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Version: V2 (Ignition 8.1)

Terms and Definitions

This document provides definitions and explanations of key terms related to Overall Equipment Effectiveness (OEE) in manufacturing. Understanding these terms is essential for effectively utilizing OEE metrics to improve production processes.

OEE (Overall Equipment Effectiveness)​

  • Definition:
    • A measure of how effectively a manufacturing operation is utilized compared to its full potential.
    • Configuration: OEE Configuration
  • Formula:
    OEE = (Availability) x (Performance) x (Quality)
  • Components:
    • Availability: The percentage of scheduled time that the equipment is available for production.
    • Performance: The speed at which the equipment operates compared to its maximum potential speed.
    • Quality: The percentage of products produced that meet quality standards.
  • Purpose:
    • Identifies Inefficiencies: OEE helps pinpoint areas where production processes can be improved, leading to increased efficiency.
    • Enhances Decision-Making: By providing real-time data on equipment performance, OEE supports informed decision-making for process improvements.
    • Drives Continuous Improvement: OEE encourages a culture of continuous improvement by highlighting performance gaps and tracking progress over time.

State​

  • Definition:
    • The current operational status of a piece of equipment or production line.
    • Data model state, state record
    • Configuration: States
  • Purpose:
    • To indicate whether the equipment is running, stopped, or in a fault condition.

Mode​

  • Definition:
    • The operational mode of a piece of equipment, such as running, setup, maintenance, or idle.
    • Data model mode, mode record
    • Configuration: Modes
  • Purpose:
    • To categorize the operational mode of equipment based on its current function or activity.

Availability​

  • Definition:
    • The percentage of scheduled time that the equipment is available for production.
    • It accounts for downtime due to maintenance, breakdowns, and other interruptions.
  • Formula:
    Availability = Total Running Time / Total Scheduled Time
  • Purpose:
    • To measure the effectiveness of equipment utilization by identifying periods when it is not available for production.

Performance​

  • Definition:
    • The speed at which the equipment operates compared to its maximum potential speed.
    • It identifies losses due to slow cycles or reduced speed.
  • Formula:
    Performance = Actual Production Rate / Ideal Production Rate
  • Purpose:
    • To assess how efficiently the equipment is operating relative to its designed capacity.

Quality​

  • Definition:
    • The percentage of products produced that meet quality standards.
    • It identifies defects and rework, impacting overall production efficiency.
  • Formula:
    Quality = Good Units Produced / Total Units Produced
  • Purpose:
    • To evaluate the effectiveness of the production process in delivering products that meet quality requirements.

Downtime Reason​

  • Definition:
  • Purpose:
    • To categorize and analyze the reasons for equipment downtime, enabling targeted improvements to reduce future occurrences.

Production Count​

  • Definition:
    • The total number of units produced by a piece of equipment or production line during a specific time period.
  • Purpose:
    • To track production output and measure the efficiency of the manufacturing process.

Good Count​

  • Definition:
    • The total number of units that were produced and met quality standards.
  • Purpose:
    • To quanity the amount of goods generated in the production process, helping to identify areas for quality improvement.

Waste Count​

  • Definition:
    • The total number of units that were produced but did not meet quality standards, resulting in waste.
  • Purpose:
    • To quantify the amount of waste generated in the production process, helping to identify areas for quality improvement.

Standard Rate​

  • Definition:
    • The expected production rate for a piece of equipment or production line, expressed in units of measure per time unit (e.g., units per minute, kilograms per hour).
    • Configuration: Standard Rate
  • Purpose:
    • To define the ideal production rate for a location, which is used as the baseline for calculating the Performance component of OEE. The actual production rate is compared against the standard rate to determine how efficiently the equipment is operating.

Production Order​

  • Definition:
    • Represents a specific production order, detailing information such as product, quantity, status, and associated customer.
    • Data Model: Production Order
  • Purpose:
    • Enables efficient tracking and organization of production orders within the TamakiMES system.

Utilization​

  • Definition:
    • The fraction of total calendar time that a location spent in a scheduled production Mode.
  • Formula:
    Utilization = Scheduled Production Time / Total Time
  • Purpose:
    • Whereas Availability measures running time against scheduled time, Utilization measures scheduled time against all time, capturing how much of the calendar the equipment was even planned to run.

TEEP​

  • Definition:
    • Total Effective Equipment Performance: OEE measured against all calendar time rather than only scheduled time.
  • Formula:
    TEEP = Utilization x OEE
  • Purpose:
    • To reflect the true, fully-loaded potential of the equipment, including time it was not scheduled to run.

State Record​

  • Definition:
    • A stored occurrence of a location being in a single State for a period, with start and end times, duration, downtime reason, acknowledgement, and (for downtime) the associated primary alarm and root cause.
    • Data model state record
  • Purpose:

Mode Record​

  • Definition:
    • A stored occurrence of a location being in a single Mode for a period, with start and end times and duration.
    • Data model mode record
  • Purpose:

OEE Alarm​

  • Definition:
    • A configured Ignition alarm watched for a location (see Alarms). When a location is down, the MES associates a primary alarm - the single alarm that best explains the stoppage - with the State Record.
    • Data Model: OEE Alarm
  • Purpose:
    • To attach the specific alarm behind a stoppage to its downtime record. Which active alarm becomes the primary alarm is chosen using the configured Primary Alarm Resolution Strategy.

Calculation Record (OEE Roll-up)​

Interruption Location and Root Cause​

  • Definition:
    • For Starved and Blocked states, the interruption location is the neighbouring location that caused the stoppage.
  • Purpose:
    • Tamaki MES uses the interruption location to trace a stoppage to its root cause elsewhere on the line, shown as the Root Location, Root State, and Root Reason on the Downtime Entry table.

OEE Data Collection Services​

  • The OEE data collection service operates on a subscribe → queue → evaluate pattern to process real-time manufacturing data.

  • Subscription Phase: The service subscribes to various expression-based data sources (tags, calculations, etc.) for each OEE configuration. These subscriptions monitor critical metrics such as:

    • Machine state (running, downtime, etc.)
    • Production mode
    • Production counts
    • Quality counts
    • Standard rates
    • Downtime reasons
    • Production orders

  • Queue Phase: When any subscribed expression value changes, an ExpressionUpdateEvent is fired. The event handler marks the corresponding OEE state as "dirty" (requiring evaluation), effectively queuing it for processing. This ensures that only states with new data are evaluated, avoiding unnecessary computation.

  • Evaluation Phase: A scheduled task runs periodically (default: every 250ms but modifiable in Tamaki MES Properties) to identify all dirty states. These states are then submitted to a thread pool executor for asynchronous evaluation. During evaluation, the service:

    • Processes state and mode changes
    • Calculates OEE metrics (availability, performance, quality)
    • Creates or updates OEE production records
    • Handles record lifecycle transitions (start/stop records based on state changes)
    • Publishes results to tags for visualization
Last updated on by SholomEllenbogenTamaki