Double Shaft Shredder — CX-D Series

Overview

The CX-D Series Double Shaft Shredder is a heavy-duty twin-shaft industrial shredding solution engineered for primary size reduction of tough, bulky, and mixed solid waste. Built around a parallel dual-rotor design with synchronous centripetal rotation, the CX-D delivers low-speed (~15–30 rpm), high-torque shredding that avoids winding, jamming, and stalling — even when processing high-hardness or heterogeneous input streams.

Each rotor shaft is fitted with four-edge indexable moving knives made of alloy tool steel (HRC 56–60), arranged in a helical pattern for progressive shearing. These moving knives interlock with serrated D2/SKD-11 fixed knives bolted to the chamber walls, forming a scissor-cut shear pair that tears, shears, and crushes material in one pass. Every moving knife is rotatable through 4 cutting edges, quadrupling service life before replacement.

Power is delivered by two independent motors driving each shaft through a synchronized helical gear reducer, ensuring strict inter-shaft timing and zero knife collision. An integrated PLC control system with HMI touchscreen manages start, stop, forward, reverse, and automatic overload reverse-return logic — when a non-shreddable object is encountered, torque spikes trigger both shafts to reverse simultaneously, eject the obstruction, pause, then resume forward rotation without operator intervention.

With six models spanning 750 kg/h to 3,000 kg/h throughput, shaft diameters from Φ350 mm to Φ500 mm, and chamber widths from 660 mm to 2,060 mm, the CX-D series scales from mid-size recycling operations to large municipal solid waste (MSW) processing plants.

Technical Parameters

System Configuration

Core Features

1. Parallel Twin-Shaft Synchronicity: Two rotor shafts driven by a synchronized helical gear reducer rotate centripetally in strict timing, ensuring moving knives never collide and shredding force is evenly distributed across both shafts.
   

2. Four-Edge Indexable Moving Knives: Each knife body carries four identical cutting edges — when one edge wears, simply rotate 90° to expose a fresh edge. Total knife life = 4× single-edge life, dramatically reducing consumable cost and downtime.
   

3. Serrated Fixed Knife Technology: Unlike flat-edge stator knives, serrated profiles create multiple shear points per tooth, increasing cutting efficiency, reducing motor load, and producing more uniform shredded output.
   

4. Dual Independent Motor Drive: Each shaft is powered by its own motor (30–90 kW), delivering low-speed (~15–30 rpm) and high-torque output. This prevents rotor winding, material wrapping around shafts, and jamming — a chronic failure mode of single-motor shredders.
   

5. PLC Automatic Overload Reverse-Return: When a non-shreddable object enters the chamber, torque spikes beyond the PLC threshold. The system commands both shafts to reverse simultaneously, eject the foreign object, pause briefly, then automatically resume forward rotation. Zero operator intervention required.
   

6. Replaceable Discharge Screen: Bottom-mounted screen with swappable aperture sizes controls final particle dimensions. Fast screen changeover enables one machine to serve multiple downstream processes (RDF production, pre-crushing, landfill reduction) without re-tooling.
   

7. Heavy-Duty Alloy Rotor Shafts: Φ350–500 mm 40Cr quenched & tempered shafts with precision bearing seats machined to tight tolerances. Massive diameter provides high bending stiffness, preventing shaft deflection even under full-chamber load.
   

8. Modular Wear-Part Architecture: All high-wear components — moving knives, fixed knives, hopper liners, screen grates — are bolt-on replaceable. No welding, no shaft disassembly required for routine knife rotation or replacement.
   

9. Industrial Safety Interlocks: Perimeter guard railings wired to PLC safety circuit. Any guard access point opened during operation triggers immediate dual-shaft stop. Compliant with CE / ISO 12100 machinery safety principles.
   

10. IP55 Motors & IP54 Electrical Cabinet: Dust-tight, water-jet-resistant motor enclosures paired with a sealed control cabinet rated for harsh recycling facility environments (dust, moisture, vibration).

Applications

The CX-D Series Double Shaft Shredder excels in primary coarse shredding of hard, bulky, and mixed feedstocks that single-shaft shredders cannot efficiently process. Typical applications include:

• Municipal Solid Waste (MSW): Bag-opened household waste, mixed domestic refuse, bulky items prior to sorting and separation.

• Industrial Solid Waste: Factory scrap, production rejects, packaging waste, textiles, leather offcuts, and composite materials.

• Bulky Waste Volume Reduction: Discarded sofas, mattresses, furniture, office partitions, and large appliances — shredded for landfill volume reduction or incineration pre-treatment.

• Scrap Metal (Light Gauge): Aluminum extrusions, light steel scrap, thin-gauge sheet metal, aluminum alloy frames, and non-ferrous metal offcuts.

• End-of-Life Tires (ELT): Whole passenger and truck tires shredded into chips for pyrolysis feedstock, TDF (tire-derived fuel), or crumb rubber downstream processing.

• Plastic Drums & IBC Totes: HDPE drums, plastic barrels, intermediate bulk containers (IBC), large blow-molded containers — pre-shredded before granulation.

• Waste Electrical & Electronic Equipment (WEEE): E-waste pre-shredding including printers, computers, household appliances, and cables prior to metal recovery.

• Scrap Cables & Wires: Mixed cable looms and wiring harnesses torn open to liberate copper and aluminum conductors from insulation.

• Construction & Demolition Waste (C&D): Wood pallets, timber offcuts, gypsum board, light concrete debris, and mixed C&D waste.

• Wood Pallets & Waste Paper / Cardboard: Whole wooden pallets, crates, corrugated cardboard bales — shredded for biomass fuel or recycled fiber.

• Refuse-Derived Fuel (RDF) / SRF Preparation: Primary shredder in RDF production lines, reducing mixed waste to uniform particle size for secondary shredding and fuel pelletizing.

Positioning Note: The Double Shaft Shredder is complementary to single-shaft shredders — it handles the hard, bulky, mixed front-end duties, while single-shaft units provide precision size reduction on soft, uniform materials downstream.

Production Process

1. Material Feeding: Waste material is loaded into the top hopper via grab crane, conveyor belt, or forklift / bin tipper. The large open hopper accepts irregular, bulky items without pre-sorting.
   

2. Dual-Shaft Shear Shredding: Material descends into the interlocking zone between two counter-rotating rotor shafts. Four-edge moving knives and serrated fixed knives form a scissor-shear pair, performing simultaneous tearing, shearing, and crushing.
   

3. Screen-Controlled Discharge: Shredded particles fall through the bottom discharge screen. Material exceeding the target aperture size remains in the chamber for continued processing until it passes.
   

4. Overload Auto-Reverse Ejection: If a non-shreddable hard object enters, torque surge triggers the PLC to reverse both shafts simultaneously — the obstruction is ejected upward into the hopper area. After a timed pause, forward rotation resumes automatically.
   

5. Normal Operation Resumed: The machine returns to continuous shredding without operator intervention. Conveyor take-away systems transport shredded output to the next processing stage (magnetic separation, secondary shredding, screening, or baling).

FAQ

Q1: When should I choose a double shaft shredder over a single shaft shredder?

A double shaft shredder is the correct choice when your feedstock is hard, bulky, heterogeneous, or contains non-shreddable contaminants. Twin-shaft machines operate at low speed (~15–30 rpm) with high torque, using two intermeshing rotors to shear material through a scissor-cut mechanism. They handle MSW, scrap metal, whole tires, electronic waste, and bulky items without pre-sizing. Single shaft shredders, by contrast, rely on a high-speed rotor pressing material against a single stationary blade and screen — ideal for soft, uniform plastics, wood chips, and film, but prone to jamming or damage on hard / mixed waste. For facilities processing unsorted or heavy-duty input streams, the CX-D double shaft shredder is the primary coarse shredder of choice, often paired with a downstream single shaft for finishing.

Q2: How does the four-edge indexable knife design reduce operating costs?

Each moving knife on the CX-D series is machined with four identical cutting edges around a square/cross profile. When one edge dulls, the operator simply rotates the knife 90° to present a fresh edge — no sharpening, no welding, no replacement required for that rotation cycle. This means each knife body delivers 4× the service life of a single-edge blade before needing to be replaced. In high-wear applications (e.g., scrap metal or glass-laden MSW), the cost-per-ton reduction is significant: fewer knife purchases, less inventory, and dramatically reduced machine downtime. We recommend inspecting knives every 80–120 operating hours and rotating edges at ~50% wear to maintain optimal shearing geometry and power efficiency.

Q3: What is the difference between dual independent motor drive and a single-motor dual-output gear reducer?

Both configurations are available on the CX-D series. Dual independent motor drive (standard) uses two separate motors, each powering one shaft through its own coupling, providing true electrical load balancing and redundancy — if one motor trips, the opposing shaft stops simultaneously via PLC interlock. This configuration offers higher total torque, independent current monitoring per shaft, and easier maintenance (each motor can be serviced separately). Single-motor dual-output-shaft gear reducer uses one larger motor driving both rotors through a gearbox with two output shafts. This reduces footprint and electrical infrastructure cost but offers less operational flexibility. For heavy-duty, high-contaminant streams (scrap metal, C&D waste), we recommend the dual independent motor configuration; for lighter, more uniform streams with budget constraints, the single-motor option is viable.

Q4: How does the PLC automatic overload reverse-return system work, and what torque threshold triggers it?

The CX-D PLC continuously monitors motor current draw (proxy for rotor torque) on both motors via current transformers. A torque threshold — calibrated during commissioning based on the specific material and desired throughput — is programmed into the HMI. When a non-shreddable object (e.g., a solid steel bar, large bearing, or refractory block) enters the shear zone, the instantaneous current spike exceeds the threshold. Within milliseconds, the PLC commands both VFDs to reverse motor direction. Both shafts rotate backwards simultaneously, ejecting the obstruction back into the hopper area. After a configurable pause (typically 2–5 seconds), the PLC resumes forward rotation automatically. If the obstruction re-enters and triggers a second spike within a short window, the system performs a second reverse cycle. After a third consecutive trip (configurable), the machine enters a lockout state and triggers an alarm on the HMI, prompting operator inspection. This fully automatic sequence is a key advantage over hydraulic-coupling-only protection, which requires manual reset.

Q5: Why use serrated fixed knives instead of flat-edge fixed knives?

Serrated (toothed) fixed knives create a discontinuous shear line against the moving knives, which produces multiple localized high-pressure shear points rather than one continuous edge contact. This has three measurable effects: (1) higher shredding efficiency — the serrations grip and tear material, requiring less motor torque per unit of throughput than a flat-edge knife; (2) more uniform output particle size — serrations prevent long strips or slabs from slipping through uncut, as the toothed profile mechanically traps material between teeth until it is severed; (3) reduced power spikes — the progressive engagement of individual teeth smooths out motor load, reducing peak current draw and extending drive component life. In practice, switching from flat to serrated fixed knives on mixed MSW can improve throughput by 10–15% at the same motor power while tightening output size distribution.

Why Choose Chenxing

With decades of manufacturing excellence in industrial machinery, Chenxing Machinery delivers robust, application-engineered recycling equipment trusted by processing facilities worldwide. Our comprehensive product ecosystem covers every stage of size reduction and reprocessing:

Size Reduction & Shredding — The CX-D Double Shaft Shredder is complemented by our crushing & grinding machines, SMF Series Disc Grinding Pulverizers, and SMP Series Knife Pulverizers for secondary and fine grinding.

Extrusion & Compounding — Our Conical Twin Screw Extruders and High-Output Single Screw Extruders form the backbone of plastic processing lines.

Complete Production Lines — From Water Strand Pelletizing Lines and Waste Recycling & Granulating Lines to PVC/WPC Profile Extrusion Lines, PPR/PPH Pipe Production Lines, and PVC/WPC Celuka Foam Board Lines.

Application Coverage — Explore our full application portfolio, auxiliary equipment, and stay updated via Company News. Learn more about our company and our values.

Whether you need a single shredder or a complete turnkey recycling line integrating shredding, pulverizing, washing, and pelletizing, Chenxing's engineering team delivers pre-configured and custom solutions with single-source accountability — from material handling through extrusion to finished product.

Get Your Custom CX-D Solution — 4 Simple Steps

Step 1 — Tell Us About Your Material

Email us at ceo@cxsljx.com or contact Nicole at +8615951187228. Share your feedstock type, approximate input size, desired output particle size, and target throughput (kg/h). Photos or video of your waste stream help us recommend the right CX-D model immediately.

Step 2 — Receive Your Tailored Proposal

Our engineering team evaluates your requirements and provides a detailed technical proposal including recommended CX-D model, system configuration (dual independent motor vs. single-motor dual-output, screen aperture range, hopper dimensions), lead time, and FOB/CIF quotation.

Step 3 — Factory Visit or Virtual Inspection

Visit our manufacturing facility in Zhangjiagang City, Jiangsu Province — Zhangjiagang Chenxing Machinery Co., Ltd. — or join a live video walkthrough to inspect build quality, test-run your CX-D shredder with sample material, and review our quality control documentation.

Step 4 — Production, Delivery & Commissioning Support

Upon order confirmation, we manufacture your CX-D shredder, conduct a factory acceptance test (FAT) on your material, arrange shipping, and provide on-site or remote commissioning support with operator training.