A packaging line tubing example is most useful when it follows the air path from the preparation unit to the actuator, rather than treating tube as a generic consumable. On a cartoning, filling or end-of-line system, tubing affects response time, routing safety, washdown suitability and the ease of fault-finding. A correctly selected tube and fitting combination helps cylinders, grippers and vacuum equipment operate consistently through repeated production cycles.

Consider a medium-speed food packaging line handling sealed trays. Compressed air operates an infeed stop, a tray positioning cylinder, a pick-and-place unit, carton guides and a reject mechanism. The line has a main valve island within the guarded machine frame, with local pneumatic devices distributed along the conveyor. This is a typical arrangement, but the right tubing specification still depends on movement, temperature, cleaning regime, available installation space and required airflow.

Packaging line tubing example: system layout

In this example, air enters the machine through a filter-regulator assembly and feeds a valve island mounted near the centre of the line. A larger supply tube connects the air preparation equipment to the valve island. Individual outlet tubes then run from the valves to each cylinder or gripper.

This division matters. The supply run must carry the combined demand of several devices, particularly where several actuators move at the same time. A tube that is too small can restrict flow and contribute to pressure drop at the valve island. The result may be slower cylinder strokes, inconsistent gripping or a reject station that does not complete its movement within the machine cycle.

For a compact machine, 10 mm or 12 mm outside diameter tubing may be appropriate for the main supply, subject to the required flow, run length and pressure conditions. Branch runs to standard compact cylinders may use 6 mm or 8 mm OD tube. A small sensor blow-off or a low-air-consumption device may use 4 mm tubing. These sizes are examples, not universal rules: a long 6 mm run feeding a fast actuator can perform less effectively than a shorter 8 mm run, even when both connect to the same valve port.

Position the valve island as close as practical to the actuators it controls. Reducing the tube volume between valve and cylinder improves response and limits the amount of compressed air released during every cycle. There is a trade-off. A central valve island simplifies electrical connection and maintenance, while decentralised valves can shorten pneumatic runs on a longer conveyor.

Example tube allocation

For the tray positioning station, 8 mm OD tube runs from a 5/2 valve to a guided cylinder. The cylinder has a short stroke but must extend quickly enough to align each tray before the sealing operation. Equal or near-equal tube lengths on the extend and retract sides make commissioning more predictable, although the required speed may justify different flow control settings.

The pick-and-place head uses tubing on moving axes. Here, bend radius, flex resistance and cable carrier routing take priority over the simple question of tube diameter. Tube should not be pulled tight at either end of travel. Allow sufficient service loop and ensure the bend is not concentrated at the push-in fitting, where repeated movement can create stress.

Carton guide cylinders use 6 mm OD tube because their air demand is lower and the valve manifold is nearby. The reject pusher, located further downstream, uses 8 mm OD tubing to avoid unnecessary restriction during a rapid stroke. The compressed-air supply to a vacuum generator may require a larger bore than the associated vacuum sensing or blow-off lines, depending on the generator design and its consumption.

Select material for the operating environment

Tube material should be selected around the real environment, not only the nominal pressure rating. Standard pneumatic tubing is often suitable for protected machine interiors and general automation duties. Where the tubing is repeatedly flexed on robotic pick heads or moving guards, flexibility and fatigue performance deserve closer attention.

Food and pharmaceutical machinery introduce further considerations. The tube route may be exposed to cleaning chemicals, moisture or frequent washdown. In these areas, the material must be suitable for the chemicals and temperatures involved, while fittings should be chosen with the same care. A hygienic machine is not improved by fitting suitable tube to connectors that are difficult to clean or unsuitable for the environment.

PTFE tube is a practical option where chemical resistance, elevated temperature capability or a low-friction internal surface is required. It is not automatically the best selection for every packaging machine. PTFE is less flexible than many standard pneumatic tube options, so it can be less convenient for tight routing or constantly moving applications. Use it where its material properties solve a defined operating requirement.

For cold stores or outdoor loading-line equipment, check the full operating temperature range of both tube and fittings. Materials that perform well in a warm production hall can become less flexible in low temperatures. Likewise, installations near heat-sealing equipment should be assessed for radiant heat and local temperature peaks, not merely the ambient factory temperature.

Match fittings to tube size and access requirements

Push-in fittings speed up installation and make routine replacement straightforward, but they rely on correct tube preparation. The tube must have a clean, square cut and an undamaged outside surface. An angled cut, crushed end or deep score can compromise the seal and create a leak that only appears when the line is vibrating or cycling.

Select fittings by the tube outside diameter and the machine port thread, then consider the route. Straight fittings suit direct connections. Elbows help maintain a controlled bend radius where space is limited, while swivel elbows can make final tube alignment easier. Avoid forcing tube into a tight turn immediately after a straight fitting simply because the fitting was available on the assembly bench.

Plastic push-in fittings are suitable for many general compressed-air applications. Stainless steel push-in fittings may be more appropriate where corrosion resistance, washdown exposure or a demanding process environment calls for a more durable fitting body. Material compatibility should be assessed across the complete assembly: tube, fitting seal, thread sealant and the substances present in the area.

Where maintenance teams need to isolate a section quickly, label tubes by function and use a consistent colour or marking system. This is particularly valuable on machines with many identical valves. A clear identification scheme reduces the chance of reconnecting a cylinder to the wrong valve port after servicing.

Design the route for maintenance, not just installation

A tubing layout that looks neat on the build bench can still be difficult to maintain in service. Avoid routing pneumatic tube across access panels, sharp metal edges, hot surfaces or areas where operators regularly place tools and product containers. Use suitable clips and supports at intervals that prevent sagging without crushing the tube.

Separate pneumatic lines from moving mechanical parts and leave access to valve manual overrides, flow controls and cylinder fittings. Where tube passes through sheet metal, use an appropriate protective method to prevent abrasion. On a conveyor frame, protect against rubbing caused by vibration and repeated guard movement.

Do not hide every line inside a densely packed trunking route. Controlled organisation is useful, but technicians must be able to trace a tube from valve to actuator during a breakdown. For longer runs, clear labels at both ends are usually more useful than labels only at the valve island.

Commission against the machine cycle

Once installed, test the pneumatic circuit at operating pressure and during the actual production sequence. A static leak check is necessary, but it does not reveal every issue. Watch for tube movement at fittings, delayed cylinder movement, pressure loss during simultaneous actuation and changes in behaviour after the machine has warmed up.

Set flow controls at the actuator ports where possible, then tune motion to protect product and mechanics. Excessive speed can damage trays, cartons or end stops. Too little speed can cause missed timing windows. The objective is repeatable movement at the required cycle rate, not the fastest possible cylinder stroke.

For a practical packaging line tubing example, start with airflow and routing, then confirm material and fitting suitability for the environment. Nexo Air supplies pneumatic tubing and push-in fittings in sizes from 4 mm to 12 mm OD, allowing machine builders and maintenance teams to match components to each part of the circuit rather than forcing one tube size across the entire line. A well-routed, clearly identified system gives the maintenance team something more valuable than a tidy installation: a pneumatic circuit they can diagnose and return to service quickly.