“For Indian toolmakers to capture this demand, they must shift their outlook from short-term cost-cutting to long-term investments in premium technologies and competence building,” says Avinash Khare, Industry Consultant, in conversation with Sanjay Chavre, Advisor, TAGMA India.
How are hot stamping dies different from conventional stamping dies? What special materials or coatings are required to handle the process?
Hot stamping dies differ significantly from conventional stamping dies. Since the blanks are heated, the forming forces, speeds, and energy required are much lower, and importantly, there is no spring-back. However, once the part is hot-formed, the shape cannot be corrected or reworked; everything must be achieved in a single die and operation. Cutting, trimming, and piercing cannot be accommodated in the same tool; instead, they are performed through laser cutting.
A major addition in hot stamping dies is the need for heat flow control. Dies are made in self-guided, hydraulically pressurised segments, each containing embedded curved cooling channels parallel to the surface profile. This conformal cooling system can only be achieved with metal additive manufacturing.
In terms of materials, dies require coatings that not only enhance hardness and wear resistance against the extremely hard aluminium nitride surface layer formed on hot-stamped parts, but also improve heat conduction. For parts that require tailored strength in different zones, coatings of varying thermal conductivity may be applied to achieve differential cooling rates.
What are the key technical challenges in hot stamping? What types of skills and training are essential to meet them?
The most critical technical challenge in hot stamping is ensuring tailored rapid cooling of the parts through the dies. This step is vital to achieving the desired strength and microstructure. Overcoming such technical demands requires specialised skills.
On the operations side, the training must focus on integrating manual logistics and post-operations seamlessly with highly automated hot stamping lines. On the maintenance side, expertise in industrial hydraulics, cooling systems, laser cutting, annealing, and robotics is essential. A particularly important emerging capability for India lies in hot forming die design, manufacturing, and simulation, which will be crucial as adoption grows.
Could you outline the manufacturing process of a hot stamping die? What roles do advanced tools like CAD, CAM, and CAE play?
The process begins with design and iterative simulation to confirm the strength requirements in different zones. This is followed by the procurement of bought-out parts, thermocol (expanded polystyrene) blockpattern making, and the casting of die bases. The machining steps include base machining, semi-finishing (2D and 2.5D features), and free-form CNC machining, preferably on 5-axis machines, for both roughing and finishing. The die is then assembled and spotted, as per static checklists, coated, and bedded at the production press. Try-outs are carried out with dynamic checklists, and part inspections cover geometrical accuracy, material strength, and metallurgical phase distribution, followed by PPAP approval and buy-off.
Advanced tools such as CAD, CAM, and CAE are mandatory in each of these steps. Simulations must evaluate not just stress-strain formability, but also heat flow, cooling, fluid dynamics, die and press thermal behaviour, and potential distortions. Predicting strength in various part zones based on metallurgical phase distribution is equally critical.
It should also be noted that while hot stamping could be applied to standard automotive parts, its true advantage is realised only when vehicle components are specifically designed for the process. This makes training car designers in ‘design for hot forming’ equally important.
What concrete opportunities exist in the hot stamping supply chain for India’s tool rooms and die makers? What barriers must be overcome to reduce import dependency?
The opportunities in the hot stamping supply chain for India’s tool rooms and die makersare significant; they depend on how quickly automotive OEMs introduce hot-formed parts into their vehicles. The demand is likely to grow to around 120 hot-forming dies annually within the next few years. Today, many of these dies are imported from China, Korea, and Germany. For Indian toolmakers to capture this demand, they must shift their outlook from short-term cost-cutting to long-term investments in premium technologies and competence building.
The main barriers are both technological and strategic. Domestically, there has been hesitation to invest in advanced simulation, additive manufacturing, and conformal cooling expertise, which are essential capabilities for competing globally. Financial conservatism and skill gaps also limit progress. Once these barriers are addressed, Indian toolmakers will be well-positioned to emerge as an attractive and competitive alternative to imports.
How can MSMEs, which form the backbone of the Indian tooling industry, participate in this evolving ecosystem?
The hot stamping ecosystem consists of multiple elements, including part design, hot forming presses, automation, tool making, die design and simulation, and inspection. MSMEs can choose to participate in several of these areas. In the initial stages, collaborations or joint ventures may be needed to fill capability gaps, especially in advanced die design and simulation.
As MSMEs build competence, localisation of stamping and tool manufacturing can be the initial steps. Eventually, Indian partners have the potential to grow into complete design and engineering centres that not only support domestic demand but also serve as global back-end design hubs.
Are there successful international models of collaboration between OEMs, die makers, and hot stamping line manufacturers that India could replicate?
Globally, strong collaborations between OEMs and hot stamping suppliers have proven successful. For example, Volkswagen and Skoda work closely with Gestamp, a dedicated stamping partner managing hot-formed parts. Specialised die makers like Matrici S. Coop. in Spain and Schuler in Germany produce both dies and hot stamping presses. For hot forming furnaces and automation, Benteler holds a near monopoly, indicating the importance of integrated supplier ecosystems. India could look to such partnerships as models to build cohesive collaboration within its own hot stamping supply chain.
Could you elaborate on the importance of hot stamping in meeting today’s automobile crash safety standards?
Evolving crash safety requirements demand a stronger vehicle structure, while at the same time, stricter emission norms and consumer expectations for fuel efficiency and performance require lighter overall weight. This creates a challenge wherein manufacturers must design components that are both lighter and stronger.
Conventional stamping requires higher press tonnage and significant forming energy when dealing with stronger materials, which is not always practical. Hot stamping overcomes this limitation. In this process, the steel blanks are first heated so the material becomes softer and easier to form. Once shaped, the part is rapidly cooled within the die. This quick cooling transforms the steel’s internal structure, forming martensite in line with the Temperature-Time-Transformation (TTT) curve. The result is a component that combines lightness with very high strength.
Considering India’s growing automotive industry, how many hot stamping lines do you foresee the country requiring in the next 5-10 years?
Let me explain this with a supposition. If each major OEM in India, like Tata Motors, Mahindra and Mahindra, Maruti Suzuki, Hyundai, Honda, or Toyota, plans to launch two new models in a year, each OEM will require at least 10-14 hot-formed parts. This requirement will boost demand. One hot stamping line can typically support around five models, which translates into a requirement of about two new hot stamping lines annually. This would also create a need for nearly 120 new hot forming dies every year.
To offer you a global perspective, while European and Chinese OEMs already use hot forming extensively, Japanese OEMs are conservative and are still exploring alternatives before considering wider adoption.
This interview was published in TAGMA Times.
About the Author
Sanjay Chavre is Advisor to TAGMA India.
A respected technocrat and policy strategist, Mr. Chavre has been a pivotal figure in the evolution of India’s manufacturing and tooling ecosystem. With decades of experience at the intersection of government and industry, he has contributed to the development of forward-looking policies that promote indigenous technology, strengthen domestic capabilities, and uplift MSMEs within the tooling and precision engineering sectors.
Mr. Chavre has held key roles in various government departments. He has been instrumental in formulating and executing initiatives that align with India’s long-term vision for industrial growth and self-reliance. His expertise lies in enabling public-private collaboration, fostering innovation ecosystems, and building frameworks that support sustainable industrial development.
In his current role as Advisor to TAGMA India, he continues to guide efforts aimed at enhancing the global competitiveness of Indian toolmakers. His insights have been vital in positioning the Indian tooling industry as a reliable and technologically advanced partner in the global supply chain.
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