Engineered for a National Laboratory: A Custom Roll-to-Roll Dip-Coating Machine for Los Alamos National Laboratory

Some projects test a manufacturer's catalogue. Others test its engineering. In 2023, Tech Inc. was asked to deliver something that was not on any catalogue page: a Flat Sheet Roller Casting Machine with Dip Coating & Heating Facility, built for a membrane research team at Los Alamos National Laboratory (LANL) in New Mexico, USA.

This is how a Chennai-based team turned a niche research requirement into an approved, tested and delivered instrument in about six months.

The Brief: Continuous, Controlled Coating of a Porous Support

The research team needed a compact roll-to-roll line that could carry a porous support through a polymer coating solution, remove the excess, and dry the coated membrane completely before rewinding it, all at very slow and precisely controlled speeds.

Working from the laboratory's process requirements, Tech Inc. engineered a system with the following stations:

• A machined and fabricated SS304 mounting frame carrying every roller, the coating and heating stations, and the rewind, with levelling adjustment.

• A gear-driven web transport with an adjustable linear speed of 1 to 5 cm per minute (about 0.6 to 3 metres per hour), matching the laboratory's target production rate.

• A feed roller with stiffener rollers and spring tensioning to keep tension constant on porous media about 350 mm wide and about 5 m long.

• A dipping tank where the support is coated, followed by pinch rollers that wipe away excess solution.

• A top-and-bottom heater assembly with two 1 kW aluminium heater plates, temperature sensing and panel-based control. The membrane passes through the gap between the plates without touching them.

• A motorised rewind roller to collect the finished membrane.

• An electrical control panel for the motors, heaters and temperature controller, built for the US 120 V, 60 Hz supply.

Engineering Through Dialogue

What set this project apart was how closely the design was worked out with the research team. Tech Inc. raised clarification questions on the laboratory's process diagram, and the two teams settled each parameter point by point.

Residence time. With a 20 cm down, 20 cm across and 20 cm up path through the tank, the support would stay in the coating solution for 12 to 60 minutes across the speed range. A 30 cm heater zone gave 6 to 30 minutes of drying. The laboratory confirmed these windows, provided the air in the heater gap reached at least 80 °C. Because the membrane never touches the plates, the temperature that matters is the air in the gap, not the plate surface. That point shaped the heater design.

Reducing solution waste. After reviewing Tech Inc.'s detailed 3D dimensional drawing, the laboratory asked whether the dipping tank could hold less polymer solution. Tech Inc. worked out the options. The original rectangular tank held about 25 litres. An inverted triangular tank with a single central roller would hold about 12.7 litres and give a dipping length of about 40 cm, for a contact time of 8 to 40 minutes. The laboratory chose the inverted triangular design.

Material selection. At the laboratory's request, every roller after the dipping stage was specified in polypropylene (PP). The final drawings were revised, then signed and approved by the laboratory in early June 2023.

Improvements Found on the Shop Floor

Tech Inc. tested the machine in its own lab before shipping. Coating trials showed that small amounts of chemical residue could drip onto the plate heater as coating proceeded. The team decided to improve on the approved design rather than ship it as drawn:

• A hinge-and-handle arrangement lets users open and close the plate heater easily for cleaning.

• A perforated sheet hood protects users' hands from the heater.

Neither was in the original drawing; both make daily use and maintenance easier and safer.

Factory Acceptance Across Continents

Tech Inc. sent a full video of the machine's construction and operation, followed by a live online demonstration and inspection on 1 September 2023.

After watching the video, the laboratory decided that no further physical inspection was needed. The Final Factory Acceptance Test Certificate records that the system's construction and operation were explained, that it was tested and inspected and found satisfactory and as per the purchase order, datasheet and approved drawing, and that it ran without defects or leaks. It also records that the spare kit and tool kit were checked. The laboratory signed the acceptance report and a dispatch clearance certificate.

The machine was then shipped to the USA and delivered to the laboratory.

Meeting the Standards of a US Government Contractor

Supplying a US national laboratory involves more than engineering. Tech Inc. completed the laboratory's supplier registration on its e-procurement portal and filled in the required representations and certifications. It also prepared the signed acceptance and dispatch documents needed for an international export.

What This Project Demonstrates

• Custom engineering: a special configuration designed for one research process.

• Collaborative design: each parameter, from residence time to tank shape, was agreed with the end user.

• Improvement beyond the drawing: usability and safety features were added during in-house trials.

• Remote acceptance: video-based factory acceptance testing that a demanding international customer signed off.

Have a Membrane Process That Needs a Custom Machine?

Tech Inc. designs and manufactures membrane research equipment, including casting and coating machines, test cells and test skids, porometers and SDI analysers, for universities, national laboratories and industry around the world.

If your research needs equipment that is not in a standard catalogue, talk to our engineering team. Visit techincresearch.com or write to mail@techincresearch.com to start the conversation.