All effective air-conditioning, refrigeration, or process-cooling systems are based on heat exchange coils to transfer thermal energy between fluids. Although the end users will feel comfortable or control the process, it will be very rare to see the elaborate manufacturing process that converts raw copper, aluminum and steel into precisely-engineered coils. Behind the scenes at Mistcold Sales & Services Pvt. Ltd. is the convergence of technology and stringent quality along with expert craftsmanship to produce coils used in the modern HVAC-R systems.
Facility and Workflow Map
The 50,000 square foot facility of Mistcold in Bawal, Haryana is divided into specific areas: raw material intake, tube bending, fin making, coil assembly, testing and packing. These areas are arranged in a sequence whereby materials pass through on overhead conveyors and carts loaded by forklifts and through the zones with streamlining production flow. Every zone is dedicated to its particular activity, which reduces cross-contamination and provides specialized environmental conditions, i.e., humidity in the fin press to preserve the ductility of aluminum fins.
Raw Material Check and Readiness
The process starts with the receiving inspection of copper tubes, aluminum fin stock and headers or distribution pipes. Quality engineers check tube outside diameter tolerances (7mm, 9.52mm or 12.7mm), wall thickness and straightness with a micrometer and laser gauge. Aluminum fins, bare or sacrificialized with hydrophilic blue are checked in regard to uniformity of thickness and adhesion of the coating. Brass, galvanized iron, stainless steel or aluminum headers and distributors, are subjected to pressure tests to ensure integrity without leakage before fabrication.
Tube Bending and End-Forming
Then, copper tubes proceed to the CNC bending. Computerized controls provide accurate bends to fit the geometry of the coil design, whether plain serpentine or complicated L-shape or U-shape design. Alignment Laser-driven alignment guarantees the radius and angle of each bend to be within CAD requirements at a tolerance of ± 0.5 mm. Bent tubes are then inserted in end forming machines which flare or swage the ends to enable a smooth connection with the headers to provide reliable refrigerant or water flow.
Corrugation and Fin Stamping
At the same time, aluminum fins are stamped and corrugated. NCT (Numerical Control Technology) punching machines mark fins to precise heights, widths and pattern of holes to allow optimum tube insertion. Wave-type or louvered patterns are produced by the use of fins which then go through corrugators to increase the surface area that facilitates heat transfer. Controlled depth and pitch of corrugation is key; Mistcold uses 0.02mm tolerance repeatability to maintain constant airflow resistance and thermal performance through the coil face.
Basic Assembly: Tube-and-Fin Assembly
Bent tubes and stamped fins are married into the heart of the coil in core assembly. Fin press machines are automated machines that insert the tubes through holes in the fins pushing each fin firmly against its neighbors. Force sensors are used to measure ram pressure and stroke depth in order to keep the spacing of the fins constant, usually 4, 6, 8, or 10 fins per inch. It is operated under a skilled operator, making modifications as required due to variation in high-fin-density or heavy-duty coils. This incorporation achieves the maximum amount of contact between tube and fin essential in quick heat exchange.
Header and Distributor Fabrication
In parallel fashion with core assembly, distributors and headers are made. Pre-inspected piping is cut, grooved and soldered/brazed into multi-pass headers that provide balanced distribution of refrigerant or water through tube circuits. Where the user needs condensers or water-cooled systems, brass or stainless steel headers are machined to 1 mm concentricity tolerance to avoid maldistribution and capacity loss. Brazed joints are leak-tested at 1.5 times design pressure, and X-rayed to provide complete assurance of integrity.
Coil Brazing Leak Testing
After assembly, tube-and-fin core is brazed to the header assembly in either controlled atmosphere furnaces or O 2 -acetylene brazing stations, based upon batch size and alloy requirements. Gas-mix and temperature profiling which are automated ensure uniform braze fillets and prevent overheat destruction of copper tubes and aluminum fins. Once brazed, all the coils are subjected to helium leak testing and hydrostatic testing- immersed in water at 1.5 times the working pressure- to detect the tiniest leaks. Coils are then passed to cleaning facilities where remaining flux is eliminated to eliminate corrosion.
Surface Treatments and Coatings
Mistcold provides hydrophilic blue coating on aluminum fins and epoxy/PTFE coating on copper tube or header in severe environments. Pretreatment on coil surfaces also consists of degreasing and phosphatizing processes designed to enhance adhesion of coating. Spray booths use robotic arms to achieve uniform buildup of the film, which is confirmed by thickness gauges. Such coatings do not only increase the life of coils in a corrosive environment but also allow condensate to drain off evaporator coils, lessening blockage and microbial proliferation.
Last Check and Testing of performance
Final inspection stations are then subject to completed coils. The compliance with design prints is checked with the help of dimensional checks, whereas any damage or finish defects are detected with the help of visual inspection. Throughout thermal performance testing can be performed in the in-house thermal test lab at Mistcold, where coils are bench-tested and the airflow and water or refrigerant are under control to validate capacity and pressure drop. The logging of test data is provided to ensure traceability as this will allow Mistcold to continuously optimize the manufacturing parameters and use them in the subsequent batches.
Packaging and Logistics
Coils with high precision have to be carefully packaged so as to avoid harm during transit. Mistcold uses custom crates, foam cushions and shrink wrap to hold coils and essential parts such as distributor fittings and nozzles are boxed. A package has got a QC report and installation instructions. Using the connection of Bawal, Mistcold arranges multimodal logistics, transporting coils of the company to the Carrier chiller plant or HVAC contractor, or a foreign distribution center, at the right time and place.
On-Going Improvement and Innovation
The excellence of Mistcold goes beyond established processes. The company undertakes R&D partnerships with materials suppliers and HVAC end-users to look at new alloys, nanocoatings, and fin geometries. The quality management systems as provided by ISO 9001:2015 spur root-cause analysis of any production challenge, and periodic lean manufacturing projects help to remove waste and shorten lead times. The training of employees and cross-functional abilities are associated with a culture of innovation, which keeps Mistcold on the leading edge of the coil manufacturing technology.
Customer Support and Dynamics
Finally, the experience of Mistcold in the background would be transferred into the market of high-quality coil solutions to customers. Mistcold also fosters lasting relationships through consultation with designers in the early design stages, on-site assistance during installation and proactive after-sales service. Carrier chillers, bus air-conditioning systems, fan coil units and others are driven by their coils, all of which enjoy the advantages of the company: accurate production and insisting quality ethos.
Conclusion
The production of heat exchange coils is a multidisciplinary task, which involves accuracy and precision in engineering, reproducibility, and control of quality. The plant located in Haryana, by Mistcold Sales & Services Pvt. Ltd. is one such example that provides more than 100,000 coils within a month that make up effective cooling and heating systems across the globe. Between inspection of raw materials and the final packaging, each of the processes represents the engineering excellence and innovativeness at Mistcold. Though all that end-users can perceive is cool air or chilled water coming out of their equipment, behind the scenes, the craftsmen and engineers of Mistcold tirelessly utilize copper, aluminum, and steel to create the coils that make the process of cooling and making modern comforts a reality.
Follow Us