DYNAPIXEL: automated, reconfigurable molds

 

CIKONI (Stuttgart, Germany) is an engineering company that specializes in composites design, simulation, automation and process innovation. CW has reported on a number of the company’s developments, including its use of 3D-printed cores and 3D filament winding to produce lightweight truss structures (see “Filament winding, reinvented”) and its work with preforming, including draping simulations and tension devices to prevent wrinkles and other defects (see “Preforming goes industrial: Part 2”). The latter is actually how DYNAPIXEL originated.

“We do a lot of draping simulations,” says Farbod Nezami, one of CIKONI’s co-founders. “The OEMs have good material data, but we always need a mold to validate the simulation. We wanted a system that would allow us to iterate designs on a daily basis.” The conventional process chain for molds takes weeks: part design, mold design, quotation and purchase process, machining/production of the mold, surface preparation and delivery. “With DYNAPIXEL, we simply use the CAD data to generate the mold surface,” says Nezami. “Now, if we have a draping issue, we change the CAD geometry and have the ability to produce a small prototype in a couple of hours.”

 

Automated system for reconfigurable molds

“There is no manual manipulation,” Nezami explains. “The process starts with the digital data from the part design, which is loaded into the DYNAPIXEL software. The software then generates the control array for actuating the pins and managing the parameters.”

The idea of using actuated pins to provide a reconfigurable mold has been used for decades in metalworking and recently adapted for composites by Adapa adaptive moulds (Aalborg, Denmark), discussed in CW’s 2017 feature on reconfigurable tooling. How is DYNAPIXEL different?

Nezami explains that because Adapa’s main applications are architecture and thermoforming glass, plastic and foam, they are producing bigger geometries and more continuous curves. “Compared to DYNAPIXEL, they use a smaller number of larger-sized actuators. Between these, the surface is interpolated and molded using a silicone sheet on top. Our system can produce sharp corners and more complex geometries. We also use a different estimation method. So, which technology fits depends on the application.”

Nezami points out that DYNAPIXEL also uses a silicone membrane, which can be used as a laminating surface and with molding processes up to 180°C.  For double-diaphragm forming, you would enter the CAD data, let the software actuate the mold geometry, apply vacuum to drawn down the silicone surface on top, laminate the composite plies, close the matched mold with second membrane and complete cure.

“We have a golfball-type surface texture, but using a thicker membrane will alleviate this,” he adds. CIKONI uses three membrane thicknesses: 0.5, 1 and 3 millimeters. “The thickest gives a smoother surface but less detail,” Nezami observes, “while the 0.5-millimeter membrane gives a more accurate realization but a lower-quality surface finish.”

Surface finish has not been a driving issue because DYNAPIXEL was developed as a tool to speed R&D. “Our goal was to produce additional molds and design iterations without much additional cost,” says Nezami. “Once you freeze the part design, you would then switch to CNC-machined metal molds. You can also use this as a preforming tool.”

 

New applications

CIKONI is now developing additional uses for DYNAPIXEL, including flexible automotive jigs for bonding/adhesive joining and production of tailored, individualized helmets and protective apparel/structures. It also has an R&D project for customized orthotics. “We see value for this type of reconfigurable tooling where you need shapes tailored to each patient,” Nezami says. “Connection to the human body must match precisely to avoid irritation and sores. There is a lot of R&D into 3D printing for this type of application, but typically the material costs are high. Using DYNAPIXEL, you can significantly cut molding costs for individualized parts.”

To learn more about DYNAPIXEL, visit CIKONI at JEC World 2020 (Mar 3-5, Paris, France) in Hall 6, N72.