Motionwell Automation builds conveyor and material handling systems in Singapore, and the delivered work covers most of the families this page describes: Interroll drum motors driving 24 V motor-driven roller zones on a carton palletizing infeed rated at 30 metres per minute, a Bosch Rexroth TS 5 heavy-duty belt conveyor rated for 500 kg per pallet position on an EV battery disassembly line, Intralox modular belt where product changes direction, and a closed-loop belt line with tray positioning moving units between four to six test stations inside an ISO Class 7/8 cleanroom enclosure. This page is the taxonomy behind those choices: what each conveyor family actually carries, and where each one stops working.
The short version, before the detail. Conveyor type is decided by the product, not by the distance. A belt carries anything that will sit still on a flat surface. Rollers carry anything with a rigid flat bottom long enough to span three rollers. Modular belt carries what needs to go round a corner or through a wash. Chain and slat carry what is too heavy or too hot for any of them. Everything else on a conveyor specification, speed, length, width, drive size, follows from that first decision and can be changed later. The family cannot.
How Many Types of Conveyor Are There, and What Does Each One Carry?
| Family | What it carries | Where it stops working |
|---|---|---|
| Flat belt | Almost anything that sits still: bags, loose product, small or irregular items, product with no rigid base | Sharp or hot product cuts or melts the belt; a long run stops as one piece |
| Modular plastic belt | Product that must turn a corner, climb, or pass through washdown; bottles, trays, packs | Higher cost per metre; heavier product needs a wider pitch and a bigger drive |
| Gravity roller | Rigid flat-bottomed cases, moved by hand or by slope | Anything without a rigid base; no control over where product ends up |
| Powered roller | The same rigid cases under drive, at a controlled rate | Short product noses between rollers; light product does not drive reliably |
| Motor-driven roller (MDR) | The same again, but split into independently driven zones | Costs more per metre; the value is in the controls, not the hardware |
| Chain | Heavy unit loads, pallets, hot or oily product that would attack a belt | Not for small or light items; the chain itself is a maintenance item |
| Slat | Heavy or hot product needing a flat carrying surface | Heavy, noisy, and expensive per metre |
The first column is the one that decides. A conveyor question that starts with “how many metres” has skipped it.
What conveyor belts are made of
Seven families sit in the table above and two of them are belts. A flat belt is a fabric carcass under a polymer cover, and the cover is the part that gets specified rather than the carcass: on the EV battery disassembly line the belt surfaces are carbon-fibre-loaded PVC with surface resistivity in the dissipative range under IEC 61340-5-1, because charge sitting on the carrying surface near an exposed terminal is the hazard being designed against. A modular belt is not a single surface at all. It is moulded plastic links pinned into a mat, which is why a damaged area comes out by hand instead of going to a splice press. Slats are steel or plastic carried on chain, and the chain itself is steel. Ask what the carrying surface has to survive, meaning the product, the debris that gets under it and the cleaning agent, and the material follows from that.
The three-roller rule
For any roller conveyor the working rule is that the product must always be supported by at least three rollers. That fixes the maximum roller pitch from the shortest product on the line, and the shortest product is frequently not the one people quote. A line specified around a 400 mm carton will not carry the 120 mm carton that arrives with a new SKU two years later, and the fix is either a new roller bed or a belt section spliced into the middle of the run.
How Do Belt, Modular Belt and Roller Differ in Practice?
The three families cover most of what a factory needs, and the differences that matter are not the ones in a catalogue.
| Flat belt | Modular plastic belt | Roller | |
|---|---|---|---|
| Product base | Any | Any | Rigid and flat only |
| Curves | Needs a separate curve section | Drives itself around the bend | Tapered rollers, or a transfer |
| Incline | Limited by friction; cleats extend it | Flights and side guards moulded in | Gravity only, or powered with a hold-back |
| Washdown | Belt seams and take-up are the weak points | Open construction, cleans through | Bearings and drive chain are the weak points |
| Repair | Splice or replace the whole belt | Replace individual modules by hand | Replace one roller |
| Accumulation | Product slides under a stopped product; pressure builds | Same | Zone control removes pressure entirely |
The repair row is the one that changes ownership cost. A flat belt fails as a unit and stops the line until it is spliced or swapped. A modular belt fails as a module, and a maintenance technician replaces the damaged section by hand in minutes without a splice press. On a line running two shifts, that difference outweighs the higher price per metre more often than the purchase decision reflects.
The washdown row decides a different thing. A drum motor puts the drive inside the pulley rather than beside the frame, so no external gearbox, coupling or chain guard stands in the wash path, which is why hygienic lines converge on drum motors and modular belt regardless of what the rest of the plant runs. The full hygiene argument sits on our conveyor and material handling page.
When Does a Conveyor Need Driven Zones Instead of One Long Run?
A single conveyor run has one motor and one state: running or stopped. Everything on it moves together, and when it stops, the product at the back pushes into the product in front. For rigid cases that is tolerable. For anything with a printed panel, a label, a cap, or a soft wall, it is not.
Splitting the same distance into independently driven zones changes the behaviour. Each zone holds one item, sees whether the next zone is occupied, and releases only when it is clear. Product stops without touching the product ahead of it. On a delivered carton palletizing infeed this is built from Interroll drum motors driving 24 V motor-driven roller zones, with a three-zone buffer whose occupancy is read by SICK WTB4S photoelectric sensors.
The reason to know this at the type-selection stage is that zoning is not something added later. It changes the frame, the drive count, the cabling, the sensor count and the PLC I/O. A quoted “roller conveyor” and a quoted “MDR conveyor” are different machines at a similar description.
| Question | Single driven run | Driven zones |
|---|---|---|
| What happens on stop | Everything stops together; back pressure builds | Each item stops in its own zone, no contact |
| Adding buffer capacity later | New section and new drive | Configure existing zones |
| Cost driver | Metres of frame | Zone count and I/O |
| When it is the right answer | Rigid product, no buffering needed | Product that must not touch, or a downstream machine with variable cycle |
Which Types Handle a Change of Height?
Elevation change is where conveyor selection goes wrong most visibly, because the constraint is the product rather than the conveyor.
| Method | Typical angle | What it needs from the product |
|---|---|---|
| Plain belt incline | Up to roughly 15-20 degrees | Enough friction; nothing that slides or rolls |
| Cleated belt | Steeper, product-dependent | Product that sits between cleats without tipping |
| Modular belt with flights and side guards | Steeper again | Product that tolerates being carried in a pocket |
| Spiral | Continuous rise in a fixed footprint | Product stable on a curve while climbing |
| Vertical lift or elevator | 90 degrees | Product that can be indexed and released, and a cycle that tolerates the index |
| Servo lift axis | 90 degrees, positioned | Anything, but the axis becomes a machine with its own safety case |
The last row is the boundary between conveying and machine building. Once the vertical move has to stop at a position rather than simply arrive, a controlled axis is doing the work and the falling-load question replaces the friction question.
What Types Exist for Product a Belt Cannot Carry?
Some product rules out the main families entirely, and the specialist answers are worth knowing by name so they can be asked for.
- Chain conveyor, pallets and heavy unit loads, or anything hot or oily. It is what an automated storage entry and exit runs on, and what an AGV hands a pallet to, as covered on the AGV and AMR integration page.
- Slat conveyor, a flat carrying surface built from steel or plastic slats on chain, for heavy product needing full support.
- Magnetic conveyor, ferrous parts held to the belt, which lets the run climb steeply or run inverted.
- Vacuum conveyor, the same idea for non-ferrous sheet or film, holding light flat product against the belt.
- Overhead conveyor, product hung from a track above head height, which is a floor-space answer rather than a handling one.
- Screw and pneumatic conveyor, bulk powder and granulate, which are not unit-load handling at all and belong to process engineering.
The last entry matters for scoping. A request for “a conveyor” from a plant that moves powder is a process question, not a handling question, and the two do not share a specification format.
How Do You Read a Conveyor Specification?
A conveyor quotation is easy to compare on the wrong numbers. These are the fields that decide whether two quotations describe the same machine.
| Field | What it actually tells you |
|---|---|
| Belt or roller width | Not the same as usable product width; guides and clearance take part of it |
| Speed | A maximum, not a rate. Throughput is speed divided by pitch, and pitch is set by the product and the gap |
| Load rating | Per metre, per zone, or per pallet position. A 500 kg per pallet position rating and a 500 kg per metre rating are different machines |
| Drive location | Head, centre or drum. Decides the wash path, the guard count and whether a drive swap needs the section stripped |
| Zone count | The real cost driver on an MDR run, and invisible if the quote is priced per metre |
| Transfer type | Dead plate, nose-over or driven. Decides which product sizes survive the join |
| Controls scope | Whether the conveyor arrives with its own logic or expects your PLC to run it |
The last row is the one that produces disputes late. A conveyor supplied as hardware with a set of contacts is a different scope from a conveyor supplied as a controlled subsystem, and the difference does not appear in the mechanical description.
Which Type Fits Which Kind of Line?
| Line | Usual answer | Why |
|---|---|---|
| Carton palletizing infeed | MDR zones into a driven roller infeed | Cases must arrive squared and singulated, without pressure at the pick |
| Bottle or vial filling line | Modular belt through the machine, table tops between | Corners, wet environment, and product that must stay upright |
| Heavy pallet handling | Chain conveyor | Load and the need to hand off to a lift or a vehicle |
| Cleanroom test line | Closed-loop belt with tray positioning | Trays returning to the start; particulate control rules out open chain |
| Battery module line | Heavy-duty belt with accumulation zones between stations | Pallet-mounted modules at high mass, with buffers between disassembly steps |
| Bulk powder | Screw or pneumatic | Not unit-load handling |
What Does Each Type Ask of Maintenance?
The family decides who can fix the line and how long it is down, and that is settled at selection rather than at handover.
| Family | Failure that stops the line | Who can clear it | Line down for |
|---|---|---|---|
| Flat belt | Belt cut, tear or tracking off | Belt splicing skill and a press, or a supplier visit | Hours to a day, depending on splice method |
| Modular belt | Damaged modules | A technician with hand tools | Minutes, module by module |
| Powered roller | Failed roller or drive chain | A technician, if the section can be reached | Minutes for a roller, longer if the drive train is behind guarding |
| Motor-driven roller | Failed zone drum motor | A technician, one module out and one in | Minutes, and only that zone stops |
| Chain | Chain wear, tension, lubrication | Scheduled work rather than reactive | Planned, if the schedule is kept |
Two things follow that are worth deciding before the order.
Can a drive be replaced without stripping the section? A drum motor comes out as one module. A motor, gearbox, coupling and chain does not, and on a line built tight against a wall the difference is measured in hours.
Does the failure stop the whole run or one zone? This is the same zoning decision as before, seen from the maintenance side. A single driven run has one drive and one failure mode that stops everything on it; a zoned run degrades rather than stops, and the line can frequently be run around a dead zone until the next planned stop. Which behaviour you need is a production question, and it belongs in the specification rather than in the first breakdown.
Lubrication is the quiet one. Chain needs it, and a chain conveyor over a product zone needs either a lubrication regime with a catch tray or a dry-running chain specification. Neither is expensive; discovering the requirement after the line is installed above an open product is.
How long does a belt last? A belt is consumed by what runs on it rather than by hours on the clock, so a life figure quoted without the duty behind it is a number about somebody else’s line. What shortens it: sharp or hot product, abrasive debris ground between the belt and the slider bed, a splice dragged over a knife-edge transfer, a cleaning chemistry the cover was not selected for, and a take-up left slack so the belt tracks into a frame edge. What extends it is the same list read backwards, plus tracking set again after the first weeks of running rather than only at commissioning. The question worth putting to a supplier is which wear mechanism they expect on your product and what the replacement part number is, because that answer can be checked against the line and a duration cannot.
What Does the Type Choice Decide That You Cannot Change Later?
Three things.
The frame geometry. Belt height, width and support spacing are set by the family. A belt-to-roller change mid-life means new frame sections, not a swap.
The product size window. Roller pitch fixes the shortest carriable item on a roller bed; belt width and side guides fix the widest on a belt. Both are decided at design and neither moves without hardware.
The regulatory position of the finished line. A conveyor supplied on its own is a component. Linked conveyors and machines that function together are an assembly of machinery, and on the EU market the European Commission treats products placed on the market for the first time, or existing machinery modified so far that it becomes de facto new machinery, as the manufacturer’s responsibility. Adding a conveyor to link two previously separate machines is the case worth checking before the order rather than after, because it can change who carries the conformity work for the whole line.
Speed, motor size, sensor brand and controls platform are all changeable. The three above are not.
Conclusion
Conveyor selection is a product question wearing a length question’s clothes. Name the heaviest item, the shortest item, whether it has a rigid flat base, whether it can be touched by the item behind it, and what the environment does to a bearing, and the family is decided before anyone measures the floor.
If you have a product list and a rate you are trying to hit, send them to an engineer and we will tell you which families the line needs, and where the transfers between them have to sit.