the right throat size does the whole job. Plenty of our customers run one RE-series grinder and nothing else.
How do I work out the plastic shredder capacity I need?
Take your real waste generation in kg per day and divide by the hours you will actually run the machine. A unit producing 800 kg of scrap daily over an 8-hour shift needs 100 kg/hr, plus 25–30% headroom, so a 125–150 kg/hr machine. Remember that rated capacity varies with material density and feed rate: 125 kg/hr of dense lumps is not the same duty as 125 kg/hr of film. When in doubt, size up.
Can I test the machine with my own material before buying?
Yes. We encourage it. Bring your actual waste to our works at Andheri East, Mumbai, and we will run it through the recommended machine in front of you. You see the true throughput, the output size, and how the machine behaves with your specific material. No brochure or video replaces that. Contact us to schedule a trial.
How much does a plastic shredder machine cost?
Every machine is quoted to the job. What moves the number is the type and model, capacity, throat size, motor rating, MS or SS construction and the options you add, such as a blower, a conveyor or a control panel. Our plastic shredder machine price guide walks through each of those. Send us your material and daily volume and we will size the machine and send a written quotation.
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