A robot arm that picks products from a carousel at a speed of nearly 1.5 metres per second – yet another milestone in the development of additive manufacturing, also known as 3D printing. With this and other advances TNO is increasing the speed, affordability and flexibility of 3D printing. The researchers are keen to get in touch with companies wishing to use these innovative machines.
One of the ‘classic’ 3D printers is a machine that builds up the product layer by layer from powder, moving it down each time. Thin layers are constantly added to the top (‘recoating’) and heated by a CO2 laser, with the product slowly but surely gaining in shape and strength. This principle works well and is suitable for a variety of raw materials, but it is a batch process using a single material. For the process to be economic the entire volume needs to be filled. It is also time-consuming, as the machine takes hours to heat up, build the product and cool down again. This all results in rather expensive products.
Since 3D printing is a promising application, a European consortium including CCM and TNO has been looking for a faster and cheaper way of producing 3D printed parts. The solution is Hyproline, a hybrid system that prints 3D products rather like a train riding round in circles and is able to finish metal products using a laser. The patented system has an eight-metre long belt with a hundred ‘product pallets’ that pass by various processing stations. This makes the process continuous and speeds it up. Whereas in a batch machine the recoater and the inspection camera sit idle while the laser is working, for example, these and other processes now take place simultaneously, and with a hundred unique variations.
Hyproline can finish titanium and stainless steel using a laser ablation and polishing module (work is in progress on copper). Quality control is carried out by an inline inspection module that creates a point cloud of each product as it passes by, using a fast laser scanner. This is compared with the CAD design to see how far the work has progressed.
The latest addition is a pick & place robot made by Codian Robotics, driven by Beckhoff software. Until that came along the carousel had to be halted when all the products were complete. In the new system the products are built on removable magnetic pallets. As soon as a product is complete the robot arm takes the pallet on which it sits from the carousel at lightning speed (1.3-2 m/s) and work starts on a fresh product straight away. For finishing purposes the machine prints a holder that fits the product precisely. This also enables products to be handled that do not have a flat base but are truly three-dimensional.
Meanwhile the experts are considering how to take the system further, for example with a line where each pallet has its own powder tray. Other ideas under consideration are full-colour printing and incorporating intelligence, e.g. by installing an RFID chip during the process. Thus the combination of 3D printing, pick & place, laser treatment and IT is giving rise to a completely new way of making affordable products economically. If you would like to join in the discussion on the uses of these advances or experiment with a machine to make your own products please get in touch with Frits Feenstra.