In modern recycling operations, the first step toward recovering valuable materials is reducing the size of incoming waste. Large items such as discarded refrigerators, old cables, spent batteries, and printed circuit boards cannot be processed directly by separation equipment. They must first be broken down into smaller, uniform pieces. This is where shredder and pre-chopper equipment plays an essential role.
San Lan Technologies Co., Ltd, established in 2007 and based in Jiangxi Province, China, designs and manufactures a full range of size-reduction machinery for e-waste and WEEE recycling plants worldwide. With more than 15 years of experience in mechanical engineering and EPC project delivery, the company supplies equipment that prepares materials for efficient shredding, sorting, and refining.
What Is Shredder and Pre-Chopper Equipment?
Shredder and pre-chopper equipment refers to the machinery used at the front end of a recycling line to cut, tear, or shear bulky waste into manageable fragments. Although the terms are sometimes used interchangeably, pre-choppers and shredders usually serve slightly different purposes in the material preparation stage.
A pre-chopper is typically the first machine that receives large or awkward feedstock. It reduces the overall dimensions of the material so that downstream equipment can handle it safely. For example, a refrigerator shredding line may use a pre-chopper to cut the appliance body into fist-sized chunks before feeding them into a fine shredder.
A shredder then takes these pre-cut pieces and reduces them further to the target particle size, often between 20 mm and 100 mm. The shredded output has a larger surface area, which improves the efficiency of magnetic separation, eddy-current separation, air classification, and washing processes that follow.
How the Process Works
The size-reduction process relies on three primary mechanical actions:
- Shear force — Moving cutters pass stationary cutters with minimal clearance, slicing through rigid materials such as metal shells and hard plastics.
- Tearing force — Hooked or toothed blades grip and stretch material until it fractures. This is effective for cables, woven materials, and mixed composites.
- Extrusion force — Material is compressed between rollers or shafts, breaking hollow containers and bulky structures.
Most industrial shredders operate at low rotational speed, typically between 8 and 40 RPM, while delivering very high torque. This low-speed, high-torque design prevents overheating, reduces dust generation, and allows the machine to handle dense metal waste without stalling.
Types of Shredders for Recycling Applications
San Lan Technologies offers several configurations of shredders to match different material types and throughput requirements:
Single Shaft Shredder
The single shaft shredder equipment uses one main rotor equipped with cutting blades, assisted by a hydraulic pusher plate that presses material against the rotor. Models such as the SS-600 (22 kW motor, 300–500 kg/h capacity) and SS-900 (30 kW motor, 1000 kg/h capacity) are widely used in cable recycling plants, circuit board recycling lines, and plastic recycling operations. The single-shaft design produces relatively uniform output and works well when the downstream process requires controlled particle size.
Twin Shaft Shredder
Twin shaft shredders, also known as dual-shaft shredders, use two counter-rotating shafts with interlocking blades. The IC-500, IC-600, and IC-800 series from San Lan offer capacities ranging from 200 kg/h to 800 kg/h. These machines are versatile and can accept a wide variety of feedstock, including mixed e-waste, light metals, and plastics. The counter-rotating action pulls material into the cutting chamber automatically, reducing the need for manual feeding.
Four Shaft Shredder
For heavy-duty applications, the 4 shaft shredder equipment provides high throughput and robust cutting power. San Lan’s IC-1100 model handles 2–3 metric tons per hour with dual 11 kW motors, while the larger IC-1800 reaches 4–6 metric tons per hour with dual 22 kW motors. Four-shaft designs are suitable for bulky items such as refrigerator shells, washing machines, lead-acid batteries, and lithium batteries. The additional shafts improve gripping and tearing action on large, irregular loads.
Dual Single-Shaft Shredder
The DSS-3000 model features two independent single shafts inside one cutting chamber. This configuration was developed specifically for cable scrap shredding as a pre-chopper stage before granulation. With dual 37 kW motors and a capacity of 2–3 metric tons per hour, it can process thick cable bundles that would otherwise overload a standard single-shaft unit.
Why Proper Material Preparation Matters
Feeding oversized or unprocessed material directly into separation equipment causes jams, increases wear, and lowers recovery rates. Pre-chopping and shredding solve these problems in several ways:
- Volume reduction — Shredded material occupies significantly less space, lowering transport and storage costs.
- Exposure of internal components — Cutting open refrigerator shells, motor housings, or battery casings releases the valuable materials inside.
- Uniform feed size — Consistent particle dimensions help downstream screens, magnetic separators, and air classifiers operate at peak efficiency.
- Safety — Reducing the size of hazardous items, such as lead-acid batteries or CRT monitors, minimizes the risk of accidental breakage and chemical leaks during manual handling.
Applications in E-Waste and Recycling Plants
San Lan Technologies supplies shredder and pre-chopper equipment for a broad range of recycling lines:
Refrigerator and Air Conditioner Recycling
Refrigerators are large, multi-material appliances containing refrigerants, polyurethane foam, steel, copper, and aluminum. A typical line begins with a pre-chopper to cut the body into chunks, followed by a four-shaft shredder to create 20–100 mm particles. After shredding, magnetic separation recovers ferrous metals, while eddy-current and air separation isolate aluminum and plastics.
Cable Recycling
Scrap cables arrive in long lengths and mixed diameters. Pre-choppers cut them into short segments, and shredders further reduce them before granulation. San Lan’s shredders are designed to handle cable diameters from 1.5 mm up to 150 mm, preparing the material for copper-plastic separation.
Battery Recycling
Both lead-acid and lithium-ion batteries require controlled size reduction. Pre-choppers break the external casing, while shredders reduce the internal components to expose lead paste, lead grids, plastic separators, and black mass. San Lan’s four-shaft shredders are commonly installed in battery recycling plants with capacities of 1–10 metric tons per hour.
Circuit Board Recycling
Printed circuit boards contain copper, precious metals, and fiberglass. Pre-chopping and shredding liberate metal particles from the board substrate, enabling wet or dry separation methods to achieve copper powder purity levels of 96–98 percent.
Key Selection Considerations
When choosing shredder and pre-chopper equipment for a recycling plant, several factors should be evaluated:
- Material type and hardness — Soft plastics, hollow metals, and dense battery casings each require different cutter geometries and shaft configurations.
- Feed dimensions — The hopper opening and shaft diameter must accommodate the largest expected item without pre-cutting.
- Required output size — If the next stage is a granulator or mill, a finer shred is needed. If the next stage is manual sorting, coarser output may be acceptable.
- Hourly capacity — ｓｅｌｅｃｔ motor power and shaft speed to match the overall line throughput, whether it is 500 kg/h or 6 metric tons per hour.
- Maintenance access — Split-type housings and assembled cutter seats allow faster blade replacement and reduce downtime.
Conclusion
Shredder and pre-chopper equipment forms the foundation of every efficient e-waste and recycling operation. By reducing material size, exposing valuable contents, and creating uniform feed for separation equipment, these machines directly influence plant productivity and metal recovery rates. San Lan Technologies Co., Ltd provides a comprehensive range of single-shaft, twin-shaft, and four-shaft shredders designed for cable, battery, circuit board, refrigerator, and general e-waste recycling applications. With capacities from 300 kg/h to 6 metric tons per hour, the company’s equipment can be matched to the specific needs of recycling plants in more than 21 countries.
