The intensity of electronics in the four-wheeler segment is ever increasing, but the humble cable is a component that is used in both manual and electronic systems alike. Suprajit Automotive Ltd (SAL) is a 100 % export-oriented subsidiary of Suprajit Engineering, which specialises in the large-scale manufacturing of cables to customers worldwide. In this report, Auto Tech Review takes a look at SAL’s manufacturing processes, its growth and the future of the cables segment.
The overall design and utilisation of cables has come a long way. They are still used for providing the connection required in simple, yet important basic functions, including opening doors, engaging & disengaging handbrake, opening & shutting bonnet, boot & fuel filler caps, adjusting mirrors & seats and regulating windows. Even though some of these systems have turned electronic in nature, cables are used to perform the mechanical aspect of these mechatronics systems.
Suprajit Automotive Ltd (SAL), a 100 % export-oriented subsidiary of Suprajit Engineering, provides cables for a large number of applications mentioned earlier, with regards to passenger vehicles and trucks. Auto Tech Review visited the company’s export-oriented unit (EOU) in Doddabalapur industrial area near Bengaluru, and met up with Mahesh Hegde, Plant Head, SAL.
The SAL plant was established in 2005 as a joint venture with the cables division of CTP Gills Company of UK and was subsequently acquired by Suprajit Engineering in 2006. CTP Gills’ UK operations of the cables division was also acquired by the company, with the mass manufacturing of cables moving to the SAL plant, and only low-volume, high-tech products manufacturing being carried out in the UK.
SAL began producing cables only for General Motors in an area spanning over 40,000 sq ft. The company added another 54,000 sq ft in 2013-2014 that scaled up its production capacity to 24 mn cables per year, which are exported to 30 countries and 100 plants. Of the total production capacity, a little over half caters to OEMs, with the rest going to component suppliers.
Unlike two-wheeler customers, the time taken to realise a new order for cables from four-wheeler manufacturers, typically takes anywhere between four to five years, said Hegde. Accordingly, the company has set a roadmap, wherein it expects to double its turnover over a four-year period, as a result of gaining new orders from customers for supply of cables. In order to address this growth in demand, the company is also setting up an additional manufacturing space of 120,000 sq ft that is expected to be functional by early 2019. This new manufacturing set-up will add another 35 mn cables to the annual production capacity, taking the total number up to 60 mn cables.
The SAL plant manufactures cables for US and European vehicle models of its customers, along with some parts for domestic models as well. The product portfolio contains cables for the operation of doors, seat adjustment, window regulators, handbrake/ parking brake, fuel filler cap, and release of front bonnet and rear boot. Around 30 % of the raw materials required for manufacturing of cables are imported, since this plant benefits from import duties and a number of raw materials specified by customers are only available internationally. The typical raw materials imported include plastic granules and steel wires.
This plant has an equal number of female and male operators on the shopfloor and makes use of special purpose machines (SPM) that the company co-develops along with machine manufacturers. Although this plant is an EOU, around 12 % of the company’s business comes from the supply of cables to the domestic market, albeit from existing customers that procure components for global markets, noted Hegde. The domestic supply of cables is also increasing with the procurement of business contracts from global manufacturers for their domestic vehicle models, Hegde added.
DEVELOPMENT & TESTING
The SAL manufacturing facility conducts R&D activities in-house, along with its testing laboratory. SAL also carries out co-development activities with the technical teams of Suprajit Engineering situated in the US and UK, said Hegde. Typically, a customer provides SAL with a target price and routing diagram for a cable application and the development team works to return with a few options. The past experiences of the development teams helps them in providing customers with appropriate options for the final design of the cable, he explained. The R&D team identifies the materials and components to be utilised as well as their design, and ultimately fit and function of the cable within the quoted price.
The plant’s testing laboratory carries out testing functions on a regular basis, with the help of test rigs built in-house for customised validation requirements. These rigs carry out endurance and performance tests, in addition to environmental testing that is carried out in a specially-designed chamber. Hegde said that the company plans to increase the level of automation in the area of end-of-line inspection and testing since a sizeable manpower is currently required for this process. In terms of materials being used, Hegde noted that there is a growing trend of cable end-fittings being moved from steel to plastic. A major factor towards this is the high cost involved in utilising steel, in addition to issues of weight and rust. Plastic, on the other hand, ensures reduced weight saving as well as lower cost.
PREPARATION & ASSEMBLY
The manufacturing facility is segregated into the Preparatory Shop and Assembly Shop, with the former providing the child parts and sub-assemblies required for the final assembly. The first process in the preparatory shop is that of wire flattening and automatic winding of the wire, where the spirals of wire for the outer cover is wound, and the inner plastic layer of the outer cover goes on. This outer cover is called conduit, through which the inner cable passes and is the protective layer of the cable. The next step is called outer coating extrusion, where the outer cover is given its plastic coating. The speciality with SAL is that it uses 15-20 types of materials for this process, in order to meet specific environmental regulations and test requirements prescribed by customers, noted Hegde.
This is followed by the inner wire preparation, where the inner cable that is procured from suppliers is unwound from the roll and cut into required lengths. This process is carried out by automated machines to cut and offset the wires. The next step in the preparatory process is that of die-casting, which is where the zinc cable-ends are fixed onto the inner wire. This process, called insert die-casting, offers a good combination of cost-efficiency and strength for the fitting of cable-ends. The final step in the preparatory process is that of over-moulding, where plastic end-fittings are fixed onto the cables, mainly to provide sealing from water and other weather-related intrusions. After this final process, the cables are placed in temporary packaging and moved into final assembly.
The standard hydro-pneumatic machines used for the final assembly are highly-flexible and can accommodate the manufacturing of different cable models with the alteration of tools and fixtures, observed Hegde. He added that the company also has a tool room that develops tools and fixtures required for manufacturing. The various plastic, steel, die-cast end-fittings, rubber, forged and heat-treated components for the final assembly are directly supplied by vendors. The cables go through the final assembly on a conveyor that is fitted with a number of poka-yokes for efficient manufacturing that adheres to high quality standards. The last step in the assembly process is called firewall station, where the completed cables are given a thorough check for visual appearances and defects. The completed cables are put into cardboard packaging that is returnable, thereby enabling cost-savings as well as growing sustainability in terms of packaging material reuse. Hegde said that the company has almost completely moved to this returnable form of packaging.
SAL is expanding the level of automation at its facility for preparatory as well as assembly processes, aimed at integrating two or more operations. With regards to the assembly line, automation is being targeted to club various operations, especially testing and validation. Hegde said there is also a constant push from the management to augment the level of automation in manufacturing. Developed by machine suppliers along with SAL inputs, there is more confidence in handling these machines, he said.
SAL has assessed the market for future threats to cables at large, and found that there are a minimum number of cables that will continue to exist in vehicles, regardless of the increased level of electronics, Hegde said. Every car with four doors will require eight cables, in addition to two cables per window as well as others for boot & bonnet release, seat adjustments, handbrake and so forth. The cable market will definitely grow as long as the overall vehicle market grows. While cables were earlier used only to perform certain actions, they are now required to provide a smooth feel and comfort during operations. This has altered the entire design process for cables, which needs to work along with various electronic systems to offer enhanced comfort to vehicle owners. This brings up the expertise gained by the company over the many years of operation, since almost all cables utilised in vehicles at present are meant to be fitted and forgotten, without the requirement for changing over the lifetime of the vehicle.
Hegde said the company is changing along with the times in terms of customer requirements, for which SAL’s entire team is supporting all its functions in catering to the market demands.
TEXT & PHOTO: Naveen Arul