3Dwiser

So, we are halfway through the holidays and the time is approaching when the work process will once again become our everyday routine. Yesterday I used the offer of Mrs. Vykoukalova from Czechimplant for a presentation of 3D printing and scanning by the company 3Dwiser in Prague. It was interesting and informative. Both lecturers, Lukáš Tisoň, an expert in scanning and scanners, and Milan Hora, a specialist in printers, gave us a very good introduction to the issue.

Fig. 1 – Lukáš Tisoň, presentation of 3D scanning on scanners from the SHINING 3D company

Fig. 2 – Handheld scanner and capture 3D data from the hand

That it seems impossible? This example has shown that this is not the case. Scanners can work in IR mode or in laser mode. The first one gives the correct image, but it will have a lower resolution. But scanning is fast and sufficient for many applications. In laser mode, it is necessary to create a network of reference points on the scanned part, from which the scanner then starts. It’s amazing how the scanner can handle it. Not only does it identify individual points with its internal code, but it can also follow up on these points at any time. This is very important if it is a body where we do not scan everything for one scanning cycle. It is then possible to combine multiple images into one, with exact continuity through these control points. Everything is intuitive and perfect. The accuracy of the scanner is up to 20 microns.

Applicability is worse. The data from the scanner does not have its own dimensions and has to be transferred to another software, where it gets what we need for production, inspection or to repair the part. With a bit of skill, we need about 10 minutes for such a complex body as the one in the picture.

When it comes to printers, 3Dwiser specializes in FFM/FDM (Fused Filament Fabrication/Fused Deposition Modeling) plastic printing. The results are almost perfect, although even plastics have their pitfalls. The print head can have multiple nozzles and simultaneously print different types of material. This is an advantage when, for example, we want to differentiate supports and our own product. Then we don’t have to orient ourselves in where what starts and where what ends. But this is a simplified view. 3Dwiser offers an interesting portfolio of printers, but above all it offers full support for them. So, if you buy a printer here, you are sure that they will help you with your problem even in a few years.

Fig.3 – Ultimaker printer with two print nozzles

The second type of printers are printers from Markforged. This is already a matter of printing metal powder with a binder, similar to the MIM technology. But the resource is already prepared in advance in the form of a print string. There is one more string with ceramic material in the printer. This is applied as a separation layer or used for supports. Quite a funny technical solution.

But it is worse in terms of material properties. Although Markeforged offers H13 (1.2343) or D2 (1.2379) or A2 (1.2363) type materials, as usual it does not have an output to the entire process flow. After printing, the part goes into a special water bath, where roughly 50% of the binder is removed. However, the washing time is very long (min. 9 hours), longer than the printing itself (e.g. 3 hours). Next is the sintering furnace, where the remaining binder is removed and the powder is sintered at the same time. The resulting density is around 98-99.7%, shrinkage up to 20%. Sintering time 16h.

After this operation, the part is ready for machining. Here the interpretation ends. A short video from Markforged shows the mechanical properties of a part printed in this way.

But there is no longer any instruction on how to bring the printed part to a state where the mechanical properties will correspond to the moulded material. Especially for the mentioned tool steels, there is no heat treatment prescription or indication of how to get rid of porosity in the material, for example using HIP technology. Of course, there are a number of applications where it can end up like this. But it’s about as if we skipped quenching and tempering on a 1.2379 tool and expected tool life as long as the original forged steel part quenched and tempered a few times. So, at first glance, perfect technology, but after a detailed examination, its limits can be seen, or black space that without further explanation can lead to erroneous conclusions.

Fig. 4,5,6 – Scan of Markforged presentation

The last technology offered are printers from the company Meltio, working with the WP-LMD (Wire-Powder Laser Metal Deposition) method. It is essentially wire welding with material melting in a device with several lasers at once. Entire new parts can be printed on the device, but this method is usually used for renovations or modifications.

Fig. 7 – Different metal parts from printing process

Again, the black hole of information appears here, the correct definition of post-processes. There are many metal materials for printing, you just have to be careful about materials with martensitic transformation, but even the others need to specify what to do with it when I print it.

The overall impression of the 3dwiser presentation is very good, except for the output details that make the metal part usable. In the end, it’s also nice for playing, but it can end up like in Vibrom, where they had to buy HIP for tens of millions of crowns in addition to the MIM technology.

Jiří Stanislav

August 10,  2023