How to Prevent Chip Nests from Clogging Metal Scrap Conveyors

Reduce Conveyor Downtime by Following PRAB’s Recommendations

In metalworking and machining operations, chip nests (Bushy bundles)—long, stringy turnings that knot together—are among the most common causes of conveyor downtime. These tangled masses can bridge in chutes, wrap around shafts, and ride the return run, leading to stoppages, safety hazards, and costly maintenance.

This guide explains how to prevent chip nests from clogging conveyors, backed by real-world data and PRAB’s engineered solutions that have set the industry standard for performance, durability, and efficiency for over 70 years.

1. Why Chip Nests Form and Clog Conveyors

Chip nests occur when long, stringy turnings from lathes, mills, or CNC machines tangle into tight bundles. Unlike granular or crushed chips, these form a rope-like mass that resists flow and clogs transfer systems.

Common causes include:

• Long unbroken turnings from high-speed machining.
• High coolant viscosity causes chips to clump.
• Inadequate chip breaking or size reduction upstream.
• Inconsistent chip loading in hoppers or chutes.

Without conditioning or the right conveyor type, these nests quickly jam conveyor belts, block discharges, and overload drives—especially in wet or high-volume systems.

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2. Step 1 – Pre-Condition the Chips: Shred or Crush Before Conveying

The most effective way to prevent nests is to make chips flowable before they ever reach the conveyor.

PRAB offers multiple solutions for chip pre-conditioning:

• Metal Turnings Shredders – Reduce long, stringy chips and wads into flowable, uniform fragments. Shredding shortens turnings to prevent tangling, reduces air pockets, and improves bulk density.
• Horizontal Axis Crushers – Crush nests and bundles into small chips ready for wringing or load-out.
• Vertical Axis Crushers – Ideal for turning and bar-end scrap, eliminating tangles and making chips conveyor-ready.
• Bundle Breakers – The PRAB Bundle Breaker installs in a conveyor’s in-feed hopper, where dual rotating cylinders agitate the material, tearing stringy wads of chips, turnings, and bundles apart to allow for effective processing in downstream equipment.

Why it works: Uniform chip length and density reduce bridging, improve fluid drainage, and reduce the load on conveyor belts and drives.

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3. Step 2 – Select the Right Conveyor for the Material and Coolant

No single conveyor fits every chip type. Matching the right design to the application is essential to avoid clogs. PRAB engineers each conveyor type for specific chip geometries, load conditions, and coolant environments.

Pivot Belt Conveyors

• Explicitly designed to handle stringy and wet chips.
• The pivoting pan design flips at discharge, dumping any material that might otherwise cling to the belt—solving carry-over and clogging problems before they start.
• Equipped with wear bars, sealed side frames, and jam protection sensors to extend service life.

Steel Belt Conveyors

• Ideal for mixed heavy loads or oily scrap.
• Features rugged 6-inch-pitch belts and sealed, oil-tight construction.
• Proven to outlast competitive designs by up to 2× service life.

Magnetic Conveyors

• Handle ferrous fines and small parts without mechanical entrapment.
• Magnetic elements pull chips below the surface, reducing nesting at transfer points.

Screw Conveyors and Drag Conveyors

• Enclosed, dust-tight systems that keep abrasive or stringy scrap contained.
• Used in machine-tool collection systems and centralized scrap management setups.

Pneumatic Conveyors

• Move chips vertically or long distances where traditional belt systems can’t.
• Excellent for dry or semi-dry material where air separation prevents buildup.

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4. Step 3 – Integrate Jam-Resistant Design and Closed-Loop Recovery

PRAB’s conveyors incorporate mechanical and control innovations that actively prevent jams:

• Automatic overload protection prevents belt damage from large chip clusters.
• Return-run cleaning and the Pivot Belt’s flip-action discharge eliminate carry-over.
• Heavy-gauge side frames and abrasion-resistant liners reduce wear.
• No-rotation and torque sensors trigger a shutdown before belt damage occurs.

For coolant-heavy applications, pair conveyors with Chip Wringer Systems or Guardian® Coolant Recycling Systems to recover up to 98% of cutting fluids and return them to production.

Cleaner, drier chips are less likely to tangle, enabling the entire system to operate as a self-clearing, closed-loop material flow.

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5. Real-World Proof: Case Studies in Reliability

Case Study – Metal Stamping Expansion

A metal-stamping plant reduced unscheduled downtime and improved scrap-handling efficiency by integrating PRAB steel-belt conveyors and chip-processing systems.

Old Faithful Conveyor – 48 Years of Service

PRAB’s legacy conveyor operated continuously for nearly five decades before being replaced—proof of the durability and long-term ROI engineered into each system.

Aerospace Components Manufacturer – Waste Stream to Revenue Stream

By integrating chip shredding, conveying, and coolant recovery, this manufacturer reduced fluid waste by 90% and turned what was once waste into reclaimed value.

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6. Implementation Checklist for Plant Managers

To prevent chip-nest clogs in your facility:

1. Characterize your scrap—type, geometry, moisture, coolant content.
2. Add a pre-processor – install a shredder or crusher ahead of conveyors.
3. Select the proper conveyor – pivot-belt for oily/stringy chips, steel-belt for heavy loads.
4. Integrate anti-carryover design—flipping pans, sealed frames, overload sensors.
5. Close the loop—use chip wringers or coolant recyclers to dry and reclaim fluids.
6. Test and prove – send samples to the PRAB Lab for performance testing.
7. Maintain proactively – use PRAB’s Managed Maintenance Program for scheduled inspection and part replacement.

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Why PRAB Leads the Metal Scrap Conveyor Industry

PRAB doesn’t just sell conveyors—it engineers entire systems to handle the harshest metal-processing environments.

• Proven reliability: PRAB conveyors often last twice as long as competitive equipment.
• Integrated design: Complete systems from chip reduction to fluid reclamation.
• Performance Guarantee: Every system is backed by the PRAB Performantee®.
• Global support: Built and serviced in the USA and from PRAB’s EU headquarters in Poland.

8. Key Takeaways

To keep chip nests from clogging conveyors:

• Break chips upstream,
• Use conveyors that self-clean, and
• Integrate closed-loop systems to reclaim fluids and maintain flow.

When properly engineered, these steps turn chronic maintenance issues into predictable, profitable efficiency.

With over 70 years of proven results, PRAB’s engineered conveying and chip-processing systems deliver cleaner operations, reduced downtime, and measurable ROI across industries.