Case Study

IMPROVE 4.0 in household appliance

 

– Case study description

The household appliance sector is where Next has undoubtedly accumulated the most experience: Whirlpool, Franke, Faber, Ariston Thermo, Elica, Haier, Electrolux are the partners with whom we have thoroughly analyzed all the needs and possibilities of the industry.

It involves a type of production that is very fast, with relatively short cycle times and many specific phases.

The activities we are involved in this sector mainly include:

  • Monitoring of production efficiency

  • Quality control

  • Raw material procurement and logistics

  • Product and process traceability

  • Maintenance management

  • Label printing (energy label, product fiche)

  • Factory 4.0 projects

Houseold appliance

Summary of the process

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Monitoring efficiency (OEE & Andon)

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Control of quality

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Traceability system

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Maintenance management (Machine ledger and EWO Modules)

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Digital Shopfloor Management

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Warranty, product fiche, and energy label printing

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NFC System

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Visual SOP

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Warehouse Management System

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Safety

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Early Equipment Management

Efficiency monitoring (OEE & Andon)

IMPROVE 4.0 is capable of directly acquiring data from the field regarding downtime, rejects, and production flow speed. These three Key Performance Indicators (KPIs), combined per product, provide a percentage value known as Overall Equipment Effectiveness (OEE).

This data is acquired through PLCs, sensors, and direct input from operators via HMI devices. Real-time data on production efficiency is available thanks to the Andon system. Andon boards present on each line provide the following information for the benefit of everyone:

  • Takt time
  • Expected pieces, produced pieces, first-pass yield pieces
  • Remaining pieces for the batch
  • Number of rejects
  • Processing time, expected downtime, unexpected downtime
  • Current OEE value

Real-time aggregated data for all lines is also available in dedicated interfaces for managerial roles.

Dati aggregati

Aggregated data

 

The efficiency data is collected and made available over daily, weekly, monthly, or yearly timeframes.

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Monitoraggio efficienza OEE

Efficiency monitoring (OEE)

 

This interface also displays the causes of downtime and rejects, which are collected from PLCs or directly from operators via HMI devices.

 

 

Controllo qualità

Quality control in the appliance sector can be performed at different levels. The first level we have seen is when we talked about OEE, where we already detect quality problems and their causes.

All quality issues are analyzed using Pareto charts and further cause stratifications to obtain clear data on the major reasons behind defects and rework.

 

Pareto non conformità

Pareto of non-conformities

 

OEE stratification

 

 

VIBRATING TESTING

Another type of quality control applicable to appliances is vibration testing. IMPROVE 4.0, through the “Vibco module“, performs quality control based on vibration and noise analysis. Vibco improves the quality of your products by isolating and removing acoustic issues.

The main properties of the Vibco system are:

  • Fault characterization
  • Signal acquisition and Fourier analysis
  • Evaluation of sound intensity and sound level
  • Acoustic analysis in octave bands

This testing is integrated into the “Traceability Testing System,” associating the complete testing data (electrical/vibration) with the product’s serial numbers.

Vibration testing operations are performed automatically.

During the production changeover, the operator enters the new work order (WO) through the available touch PC, and this data is transferred to the vibration testing unit. The vibration testing unit then loads the product model’s characterization. A vibration analysis PC reads the system’s status from the PLC, detecting the startup of the testing process and the variation of speeds at which the electrical testing is performed. For each speed, the system acquires and analyzes data from the accelerometer sensor. The analysis results are communicated back to the PLC.

The vibration testing data is transferred to the traceability server. The traceability server stores this data in memory, awaiting the overall testing data that will be sent from the testing machine at the end of the testing process. When the traceability system has the complete picture, it archives all the data, associating them with the product’s serial number.

 

A.I.O.C.A.P. System: AI support

Next has implemented a system that utilizes machine learning and Bayesian networks to build a knowledge base. The project is called A.I.O.C.A.P. and is an artificial intelligence system to support decision-making in quality and process problem resolution.

The logic of this system involves making decisions by combining utility and probability concepts. The objectives are:

  • Support the operator in real-time in resolving quality problems encountered during production.
  • Enable knowledge transfer from human resources to the machine. This facilitates knowledge transfer from experienced operators to less experienced ones, improving the performance of each individual operator.

 

In-depth page: A.I.O.C.A.P.: Automatic Intelligent Out of Control Action Proposal

Traceability System

Product traceability

The traceability system comprises various hardware and software features that allow obtaining and managing the flow of individual products, from order creation to their packaging on the pallet.

The basic idea is to track every batch generated within the system.

Each batch’s progress through different production stages (testing, packaging, etc.) is stored in a database, and the management of this traceability is integrated with the client’s management system (e.g., SAP).

Each production line may include:

  • A testing station (where a control unit performs electrical tests on the product).
  • A conveyor belt zone.
  • A palletization zone where the pallet is finalized.
  • Label printers: one for the product’s characteristics, meaning the label for each individual batch, and another one for packaging (pallet) labels.
  • A PLC in the final part, just before loading onto the pallet, connected to a presence sensor (photocell), which communicates the product’s transition to the pallet to the system.

 

The lines can be of three types:

  • Manual
  • Semi-automatic
  • Automatic

 

 

 

Testing traceability

The system keeps track of the tests conducted on each individual electrical appliance produced, allowing retrieval of the measured values during testing at any time. This is achieved by associating a unique numerical code with each positively tested and produced unit, which is clearly written on the product’s characteristic label.

The uniqueness of the code must be guaranteed for every single product in every facility involved in the project.

A dedicated desktop interface allows viewing a data grid for queries, aimed at locating the tests carried out using the unique code.

The grid contains the following information:

  • Production date and time
  • Facility and Line
  • Test data
  • Production order
  • Bill of materials code.

Maintenance Management (Machine Ledger and EWO Modules)

Based on the World Class Manufacturing methodology, the Machine Ledger 4.0 tool has been developed to manage all types of maintenance in a unified environment, including reactive, preventive, autonomous, and professional maintenance. Next transformed the WCM tool (a complex Excel file) into a web-based tool suitable for all types of environments, not exclusive to WCM.

A shared platform called machineledger.it was created for machine suppliers and end users. The suppliers can upload the machine ledger and Bill of Materials (BOM) for customers through this platform.

 

Machine Ledger

Machine Ledger

 

The Machine Ledger is a calendar that gathers all types of maintenance, including planned and unplanned interventions. It interacts with the calendars of individual operators and maintenance personnel responsible for specific interventions. The system tracks scheduled events, postponed events, and completed events.

With this solution, the maintenance can be managed at higher levels, eliminating waste. It transitions from Time-Based Maintenance (TBM), where components are replaced at fixed intervals, to Hit-Based Maintenance (HBM), where component replacement is based on actual usage. Further refinement is achieved through Conditional Based Maintenance (CBM), where the end of component life is determined by a combination of one or more variables monitored through Statistical Process Control (SPC) techniques.

 

Conditional Based Maintenance

Conditional Based Maintenance

 

All information collected through the Machine Ledger allows important Key Performance Indicators (KPIs) to be acquired, such as Mean Time to Repair (MTTR) and Mean Time Before Failure (MTBF).

It also provides insights into the costs of reactive and preventive maintenance and tracks the trend of values over time.

 

Costo manutenzione preventiva

Preventive maintenance cost

 

Costi manutenzione reattiva

Reactive maintenance cost

Digital Shopfloor Management

The Digital Shopfloor Management is a solution developed in collaboration with one of our partners in the industry. Shopfloor management is a well-known tool in lean management, used for controlling the factory and the entire production process.

It provides a comprehensive view of all activities within the plant.

The Digital Shopfloor Management focuses on observing five thematic areas:

  • Safety: Aims to drastically reduce incidents and create a hazard-free working environment. Tools such as Action plans and Job Safety Observation Action (reporting incidents, near misses, or potentially hazardous situations using a smartphone) are employed.
  • Quality: Traces the causes of quality problems through integration with OEE (Overall Equipment Effectiveness). Provides evidence through Pareto charts and allows setting thresholds for acceptable scrap rates. Action plans are used to address quality issues.
  • Delivery: Focuses on service level and customer delivery times. Monitors productivity by tracking on-time and delayed deliveries. Thresholds for desired productivity can be set, and Pareto charts can be generated to identify causes of productivity issues.
  • Cost: Aims to identify hidden waste by analyzing production efficiency, non-production times due to machine downtime or changeover for new production orders, and delivery times from production lines to the warehouse. Here, the real productivity of the facility and department is verified. This area can also integrate with an OEE system if present.
  • Maintenance: Aims to minimize unexpected machine downtime by monitoring major causes and providing the ability, similarly to the Safety area, to report maintenance problems or potential issues via a mobile device.

 

Each area provides a concise visual representation of key performance indicators (KPIs) for decision-making, action planning, team formation, and tracking results over time. These areas can be considered at the plant, department, and individual production line levels.

Each area can define action plans, which are similar but tailored to their specific theme. Each action plan has a duration and a deadline for resolving the problem.

 

In-depth page: Digital Shopfloor Management

 

Warranty, Product Fiche, and Energy Label Printing

The system’s objective is to print characteristic labels, product fiche, and packaging in line. The label printing must comply with the following constraints:

  1. Serial code correspondence between the characteristic label and the packaging.
  2. Association of serial numbers with products having characteristic labels.

 

The operational flow is as follows:

  1. Before testing, the in-line operator reads the serial code of the labels (warranty, service) using a barcode reader.
  2. The system stores the serial and associates it with the first successful test, generating the characteristic label and packaging

 

The system can handle cases where no additional labels are required, as well as cases where both a service label and a warranty label need to be printed.

 

The printing of packaging labels is triggered when the product passes in front of a dedicated photocell. When the photocell is active, the system generates the packaging label. The information for the packaging label is retrieved from the memory of the line unit. As a result, the serial codes are associated with the product’s serial number and retrieved for printing.

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NFC system

NFC (Near-Field Communication) technology allows two electronic devices to establish communication when they are in close proximity to each other.

In our case study, communication occurs between an antenna and an NFC device located inside the electronic board of the product (for example, located in the casing of a water heater).

What information will the antenna transmit? The necessary information will be extracted based on the product code. Once the article code is known (through a barcode reader), the IMPROVE system is capable of selecting the correct information to transfer to the NFC device. This can be implemented in both manual and automatic assembly lines.

The hardware involved in the NFC system includes:

  • Barcode reader
  • NFC antenna
  • NFC reader
  • NUC control unit
  • The product is equipped with an electronic board

 

The workflow can be divided into three stages:

  • Barcode reading: This code, which identifies the product type, is crucial for reading a series of values that will be written on the electronic board of the product (NFC device). We import this information from the SAP database.
  • Information writing: Using the code, the system reads the dataset and writes it through the NFC reader, which physically drives an antenna.
  • Verification: Reading the NFC device and comparing it with the previously written data. It reads the information contained in the electronic board and compares it with the previously written information.

 

Visual SOP

The Visual SOP aims to support the operator on the line by replacing paper guides and manuals with a digital system. It involves a touch screen through which various multimedia information can be conveyed. The list of contents can be easily configured by an administrator.

The main purpose of this solution is to facilitate information transfer, improve transparency and compliance in activities, and facilitate automation.

The contents conveyed through the Visual SOP are organized into “playlists.” Each playlist is characterized by its position, category, and topics. Through playlists, the contents are structured and ordered according to a precise and functional sequence.

The contents can be in various formats:

  • PDF
  • Video
  • Images
  • URL

 

It is the flexibility of this solution, particularly due to the last type of content mentioned, that allows operators to use the Visual SOP terminal to display, for example, the Andon system interface or select the production order.

Visual SOP

Visual SOP

 

Gestione magazzino

Warehouse management is carried out through the Warehouse Management System. The workflow can be represented as follows:

Flusso WMS

WMS flow

 

In the initial interface, it will be possible to view and manage the list of planned warehouse shipments.

Based on the pallet’s content, the system indicates the optimal location in the warehouse to deposit the goods.

The availability of all required items and quantities for shipment preparation is then checked in the warehouse. In this phase, the system provides recommendations for each involved item, such as the number of pallets to take and from which warehouse locations based on certain criteria. Additionally, the system can communicate with the electronic Kanban system for the arrival of articles and requested quantities from the warehouse.

 

Kanban elettronico

Digital Kanban

 

Similar to inbound processes, the list of prepared shipments will be available and manageable for outbound processes.

The inventory contains the list of all pallets present in the warehouse, with information regarding their content (item), status, and exact location (location).

Safety

Personnel safety is a strategic activity that companies must take seriously. It is a cross-functional activity that concerns all sectors. We have already seen that the “Safety” area is one of the five areas of Digital Shopfloor Management, but it can also be managed as a stand-alone mode.

Everything revolves around the “Safety report” a report through which an event that caused or could have caused harm can be recorded.

The types of events that can be recorded are as follows:

  • Lost time accident: an incident without personal injury but causing a loss of time
  • Near miss: a situation that could potentially cause harm
  • Accident with medical assistance less than 7 hours: a minor incident
  • First aid small accident: an incident requiring first aid intervention

In the reporting module, the following seven steps are gradually completed:

  1. Describing what happened
  2. Indicating containment actions
  3. Defining root causes (root cause analysis)
  4. Specifying preventive actions
  5. Verifying the execution of the aforementioned actions
  6. Indicating the time lost (in days)
  7. Closing the report (by the Safety Manager)

It is also possible to attach images, documents, reports, etc., to the report.

All this information will be consolidated in the Green Cross chart, as seen in the following image.

 

Green cross report

Green cross report

 

Another important tool is the 6S Audit.

In these audits, it will be necessary to evaluate, using a score ranging from 1 to 5 (where 1 represents a low score, and 5 represents excellence), six themes known as the famous 6S:

  1. Sort
  2. Set in order
  3. Shine
  4. Standardize
  5. Sustain
  6. Safety

Lastly, the Observation Report is another tool supporting personnel safety improvement. It is an app through which potentially dangerous situations can be reported or, conversely, virtuous behaviors can be highlighted

Early Equipment Management

The Early Equipment Management (EEM) enables continuous monitoring of the design process.

The created projects are constantly monitored by a project team certified with specific skills.

The project is validated by successfully completing MPInfo and Checklist evaluations.

Each project includes seven steps:

  1. Planning
  2. Basic design
  3. Detailed design
  4. Manufacturing
  5. Installation
  6. Trial production
  7. Start-up

 

Each step involves completing a checklist of questions.

The project team is responsible for:

  • Responding to checklists
  • Reporting defects
  • Resolving defects
  • Approving the steps

 

MPInfo:

  • Defines a problem and its corresponding solution
  • Documented and accessible to all
  • Helps prevent maintenance problems

 

Checklists:

  • Consist of a set of checkpoints to be answered to complete each project step
  • Proposed checkpoints are sent for approval to designated users with appropriate skills (approvers)

 

The reports, strictly visual, allow an immediate perception of how many checklists and MPInfo have reached the “checked” status.

The data can be filtered by date, plant, processes, etc…

 

Early Equipment Management

Early Equipment Management

 

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