 Hi everyone, my name is Daniel Lyttholf and I will talk about post-processing in 3D printing production. As a 3D art producer I get in contact with a huge variety of 3D prints. For example, we have on the left side a human-sized SLA print from Alex Hanema. In the middle a huge sneaker on a concrete wall by Isabel Krieg and on the right side it's the infidential space by Christian Kered at the Biennale. It's a huge 3D print that builds a hollow room. All these 3D objects are based on the four crucial steps in the 3D production line. In the first step we create the 3D model by downloading the model, reverse engineering the model through a 3D scan or building the model with the 3D software. In the next step we bring the 3D model to a slicing software and we translate the STL, OBJ or ply file to a tool pass as called the G-code. The third step in the production line is actual 3D printing. We can choose between a various variety of 3D printers as FDM, SLA, SLS or MGF. As the print is finished we go over to the fourth step. It's like the 3D print post-processing where we work with our printed object. Today I will talk about the 3D printing post-processing, the last part in the 3D printing processing line. Especially for bigger parts the whole production is still made by 3D factories because these printers are really expensive and you need a lot of experience to maintenance them. So in the production line only the step for creating the model stay with the artist and the rest will be done in the factory. These 3D factories are mostly producing technical parts and are not used to art pieces and their special treated surfaces. Because of that fact a lot of arrows can happen in the factory and big surprises can arrive in the box. As an example we received like this huge box with the $20,000 project in it. As we opened the box the sculpture looked fine and we were really happy with the result. Here we can see the whole SLA print. It's a girl with a cell phone in her hand made by Alex Honeymon with a wide UV coating on it. After a closer look at the whole sculpture we found some huge step where the legs are glued together and also some missing structure of the pen pattern. Production error like this cost a lot of money and we had to reproduce the whole sculpture again and make sure that all the seams are well treated and we have no showing seams or steps in the sculpture. Post-processing can be really difficult and time consuming. I experienced that during my time at the ETH Zurich at the professor chair of Karin Sander. There we also made models for other professors chair. As an example we can see here on the right side a model for the professor chair of chemistry. This model was really fragile, heavy and we had to hold the model for more than an hour in our hands to put the epoxy for curing the surface. This model is a good example for errors of failure in post-production. After three weeks the professors chair of chemistry found out that we actually missed a part in the printer and it got probably vacuumed away during post-production. Just to give you an example how long post-processing takes this project also at the ETH Zurich copy of a stone we see on the right side the original one is on top and the copied stone is on the bottom of the picture. So from the left picture where the stone came out of the printer to the finished print like the treated with epoxy model it took about 18 hours sometimes also with two person because it was like a heavy print and you have to handle it really carefully because it's just a shell. These are good examples also from the ETH where we printed some parts with another company and both pictures show parts they start fading faster than the part we printed on the same time. So to the left on the left picture the left sculpture is the one that faded faster and on the right picture the one in the middle was done by us and the two on the outside were done by the company and they faded also faster. Because the post-processing process is a crucial step in the whole production line of 3D prints a lot of artists decide to do the post-processing by their own so they don't lose control over their project. So let's have a look at the 3D print post-processing the fourth step of the 3D printing production line. In post-processing we have three different groups of post-processing we have the subtractive post-processing the additive post-processing and the thermal and chemical treatment. Here we have a summary of all the post-processing we can do to a 3D print. In the subtractive area we have sand and polishing, tumbling as a way of sanding, sandblasting, CNC machining and chemical dipping. At the additive side we can fill prime brush coat, spray coat, following dip coat and powder coat apart. At the last one it's thermal and chemical treatment we can do local melting and kneeling and vapor smoothing. Because there are so many 3D print materials on the market we just go through a few of them. It comes handy that we work with the parts that are sent to us so on the left side we start with the T and the connector that's the FDM print, a few deposing modeling and then the V is the SLA print, stereolithography and the F it's an SLS print, selective laser sintering and the I it's a multi-jet fusion print. So going to the post-processing of these four different materials I will do like two groups. The first group is the FDM and the SLA, they're more plastic-y and they also need support for the printing. The second group is the SLS and the MJF print. Both prints are based on powder so they're fit together in a group. As you can see here the FDM and the SLA print they both need support during their printing and the SLS and the MJF they don't need especially support. Sometimes when the print are really small or like fragile you build the support but they're not really needed because the powder. Just to give you a summary of the different printing techniques the FDM is the one that like hot plastic comes out of extruder head and SLA is like a resin bed that different parts get cured by a laser or by light source. The SLS is a powder bed that the laser is fusing like powder together and the MJF is also a powder bed where a light source and some activator are curing powder together. Let's start with the first group the FDM and the SLA group. At first when the print comes out of the printer we have to break away the support structure. On the left side we see the support structure is quite rigid and you have to break away the structure with the plier and other tools. There's also another solution it's a soluble release support. This support can be washed away with warm water so you dip the model in warm water and the support disappears. To get rid of all the leftovers from the support you start sanding the surface of the 3D print. You can do that by a sanding block or sandpaper with a fine grain. You can go from like a little bit bigger grain to a really fine grain. Also what you do in post-processing is gluing the parts together or a cold welding them with the acetone and there you can decide if you do part by part in the sanding and then glue them together or you glue everything together first if it works for your model and the model is not too complex and then you sand the model down. After first sanding you can put the filler on gaps and cracks and also imperfection in the print and sand them again to get a smooth surface. Another way to get a total shiny surface is polishing the 3D print. First you start with the sandpaper again and then you can go over to a polishing machine and to polish the part with polishing paste and the machine. A not so common thing to do is annealing the 3D parts that works only with the FDM. So you heat up the parts and the monocolor structure of the 3D print changes and hardens the part. What happened with the annealing is the part changed its original form so you have to be sure that you don't need the part in the original shape. Another thing that's happened a lot by huge parts for car or industrial parts is following the parts with different color films so you have a really nice smooth surface on the end. If you're done with sanding and putting filler on your part you're able to put primer on your 3D piece and start painting that works with all kinds of color. A really good side to check out is JustPaint.org. They did a lot of tests with different materials. You can see them on the right side with PLA, PTG, PA12, ABS all kind of stuff. So to get a good overview about paint and 3D material you can check out JustPaint.org. Another way to paint your part is dipping. The downside is that you get rid of a lot of details because the paint feels the little details. Now we come over to the second group, the SLS, the MGF group. It's like the powdery group as I call it. The first step is get rid of all the powder on your part so you use a little brush or air to get the powder away. After that you put the part in a tumbler with like special beans in it and or you sandblast the part. Here is another example from a SLS print. We had like here the problem that the 3D factory was printing this little figurine like this barbie and on the back of the barbie was like this this imprint and when we received the puppet there was like no imprint shown anymore. It was just like a little bit there and so it was not usable. So we decided to do in the 3D file a box where we put the print into the box. So actually we just order like a box with the 3D print in it. So that way we could protect like the print from the factory and on the end we got the box to the studio and we opened the box in our studio so we are sure that the imprint was still intact when we received it. Another way to treat your SLS or MGF models is by dyeing. You can see on the left side you can mix colors and you have a huge variety of colors for this process. The common way to treat your model is by spray paint or lacquering. So first you do like the prime coat on your model and then you can treat it with all kind of colors. A special way to treat your model is by metal coating or electroplating that works for SLS and also for FDM and SLA prints. The MGF is not the best to do metal coating and electroplating. So at the end of my talk I want to do a quick summary of these four printing methods that we separate in two groups. On the left side we have the FDM and the SLA print so there we first remove all support structure and clean the surface then we start grinding with fine sandpaper. We can also polish the surface. We do glue the parts together and then start painting or coating the parts. On the right side we have the SLS and the MGF. First we remove all loose powder and start smoothing and cleaning the parts and we sand them and then we glue also the parts together and start with coating the different parts. At the end I want to talk about a really important thing that's a lot got forgotten. It's the packaging. The packaging is for me really important because I experience a lot of them. It's 3D prints during my time working with this topic so make sure that your packaging is all well constructed or well done so you're done to receive or like on the other side of the shipping line they don't receive broken 3D prints. As an example here to the left you can see some sculpture of Alberto Chocometti. They're really small months but even then we milled out the volume of the sculptures out of foam. In this way I want to thank you for listening and happy 3D printing. If you have any questions reach out to me and enjoy the rest of the TechFocus conference. Thank you.