Additive Manufacturing and Biofabrication Platform

"The backbone of the platform is the manipulation of trajectories in space" Jean-Yves Hascoët, Centrale Nantes professor, head of the Additive Manufacturing and Biofabrication Platform and pilot of the Additive Manufacturing component of the Joint Laboratory of Marine Technology.

The platform brings together several manufacturing processes: additive manufacturing, machining, forming, welding, bioprinting.

The students of the Mechanical Engineering Master and the Product Engineering option have access to the platform during their laboratory work. Their practical classes are based on simplified industrial projects.

Bioprinting is a technology which uses 3D printing technologies to print living tissue.

The Centrale Nantes team, under the responsibility of Jean-Yves Hascoët, is working closely with Professor Gilles Blancho, Head of Itun* the Institute of Transplantation-Urology and Nephrology of the University Hospital of Nantes, IHU CESTI and the RMES team.

Their collaboration led to the conclusion that it was necessary to acquire a bioprinter to dispense cells. Several such machines exist around the world, but none were available on the market. Nothing is impossible for determined minds - Centrale Nantes and the Nantes University Hospital teams decided to build the machine themselves. This much anticipated machine was assembled and installed on the Centrale Nantes campus in 2016.

This precision machine is installed in sterile laboratory conditions. It is a three-axis machine with syringes. Engineering and biology meet to determine which needle diameter to use, what pressure to apply, or what degree of viscosity to achieve. After testing, the team master the material and the process. The aim is to investigate the field of grafting and organ transplantation. To avoid patient rejection, the idea is to be able to (re) construct an organ or organ elements from the patient's own stem cells. Next step for the team: vascularize the created matter.

This laser powder additive manufacturing machine can create more precise parts, both in terms of size and surface finish, thereby making it possible to work at the micron scale.
It produces parts for all sectors of activity: aeronautics, space, shipbuilding, automotive, railways, as well as the medical field.

The machine works by placing the metal powders on a plate, a laser then melts the powders that are necessary for the producing the part and those that are not melted are set aside and then recycled and reused.

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Additive manufacturing at Centrale Nantes has progressively turned its attention to the medical field. The team began by printing knee and hip prostheses, and moved on to a number of new projects:
 

• A hand prosthesis with UTC and Hôpital Saint-Antoine in Paris, with the aim of building metal phalanges from titanium powder.
• Surgical guides for training and assisting surgeons
• A project for the repair of large bone defects combining stem cells and personalized implants

New equipment is currently being acquired/installed as part of the State-Region Plan Contract (CPER).

This cell houses a high-capacity robot, which allows a weight of 500 kg to be displaced 3 meters at arm’s length. This exceptional machine is used for the hybrid manufacture of large parts. Hybrid, because it combines several processes: wire-based (aluminum, titanium, steel etc) whereby the wire is melted with an electric arc (WAM) or powder-based (LMD). Two heads deposit the powder, one with a thickness of 2.5 mm, the other of 4 mm. The machine can also be used to finish parts (machining and polishing) whose surface finish may not be satisfactory, which simplifies the process.

This equipment is used to mix powders during manufacturing to create so-called gradient materials. Some powders have mechanical characteristics, while others have tribological (contact science) characteristics. Being able to mix them precisely as the manufacturing process progresses prevents the appearance of a solidification joint on the part, thus facilitating interaction and bonding between the two materials, making the part more resistant.

Design and calculation via applications in the field of:
 

• Mechanics
• Fluid mechanics with particle projection
• Bio-manufacturing with material mixing

The platform has several pieces of control equipment:
 

• A precision laser (to the nearest micron) capable of scanning an existing part to recover the part's "skin" and intended for the inspection of parts made by additive manufacturing.
• A scanning electron microscope (60,000 magnification) to understand the behavior of powders and the structure of manufactured parts.
• A 3D microscope designed to recover the topology of an object's surface.

This prototype machine sets in motion a mass of 150 kg, instead of several tons on other machines, by playing with the five axes of the kinematic chain. It can be used for machining, forming or welding. It is useful for manufacturers wishing to know the effort and power required to machine a part, to test and compare tools, and to assess their service life. It allows you to think about the strategy for manufacturing a part as quickly as possible, while respecting specifications.

Centrale Nantes has developed an "open" numerical control, known as "Open CN", which allows users to determine the algorithmic part themselves and modify the manufacturing process in real time. Industrial customers of this incremental forming platform can choose between different numerical controllers: NUM (French), FIDIA (Italian), Siemens (German) for their projects and/or tests.

Online tour of the platform (in French)