Packaging Line Integration Checklist: Interfaces to Confirm Before Ordering

Most integration problems on a packaging line are not caused by a machine that fails its own specification. They come from the gaps between machines: a conveyor transfer set at the wrong height, a “ready” signal that one side reads as active-high and the other as active-low, an emergency stop zone that nobody drew, or a compressed air drop that was assumed to exist. Each gap is cheap to close on paper before the order and costly to close on site.

A new machine joining a line has an upstream and a downstream neighbor, and each connection needs an owner. Below are the interfaces to confirm, a matrix naming who defines, supplies and confirms each one, and a checklist you can copy into your RFQ package.

What an interface is and where it sits

An interface is any point where something passes between two parties: product, signal, power, air, data, or responsibility. The new machine has an interface with the machine before it, the machine after it, the building, the plant network, and the people who run and maintain it.

The figure groups the interfaces into six categories around the new machine. Mechanical interfaces cover height, direction, transfer and guarding. Electrical interfaces cover supply and grounding. Signals are ready, running, fault, full and empty. Communication covers protocol, data points and PackML states. Safety covers E-stop zones and guard interlocks, and utilities cover air, water and vacuum. Accumulation or buffer sits between the machines, and documentation ties the package together.

Interface responsibility matrix

Interfaces fail when each party assumes someone else is handling them. The matrix assigns three roles to each: who defines the requirement, who supplies the hardware or data, and who confirms it works. The entries are a starting point to adjust to your project and contract. If a line integrator is involved, that role replaces or splits some of them.

Interface	What to define	Who supplies	Who confirms
Mechanical: transfer height and direction	Product path, transfer height, flow direction, guide dimensions	Machine supplier for the machine side; conveyor supplier or plant for the neighbor	Plant engineering and machine supplier, at drawing review and FAT
Mechanical: guarding at transfer	Openings, tunnels, access points, fixed and movable guards	Machine supplier and conveyor supplier for their sections	Plant safety lead with qualified reviewer, per the risk assessment
Electrical: supply and grounding	Voltage, phases, frequency, short-circuit rating, disconnect location, grounding scheme	Plant for the supply point; machine supplier for the panel	Plant electrician and machine supplier
Signals: handshakes	Signal list, direction, logic level, timing, fault behavior	Both machine suppliers or the integrator	Controls engineers on both sides, at FAT and SAT
Communication: network and data	Protocol, addresses, data points, state model, security arrangements	Machine supplier for the machine end; plant IT or line controller owner for the network	Controls engineer and plant IT
Safety: emergency stop zones and interlocks	Zone boundaries, which stops affect which machines, restart conditions	Machine suppliers and integrator for the hardware; safety design from the risk assessment	Qualified safety reviewer for the site
Accumulation and buffer	Buffer purpose, location, capacity assumption, product condition	Conveyor supplier, integrator or machine supplier	Plant operations and engineering
Utilities: air, water, vacuum	Pressure, flow, quality, connection type and location	Plant for the source; machine supplier for the take-off	Plant utilities and machine supplier
Documentation	Drawing set, I/O lists, manuals, parameter backups	Each supplier for its scope	Plant engineering, before FAT and before payment milestones

Mechanical interfaces

Mechanical interfaces cover how product physically moves from one machine to the next. Record the transfer height, the direction of flow, the side of the machine where product enters and leaves, and the support or fixing method. Note any difference between the product orientation that leaves the upstream machine and the one the new machine needs.

Sketch every transfer. Gaps, steps and speed differences at a transfer cause tipping, jamming and damage. Guarding there is a safety topic as much as a mechanical one, because openings that product passes through need to be assessed (see the safety section below).

Electrical interfaces

Define the supply the plant provides and the supply the machine needs: voltage, phase, frequency, and the disconnecting means at the machine. Specify the grounding scheme and any requirements from the electrical code that applies on your site. IEC 60204-1 covers electrical equipment of machines, and in the US NFPA 79 applies to industrial machinery. Which one applies depends on the market and the machine, and the supplier should state the standard used for the panel.

Signal interfaces

Discrete signals are the oldest and simplest line interface. A pair of machines usually exchanges ready, running, fault, full and empty, though names vary. For each signal, define:

• direction (which machine sends it),
• logic level and whether the signal is normally on or normally off,
• the behavior when the cable is broken or the other machine is off,
• the timing, such as how long a full signal must be present before the upstream machine slows or stops.

Write these in a signal table that both suppliers sign off. “Ready” can mean powered, in automatic, or able to accept product, and those are three different conditions.

Communication interfaces

If the machine passes data to a line controller or MES, define the protocol, network addresses, data points and the direction of each. A machine state model such as PackML gives states standard names; ISA-TR88.00.02 describes the PackML machine state model and tags. If you want state data, say so in the RFQ and request the tag list. A machine will not necessarily provide it.

Plant IT should confirm the network arrangements, security conditions and any remote access before the order. The control roles inside the machine are explained in the PLC, HMI and motion control guide.

Accumulation and buffer

Buffers absorb short stops so that a brief jam on one machine does not immediately stop its neighbors. Decide what the buffer is for, where it sits, and how product behaves in it. Some products accumulate without damage, while others mark, stick, tip or lose orientation. Buffer size and behavior follow from the expected stoppage pattern, which you can observe on your own line. The guide to packaging line bottlenecks shows how to see which machine limits output and how stoppages propagate.

Safety interfaces

ISO 13850 covers the design principles of the emergency stop function, and EN 415-10 sets out general safety requirements for packaging machines in the EU. The practical question at the boundary is what the other machines must do when one machine stops, and who decides. Draw the stop zones on the layout, state which stops are local and which are line-wide, and define the restart sequence. Document the result in the safety design and check it in validation.

Utilities

List the services the machine needs: compressed air (pressure, flow and quality), water or cooling, vacuum, extraction, steam or inert gas where relevant. For each, state the connection point, the size and type of connection, and who provides the take-off. Ask the supplier for consumption at the rated speed so the plant can check capacity. Air quality classes are described in ISO 8573-1.

Inspection and downstream equipment

If the line includes inspection, define where it sits and how rejects are handled. The machine vision guide covers vision stations, and the checkweigher and metal detector comparison covers sequence and reject confirmation. Reject devices and locked reject bins are interfaces too, as they connect to signals and to safety and hygiene rules.

For cartoning and case packing, the transfer from primary pack to carton and from carton to case needs the same treatment. The cartoner vs. case packer guide shows how these steps connect.

Interface checklist

Copy these into your RFQ package and assign an owner and due date to each.

Mechanical

• Transfer height at the infeed and discharge is defined, with the tolerance the supplier will accept.
• Flow direction, left or right hand, and the machine side for infeed and discharge are drawn on the layout.
• Product orientation and spacing leaving the upstream machine match what the new machine needs.
• Transfer design (plate, belt, chute or gap) is sketched and agreed by both suppliers.
• Conveyor speed matching or speed control between machines is defined.
• Guide rails, side guards and covers at the transfer are assigned to a supplier.
• Floor space, anchoring, operator access and service clearance are marked on the layout.

Electrical

• Supply voltage, phase count, frequency and disconnect location are stated.
• Short-circuit rating and protective device requirements are agreed.
• Grounding and bonding scheme is defined.
• Panel location, cable entry and cable tray routes are drawn.
• Applicable electrical standard for the panel is named by the supplier for your market.

Signals

• Signal list exists with direction, logic level, and wire or terminal references.
• Ready, running, fault, full and empty are each defined in words, not only by name.
• Behavior on cable break, power loss and mode change is stated.
• Timing and delays for full and empty signals are defined.
• Both suppliers have signed off the signal table.
• Reject, inspection and counter signals, if any, are included.

Communication

• Need for line or MES communication is stated: required, optional or not needed.
• Protocol, addresses, data points and update rates are listed.
• State model requirements, including any PackML states, are written down, and the tag list is requested.
• Plant IT has reviewed network security and remote access conditions.
• Time synchronization and data ownership are defined.
• Test method and test data for communication are agreed for FAT and SAT.

Safety

• Machine risk assessment is available or planned, with its scope covering interfaces.
• Emergency stop zones are drawn on the layout, with the effect of each stop on neighboring machines.
• Guard interlock arrangement at transfers and shared access points is described.
• Restart conditions after a stop are defined and reviewed by a qualified person.
• Safety function validation approach and records are requested.
• Lockout and energy isolation points are identified for the new machine and the interfaces.
• Applicable safety standards and the market for the machine are named by the supplier.

Utilities

• Compressed air pressure, flow and quality requirements are stated and checked against the site supply.
• Water, cooling, vacuum and extraction requirements are listed.
• Connection points, sizes and types are marked on the layout.
• Consumption data at the rated speed is supplied.

Accumulation and buffer

• The purpose of the buffer is written down.
• Buffer location and the signals that control it are defined.
• The effect of the buffer on product orientation and condition has been considered.
• Behavior on a full or empty buffer is agreed.

Documentation

• Layout drawing with machine footprints, interfaces and services.
• Electrical drawings, I/O list and signal table.
• Software version list and backup copies.
• Manuals, spare parts list and maintenance schedule.
• Safety documentation as available for your market.
• Responsibilities for the commissioning and the interface tests are in the contract.

Questions to ask suppliers

• Which interfaces does your scope include, and which do you assume the buyer or another supplier will provide?
• Can you supply a signal table and interface drawing for review before the order is placed?
• What does your machine do to the neighboring machines when it stops, and what does it expect in return?
• Which documents do you deliver, in what format, and when?

Limits and on-site verification

A checklist cannot tell you what your line physically looks like. Measure the site and check the drawings against it. Some interface problems appear only with real product, at line speed, in the actual layout.

Plan to verify these points:

• Transfers with actual product, at the speeds you plan to run.
• Handshake signals under start-up, stop, fault and recovery conditions.
• Emergency stop behavior across zones, using a test plan reviewed by a qualified person.
• Utility supply under running conditions, not only on a quiet shift.

The RFQ checklist shows where to put the interface requirements in your request, and the FAT vs. SAT guide describes how to split tests between factory and site. Safety design stays with the machine risk assessment and qualified engineers.