Continental Automotive Components' (India) manufacturing plant in Bangalore undertakes the production of components for the instrument cluster and electronic control unit (ECU) business units. It is the competency centre for the company's electronics manufacturing for India. We visited this Bangalore facility to better understand the way the foundation for operation of complex electronics is made.
Part of Continental AG, one of the world's top five automotive parts suppliers, Continental Automotive Components (India), has been steadily growing its presence in the Indian market since its entry in 2008. In the company's Bangalore facility, printed circuit boards (PCB) are manufactured and sent to its sister location in Manesar, where it is assembled. The PCBs are manufactured in what is called the front-end of the facility, while the back-end takes care of all the assembly work. PCBs manufactured at the facility cater to all the business units of the company.
The facility undertakes manufacturing components of other business units including Passive Safety and Sensorics (PSS), Engine Systems and Body and Security. The manufacturing area is spread over 3,200 sq m, with a warehouse behind the production facility.
Continental said a core focus area for it is standardisation of its components. One method that the company employs to achieve standardisation is by using the same equipments for the manufacturing process across all its facilities. The equipment to manufacture a certain component across various global manufacturing plants is similar, with the manufacturing line also being the same. This standardisation comes in handy for the transfer of knowledge between plants manufacturing similar components and products.
The facility has three lines, all of which have similar configuration and support the production of leaded, as well as lead-free components. The main advantage of lines with similar configurations is that it leads to high flexibility, while manufacturing. One example of the flexibility in manufacturing would be that when one line is fully loaded, the product can be shifted to a different line without much modification. However, the company said this can only be done after receiving approval from the customer, whose product is being worked on at that particular time.
The Indian automotive industry has small batch sizes, when compared to other countries, mainly due to the many variants available in the market. This, in turn, leads to Continental manufacturing components for Indian customers in relatively small batch sizes, when compared to that being exported.
PCB MANUFACTURING PROCESS
This facility takes up the manufacture of PCBs for a wide variety of operations and draws its computer programme from a common server. Continental manufactures PCBs of various sizes, for which the manufacturing time may range anywhere between two and 65 s, depending on the components on the board. The company uses surface-mount technology (SMT) in the process of manufacturing PCBs and manufactures about 225,000 to 250,000 PCBs per month, depending on the requirement. Currently, all the electronics, as well as the boards themselves are imported, and only certain mechanical components, like connectors, plastics, die-cast components and stamped products are localised.
The first step in the manufacture of PCBs is the application of bar code labels, which ensures the traceability of the component. The second process is a critical step, which consists of the first paste application of the PCB. This process is very similar to that of screen printing, and includes a stencil with holes in it, which brings out a print on the circuit board.
The paste application step is an important one, as it includes two important processes within SMT. The first process is to ensure the exact amount of paste to be applied on the PCB, and the second is to ensure that there is optimal paste volume in the machine. These two processes of SMT are carried out with the help of a 3D optical measuring system that checks the area, distance and volume of the paste.
The next area in the manufacture of PCBs is in the placement of components on the circuit board. Three machines combined together place about 6,000 to 6,500 components per hour, the company noted. The next process takes up the duty of soldering the PCB and the components together, where the paste that was earlier applied is heated to a pre-fixed temperature and then joined. The terminals on the board are soldered onto the surface of the component, thus resulting in this technology being called SMT. All the points are joined and soldered together at an optimal temperature to ensure the correct quality of the joint.
The final process in PCB production is the automatic optical inspection (AOI), which makes sure that the components have been placed correctly and haven't moved away from their required position. This inspection machine also needs to ensure that the polarity of the component is maintained correctly, for the right performance of the product.
ASSEMBLY OF PCBS ONTO AN INSTRUMENT CLUSTER
In the assembly process, the first step includes mounting of the stepper motor, which is required to drive the pointers on the meters. These pointers sport LEDs, which are very bright to the naked eye, necessitating the next step of applying a diffuser onto the LEDs. This second process also includes the assembly of the LCD on to the brackets. Here too, the company said, the LCD is imported, while all the plastics and other mechanical components are completely localised.
Thereon, the dials are mounted on the instrument cluster, followed by basic checks and installation of the pointers on the component. The cluster is then put through stress testing, to reduce chances of any failure during operation, the company observed. The stress testing lasts for about 20 minutes, making sure all the components of the cluster are in good working order.
The penultimate process, and considerably the most important one, is the calibration of the pointers in the instrument cluster. This calibration process has no manual involvement, with only an automated camera giving the necessary commands and then ensuring that settings are made accordingly. The last process includes packaging and final labelling of the product. While the calibration machine for this process was imported from Germany, the company has now built this calibration machine in-house.
PSS ASSEMBLING PROCESS
PSS systems like the ECU for the power steering unit are manufactured at the facility. First, the components are soldered, like in the previous products, and are then passed through an in-line AOI for controlling the quality of the product. This product is then coated with a special material, in a process called conformal coating, which prevents moisture from getting on to the board, following which the product is cured in an oven.
The next process involves the automatic tightening of screws in the product to a prescribed level. The cover of the ECU is then clinched on by using heat through an automated process. The product is first tested at the temperature of the cover clinching, which is about 85° C, and then it is brought down to the ambient temperature for a final test. Once all these processes are complete, an automatic system-generated label is applied to the product, with the complete manufacturing history attached to it digitally.
All products manufactured in the facility are put through testing in order to maintain error-free supply of components. For PCBs, there is a method of testing known as In-Circuit Testing (ICT), which is a board-level testing using a common machine for all products. The only change that is needed for validating different products is in the form of fixtures, which are suited to each product. This machine uses an optic fibre system that is connected to test pins on the board, for testing the components.
The machine also has a system to ensure that all the products are tested, since the boards have to be mounted manually, which may be missed at times. This fool-proof system writes into the microcontroller when a component is tested, which is then checked at the next testing station before carrying out further testing. Failure of a process during testing will throw up an alert at the next testing station, as well as at the back-end of the system, the company said.
The testing rig also has the capability of testing different colours of LED lights. The machine monitors the true colour, wavelength and intensity to identify the colour of an LED light, even if it has been labelled wrongly.
NEW TECHNOLOGIES, PROCESSES
Over a period of time, the company will replace the current method of soldering connectors onto a board with a technology called Single Pin Insertion. In this process, pins are mounted onto the PCB assembly one at a time, which will form the connectors on the board. This method measures the force and the depth of insertion of the pin, making it a better process than soldering, Continental said.
Continental believes in setting-up different manufacturing line layouts for different batch sizes and different products. It uses a process called SIPOC, which stands for supplier, input, process, output and customer, which involves everyone involved with the line and then comes up with a concept for the line. The manufacturing line concept is first developed through carton-box simulations, which acts as a mock run of the layout of the line. The benefits of this process come in the form of space and manpower optimisation, and improved flow of the line.
Another process being followed by the company is known as Design for Manufacturing, where the company works with customers in the designing of components to ensure their efficient production. This is something that is being done successfully off-late only, the company said. Continental also follows a concept wherein a line is stopped, as soon as it reports three failures. The line is restarted only after it is checked and necessary rectifications are made.
FUTURE TRENDS AND PLANS
The company sees technologies like colour-changing LED lights, improvements in LCDs and similar technologies coming into the Indian automotive segment. Although a lot of technologies can be incorporated into products, the company believes that the cost-conscious Indian market may not be ready for them any time soon.
Continental noted that it is focusing heavily on localisation, which in terms of software is already at a high level, but is looking more into localising machinery and production lines. The company believes that localisation will also directly lead to reduction in costs, thereby benefiting customers.
Text: Naveen Arul & Arpit Mahendra