This week is all about 3D scanning and printing. My feelings about this weeks topic are a bit mixed. A few years ago 3D printing was my first experience with digital fabrication. I bought a old broken 3D printer and fixed it - I printed some plastic stuff from Thingiverse and bravely tried to design for the 3D printer. At the time I had an old Ikea chair that was missing some caps on it's legs - since the chair was no longer being sold I couldn't get the replacement caps. This was my first real drawing to print experience. It was a huge thrill to go from digital to physical matter and to create something truyly functional.
Since than I managed a workshop with a dozen 3D printers both FDM and SLA and printed thousands of hours. What I like about them today is that they are really great for very specific tasks - it's nice to quickly make things for prototyping. For example this summer I worked on a spinning fluid table that had to create a specific splash pattern. The 3D printer allowed me to quickly draw some designs, mount them to a motor and test them out. What I dislike today are how sensitive these processes are to a plurality of things - machine, material, design, draft, dust, ... I have learned not to expect to much from 3D printers but still can be pleasantly surprised by them.
My scanning experience is a bit more limited, I have made a selfie. Also I have seen some people scanning things in the workshops, spending hours, and not ending up with the desired results. Think: shiny materials or designs with specific measurements. "Cheap scanners" just can't do this (yet).
This week we tested the design rules for printers in our Lab, I designed a 3D object that can only be made on a 3D printer and scanned a tree in my garden.
PrintrBot Metal Plus
Blue painters tape
Dutch PLA RRW 1.75 mm blue
3D4Makers ASA 2.85 mm white
At the Waag there are a few different printers in the lab. Since all the printers are different we split up into 3 groups and performed the same test on each printer. Rutger and I were assigned the PrintrBot Metal Plus. I remember this machine from my first days at the Waag a few years ago (this machine came on the market in 2014). It was put in the space and for a week people tried to make a decent print - most of them failed horribly. I don't remember much else about the machine.
Switch the printer on. On the back of the back of the power supply there is a small switch.
Connect your computer to the printer using a printer cable (USB A Male/ USB B Male). If you have USB 3 ports you might need a USB hub with USB 2 ports.
Open Cura - and load your file pressing the Load button. Scale, move your design to desired size or add extra objects.
Press print to start printing. Once the printer has reached the right temprature it will start. First by going to all 4 corners of the bed to level it self. Than it will print your build plate adhesion if you selected this, than your model (and support at the same time).
Check if you are happy with the first few layers - if not start again. Mistakes will just grow bigger.
We printed the testing file on 3 different printers the results for the PrintrBot were quite surprising. My expectations were quite low but I was pleasantly surprised that the model printed quite well in one go. We chose a testing file by ctrlV, it's a relative quick print (1 hr 15 min) and it has a lot of design features that can be tested.
|1||Nut, Size M4 Nut should fit perfectly||Fits with some effort|
|2||Wave, rounded print||Looks fine|
|3||Star, Sharp Edges||No sharp edges|
|4||Name, Complex Shapes||Name not readable|
|5||Holes, Size 3, 4, 5 mm||Are 2, 3, 4|
|6||minimal Distance: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 mm||Biggest 3 are open-ish, smaller ones are fused together.|
|7||Z height: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1 mm||First layer that's printed is 0.3 and it goes up in uneven steps to 1.1|
|8||Wall Thickness: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 mm||Only 0.5 to 0.7 get printed|
|9||Bridge Print: 2, 4, 8, 16 mm||2 to 4 mm look fine 8 mm get's messy 16 mm is a total mess|
|10||Sphere, Rounded Print 4.8 mm height||Can't measure, looks good|
|11||Sphere Mix, 7 mm height||Can't measure, looks good|
|12||Overhang: 25, 30, 35, 40, 45, 50, 55, 60, 65, 70°||25 - 50 degrees print well 50 degrees and up still print but sloppy|
|13||Warp, does it bend?||Printed on blue painters tape - no warp|
|14||3D Print Font, optimized for 3D printing||Readable but not the best|
|15||Surface, Flatness||Filament is shiny and dull - lines are very clear|
|16||Size, 100 x 100mm x 23.83 (10mm width)||92 x 93 x 1.8 (10.6 width)|
|17||Spike, minimum Layer Time, 21 mm height from Bottom (include Baseplate)||17.2 mm|
|18||Hole in Wall, 4 mm diameter, check for proper print||3.8 mm|
|19||Raft Test, raft should be just under the model||Not printed - we forgot|
|20||Retract Travel, check retract settings for longer travel||We made no changes|
The print looked and performed quite acceptable. Compared to the other machines (Ultimaker 2+ and Prusa I3) you can tell it's a little bit more sloppy, corners are less sharp and the dimensions are a little bit more of. Some of the details were lost but overall everything printed.
A few months ago I was in need for a new pour over filter holder for my coffee addiction. My fake Chemex fell to pieces so it was time for something new, something that could make a nice bold filter coffee. A obvious choice, the Hario V60. Hario makes these in glass, plastic and ceramics - glass being brittle, plastic being a bit unhealthy but a good insulator and ceramics being brittle again. The ridges on the inside of the filter holder help in the brewing process, less contact area between the filter and holder equals a bolder cup. This sparked my imagination to make a new design for the plastic filter holder, one with less contact area and one that can be made fully and only on the 3D printer.
My current filterholder has a height of 90 mm, width of 110 mm, a opening of 30 mm and a filter angle of 60 degrees.
I started with the classic Hario desgin. It counts about 12 full ridges and 12 half ones. Imagine what the holder could look like if the ridges is all you need.
I started by drawing a single "tongue". In Fusion I drew a vertical plane and thickened it - this gives a nice thick sheet that can be modified. I twisted it a bit and made sure the curves were all different.
Then I made more "tongues" by going back in the Model enviroment I gave it a circular pattern with 3 repeats. The final design needs more but 3 gives a better view. Thanks to the Fusion timeline we can always change this later. Later I changed this to 7.
To create the bottom I drew a triangle half size of the filter on the Y plane and revolved it around the axis. This is a cutting shape that cuts through every object it encounters. I finished with a small dish that catches any drips coming from the filter and doubles as a holder to stabilize the filter directly above your cup.
To improve the "3D print only" quality of my design I focussed on the center part - where all the ridges meet. To make this with a mold you would need a lot of parts but also be able to release the mold towards the centre. This could have been a bit heavier in the design but I am pretty sure this will be next to impossible to make in a other way than 3D printing.
For the material I wanted to try something new, something (kind of) food safe and heat resistant. There are no materials that I could find locally with a food safety certificate - materials can be food safe but since the printing proces is not controlled it can never be officially food safe. The best available material that I found was PEI - it's very heat resistant and food safe enough for my prototype. Also very expensive, 450 euro per roll. Next in line was ASA a relatively new material with similar mechanical properties as ABS. It can handle chemicals, UV, high tempratures and stress. Also it doesn't smell as bad as ABS.
One big downside to this material is the printabillity - it's relative new and the reviews I could find were from easy to very difficult. In the store where I bought it I asked the seller about his experience and he recommended to use the standard setting from the box. The next day in the lab I started a material test - I chose a small design with some features that were similar to my design. I printed it at the recommended settings - in Cura I made a new template in the material menu (copied ABS) for my material and changed the nozzle temprature to 250 degrees and the bed temprature to 90 degrees. The model was printed at 80% size and with a layer height of 0.15 mm and 20% infill.
Next on was the print for my filter holder. I have a Ultimaker 2+ identical to the one at our lab at home so I wasn't limited as much by printing time. To make sure my settings would also work on this machine I made a quick stringing test.
I printed my model at espresso scale (50%) for the printing test and later at full scale for the drinking test. Also I printed an experimental holder where I removed a lot of material to make the print time faster. This failed horribly - the large surface adhesion to the bed caused a lot of warping. The warping was estheticaly not pleasant but also it also caused some slight upward tension at some parts that bumped into the nozzle and combined with some bad layer adhesion these parts broke of. The final print looks pretty cool - the ridges no longer look like ridges but are like flames holding up the filter. The rigdges have a smooth surface compared to the dish part where the layer height lines can clearly be seen, this gives nice contrast. I made coffee with the holder and it works really well. All coffee drips go to the lowest point of the filter and the extraction time is similar to the Hario holder.
My goal this week for scanning was to scan my house - unfortunaltly I couldn't get my hands on a drone fast enough. Needed for this was a whole lot of pictures of the building including the rooftrop. Using photogrammetry these photo's can be stitched together to create a point cloud and 3D model. I decided that the next best thing was to try it with an app - just the front of the building and see how much detail can be captured. I have an I phone and picked one of the high ranking 3D apps - Trnio. It's a cheap app (€3,40) and it looks beautiful. The app has a camera that captures a video and/or photo's, the imagery gets send to their servers and stitched together into a model. Each scan takes about 40 minutes to get send back as a 3D file.
For my first scan I found a small yellow buddha. The statue is not shiny and a bit dirty, this should both help creating a good scan. The app gives directions on how to scan but it's basically walking around and pointing your camera at the object from different heights. I did this on a sunny day - my shadow was quite often visible on the object and I was scared this would cause an issue. After I completed my scan I waited for about 30 minutes and received message that my scan was complete.
I downloaded the file from the app and opened it in Meshmixer and extruded the surface to make it a bit more printable. I printed the final design sized 70 x 60 x 16 mm at a resolution of 0.06 with a 20% infill in ASA.