process interface

A process interface is a defined connection point where two processes interact. It specifies how inputs, outputs, information, and responsibilities are handed off between processes so that the overall system works as an integrated whole.

What a process interface includes

In industrial and regulated manufacturing environments, a process interface commonly describes:

• Inputs and outputs that move between processes (materials, information, approvals, work orders, quality records).
• Triggers and timing for when one process hands over work and when the next process is allowed to start.
• Roles and responsibilities for those sending and receiving the handoff (e.g., process owner, planner, quality, operator).
• Data structures and formats used at the boundary (MES records, ERP fields, document revisions, batch IDs, serial numbers).
• Rules and criteria that must be satisfied before handoff (inspection status, approvals, required documents, system validations).

Process interfaces can be:

• Organizational, such as the interface between production planning and shop-floor execution.
• System-level, such as the interface between ERP and MES or between MES and a quality management system.
• Physical/operational, such as the transfer of a batch from one unit operation to the next, governed by defined documentation and sign-offs.

Operational meaning in manufacturing systems

In practice, process interfaces are where many errors and variances occur if they are not clearly defined and controlled. Typical examples include:

• The interface between sales order entry and production planning, where customer requirements are translated into routings and materials plans.
• The interface between planning (ERP) and execution (MES), where work orders, BOMs, and revision data are released to the shop floor.
• The interface between manufacturing and quality, where inspection results and nonconformances are recorded and fed back into process control.
• The interface between manufacturing and logistics, where finished goods and as-built records move into inventory and shipping.

Defining process interfaces typically involves documenting:

• Which systems are involved (e.g., ERP, MES, QMS, LIMS, PLM).
• What data elements must be consistent across those systems (e.g., part numbers, revision levels, batch numbers).
• Who owns the interface and is accountable for issues that occur at the boundary.

Relation to the process approach

Within a process approach (for example in ISO 9001 based quality management systems), an organization is managed as a network of interconnected processes. Process interfaces are the defined connection points between these processes. Clearly describing them helps ensure that:

• Inputs and outputs between processes are identified and controlled.
• Measurements and risks at process boundaries are understood.
• Legacy or brownfield systems exchange information in a consistent way.

Common confusion

• Process interface vs. system integration: A process interface is a business or operational boundary between processes. System integration is the technical implementation that may support that interface (APIs, file transfers, connectors). The process interface can exist and be documented even if the supporting systems are not yet fully integrated.
• Process interface vs. process step: A process step is an activity within a single process. A process interface is the boundary between processes where one ends or hands off, and another begins.
• Process interface vs. user interface: A user interface is how a person interacts with a system (screens, forms). A process interface is about how processes interact with each other, not about screen design.

Use in OT/IT and MES/ERP contexts

In OT and IT environments, process interfaces are often formalized as:

• Data exchange specifications between ERP, MES, QMS, PLM, and SCADA/PLC systems.
• Workflow definitions describing how electronic travelers, digital work instructions, or quality records move between processes.
• Governance rules to maintain traceability and version control at each handoff point.

Clearly defined process interfaces help maintain consistent behavior across mixed legacy and modern systems without implying any specific technology or compliance status.