IOT-BASED IMPROVEMENTS IN HOME APPLIANCE MANUFACTURING AT HITACHI GLS
Page content transcription
If your browser does not render page correctly, please read the page content below
FEATURED ARTICLES Smart Life Solutions for People Everywhere IoT-based Improvements in Home Appliance Manufacturing at Hitachi GLS At the same time as the manufacturing industry is experiencing major changes brought about by factors such as the globalization of markets, worsening labor shortages, and reforms to working practices, another global trend within the industry is the consider- able activity taking place in relation to the use of digital tools. This includes a variety of initiatives in Japan based on the concepts of Society 5.0 and the Industrial Value Chain Initiative. With an emphasis on cell production and using its Lifestyle Home Appliances Unit as a model, the Products Division of Hitachi Global Life Solutions, Inc. has been adopting Internet-of-Things systems based on the concepts of enhancing transparency and connectivity while reducing reliance on particular individuals to reform its manufac- turing practices in ways that will enhance total supply chain management. This article describes these improvements. Nobuhiro Ishida Toshiki Ishida sales. This work has been underpinned by the follow- ing three concepts. 1. Introduction (1) Transparency The ability for all staff to determine in real time While retaining an emphasis on cell production, the whether or not production is running smoothly and reforms to manufacturing practices at Hitachi Global to respond promptly when problems arise. Life Solutions, Inc. (Hitachi GLS) have combined (2) Connectivity greater transparency with cell automation and system- The ability to operate production in an optimal wide optimization of the links between individual manner in terms of the overall process, linking objects processes as well as the enhancement of efficiency and processes automatically, and bringing the associ- by getting rid of process steps that do not add any ated data together in information systems. value or by making improvements or eliminating bar- (3) Elimination of reliance on particular individuals riers and bottlenecks. The Monozukuri World No. 1 The automation of tasks that rely on particular indi- Project launched in FY2017 has involved the develop- viduals or that are not best undertaken by people. ment of proprietary production techniques suitable for The aim is to enhance manufacturing capabilities wider use and work on establishing optimal systems by using the Internet of Things (IoT) to put these for high-volume production that facilitate increased concepts into practice. 90.
for the sharing of ideas as well as staff development 2. Progress of Reforms to and the fostering of an improvement-oriented cul- Manufacturing Practices ture through a workplace-led approach. This includes each of the sites presenting improvement activities at 2. 1 regular meetings attended by senior management and Cell Production holding GLS Production Innovation (G.P.I.) working In an environment where product lifecycles are short groups for workplace improvement. and where home appliances are produced in anticipa- tion of future sales, the risks are that a slow response to changing sales trends will result in potential sales 3. Manufacturing IoT being lost when demand spikes or excess inventory building up when sales are lower than expected. The Use of IT in the reform of manufacturing practices aim of cell production is to establish manufactur- has in the past been done in a piecemeal manner, with ing practices that are both efficient and able to deal activities seeking to provide more transparency in the with fluctuations in production volumes, reducing manufacturing workplace, its management, the analy- the quantity of work in progress held between and sis of operations, and so on. However, there is a need within processes and minimizing both lost time when to optimize operations across multiple sites and utilize switching production between different models and IoT technology to enhance the production systems holding costs when work in progress is held up. that monitor and automate all of the steps from the The Lifestyle Home Appliances Unit at Hitachi machining of parts to sub-assembly manufacturing, GLS introduced cell production in earnest in 2003 product assembly, inspection, and dispatch, as well as and has achieved dramatic improvements in pro- the management of the four elements of manufactur- ductivity by adopting the practice for all of its varied ing (4M): men, machines, materials, and methods, product range, which extends from washer/dryers based on orders and production planning. Hitachi to vacuum cleaners, cooking appliances, and light- GLS has consolidated the work being done on this ing. The unit’s 15-plus years of experience with the within the Monozukuri World No. 1 Project under practice has included winning a Nikkei Monozukuri the banner of “manufacturing IoT.” Award in 2008 for a proprietary cell production The aim is to develop systems that will maintain technique for large home appliances such as front- optimal safety, quality, delivery, and cost (SQDC) by loading washer/dryer cells and refrigerator and water automating the preparation and updating of produc- heater cells. tion plans that depend on the expertise of specific members of staff; handling attendance management, 2. 2 which is complicated by the diversity of ways in which Monozukuri World No. 1 Project people are employed in the manufacturing workplace; Hitachi GLS has been running its Monozukuri sharing information for safety, quality, and efficiency World No. 1 Project at all of its sites since FY2017, improvement; and providing real-time information including at overseas operations. The project seeks to on things like equipment operation. Although system improve production efficiency and reduce lead time, development is largely undertaken in-house, systems with the three key concepts listed above playing a such as those for automatically generating produc- central role. Phase two of the project, which com- tion plans are developed jointly with the Center for menced in FY2019, involves the use of automation Technology Innovation – Production Engineering of and the adoption of new systems to improve efficiency Hitachi Research & Development Group. In either so as to achieve the 2021 Mid-term Management case, the systems have been put in place through a Plan. The project is intended to raise the standard bottom-up approach that is able to incorporate the of manufacturing across Hitachi GLS by means of knowledge held in the workplace in a flexible manner, activities that run across all worksites and provide taking account of compatibility with core business Hitachi Review Vol. 69, No. 1 90–91 91.
systems and the ability to be extended to other opera- The solution to these challenges is the automatic tions at the same site. production planning system, which is made up of an The following sections present examples modeled automatic detailed scheduling system that automati- on the workplace where front-loading washer dry- cally generates production plans for finished products ers are manufactured. These front-loading washer and an internal production scheduler that generates dryers are a major product for the Lifestyle Home production plans for parts manufactured in-house. Appliances Unit. The current intention is to extend (1) Automatic detailed scheduling system this work to other products and other sites. This scheduler uses the monthly master production plan as a basis for generating detailed daily plans and 3. 1 hourly plans that look four days ahead. In doing so, Automatic Production Planning System it automatically generates optimal production plans The system is intended to provide the flexibility to that ensure efficient switching between models while keep pace with fluctuations in market demand and also taking into account product delivery schedules the rate of production by automating the prepara- and the management of worker overtime. tion and updating of production plans that previously Work is currently underway on extending its use depended on the expertise of specific members of staff to the planning of refrigerator production at the and to rationalize auxiliary tasks. Refrigeration & Heating Home Appliances Unit A background factor was that, because the Lifestyle (see Figure 1). Home Appliances Unit had a large amount of on-site (2) Internal production scheduler production machinery, a result of producing so many of This scheduler supports the most efficient use of its components itself, there was a heavy workload associ- plant and human resources by synchronizing with ated with the production planning needed to keep work finished product production, determining monthly in progress to a minimum while also ensuring a reliable work assignments, the automatic formulation of parts flow of parts to the assembly line and maintaining a production plans, and the issuing of materials pro- high level of utilization in the operation of this plant. curement orders as well as raising alarms for changes Figure 1 — Automatic Detailed Scheduling System The figure shows an overview of the system and its functions. To automate the process, the different scheduling methods used for different products are defined as parameters. ■ Overview Automated system for ■ Main functions (1) Calendar management and overtime planning Warn if maximum scheduling which models Enter daily overtime exceeded Scheduler ■ March 2018 to produce No. of days when overtime required overtime 03/01 (Thur.) 03/02 (Fri.) hours Confirm and modify 2h: 10 days Cycle time 59 (s) Production 9965 Total (no. units) 3h: 5 days (Simplified) PSI Hourly capacity Planned 9513 453 453 Hourly capacity: 453 overtime 35 2 3 (2) Detailed scheduling Determine which models GUI Color Generate daily production plans Appliance model 08 09 10 11 12 to produce scheme in accordance with given rules XXXXXX N 60 445 355 Values can also be Detailed scheduling OOOOOO S … 240 280 entered manually Schedule of which models Overtime engine AAAAAA N 535 15 to produce required (3) Production volume management/four-day-ahead schedule DB access engine Collect data on and manage Color Appliance model scheme 19 20 21 22 23 24 production volume Manufacturing Copy XXXXXX N 299 1 339 422 instructions … Prepare schedule looking four OOOOOO S 173 2 360 days ahead based on incoming Scheduler* Update Detailed Procurement AAAAAA N 32 694 159 goods for the month schedule DB instructions Detailed master Master Detailed Master (4) Determine which models to produce data 000 Shift In-house production schedule master data Product code Model Total number to be produced Planned production volume 000 production management schedule YYYYYYYY XXXXXX 1800 1800 000 00 BBBBBBBB AAAAAA 1800 1800 Schedule 0 to conveyors for next Overall Schedule Overall schedule for next Product code Model Total number to be produced Planned production volume 000 000 with excess four days schedule YYYYYYYY XXXXXX 1800 0 four days 000 00 capacity BBBBBBBB AAAAAA 1800 0 0 PSI: production sales inventory GUI: graphical user interface DB: database *Existing production scheduler used at Lifestyle Home Appliances Unit 92.
FEATURED ARTICLES Figure 2 — Internal Production Scheduler The figure shows a block diagram of the internal production scheduler and example screens. In addition to work schedules, the system also generates shift rosters. ■ Main functions Block diagram of internal production scheduler Final assembly Problems with past practices schedule (1) Production assignment and • Each line was scheduled Hourly Detailed Management manually Monthly (daily) schedule of inventory planning (monthly) • Large amounts of work in schedule schedule looking four levels days ahead (2) Parts production schedule progress due to poor (daily and hourly) synchronization between (3) Worker shift rosters appliance assembly and parts (3) Molding (5) Molding (6) Parts schedule manufacturing machine schedule machine schedule Statistics (4) Materials procurement orders • Unavailability of parts when (1) Allocated (daily) (hourly) on to production (5) KPIs needed resulting in overtime (N + 2 months) utilization (2) Worker and defect ■ Features • Schedules take account of detailed constraints affecting each line assignment (4) Materials allocation rates • Sequencing of production so as to reduce setup times Internal production scheduler • Shift rosters that take account of restrictions on working hours (overtime, work on public holidays) KPI: key performance indicator to shift plans based on worker shift rosters and pre- 3. 3 dicted overtime hours and changes to inventory levels. Cell Production Management System Work is currently underway on extending its use This system is intended to shorten the time it takes to other sites, including refrigerator production at increasingly diverse new employees to become profi- the Refrigeration & Heating Home Appliances Unit cient and to raise the level of worker training. and injection molding facilities at Hitachi Consumer With the structure of the workforce being such Products (Thailand), Ltd. (HCPT) (see Figure 2). that 70% or more of roles are outsourced, with high turnover and staff coming from an increasingly diverse 3. 2 range of national origins, shortening the time it takes Worker Recognition System new employees to become proficient in cell produc- This system is intended to automate attendance tion tasks that take about 10 minutes per worker, management and worker assignment. It shares infor- without compromising safety, is a major challenge mation with a newly implemented attendance man- when seeking to improve efficiency. agement system to provide better information about This system displays the information that cell work- attendance and uses information on the skill sets of ers need on a monitor installed directly in front of individual workers to automatically generate a staff them, providing a wide variety of instructional infor- reassignment map to deal with any worker absences. mation including images showing how work is to be Through the sharing of data with employment performed, how to avoid mistakes such as forget- management systems, it has also rationalized the aux- ting to attach certain parts, and communication (see iliary tasks of attendance managers, such as collating Figure 3). overtime details and working through the approvals (1) Better information about working hours and team process. efficiency Hitachi Review Vol. 69, No. 1 92–93 93.
Figure 3 — Cell Production Management System The system improves efficiency by interactively linking information on individual cells with the management of all areas of the cell assembly shop. Cell production management system Work guidance Overall production management screen for individual cells Multiskilling Screen for “digital poka-yoke” (mistake prevention) system Parts request screen Bi-directional communication improvement Quality Picking sensor (work instruction lamp) To raise awareness among workers and to help For purposes of quality management and maintain- supervisors provide efficient practical training, the ing efficiency, the system includes functions for using three-worker cells that are a feature of the production picking sensors to raise an alarm if parts are taken in of front-loading washing machines are equipped with the incorrect sequence and for requesting someone displays showing the target and actual work times for to bring more parts. each worker and the difference between actual and tar- get. The system also ensures maximum team efficiency 3. 4 by automatically allocating workers in a way that opti- Monitoring Cell mizes the balance of proficiencies within each team. The production efficiency of an assembly cell for (2) Communication robotic vacuum cleaners was enhanced by putting The cell monitor displays information for work- in place a single-worker cell for a monitoring tech- ers, providing details of the day’s overtime require- nique that combines the processing of images from a ments and asking them whether or not they can commercially available work assistance camera and a work overtime. The system improves the efficiency newly developed system. This was done to satisfy the of work-related communications and keeps track of requirements of a tightly packed design that features the physical condition of workers by having them the same functions as competing models in half the use touch-operated switches mounted in the cells to volume, with a high component count and a compli- respond “Yes” or “No” to these prompts. cated wiring harness (see Figure 4). (3) Use of visual aids for job training (1) Work guidance system Workers are able to view visual representations of Based on signals from the camera, the system safety- and quality-related work instructions, includ- enables work to proceed smoothly without the need ing the ability to backtrack if they want to review this to operate switches, with functions that include indi- information. This has made it possible to shorten the cating which tools to use based on the task being time it takes workers to achieve proficiency. performed and automatically positioning parts where (4) Avoidance of operator error and parts unavailability they are easy to access. 94.
FEATURED ARTICLES Figure 4 — Monitoring Cell The figure shows the functions and layout of the monitoring cell. As the worker carries out a task in accordance with instructions on the monitor (A), the system compares the actual work done (B) with data on how it is meant to be done (C). This prevents problems such as incorrect assembly or parts being left out by indicating whether or not the work has been done correctly (D). Work assistance Work instructions Work progress camera Electric screwdriver (A) (B) System monitor Tools and parts are moved into position as needed as the work progresses (C) (D) Automatic screw dispenser Correct way to assemble Assessment of result (2) Work checking system (3) Work dynamics analysis system The system uses the camera to compare the prog- This automatically collects data on assembly times ress of work against the instructions displayed on the for each work cycle. It enables each step to be ana- monitor, indicating whether or not the work is being lyzed, including the degree of variability in how the done correctly. This helps prevent incorrect assembly work is done. or parts being left out. Figure 5 — Final Inspection IoT System The figure gives an overview of the final inspection IoT system and its main functions. Server A temporary serial number is scanned Server using readers located at each step of the PP base assembly process and used to link data sub-assembly Labeled with a 2D code Final inspection to the product (temporary serial number) after molding of PP base Server 1 3 • Recording of final inspection results 2 and measurements • Recording of manual rework 2D code 4 Cell assembly line Label attached to rear of PP base Linked to serial number : Barcode reader Recording of assembly cell number Acceptance inspection Touch-panel screen • Model and other details read when product arrives at assembly line (to provide information on number of incoming products) • Real-time display of final testing, reworked items, and inspection data • Details of problems are displayed on cell monitor in real time → Rapid response and prevention of recurrence • Automated collection of quality statistics • Serial number linked to barcode (to improve traceability) # Cell 3 Problem detected! Leak check 1 Defect statistics Clip on external drain hose is out of place Rework Re-attach clip Comment IoT: Internet of Things PP: polypropylene 2D: two dimensional Hitachi Review Vol. 69, No. 1 94–95 95.
3. 5 3. 6 Final Inspection IoT System Equipment Status Management System This system has been introduced into the appliance The shop where the exterior parts of front-loading assembly process in a way that treats components washing machines are press-formed is equipped with manufactured internally and labeled with QR codes* a number of presses and robots, and operates as an as key parts. It is intended to make quality manage- unmanned production line. The equipment status ment more transparent, to provide real-time feed- management system acquires timely information about back, and to rationalize auxiliary tasks. Information the equipment setup and any problems that occur. The is recorded for each appliance on whether products intention is to shorten the time taken to restart from pass the post-assembly final inspection as well as a shutdown and to increase equipment utilization and on things like any rework or adjustments that were production volumes. A system for viewing what is hap- made. This information is linked to the serial number pening on the line has been put in place by installing a when acceptance inspection is performed. By doing number of large-screen monitors in the workplace and so, use of the monitors installed in the assembly cells displaying the layout of the line as a whole, and the to display feedback about defects in real time when a presses and robots in each unit (see Figure 6). problem is detected not only enables a quick response when the same defect recurs, but also improves trace- 3. 7 ability and automates the preparation of daily inspec- Production Real-time Monitoring System tion reports and quality statistics (see Figure 5). A production real-time monitoring system (PRMS) * QR code is a registered trademark of Denso Wave Inc. for providing information on all steps along the pro- duction process that is integrated with the systems Figure 6 — Equipment Status Management System Color coding is used to indicate the operating status of each unit. By displaying the die status (whether setup is in progress or complete), time taken for setup, and the state of interlocks for each area so that whether the equipment gate is open or closed can be seen at a glance from anywhere, this signifi- cantly improves the performing of safety checks when restarting equipment. It also makes it easier to deal with problems and determine where delays are happening based on robot control signals such as when robots take hold of a workpiece. PCM press line Center panel Press #2 Exterior 1 2 Robot 3 Press #3 (sides) 4 Press #4 Press #1 Flow of materials 6 Lower panel 5 ■ System block diagram 7 Display Automatic Shutdown or setup Production operation in progress Inspection or short halt Automatic Shutdown or setup Robot operation in progress Automatic Shutdown or setup Press operation in progress Area safety Closed Open gate Functions Area 3 Area 2 Area 1 (1) Show progress of die setup (setup time measurement) Centering mechanism, balance Seamer, Welder, press, flanging (2) Show information on holdups (utilization measurement) scales, screw tightener, robot #3 robot #2 machine, robot #1 (3) Show status of safety features (interlocks, safety gates, etc.) PCM: pre-coated metal 96.
FEATURED ARTICLES Figure 7 — Production Real-time Monitoring System Shows at a glance what is happening in the room and provides a dashboard for centralized management of different systems. PRMS for front-loading washing machines (Production Realtime Monitoring System) 14:36, Tues. 07/16/2019 Room 4B Room 3B 168 days since last accident Equipment Running Standby Halted Equipment Inventory (Jan. 1, 2019) Equipment Forming of Equipment exterior shell Inventory OK Overstocked Understocked Production [1.2] [1.0] volumes No.4 No.5 Flange [ ]: Previous cycle time (min.) Standby: 15 min. or more Halted: 30 min. or more Room 3E Equipment Equipment Scheduled 515 485 [1.2] sub-assembly [1.0] Equipment Inventory Exterior shell stocker 2 Exterior shell stocker 1 Produced 279 203 Equipment Inventory Equipment Inventory Room 5E In progress +34 −28 [1.0] [1.2] Equipment Inventory Utilization (%) 113 87 Forming Drive assembly and testing Drive assembly and testing Prime by first intent (%) 99 97 Equipment Equipment Equipment Equipment Cycle Target [0.7] [1.2] [1.2] [3.2] 1.33 1.41 time (min.) Actual 1.17 1.61 Drum forming Quality Appliance preliminary assembly [equipment] Overall [1.1] No. 4 line (SUS) Unaccepted defects On-site defects Final Appliance final Equipment Packing testing assembly 11 10 9 8 7 6 5 4 3 2 1 [0.8] [−−]  [17.9]  [5.7] [8.4] [10.9] [10.1] [9.6] [12.8] [−−] Production volumes Equipment Equipment Equipment Inventory Staff recognition Lead time Store [1.0] [1.0] [0.9] Production Main aisle status Defective parts Exterior processing (PCM) Equipment Equipment Inventory Appliance preliminary assembly [equipment] Overall [1.3] No. 5 line [1.0] Appliance final Standby or shut down equipment assembly Packing Final testing Equipment 10 9 8 7 6 5 4 3 2 1 Equipment operating times [−−] [10.9] [11.1] [12.2] [−−] [15.2] [9.4] [11.6] [8.2] [8.9] [1.2] Equipment Equipment Other Store [0.4] [1.0] Noticeboard [--][10.9][11.1][12.2][--][15.2][9.4][11.6][8.2][8.9] PRMS: production real-time monitoring system SUS: steel use stainless mentioned avobe was installed to identify bottlenecks The areas that Hitachi GLS plans to work on in the across the entire production process and to provide future are the upgrading of its core business systems by productivity information (prime by first intent and adopting integrated enterprise resource planning (ERP), plant utilization) (see Figure 7). The same philosophy the efficient allocation of design and manufacturing was adopted in the installation of a similar system on resources through the enhancement and integration the refrigerator assembly line at HCPT. The system is of supply chain management (SCM) and engineering used to make improvements aimed at reducing losses chain management (ECM), and the use of digitalization by providing information about what is happening on for better quality traceability. By achieving highly effi- the refrigerator production line. cient workplaces, Hitachi GLS is aiming for the faster and more accurately targeted supply of value-laden products that suit the needs of individual consumers. 4. Conclusions Because the installation of IoT systems makes it pos- Authors sible to collect data from “things,” data can be shared Nobuhiro Ishida MONOZUKURI Management Unit, Products Division, between people, and between people and equipment. Hitachi Global Life Solutions, Inc. Current work and As anyone can make use of this data, it is possible to research: In charge of Monozukuri management promotion for Hitach GLS in Japan and abroad. identify where the problems lie in a workplace, come up with the best possible solutions in an efficient manner, and implement improvement actions quickly. Toshiki Ishida SCM Reform Promotion Center, MONOZUKURI By facilitating human resource management and Management Unit, Products Division, Hitachi Global training at manufacturing workplaces, where diversity Life Solutions, Inc. Current work and research: SCM reform support work. is on the rise, these IoT systems are an important fac- tor in enhancing SQDC. Hitachi Review Vol. 69, No. 1 96–97 97.
You can also read
NEXT SLIDES ... Cancel