Conveyors look interchangeable on a layout drawing. They are not. A belt conveyor carrying a part that should have been on rollers wears out and marks the product; rollers under a part with no flat base jam; a line built without accumulation stops end to end every time one station hiccups. Almost every conveyor complaint we are called to look at is a selection decision made before anyone drew anything.
This guide is the selection conversation we have with customers, written down.
Six questions that decide it
- What is the product's contact face? Flat and rigid, or irregular, soft or finished?
- What does it weigh, and how concentrated is the load?
- Does it have to stop on the conveyor? If yes, does the conveyor need to keep running underneath it?
- Do operators work on the product while it moves, or beside it while it is stationary?
- What is the environment? Oil, swarf, weld spatter, coolant, washdown, paint, heat?
- Does it need to change level or direction?
Answer those six honestly and the type usually chooses itself.
Belt conveyor
Good at: small, light, irregular or unstable products. Anything without a flat rigid base — bags, loose components, parts that would fall between rollers. Inclines and declines up to the belt's grip limit. Quiet, gentle on the product.
Weak at: accumulation — a stopped product on a moving belt scuffs. Heavy point loads. Oily or hot environments that attack the belt. Anything that needs to be pushed off sideways.
Choose it when the product is light and the base is not reliably flat. Belt conveyors
Roller conveyor
Good at: products with a flat, rigid base — totes, cartons, pallets, fixtures, trays. Gravity roller costs almost nothing to run. Driven roller gives zone control and genuine accumulation. Easy to transfer off sideways, easy to maintain, tolerant of dirty environments.
Weak at: small parts that fall through, soft products that sag between rollers, anything without a flat base. Gravity sections need a reliable slope and a stop you trust.
Choose it when the product has a flat base, especially if it has to queue. Roller conveyors
Pallet and free-flow conveyor
Good at: assembly lines where stations have different cycle times. The product rides a pallet or fixture; the chain runs continuously while the pallet is stopped at a station. This is what lets one slow station stop being everyone's problem. Precise location at the station because the pallet is the datum.
Weak at: cost — it is the most expensive per metre. Pallet management adds complexity, and empty pallets have to return.
Choose it when station cycle times differ, or when the product has to be precisely located at each station. The extra cost is usually recovered in output within a year. Pallet and free-flow conveyors
Slat and chain conveyor
Good at: heavy products, hot products, dirty environments. Operators walking with the product — automotive final assembly, appliance lines. Flush floor installation so people and trolleys cross it. Very tolerant of abuse.
Weak at: cost and civil work if flush-mounted. Not suited to small light parts. Accumulation needs a separate arrangement.
Choose it when the product is heavy, the environment is harsh, or people need to move with it. Slat and chain conveyors
Overhead and power-and-free
Good at: carrying product through a process that occupies the floor — paint booths, ovens, wash tunnels, plating. Frees the floor beneath for people and other work. Power-and-free adds the ability to stop and sequence parts independently of the chain, which matters when dwell times differ between process stages.
Weak at: cost and lead time. Carrier design is critical — get it wrong and the part swings, marks or drops. Maintenance access is at height.
Choose it when the part must pass through a process, or the floor cannot be spared. Overhead and power-and-free conveyors
The accumulation question, because it catches everyone
If products must queue, say so at enquiry stage. It changes the selection more than any other single requirement.
| No accumulation needed | Belt or driven roller, simplest and cheapest. |
|---|---|
| Light accumulation | Gravity roller with a stop, or low-pressure zoned roller. |
| Zero-pressure accumulation | Zoned driven roller — each zone stops independently so products never touch. |
| Accumulation with station work | Pallet free-flow — the only clean answer when the product must stop, be worked on and be precisely located. |
Sizing: the four numbers we ask for
- Product weight and footprint, including the heaviest variant and the fixture if it rides along
- Throughput in parts per hour, and whether that is peak or average
- Pitch — how far apart products sit, which with throughput gives the speed
- Accumulation length — how many products must be able to queue, and where
Speed follows from throughput and pitch, not the other way round. A conveyor specified by speed alone almost always turns out to be the wrong speed.
What conveyors cost
Indicative planning bands for India, per running metre of installed conveyor, excluding controls, guarding and installation. They move with load, width, speed, finish and the make of drives.
| Gravity roller | Roughly ₹3,000–8,000 per metre. No drive, no controls — the cheapest way to move anything with a flat base downhill or by hand. |
|---|---|
| Belt conveyor | Roughly ₹8,000–20,000 per metre for light and medium duty. Belt specification and the drive package account for most of the spread. |
| Driven roller, non-zoned | Roughly ₹10,000–22,000 per metre. |
| Zoned accumulation roller | Roughly ₹18,000–40,000 per metre. Each zone brings its own drive or clutch and its own sensor and logic, which is where the difference goes. |
| Pallet free-flow | Roughly ₹25,000–60,000 per metre, plus the pallets themselves — commonly ₹8,000–30,000 each depending on the locating accuracy required. |
| Slat or chain | Roughly ₹25,000–70,000 per metre depending on load and slat construction. |
| Overhead and power-and-free | Roughly ₹20,000–80,000 per metre, plus carriers. Track engineering, supports and the building's roof structure drive the number. |
Two items regularly left out of budgets: the transfers — right-angle transfers, lifts, turntables, indexers — which are individually engineered and often cost more than the straight runs either side of them; and the carriers or pallets, where the quantity needed is set by the length of the loop and the accumulation, not by the number of stations.
Controls, integration and safety
The conveyor is mechanical; what makes it useful is the control layer around it. Decide these at specification time, because retrofitting them is disproportionately expensive:
- Zone logic. How a zone knows it is occupied, when it releases, and what happens when the downstream station stops. Sensor type and position are part of the mechanical design, not an afterthought.
- Stops and locating. Where products must stop precisely for an operation, the conveyor needs a stopper and a lift-and-locate unit at that point, with repeatability quoted as a number.
- Identification. Barcode or RFID on the pallet or product, so the line knows which variant is arriving and each station can configure itself. On mixed-model lines this is usually cheaper and far more reliable than sensing the part.
- Interface to stations and to your systems. Agree the signal exchange with each station and whether production counts and fault states feed your MES or a simple dashboard.
- Safety. Nip points at drives, transfers and elevating sections; fixed guards over drives and returns; pull-cords or emergency stops within reach along the length; interlocked access where operators must cross or enter. Specify it with the conveyor and it is a small percentage; add it after an audit and it is a shutdown.
- Maintainability. Take-up access, belt-change time, standard bearings and drives available locally, and lubrication points reachable without dismantling guards.
Five mistakes worth avoiding
- Specifying speed instead of throughput. Give parts per hour and pitch; let the speed be calculated.
- Forgetting the fixture. If the product rides a pallet or carrier, that weight and footprint is the load, not the product's.
- Ignoring the environment. Weld spatter destroys belts. Coolant destroys bearings that were not specified for it.
- Leaving out accumulation. Added afterwards it is a rebuild, not a modification.
- Guarding as an afterthought. Nip points, drive guards and pull cords are cheap during build and disruptive to retrofit.
Quick reference
| Light, irregular parts | Belt |
|---|---|
| Flat base, needs to queue | Driven roller, zoned |
| Flat base, gravity feed | Gravity roller |
| Assembly, differing cycle times | Pallet free-flow |
| Heavy, hot or dirty; operators walk along | Slat or chain |
| Through paint, oven or wash | Overhead or power-and-free |
If you are not sure, send the product weight, footprint, throughput and a photo of the station. That is usually enough for us to tell you which way to go, and we will say so even when the answer is the cheaper option.