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Chip Conveyor Manufacturer: Hinge, Scraper and Magnetic Belts

2026-10-10

01What a Machine-Tool Chip Conveyor Actually Has to Do

A chip conveyor is not a scaled-down bulk materials conveyor, and treating it like one is where most of the trouble begins. On a quarry face or a coal stockyard the belt moves a reasonably consistent, free-flowing load at a steady rate, and the real design questions are tonnage, lump size and abrasion. A chip conveyor on a CNC lathe, a machining centre or a transfer line lives in a completely different world. The load arrives in slugs, bundles and matted clumps rather than as a continuous stream. It arrives hot, because 60 °C to 120 °C is routine off a dry-cut steel job and we have logged cast-iron swarf leaving a heavy roughing pass at close to 180 °C. It arrives soaked in cutting fluid that may be alkaline, may be mildly acidic, and often carries so much fine ferrous dust that the mixture behaves like lapping compound against every pin, bush and hinge in the chain.

Then the machine stops. Then it starts again. Intermittent, heavy and sometimes sticky duty is the normal operating mode here, not the exception.

Strip the task back and the conveyor belt has a narrow, unforgiving job. Carry swarf clear of the machine enclosure, let the cutting fluid drain back to the coolant tank instead of onto the floor, and keep doing it through three shifts a day without pulling itself apart. Because the load is not uniform, the belt cannot be designed around an average; it has to survive the worst slug the process throws at it. That single fact shapes every later choice of pitch, chain plate thickness, side wall height and drive protection. Anyone comparing this duty against the assumptions behind a general industrial conveyor belt will find the two diverge within the first two engineering questions.

Send us your machine, swarf type and duty cycle — get a chip conveyor belt recommendation

Put the two duties side by side and the reason a mine-style specification falls apart on a machine tool becomes obvious. Very little of what makes a good bulk-handling belt matters here, and a lot of what matters here is simply absent from bulk-handling practice.

Design question	Machine-tool chip conveyor duty	Bulk materials conveyor duty	Practical consequence on the shop floor
Load character	Intermittent slugs, birds-nests, matted clumps and fine powder, arriving in bursts as the machine cycles	Continuous, free-flowing stream with a known bulk density and a fairly stable feed rate	Capacity must be sized on the worst surge, not the average; surge bins and crushers appear where a bulk line would not need them
Load temperature	50 °C to 180 °C direct off the cut, with dry machining running hotter than wet	Ambient to roughly 60 °C in most quarry and port work	Hinge plates and pins need material that holds up to thermal cycling; rubber-only designs are out of their depth
Fluid exposure	Constantly wet with water-based coolant, tramp oil and fine metal; pH often 8–9, occasionally acidic	Mostly dry, or water from rain, washdown and de-dusting sprays	Carbon-steel chains rust and seize unless specified otherwise; coolant return paths have to be engineered in
Abrasiveness	Fine cast-iron and hardened-steel dust that acts as a grinding paste on pins, bushes and troughs	Coarse rock and ore that gouges top covers and cuts through covers at transfer points	Wear parts are chain joints and trough liners here, not the top cover; different spares strategy entirely
Duty cycle	Start-stop every few minutes, sometimes hundreds of cycles per shift, often left jogging slowly	Continuous running at constant speed for hours at a time	Overload protection must tolerate frequent torque spikes; shear pins sized for steady load will break constantly
Scale	Belts typically 100 mm to 1,200 mm wide running at 0.5–3 m/min inside a machine footprint	Belts 650 mm to 2,400 mm wide running at 1–6 m/s across hundreds of metres	Speed and tonnage vocabulary from a bulk line is meaningless here; swarf form and jam risk set the design

One number is worth holding on to. A chip conveyor moving 400 kg/h of mixed steel swarf at 1.2 m/min carries roughly 5.5 kg on the belt at any instant. It looks trivial next to a 2,000 t/h bulk line, and that is exactly why inexperienced buyers under-specify the chain. The load is light, but the belt has to survive a jam that can multiply torque tenfold in a second, plus years of grinding-paste wear. A dedicated conveyor belt manufacturer that also builds machine-tool conveying hardware will flag this early; a general belt trader usually will not.

02Hinge-Type Steel Belts: The Default for Mixed and Curled Swarf

Ask most machine shops to picture a chip conveyor and they picture the hinge type. Overlapping steel plates shingle over one another, held together by pins and driven by two side chains that carry every kilogram of pull. The plates themselves never carry tension; they only carry swarf. That division of labour is why the hinge belt is so tolerant of mixed, hot, wet and slightly abusive loads, and why it is the first choice on turning centres, mill-turn machines and anywhere the swarf is a genuine unknown.

Pitch is the number that defines a hinge belt. It is the centre-to-centre distance between adjacent pin centres, and it comes in standard steps of 31.75 mm (1¼ in), 38.1 mm (1½ in), 50.8 mm (2 in) and 63.5 mm (2½ in). Go up in pitch and the open area between plates grows, so fine swarf falls through and coolant drains faster, but small parts and long fine chips can also slip through the gap and jam the return run. Go down in pitch and the belt carries fines better, but drains fluid more slowly and tends to hold a wet film that rusts a carbon-steel chain from the inside.

Plate thickness sits between 1.5 mm and 3 mm on most machine-tool belts, and it is the hinge plates, not the chain, that fail first when a slug of hot cast iron lands on them. We have seen 1.2 mm plates dish and open up their pin joints within a year on a heavy grey-iron line, while the same conveyor fitted with 2.5 mm plates was still in service after four.

Hinged steel chip conveyor belt supplied by a chip conveyor manufacturer for CNC machine tools

Where the hinge belt wins

Mixed swarf is the hinge belt's home ground. A shop that machines steel, stainless and aluminium on the same floor, and cannot predict what will arrive on the belt, is usually better served by one hinge conveyor than by three specialised machines. Curled C-chips, short spirals, heavy slugs off a roughing pass and even the occasional dropped tool all travel well. The belt also tolerates heat, abrasion and constant coolant contact, provided the material grades are chosen with those three things in mind. And because it is a mechanical, positive-displacement design, it does not care whether the chip is ferrous or not — a big advantage the moment aluminium or stainless appears.

The limits are just as clear. Very stringy birds-nest swarf from a low-feed, high-speed finishing pass will wrap around a hinge belt, climb the side plates and bridge across the discharge. Very fine powder, especially dry cast-iron dust, tends to fall through the plate gaps and build up in the return run rather than reaching the discharge chute. Neither is a reason to abandon the hinge belt; both are reasons to add a crusher ahead of it or a scraper stage after it.

Getting the hinge-belt specification right

The four specification numbers that cause the most disputes are pitch, plate thickness, chain type and overload protection. Buyers routinely fix the first two and leave the other two vague, then wonder why a conveyor that looked correct on paper jams within a month. The table below sets out what each choice actually controls and what happens when it is made wrong.

Parameter	Typical machine-tool range	What it controls	What goes wrong when it is misjudged
Belt pitch	31.75 mm, 38.1 mm, 50.8 mm or 63.5 mm pin-centre spacing	Open area for drainage, small-part retention and how freely long chips nest	Coarse pitch drops fine swarf through to the return run; fine pitch holds fluid and short-cycling swarf bridges over the discharge
Plate thickness	1.5 mm to 3 mm cold-rolled or stainless plate	Resistance to dishing under hot slugs and to pin-joint opening under repeated impact	Thin plates dish, pinch the pins and tear at the hinge line; the belt then tracks badly and shreds the side guides
Chain type and material	Roller chain to ISO 606 / DIN 8187, carbon or stainless, sometimes with hardened pins	All the pulling load and the wear life of every joint in the loop	Carbon chain in a wet alkaline machine corrodes and stiffens at the pins; a non-hardened chain wears oval and stretches within a season
Belt width	100 mm up to 1,200 mm across the plates	Throughput and the spread of swarf across the width after it leaves the machine chute	A narrow belt fed from a wide enclosure loads one side, runs off-centre and climbs the side wall within weeks
Speed	0.5 m/min to 3 m/min, often variable to suit the machine cycle	Drainage time on the belt and how far swarf is carried before it releases at the discharge	Too fast and wet swarf flies off with the coolant still on it; too slow and the belt floods and jams behind the incline
Overload protection	Slip clutch, torque limiter, shear pin or electronic motor protection	Whether a jam stalls the belt harmlessly or tears the chain apart	A shear pin sized for steady load breaks every shift; a fixed clutch set too high lets the drive bend the head shaft before it slips

Buyers who want the plates and chain to live longer under abrasive fines should treat the belt as a wear item and plan for it. A standard abrasion resistant conveyor belt mindset applies in spirit, but the wear here concentrates on joints and liners rather than a top cover, so the spares list looks different. It is also worth buying through a supplier who keeps hinge plate, pin and chain spares on the shelf; a conveyor belt supplier that only stocks finished belts will leave you waiting weeks for a single broken plate. If the machine is the bottleneck of the whole cell, an annual service check of tension, tracking and joint wear pays for itself in avoided downtime, and roller-style return support on longer runs is covered in more detail under conveyor rollers.

03Scraper-Type Chip Conveyors for Fine and Powdery Swarf

Where the hinge belt likes to be fed mixed and lumpy, the scraper type prefers the opposite. A scraper conveyor drags steel flights along the bottom of a shallow trough, pushing swarf ahead of it like a plough. There are no wide hinged plates, so nothing falls between plates and into a return run. Everything the flights can reach is swept to the discharge, which makes the design unusually good at fine granules, millings, grinding sludge and the powdery grey dust that pours off cast iron.

That sweeping action comes with a price, and the price is trough wear. Fine hardened cast-iron dust in a wet trough is close to the worst abrasive slurry a conveyor ever sees. Flights and trough floors scrape against each other thousands of times a shift, and a trough in 3 mm mild steel will show visible thinning inside eighteen months on a busy cast-iron line. The usual answers are replaceable wear strips, a hardened or stainless trough liner, and flights fitted with sacrificial wearing shoes so the shoe fails instead of the flight or the trough.

Scraper conveyors are also common as part of a two-stage system. The first stage, often magnetic or a coarse scraper, pulls the bulk of the metal out of the coolant; the second stage, a fine scraper or drag filter, polishes the returning fluid so the coolant tank does not silt up. This is ordinary practice in high-production cast-iron machining, where coolant life and surface finish both depend on getting the fines out fast.

What drives scraper selection

Three variables decide whether a scraper conveyor works on a given job. They are the swarf size, the amount of fluid being carried along with it, and the incline the flights have to climb. Flights on a steep incline push a load that wants to slide back down; on fine powder with plenty of coolant this is manageable, but on wet heavy granules the flights can ride up over the load and leave it behind, which then packs at the base of the incline and stalls the chain. Choosing a shallower angle, wider flights, or a short hinge section at the incline are the standard fixes, and they are cheaper to build in from the start than to retrofit.

Scraper chains are usually lighter and run slower than hinge-belt chains because they never carry the belt's own weight, but they are exposed to trough friction every metre of travel. Over-tensioning to stop a skipping flight is a classic mistake; it simply accelerates pin and flight wear without curing the root cause. On a busy line I would rather see a slightly slack chain with a correctly sized torque limiter than a tight chain with a fixed drive.

Selection factor	Favours the scraper type	Works against it	Field consequence
Swarf form	Fine millings, granules, powder and grinding sludge that would fall through a hinge belt	Long birds-nest clumps that wrap the flight bar and stall the chain	A crusher ahead of the scraper is often the difference between a clean sweep and a weekly jam
Fluid carry-over	Heavy coolant carry, because the trough naturally acts as a drain and settling channel	Dry dust with no fluid, which is abrasive and has no medium to help it flow	The trough drainage detail decides whether the coolant tank silts up or stays clean
Incline	Shallow climbs up to roughly 30° with fine, low-mass load	Steep climbs with wet heavy granules, where the load slides back under the flights	Material packs at the base of a steep incline and eventually stalls the drive
Wear items	Replaceable shoes, liners and hardened trough floors are cheap and quick to change	A welded, unlined trough that wears through in the middle of a shift	Consumable design turns a two-day repair into a two-hour shoe swap

Metal swarf is not the only thing a scraper handles well. Shops that also process scrap cable, stamping skeletons or mixed plant waste sometimes run swarf and light scrap on the same footprint, and the flat-trough scraper is a reasonable compromise there; the general scrap stream is covered on the recycling page for anyone planning that kind of combined line. Bracket details for mounting drives, troughs and discharge chutes are catalogued with the other conveyor brackets, which matters when a retrofit has to fit an existing machine footprint. And if you are standardising a whole plant on one supplier, a wholesale conveyor belts agreement usually brings spare flights and trough liners into the same delivery as the belts themselves.

04Magnetic Chip Conveyors for Cast Iron and Ferrous Fines

The magnetic conveyor does not push or carry swarf in the usual sense. A permanent-magnet drum, plate or roller attracts ferrous material and holds it against a moving surface until a scraper or a belt edge peels it off at the discharge. There are no flight bars to wear, no hinge plates to dish, and very little to jam, which is why the design has a loyal following wherever the swarf is almost entirely ferromagnetic and fine.

Read "almost entirely ferromagnetic" carefully, because that one phrase contains the entire applicability boundary. Carbon steel, alloy steel and cast iron are strongly attracted. Austenitic stainless steel, aluminium, brass, bronze, copper and titanium are not, or barely. Put a mixed stream of stainless and aluminium through a magnetic conveyor and the magnet simply ignores most of it while the coolant drags the non-ferrous portion past the drum and back toward the tank. The machine then looks like it is working while quietly returning most of the load to the sump.

That is the single most common mistake we see with magnetic units. A buyer upgrades from a hinge belt to a magnetic conveyor to solve a fines problem on a cast-iron cell, then copies the same specification onto a stainless job in the next bay. On the stainless machine it discharges almost nothing. The unit is not faulty; it was simply specified for the wrong metal.

Where magnetic earns its place

The strongest case for magnetic separation is grey cast iron. The swarf from grey iron is short, powdery, highly ferromagnetic and difficult to carry on a hinge belt because it falls through the plate gaps and silts up the return run. A magnetic drum pulls that fine dust out of the coolant before it ever reaches the tank, and it does so with almost no wearing parts. Grinding operations on hardened steel produce a similar fine, magnetic sludge, and here too the magnetic approach often beats a scraper on total cost of ownership because there is nothing to rub.

Magnetic units also handle small ferrous parts that would jam or fall through a hinge belt — things like small stampings, screw-machine parts and magnetic hardware. They are less useful where the swarf is long and stringy, because a long tangled bird's nest bridges across the magnet face and blocks the gap, and less useful again where the load is hot enough to reach the Curie point of the magnet material. Above roughly 80 °C for standard ferrite and 120 °C for some high-grade assemblies, holding force falls off, and above a few hundred degrees even the best permanent magnets lose their pull. Dry machining at high metal-removal rates is therefore a poor fit for a magnetic unit unless the swarf is cooled before it reaches the drum.

Material in the swarf	Magnetic response	Suitable chip conveyor type	Reason to avoid the wrong choice
Grey cast iron	Strongly ferromagnetic, powdery and short	Magnetic drum or roller, or a scraper with a magnetic pre-stage	A hinge belt alone drops this dust through the plates and silts the return run
Carbon and alloy steel	Strongly ferromagnetic, but often long and stringy	Hinge belt, magnetic only when the chip is short	Long nests bridge across the magnet face and block the discharge gap
Austenitic stainless steel	Weakly magnetic or effectively non-magnetic	Hinge belt or scraper; never rely on a magnet	The drum ignores the swarf and returns it to the coolant tank
Aluminium, brass and copper	Non-magnetic	Hinge belt, scraper or a belt-type conveyor	Magnetic units pass essentially none of this material; the machine appears to run empty
Titanium and exotic alloys	Non-magnetic, often hot and pyrophoric in fines	Hinge belt with heat-tolerant plates and careful fire control	Magnetic and rubber options both fail; hot fine titanium needs a metal-only path

Magnetic separation has a second life beyond swarf. Where a plant treats mixed scrap and wants the ferrous fraction pulled out before further processing, the same principle is scaled up into overband and drum separators, and our notes on the ferrous side of metal recycling flows use the identical physics. When a conveyor has to marry a magnetic stage with a belt that also resists oil and coolant, the base belt often has to be a rubber conveyor belt grade chosen for fluid resistance rather than a bare steel surface, and the drive package usually pairs with a compact timing belt or geared motor to keep the head end short.

05Matching the Belt Style to Swarf Form and Workpiece Material

Choosing a chip conveyor by machine model is the wrong way round. Two identical lathes cutting different materials produce swarf that behaves completely differently, and the belt that suits one will jam on the other. The reliable route is to start from the swarf, describe it honestly, and let the form and the material together point at the type. Mechanically the three families divide cleanly: the hinge belt carries almost anything, the scraper carries fine wet material best, and the magnetic unit carries only ferrous fines and small parts.

The awkward cases are the mixed ones, and they are also the most common. A job shop that turns stainless in the morning and grey iron in the afternoon cannot justify a different conveyor for each. In practice the answer is usually a hinge belt with a crusher, or a scraper with a magnetic pre-stage, because both tolerate an erratic feed and neither depends on the metal being magnetic. Specifying on the basis of the worst material the machine will ever run is safer than optimising for the material you happen to be running today.

Swarf form	Typical source operation	Best-fit belt type	Features to write into the spec	Failure mode if the type is mismatched
Long stringy birds-nest	Ductile alloy turning at low feed and high surface speed	Hinge belt with a swarf crusher ahead of the head pulley	Coarse pitch, tall side walls, crusher rotor, generous discharge throat	Nests wrap the belt, climb the side walls and bridge the discharge until the drive stalls
Short curled C-chips	General steel turning and boring with a chipbreaker	Hinge belt, standard configuration	31.75–38.1 mm pitch, 2 mm plate, hardened chain pins	Rarely a mismatch; this is the design's home ground and jam risk is low
Heavy bushy coils	Heavy roughing passes on large forgings and castings	Heavy-duty hinge belt, high-tensile chain	50.8–63.5 mm pitch, 2.5–3 mm plate, reinforced side chains	Light plates dish under the impact and open at the pin joints within months
Fine granules and millings	Milling, drilling and medium finishing cuts	Scraper or fine-pitch hinge belt	Wear shoes on the flights, replaceable trough liner, drainage weirs	Coarse hinge pitch drops granules through the plates and they pack the return run
Powder and dust	Grey cast iron machining, dry or near-dry	Magnetic drum or roller, or scraper with magnetic pre-stage	Magnet grade suited to temperature, coolant-tolerant surface, close discharge scraper	Hinge belts silt the return run; a weak magnet lets the fines back into the tank
Grinding sludge	Surface and cylindrical grinding with heavy coolant flood	Magnetic separator plus fine scraper, or a drag filter	Two-stage separation, sludge box, magnetic drum ahead of the fine scraper	A single stage either passes fines to the tank or blocks on sludge and stops draining
Small ferrous parts	Screw machines, stamping and bar-fed automatic turning	Fine-pitch hinge belt or magnetic conveyor	Fine pitch to stop parts falling through, and a part-collection chute at the discharge	Coarse pitch drops small parts into the return run and jams the chain
Non-ferrous swarf	Aluminium, brass and copper machining	Hinge belt or scraper; magnets cannot be used	Stainless or coated surfaces, oil-resistant components, no magnetic separation stage	A magnetic unit silently returns almost all the swarf to the coolant tank

Two structural rules follow from this table. The first is that a crusher is rarely wasted. Even on a line that mostly makes short chips, an occasional stringy batch will find its way to the belt, and a crusher turns an overnight jam into a five-second interruption. The second is that two-stage separation — a coarse or magnetic first pass and a fine second pass — is normal practice on anything producing fines, because no single type does both jobs well. A belt-and-drive package built for a standard machine should be traceable to a defined conveyor belt factory so that the material grades and heat treatments are documented; that paperwork matters more here than on a general bulk line, because the whole belt is a wear item and a chain that fails a grade check fails early. Return support along the loop is a small but real detail, and the plain roller options described under steel conveyor roller are what keep a long hinge loop from dragging on the frame. Where the machine is driven by a compact geared head, a properly rated transmission belt manufacturer range gives you the drive belt as part of the same supply.

06Cutting Fluid, Temperature and Chemistry: What They Do to Belts, Hinges and Chains

Coolant is the quiet killer of chip conveyors. It attacks metals, washes out lubrication, carries abrasive fines into every joint and changes chemistry as it ages. A water-based coolant starts life as an emulsion at a controlled concentration and a pH between about 8 and 9. Over weeks it picks up tramp oil, bacteria, dissolved iron and fine swarf, and its pH drifts. It can turn mildly acidic, and acidic coolant eats a carbon-steel chain far faster than any abrasive ever will. I have pulled chains off machines where the pins were not worn oval at all but simply corroded solid, still bright in the middle and crusted at every bush.

Temperature compounds the problem. A hinge plate that swings between 30 °C on the return run and 150 °C under a hot slug two or three times a shift is being thermally cycled thousands of times a year. Cold-rolled steel tolerates that reasonably well, but thin plates still warp, and warped plates do not sit flat on the chain. They ride up, pinch the pins and eventually tear at the hinge line. On dry-cut cast-iron jobs, where swarf can come off near 180 °C, we recommend keeping any elastomer or rubber component well away from the hot zone and specifying metal-only surfaces on the direct path.

Material choices that survive the chemistry

The instinct on a wet machine is to reach for stainless everywhere. That is often right for the wetted parts — the trough, the side skirts and the chain — but it is not free, and it is not necessary in every position. Stainless chain costs roughly two to three times a comparable carbon chain and has lower fatigue strength, so on a heavily loaded hinge belt the carbon chain with hardened pins and regular lubrication can outlast a soft stainless one despite the rust risk. The decision hinges on pH history, tramp-oil level and how often the machine sits idle wet.

Rubber and elastomer components only appear at the perimeter of a chip conveyor — drive belts, seals, flexible connectors, sometimes a discharge wiper. Each has to be matched to what it touches. A drive belt running near oil mist or coolant splash needs an oil-resistant compound, not a general-purpose one, and a belt near a hot discharge needs a heat-resistant grade. Getting this wrong is cheap to do and expensive to discover, because the belt usually fails during a production run rather than during a commissioning check.

Fluid or thermal factor	Effect on belt, plates and chain	Mitigation to specify	Material note worth writing down
Water-based coolant, pH 8–9	Corrodes carbon-steel pins and bushes; washes grease out of chain joints and stiffens them	Stainless chain or coated pins, sealed or oil-bath lubrication, regular re-greasing	Chain built to ISO 606 / DIN 8187 in a corrosion-resistant grade
Acidic aged coolant	Speeds up metal loss at joints; pitting appears on plates and trough walls before any visible wear	Coolant monitoring and pH control, plus a conveyor a size up in corrosion protection	Stainless trough, skirts and flights rather than painted carbon steel
Tramp oil and neat cutting oil	Swells and softens general-purpose elastomers; leaves oily film that holds fines against joints	Oil-resistant seals and drive belts, a skimmer or coalescer on the tank	Oil-resistant rubber grade for every wetted elastomer, no exceptions
Hot swarf, 120–180 °C	Thermally cycles plates, warps thin sections and galling at the pin joints; can damage rubber faces	Thicker plates, heat-tolerant material, metal-only path through the hot zone	Heat-resistant grade for any elastomer left in the hot path
Abrasive fines in fluid	Turns the coolant into a lapping paste that wears pins, troughs and pump internals together	Two-stage separation, hardened wear surfaces, frequent tank cleaning	Replaceable liners and wear shoes as scheduled consumables

Where a plant also runs wider rubber belting alongside the machine tools, the same fluid logic carries over, and our notes on oil resistant and chemical resistant grades explain how compound selection changes with the fluid. For anything feeding a hot discharge or an oven after the machining cell, the thermal behaviour is closer to what is covered under heat resistant conveyor belt construction. Drive packages for the head end often use a wrapped V-belt, and a V-belt manufacturer that also supplies anti-static and oil-resistant compounds will keep the drive inside the same fluid specification as the conveyor. Buyers who need a single point of contact for the whole package should work with a conveyor belt distributor who can co-ordinate belt, chain and drive as one bill of materials.

07Jam and Pull-Through: Root Causes and How to Prevent Them

Almost every chip conveyor that fails in service fails in one of two ways. It jams, or it pulls apart. The two are related, because a jam is the event that most often converts into a pull-through when the drive refuses to let go. Understanding the difference matters, because they call for different fixes and only one of them is a belt problem at all.

A pull-through is what happens when the drive keeps pushing after the belt has stopped somewhere downstream. The resisting load can climb to five or ten times the running torque in under a second. If the drive has no way to relieve that, the weakest link in the loop gives way. Sometimes it is a chain pin shearing, sometimes a hinge joint opening up, and occasionally the head shaft itself twists. We have seen a conveyor lose an entire side chain because a crushed aluminium can had wedged under the incline and the operator kept resetting the starter instead of clearing it. The belt was blamed; the missing overload protection was the real fault.

The most common jam precursors are stringy swarf that bridges at the incline, foreign objects dropped into the machine sump, a belt that has started to track off its sprockets, and a discharge chute that has quietly filled with packed, wet, fine material. Some of these build up over days before they stop the belt. A conveyor that jams "for no reason" is usually a conveyor whose tracking or discharge has been drifting for a fortnight.

Machine-tool cell with a chip conveyor manufacturer's hinged steel belt removing swarf on the shop floor

Reading the signs before the break

Chain elongation is the single best early-warning indicator you have. Measure it across a fixed span of links — say ten pitches — when the conveyor is new, record the number, and re-measure quarterly. Most machine-tool chains should be replaced once elongation passes roughly 2% of the original span, because beyond that the chain starts to ride high on the sprocket teeth, skip under load and shock the whole loop. A stretched chain that is still "running fine" is living on borrowed time, and the failure, when it comes, is usually sudden. A month-on-month growth in motor current at the same load tells the same story through a different channel.

Symptom	Most likely root cause	Immediate fix	Prevention to build in
Belt stops under load, chain intact	Swarf bridging at the incline or a foreign object wedged between belt and frame	Isolate, reverse jog if fitted, clear the bridge by hand with the drive locked out	Swarf crusher ahead of the belt, taller side walls, a coarse drop-out grid on the sump
Chain skips a sprocket tooth	Significant chain elongation, or tension too low after re-tensioning was forgotten	Re-tension as a stop-gap, then replace the chain at the next planned stop	Quarterly elongation measurement with a written 2% replacement trigger
Belt runs off to one side	Unequal chain tension, worn sprockets, or uneven loading from an off-centre machine chute	Align the head and tail shafts, level the belt, then correct the feed position	Tracked side guides, a spreader bar under the machine outlet, matched chain pairs
Discharge blocking and backing up	Wet fine swarf packing in the chute because the belt never drains long enough	Clear the chute, increase belt speed or incline, add drainage holes to the chute base	Specify a drainage weir and a minimum belt dwell time before the discharge
Chain or hinge plates torn apart	A jam that the drive did not relieve, so torque spiked through the loop	Replace the damaged section or chain, then correct or re-set the overload device	A slip clutch, torque limiter or correctly sized shear pin, tested on commissioning
Plates cracked near the hinge line	Thermal cycling plus a heavy hot slug on plates that are too thin for the duty	Replace cracked plates; do not run a cracked belt hoping it will last the week	Thicker plates for hot or heavy swarf; a crusher to break up the worst slugs
Rust crusting at pins after a shutdown	Idle wet carbon-steel chain with acidic or tramp-oil-loaded coolant	Clean, re-grease and free the joints; run the belt periodically during shutdowns	Stainless chain on wet alkaline machines, plus a scheduled coolant change

Overload protection deserves its own line in the maintenance schedule, because a device nobody tests is not protection at all. On a transfer line running 22 hours a day I once found a conveyor fitted with a torque limiter that had been wound fully shut by a well-meaning fitter who was tired of the belt stopping. The belt no longer stopped; instead it tore out a chain end every few weeks, and nobody connected the two facts for months. Set the limiter to trip at roughly 1.5 to 2 times the normal running torque, then log the trip setting and check it at every service. On belts that take a beating, a sacrificial element that fails before the chain does is often worth more than a rigid trough, and the same hardness-versus-toughness trade-off is familiar from our notes on impact and cut resistant constructions. Head and tail shafts, sprockets and take-up arrangements are the parts that carry the whole load, and the pulley families described under conveyor pulleys show how shaft and hub design changes once real torque enters the picture. Everything else that holds the machine together — brackets, guards, chute supports — sits in the general conveyor components range.

08What to Write in a Chip Conveyor Belt Purchase Specification

A vague enquiry gets a vague quotation, and a vague order gets a belt that nearly fits. The remedy is a short, specific specification sheet sent with the RFQ, covering construction, materials, the actual swarf stream and the environmental conditions. It takes thirty minutes to write and saves weeks of rework. The sections below are the fields that come back to bite buyers when they are left blank.

Start with the belt itself, because that is where most disputes originate. Pitch, width, plate thickness, plate material and hinge style together define the whole carrying surface. Then describe the chain, since it carries every kilogram of load: type, pitch, material, pin hardness and the standard it is built to. After that, the machine and the duty — incline, centre distance, speed, motor, and the maximum swarf form the belt will ever see. Finally, the protection and the environment: overload device and its setting, coolant type and pH, ambient and swarf temperatures, and the discharge arrangement.

Detail of hinge pitch and chain of a chip conveyor manufacturer's belt for machine tool swarf

Spec field	Why it matters in metalworking	Typical value or range	Risk when it is left unspecified
Belt pitch and width	Sets drainage, small-part retention and how the swarf spreads across the belt	31.75–63.5 mm pitch; 200–800 mm width typical for a machining centre	Supplier guesses; belt drops fines or floods, and the machine chute no longer matches the belt
Plate thickness and material	Controls resistance to hot-slug dishing and to corrosion from wet coolant	1.5–3 mm cold-rolled or 304 stainless, hardened option for abrasive fines	Thin or mild plates dish, crack at the hinge line and rust into a seized chain
Hinge style	Plain, dimpled or perforated plates drain fluid at very different rates	Perforated for wet jobs, plain or dimpled for dry and fine-swarf jobs	Wrong surface either retains coolant or lets it drop straight through to the floor
Chain type, pitch and material	Carries all the tension and absorbs the jam torque spikes	Roller chain to ISO 606 / DIN 8187, carbon with hardened pins or stainless	A soft or corroding chain stretches early and pulls apart under load
Side walls and skirts	Keep swarf and coolant on the belt instead of over the edges	50–150 mm skirts, wear-resistant or stainless, with tracked guides	Swarf spills, the belt tracks off and wears the frame at the guide line
Incline and centre distance	Decides whether wet load slides back and how much chain is in the loop	Typically 15–30°; centre distances from 1 m up to 6 m or more	Too steep, the load rides back and packs; too long, return support is forgotten
Speed and drive package	Sets drainage dwell time and the torque available to survive a jam	0.5–3 m/min, geared motor sized to the surge load not the average	An under-sized drive stalls on the first surge; an over-sized one tears a jammed belt
Overload protection	The difference between a harmless stop and a destroyed chain	Slip clutch, torque limiter or shear pin, set at 1.5–2× running torque	Without it every jam becomes a repair; with a wrongly set one it protects nothing
Coolant return and drainage	Returns fluid to the tank and keeps fines out of the sump	Drainage weirs, settled return chute, filter mesh matched to the fines	Coolant silts the tank, pump wear rises and surface finish drifts
Temperature and fluid conditions	Drive the material and elastomer choices throughout the machine	Swarf up to 180 °C, coolant pH 8–9, tramp oil present	General-purpose materials corrode, warp or swell inside the first year
Capacity and swarf form	Lets the supplier size the belt on the worst case, not the average	State kg/h, peak surge, and the worst swarf form the machine ever makes	An average-based design jams on the first bad batch and looks "under-specified"
Spares and documentation	Keeps a wear item like a chip belt serviceable without long lead times	Plates, pins, chain sections, wear shoes and a marked-up parts list	A single broken plate idles the machine for weeks waiting on a spare

One caution about context. A machine-tool chip conveyor is a specialised device, and it shares the scconveyorbelt catalogue with a very different family of heavy black belts for quarrying and port work. Those products are described on the mining and quarrying pages and include constructions like steel cord conveyor belt designed for thousands of tonnes an hour. Do not borrow their vocabulary for a swarf job, and do not borrow a swarf belt for a bulk line. The right answer for a machine tool sits in the metalworking section of the product range, and every batch should arrive with material certificates traceable through the supplier's quality assurance system so the grades in the spec sheet match the grades in the belt.

Ask for a chip conveyor belt datasheet and RFQ checklist

09Frequently Asked Questions

Can one chip conveyor handle both ferrous and non-ferrous swarf on the same line?

Usually yes, but the choice narrows to a hinge belt or a scraper. Both move metal by contact rather than by magnetism, so they neither know nor care whether the swarf is steel, stainless, aluminium or brass. A magnetic unit cannot do this job, because it only picks up ferromagnetic material and will pass aluminium and austenitic stainless straight back to the coolant tank. On a genuinely mixed shop the safe answer is a hinge belt with a crusher for the stringy batches, because that combination tolerates an erratic feed and a genuine unknown in the material mix.

Why does a hinged steel belt keep jamming on long stringy swarf?

Long, tangled birds-nest swarf is the hinge belt's one real weakness. Instead of travelling as individual chips it forms a mat that wraps the belt, climbs the side plates and bridges across the discharge throat, and once it bridges, the belt is pushing against a solid wall. The fix is not a bigger motor — that just tears the chain — but a swarf crusher ahead of the head pulley to break the nests into short pieces, taller side walls to stop the climb, and a generous discharge throat so a partial bridge can still pass. A coarse drop-out grid over the machine sump also helps by stopping the worst bundles from ever reaching the belt.

How often should the conveyor chain be replaced?

Replace on condition, not on the calendar, and use elongation as the condition. Measure a fixed span of links — ten pitches is enough — on the new chain, record it, and re-measure quarterly. Once elongation reaches roughly 2% of the original span, order a replacement and fit it at the next planned stop, because a stretched chain rides high on the sprocket teeth, skips under load and shocks the whole loop. A slow rise in motor current at the same load points the same way. Waiting until the chain visibly sags or a sprocket jumps is waiting until the failure is already under way.

Why does a magnetic conveyor discharge so little on a stainless job?

Because austenitic stainless is effectively non-magnetic. The drum, plate or roller simply has nothing to attract, so the coolant flow carries the swarf past the magnet and back toward the machine sump, and the unit looks like it is running while discharging almost nothing. The same happens with aluminium, brass, copper and titanium. Magnetic separation is a strong fit for grey cast iron and hardened-steel grinding fines and a poor fit for anything non-ferrous. If the material mix is variable, do not specify on magnetism at all; use a belt that carries by contact.

Does cutting fluid damage the conveyor, and how do I protect against it?

Water-based coolant is the main aggressor. It sits at pH 8 to 9 when fresh, drifts toward acidic as it ages, and can corrode carbon-steel pins and bushes until a chain that looks unworn is stiff and seized at every joint. Tramp oil softens general-purpose elastomers, and fine metal in the fluid turns it into a lapping paste that wears pins, troughs and pump internals together. Protection is straightforward if it is planned: stainless or coated chain on wet machines, oil-resistant and heat-resistant compounds for every wetted elastomer, two-stage separation to keep fines out of the tank, and a coolant change and re-greasing schedule that does not slip. The same seal and bearing logic that protects conveyor hardware in other wet duties applies here, and our notes on bearing and seal selection explain how the protection is chosen.

What should I put in an RFQ to get the right belt the first time?

Send a short specification sheet, not a one-line email. Cover the belt construction — pitch, width, plate thickness and material, and hinge style — plus the chain type, pitch, material and pin hardness. Add the machine and duty data: incline, centre distance, speed, and the motor or gearbox if it is fixed. Then state the environment, meaning coolant type and pH, ambient and swarf temperatures, and whether tramp oil is present. Finally, give the load honestly, including the peak surge and the worst swarf form the machine ever makes, and ask for the overload protection type and its setting, the drainage arrangement, and a spares list. The discipline that makes a conveyor enquiry easy to answer is much the same as the one behind a good RFQ checklist, and the verification steps that apply to any belt order are set out in a buyer's pre-order inspection guide. When the swarf stream is genuinely unknown, say so and ask the supplier to recommend on the worst case rather than the average — that single sentence prevents most of the rework that follows a vague order.