The sophisticated mass production techniques that are seen today have many that originated in the automotive industry, and provide the key to delivering complex products at affordable prices. Lean manufacturing has evolved from that foundation to enable higher productivity and greater cost-effectiveness by eliminating waste throughout the supply chain.
The automotive industry continues to drive manufacturing innovation, as customers demand better performance and more features in an affordable package tailored to meet their desires and preferences. Moreover, pressure to deliver new and more exciting choices on a frequent basis demands extremely fast time to market and is shortening the overall product lifecycle.
On-board electronic systems offer solutions for meeting many demands of today’s customers, and are at the heart of important safety features such as tyre pressure monitoring, stability control, brake assist and emergency-call. The latest innovations in connected infotainment and Advanced Driver Assistance Systems (ADAS) including autonomous driving modes continue to increase the value share of electronics in today’s cars.
This is currently about 40% in high-end conventional vehicles, or as much as 75% in electric or hybrid vehicles. Industry analysts see this trend continuing to accelerate. A 2014/15 report by Germany Trade and Invest predicts the global automotive electronics market will exceed $300bn by 2020.
Advancing automotive electronics
These conditions present tremendous opportunities for electronics manufacturers, including Tier-1 equipment providers, high-tech specialists, and Electronic Manufacturing Services (EMS) businesses. Although overall volumes are high and the product mix remains relatively low, Just In Time (JIT) lean manufacturing demands small batch sizes to keep materials flowing through the supply chain and avoid stockholding expenses.
The batch sizes can range from a few units for low volume products up to about 30 or more for higher-volume items. As a result, frequent product changeovers are needed on surface-mount assembly lines to meet the car makers’ short-term build requirements. It is important for electronics assemblers to minimise the time taken to accomplish these changeovers, in order to deliver on time against tight schedules and to maintain productivity. Minimising changeover times calls for careful planning on three levels: strategy, logistics and technology.
Strategy, logistics and technology
At the strategy level, conditions for success are created by organising manufacturing resources so as to minimise the number of changeovers needed to meet overall production targets. Individual business units of a large Tier-1 supplier, for example, tend to be focused on specific types of assemblies, such as instruments and displays.
Moreover, assembly lines within the factory may be dedicated to one or a small number of customers. Going further, each line may be reserved for a small number of product types and assigned only to assembling the top-side or bottom side components. In this way some manufacturers may be able to reduce the number of boards built on any one line to two or three, although there may be several variants in any one family. Ultimately, a given line may be required to assemble boards according to 20 or more programs.
After minimising the number of changeovers required, the next aspect to consider is to ensure those changeovers can be accomplished in the shortest possible time. Efficient logistics on the factory floor have a key role in this, by ensuring that any new items such as the printer mask and replacement feeders required for the following program are readily to hand when required.
Any tools or other consumables needed to complete changeovers are kept conveniently close to the point of use. Moreover, efficient replenishment of empty feeders is vital to ensure continuous operation. A Kanban system, managed by a dedicated logistics operator, is often used to ensure needed components are brought to the line at the right time.
Kanban is just one of the aspects that can be improved upon by using the high level of automation now available to help cut changeover times to the bare minimum and ensure optimum productivity with the least possible operator intervention. Linking machines on the line directly with automated component storage towers allows the machines to alert the storage system automatically when replenishment is needed. The storage system retrieves and presents the required components at exactly the right time to be taken to the machine, with no human intervention required.
In addition, individual machines such as screen printers and mounters can provide special on-board features that help guide operators through the changeover. Some examples include verification of the solder paste, squeegee and stencil fitted on the screen printer, or automatic conveyor-width change and re-positioning of support pins inside the mounter during auto-program changeover.
Making the most of software assistance
From a higher-level perspective, assembly-management software that links all machines in the line helps coordinate and manage product-setup and changeover processes, and also enables electronic manufacturers to monitor equipment status, access diagnostic information, and collect quality and traceability data. The Yamaha Factory Tools SMT Assembly Management software is one example of a line-wide suite of tools that addresses programming, setup, line monitoring and traceability to allow lines to be managed efficiently from a remote desktop.
Data programming tools provide help to accelerate New Product Introduction (NPI) and maximise efficiency. With the growing diversity of automotive electronic systems, and more and more individual variations, the number of different assembly programs used on a line is rising. Manufacturing is moving towards a higher-mix scenario than has been typical in the automotive electronics sector and this is bringing demands for increasingly frequent NPIs.
Automatic product preparation and program editing tools streamline laborious tasks such as data import, reverse-engineering of CAD files and program verification, helping to accelerate programming, eliminate errors and avoid trial runs thereby improving both NPI time and productivity. In addition, optimising and balancing tools operate from line level down to individual machine level, ensuring efficient assignment of feeder positions to minimise component placement times and automatically arrange feeders for optimal efficiency when producing multiple PCB types on the same line.
During setups and changeovers, automatic navigation software such as Yamaha’s Setup Navigation package reduces the time spent verifying the setup and component information such as LED binning, component expiry dates and storage information for moisture-sensitive devices. While the line is operating, monitoring tools give real-time information on line and factory-floor performance, operating status, and the number of parts remaining in each feeder on each machine.
Parts-remaining updates sent to the operator’s mobile indicating when replenishment is needed, helping to maintain continuous operation and avoid stoppages. The data gathered by line monitoring can also be used to drive an external display that can provide at-a-glance statistics, such as the line working ratio, to keep supervisors abreast of each line’s performance.
Taking advantage of the consistent data structures and communication interfaces that are consistent across all Yamaha equipment such as the printer, mounters and inspection stations, the Factory Tools can access all of the information available and allow complete control of the operating modes and integrated features.
If the line contains equipment from a single vendor, the operator may reasonably expect line-management software to be able to interact with all features of all machines in the line. In many factories, although the printer, mounters and optical inspection may come from the same supplier, specialised vendors are often chosen to supply equipment such as conveyors, stackers and the reflow oven.
Yamaha includes support for these types of equipment in the Factory Tools suite, thereby enabling a true single point of control from which production managers can monitor and manage all aspects of the line. The software is able to control board-width settings throughout the line, for example, and can automatically select the appropriate reflow-soldering profile for each new product type upon entering the line.
With this capability, program changeovers can be fully automated on detection of the incoming board identity scanned directly from the board or from a production order sheet. Auto changeover encompasses selection of the correct machine programs, conveyor width adjustment, and repositioning of support pins. Setup verification automatically collects paste and setup data from the printer, and checks the correct feeders needed to supply all the required components have been fitted to the mounters. Consolidating this information in a report that the supervisor can access from a desktop across the network enhances efficiency and allows any problems to be identified and solved quickly.