Industrial conveyors — how to match part transport to the process

Industrial conveyors are the least glamorous element of a line — and one of the most frequently underestimated. Poorly selected transport jams parts, loses the pitch in front of a machine, needs constant correction by the operator's hand and can stop a line just as effectively as a machine-tool breakdown. And because a conveyor is "just a belt", the selection decision is often made at the end of the project, in a hurry and on the lowest price.

This article organises the topic from the practical side: what the basic conveyor types are and what each is suited to, what data must be collected before selection, and how to treat transport as part of the process — with integration and buffering — rather than as an add-on to the machines.

Types of industrial conveyors and what they are suited to

Four designs cover most applications in part transport.

Belt conveyor

A continuous belt running on two drums. The universal choice for light and small parts: plastic components, low-weight turned and milled parts, small cartons, packaged goods. The continuous surface means a small part cannot fall between the carrying elements, and part orientation stays reasonably stable. Limitations: load weight, sharp edges and hot parts that destroy the belt, and oils and coolants that degrade some covers.

Roller conveyor

The load rolls on rollers — by gravity or powered. Its natural environment is containers, crates, pallets and parts with a rigid, flat base. High load capacity, simple construction, easy zoning for accumulation. The basic limitation: the part must be longer than the spacing of at least three rollers, otherwise it falls between them or rocks. Small parts and parts with irregular undersides are out.

Chain conveyor

The part rests directly on the chains or on carriers. The choice for heavy, hot loads or ones aggressive to a belt: forgings, castings, metal pallets, welded structures. It tolerates harsh conditions — scale, high temperature, oils. Limitations: it requires lubrication, can be noisy, and the part must have a surface that can contact the chain without damage.

Modular conveyor

A belt assembled from plastic segments joined by pins. Its biggest strengths: routes with horizontal curves and spirals, resistance to water and washdown, and replacement of a single damaged segment instead of the whole belt. The standard in the food industry and wherever hygiene or complex route geometry matters. Limitations: the segment pitch leaves small gaps (a problem with very small parts) and a higher cost than a plain belt.

Decision table: type, application, limitations

The table gives a first direction, not a final answer. For example: small turned parts in emulsion point in theory to a belt, but because of the coolant the solution often ends up being a steel belt or a scraper conveyor — which is why selection always starts from the actual part, ideally from samples.

Selection data: part, throughput, route, environment, control

A solid transport specification fits into five points:

• part: dimensions, weight, material, temperature, surface condition (oil, burrs, paint), whether parts may touch each other,
• throughput: pieces per hour now and in the future, continuous or indexed operation, the required pitch at the outfeed,
• route: length, width available in the hall, height differences, curves, crossings for people and forklifts,
• environment: dust, humidity, oil mist, temperature, hygiene requirements, washdown zones,
• control: start-stop from the machines, speed regulation, accumulation sensors, signals to the supervisory controller.

This set resembles the design brief for any dedicated machine — and rightly so, because a conveyor engineered for a process is a machine too. We describe the full structure of such data in the article how to prepare the design brief for a special-purpose machine.

The most common selection mistake is ignoring the environment and the "bad day" part: a conveyor tested on clean samples stops after a week on parts that are oily, burred or at the extreme ends of the tolerance range. Good practice is therefore to hand the supplier samples from current production — including extreme and defective pieces — and, for unusual parts, to run a test on a trial section before building out the whole route.

Integration with machines and buffering

A conveyor rarely works alone — it usually links machines, and then its value is decided at the interface with the process:

• feeding into the machine: the part must arrive oriented and at a pitch the machine will accept — sometimes that is the conveyor's job, sometimes a separate feeding unit's,
• collection from the machine: the collection takt must keep up with the machine cycle, including during momentary surges,
• signals: buffer full, buffer empty, permission to feed — without this exchange the line will "choke" despite good transport,
• a buffer between machines: an accumulation section evens out takt differences and lets the line survive short stoppages of one machine without stopping the others.

An indicative example: if the feeding machine stops a few times per shift for two to three minutes, a buffer holding 20 parts at a 10-second takt covers just over three minutes of the next machine's work — enough for most micro-stoppages to stop halting the line. Sizing the buffer is a simple calculation on takt times and stoppage statistics, not guesswork.

Buffering is often the cheapest way to raise line output: instead of speeding up the machines, it is enough to stop them halting one another. Where a buffer delivers the most is shown by the flow analysis from the article the production bottleneck. When designing conveyor systems, we therefore treat transport and buffering as part of the control system of the whole line, not as a separate purchase.

When a standard conveyor, and when one engineered for the process

A catalogue conveyor makes sense when the part is "well-behaved": stable, insensitive, within typical dimensions, and the route is straight. Engineering for the process begins where the standard requires compromises: a delicate or unusual part, orientation that must be maintained, a route that has to dodge existing machines, or transport that must dose parts in takt into an automatic machine. In practice many implementations are a hybrid: standard components (drives, rollers, profiles) in a structure designed for the specific part and hall — a sensible compromise between price and fit. If the transport is part of a larger automation project, it is worth keeping both scopes with one supplier, because responsibility for the interface between machines and transport then does not dissolve between vendors.

Whatever you choose, also ask about operation: whether the drives, rollers and belts are catalogue items available off the shelf, how a belt is replaced in the hall without dismantling the route, where the lubrication points are and how long a typical inspection takes. A conveyor often works longer than many a machine in the line, so maintenance costs over the years can outweigh the difference in purchase price.

Summary

Industrial conveyors are selected from the part and the process: a belt for light small parts, rollers for containers and pallets, a chain for heavy and hot loads, a modular belt for curves and washdown zones. The complete data set — part, throughput, route, environment, control — lets the design be chosen without guessing, and well-thought-out buffering often gives the line more than speeding up the machines.

Planning part transport between stations? Describe the part and the route via the contact form — we will propose a concept and a quote within 48 hours.