0:15 Hi, welcome to our presentation about computational design personalized. My name is Pasman. I’m a researcher at elect industrial design from University of Sling University of Applied Science and this is my colleague Em and we are research sorry we are research group initial design of the university for applied sciences that means we don’t focus mainly on academic research we but we are more more focused on research together with smaller companies or private entities such as hospitals which this project we have two research lines focused on design of care and designing sustainability.

0:59 And a lot of time we do the research is we not do a lot of develop technology ourselves but we try to bring technology towards the industry. One examples is that we have done a lot of research towards personalized medical product development. Think about Lex tube to bypass the air. We make that as you can see in writing we make that personalized accessory for people who have women who have a prolapse or an orthopedic for in the o completely different research but also kind of similar.

1:35 You also have quite some experience with more light printing and printing with different materials. Think about concrete and now doing research towards new polom printing. We have done wood printing with recycled wood fibers and we’ve now done several projects for silicon printing to see how what are the right applications how can we bring them into the technology and how can we design with it and this project is one for example of silicon building yeah previous to the seat study there was a survey done yeah of 1400 respondents by our corresponding hospital and 25% of This patient who experienced yeah trouble with their seat belt mask.

2:19 It did not work due to ill-fitting masks and those ill-fitting masks they lead to air leakage, irritated eyes, irritated skin etc. Or in worst case it’s not working. So that’s why actually this study came to life. What is sleep apnoa? So CBP is used for sleep apnnea. Sleep apnnea is a very common sleeping disorder. During night breathing stops from time to time due to collapse of the airway and by yeah pushing air into the airway due to the CPAP mask this can be treated.

2:58 Yeah there are multiple different CPAP masks on the market right now but we are focusing on the full face mask. So covering the nose and the mouth the most because it’s yeah the most yeah the mask that gives the most problems with the fit. So yeah it’s a real common disease or disorder. 30% of the Dutch population has sleep a worldwide this is around 1 billion people.

3:26 Our goal is to develop a simple cost effective solution using in-house resources like 3D software 3D scanners and we all use this to rapidly generate personalized masks with MST hospital right over there. We aim to do clinical trials later on this year and so then we can already test if our mask is going to work or not. Yeah so all of our masks are use the starting point of a reset mask.

3:58 I have it here. So these are commercial masks and we use them as our starting point and from there on we have developed an in between cushion. So you use it in between the commercial mask and your face and this ensures a better fit to the patient’s face. If this doesn’t work then we also have a fully personalized mask. So how did we get there? Well the entire process is looking like this.

4:30 So first we start off with scanning in the face collect pressure point data and then we use this data together to model the mask. And it can work for the in between mask but also for the fully personalized mask. Then of course we need to manufacture it and then final step is assembling the yeah the masks. First of all scanning scanning usually the MST hospital or in other previous studies they use the ve scanner.

5:01 The vector scanner is basically yeah you make basically a picture of your face and then you have your scan. The cool thing about it is that you have landmarks on your face. The downside is that you scan standing upright. People don’t sleep standing upright. They sleep laying down. So this was already something that yeah that we noticed. Okay, we were wondering is this going to make a change in the fitting of the mask?

5:25 Because if you’re going to do it standing upright, you have a fit for standing. So we did a test. We also scanned in ourselves while laying down down. And yeah, we looked at where the volume changes were going to be. So, as you can see right here, there is more volume around the cheeks and less volume around the mouth. And yeah, it goes up to a difference of 7 mm up to 4 mm approximately.

5:49 And because this difference is quite big, we decided to continue with scanning in horizontally. And Anna will tell you how those data came together. Yeah, I will take you a little bit more in the modeling part of this process. So first we had a student and he just scanned his face and made a perfect fit mask which is quite feasible to do in Rhino. But the disadvantage is if you have a perfect fit mask and you sleep forget on your side on different sides and your cheeks are more soft than your nose, you will still get leakage.

6:27 So you don’t actually want a perfect mask because also in the conventional mask they have little bit more space in the nose so that it takes account a little bit also move around. So we actually want to have a mask that is more indented in the cheeks and less in the nose at the heart areas so that when you move around it will be still nicely sitted in the face.

6:48 So the challenge was okay how will we do that with a nice design. So we implemented pressure sensors. So we made an extra yeah kind of mold with 10 thin film pressure sensors that we applied between the current masks and the face to measure the pressure data on different places on the face. And then we can use that in actually perform the mask. So at the cheeks it will be more in creat more effect than the note it will be more stable position.

7:24 So in the end the full as any said we have two designs one of them is only an in between cushion and one of them is a fully personalized mask. The fully personalized mask you will see here it consists of a pedi frame which is hard on the huge if you have a large skill can also be mass produced as a fixed product and we have actually soft cushion that has interacted that interacts with your face.

7:48 So how did we model it? So we have some anatomical data and we actually first generate the main curve on the face then you we generate the inner edge the of the mask on the inside. So actually this act which inside your face then we input the pressure data and actually transform these inner and outer edges based on the data and of someone has really stall cheeks.

8:23 We will generate a lot. This was a little challenge because and we were going to go printing. So you want to have a most even wall thickness in the XY plane. Some bits on turn around. And then we have a really nice the soft part of the product. In this case we still generate the the frame. So we could also because we have anatomical markers we could design it in a way that air flows come really nicely from the inside directly into the nose.

8:56 And then we have a nice assembly of a personalized mask. So what you see here is actually the head of the screw in the rest head mask and then we combine the frame and the silicon bar which is now just flicked into each other. Yes and the second design we developed is the init cushion. This is also a little bit because of the business case that we work with later like it might be cheap to just produce an in between cushion and that will be have a higher chance of adoption.

9:27 So what we did is we first had to in the patterning of course you have to replace the scanner make it u in nice shape that you can work with it and then we have to align the mask with the face we use some anatomical marks for it. So like the nose bridge nose with top of the nose and the mouth points. And then we got this this is going to come back.

9:51 This green one’s actually the projected curve on the face that we use as a that we use in next steps and these curves are the interface with the mask. So if you’re really confused later that are the curves that are coming back. So we thought our colleague let’s just give us a nice cross-section we can make anything. So he gave us a really difficult one. So that was a little bit of mistake.

10:15 H so we have this wave shape. So to ensure that it even has a little bit more damping. In your face. So we imported it and so here you have these red lines are the curves from the mask. These are your curves from your face. We have the fle on 10 points from the pressure sensors. We projected the cross-section all these 10 points and transform them to the shape of the mask actually.

10:42 And then we transform them again based on effect of the distance between the mask and face and pressure center data. And then we have this. So we have different cross-sections. We made it a little bit nicer. So for for casting or printing, you won’t have to small t angles and such. We love it really nice. And then we have a nice in between cushion which we added some flaps for the connection so that it will stay in place.

11:18 Yeah. And then we’re going to manufacture it. We tried several things with this. Well, we will explain. Yeah, like Anna already showed the sharp corners were already rounded off and that was yeah a key point for manufacturing. Because we have been looking at two different manufacturing methods. So first up is the link driver silicon printing but we also looked at cocoon molding actual molding with formats. I already spoiler it.

11:41 We decided to continue with koku molding because yeah even though direct silicon printing gives a lot of yeah okay gives a lot of advantages because you don’t need a mold. You can directly print your silicone. So the development process goes way quicker than first printing mold and yeah etc. But it gave some issues. So the level of quality was not as what we hoped for. This is mainly due to the many start and ends that you have with printing.

12:13 So you have a viscous material and every time you stop you drag a piece of material with with it. I think you can see it. Yeah. I’ll pass it around. You can see it at the nose bridge. You drag a piece of material. So the gray bar is support material and yeah if you don’t support your silicones it collapses so you need to support it. And here you see the dark blue lines and the green lines and the light blue lines.

12:43 So the dark blue lines are the outer walls. The green lines are filling lines. So they’re not equal. So you have different lines. And this gave a lot of problems. So what we did and I already showed it. We decided or we tried to make everything even. So even wall thicknesses and in that way you could you kind of want to avoid the light blue lines because every time you go from the green light to the light blue light you have to stop it and you have to restart it again and that gives the start and stop points.

13:16 And so lesser quality of your print. Another thing is the more support you use, the lower the service quality is going to be on the side. So, you also want to limit your support use. Do we have another slide of this? Yeah. Yeah. Oh, sorry. All right. So, even with the same wall thickness everywhere, we would still get at some random places the light blue lines. And it’s something yeah that was really troubling us.

13:57 So because of the yeah the service quality and because of requirements because it’s a medical product in the end or it’s going to be a medical product we decided to continue with conc. In between we did get some really nice prints, but it was really, especially if you have different product, it was a little bit a challenge to really optimize each yeah, each slicer, each print preparation.

14:21 So, that would need more work. Yeah. Yeah. And yeah, the nice thing about molding is that you Yeah. You have So, what is cocoon molding? Coco molding is basically you print a thin W mold in one go. So you have injection points and air points and you don’t have any parting lines. The downside is is that you break away your mold in the end. So you have waste to get a really nice smooth surface and you can create really complex geometries without having the need to make really complex molds because you print it in one go.

14:53 And since we yeah for making personalized medical masks, you don’t need the mold another time. So we can throw it away. Yeah and it’s commonly used in the hearing protection industry. So but we needed an extra script for this because we needed a mold. I will walk you through it. So with some spaghetti so of course first we imported our model but already with some points. So with some recognition points and we use those points to project it on the mesh and those points are later on used to create the channels.

15:33 So you refit the points on the mesh so they have a good connection to the mesh. Then next up is creating the cavity of where the silicone is going to be poured in. It’s a basic function. It’s a mesh offset and that’s how you get this. So it’s 0.6 mm. Yeah, so you can see where the silicon is going to be in. So next up, you need holes in that mesh offset.

15:59 So we use the channels again to cut away this material. So here we generate the channels and then we create walls around it and cut it away and you’re done with your mold. So it’s actually pretty easy to make something like this. Yeah, like I already said, we printed it with Formlabs printers. So prototyping went with clear resin, but later on we we’ll be doing it with biomat clear because it’s bio compatible.

16:28 Really important though is to make sure that you fully cure it and fully wash it because any left residue of resin. Yeah, it will react with silicone and then make it the other licking won’t happen and then you’re left with a very sticky silicone part and that’s something we don’t want. But casting happens like this. So we use a cartridge system A and B. You mix it together linking starts and after curing you can break away the mold.

17:01 And then you’re left with this part. So this is that I will still a little bit sticky because yeah happens. But yeah, then we need to assemble it. So right now there are no holes in it to assemble it to the the rest of the mask. And then you’re done. Then it’s ready for a clinical trial. And yeah, I hope that in the future, yeah, it will succeed and then maybe we can go to the market with something like this.

17:35 But for now, thank you for your attention and yeah, if you have any questions about silicon printing or whatever, please let us know. To learn more about the CDFAM computational design symposium, access the archive of previous presentations, interviews with speakers, and information about future events around the world, visit CDFAM.com. Com.