Making a good impression

CERN’s Polymers Laboratory (part of the TE-MSC-MDT Section) was created in the 1960s and is still working on many complex technical challenges today. Thanks to a new 3D prototyping printer, the Laboratory can now produce functional parts for use directly in our accelerators.


This part, made from transparent resin and produced using the new 3D prototyping printer, will be used to hold and electrically insulate a copper RF antenna as shown below. The fine transparent "fence" surrounding the part is a manufacturing support. This is produced at the same time as the part and supports it during printing.

The Polymers Laboratory is undoubtedly one of the most versatile facilities at CERN. Whether you need an electrically insulated part, supports for scintillating crystals, winding separators or fibre optic distributors, resin is probably one of the solutions. Several different resins, based on epoxy, silicone or polyurethane, are available at the Polymers Laboratory, with various characteristics responding to different needs: highly reliable bonding, moulding, electrical insulation, or resistance to cryogenic temperatures or radiation.

And now the Laboratory can call upon the magic of 3D printing, so almost anything is possible. The Laboratory’s recently-acquired 3D prototyping printer allows the team to respond to almost 70% of requests for this type of technology. The printer works through the polymerisation of a liquid resin using a laser (see box). At CERN, three resins are currently available for this type of printing: white, which is very flexible and low-cost; transparent, which is more resistant (see first photo); and blue, a composite resin containing ceramic particles, which is particularly resistant to extreme temperatures and radiation but more expensive (see second photo). Polymerised layer by layer according to a digital 3D model created in advance using dedicated software, the resin is formed into the desired shapes with a precision of up to 0.01 mm (depending on the polymer used and the time taken). “The main advantage of this machine is that it allows us to manufacture functional parts with strict mechanical properties,” says Marco Goncalves Lopes, a materials engineer in the Polymers Laboratory, who is attached to the Portuguese Science and Technology Foundation. “The Laboratory also has another 3D printer, which works by bonding fine layers of polymer powder. This is used to study the shape of certain prototypes, but is not suitable for the production of functional parts.”

This component (in blue) was produced for a winding test and uses the most resistant resin currently available in the Polymers Laboratory.

Although the Polymers Laboratory is not intended for large-scale production, every effort is made to respond to very specific needs. “In some cases, we work on the development of specific techniques with industry or other laboratories," explains Paolo Fessia, who was responsible for the purchase of the new 3D prototyping printer. “Generally we create prototypes in-house, as we did for example for the spacers designed for winding tests carried out in parallel at CERN and Fermilab (see second photo) as part of a partnership for the HL-LHC project. Of course, our core business is the urgent production of parts or the repair of certain machines.” Several CERN Departments (particularly PH, EN and TE) and Groups work with the Polymers Laboratory on a daily basis to resolve increasingly complex challenges.


This prototyping process was developed in the 1980s and relies on the fact that certain resins polymerise, i.e. they transform into solid polymers under the influence of light and heat. The resin used for 3D prototype printing includes a photoinitiator, which initiates the polymerisation process under the influence of light from the laser.


by Anaïs Schaeffer