[HN Gopher] How to make (almost) anything (2020) ___________________________________________________________________ How to make (almost) anything (2020) Author : akeck Score : 172 points Date : 2022-03-07 15:45 UTC (7 hours ago) (HTM) web link (fab.cba.mit.edu) (TXT) w3m dump (fab.cba.mit.edu) | DoingIsLearning wrote: | All the videos linked in the class show me a message "video is | not rated", saying I am unable to watch? | ksdnjweusdnkl21 wrote: | I wonder how one should host their educational videos to have | them be available without ads or other nonsense like this. Any | affordable solutions? | lupire wrote: | What do you mean? | DoingIsLearning wrote: | As in the video is not porn/violence rated and I am too | anonymous for Vimeo to know if I am an inocent unsupervised | child on the internet. | nomemory wrote: | If i am allowed to joke, I was expecting to read an article on | Rust. | bogwog wrote: | I think you misread the title as "how to remake (almost) | anything" | chasd00 wrote: | Next weekend can't come soon enough :) | | I'm in the high power rocketry hobby and got a Prusa i3 mk3 for | myself for Christmas. It's pretty amazing to sketch a bit while | on conference calls, then after work model my sketch in | Fusion360, export the mesh, import to Prusa slicr, export gcode | to an sdcard, start the printer and goto bed. Next morning, | there's my part waiting for me. | | Electronics is the next bridge to cross and i really hope this | class helps with that. I know a guy in the hobby who went from | nothing to selling a custom designed altimeter for rockets on his | website in about 6 months which was pretty impressive to me. | https://flightsketch.com/store/catalog/flightsketch-mini_1/ | andi999 wrote: | What annoyed me was that the slicer does not mantain hole | diameters, somehow holes are smaller. In my case I was planning | to prototype cnc milled stuff (which is kind of expensive), but | this killed to use case. | joshvm wrote: | This is, I think, partly due to how the slicer routes the | filament paths. I've had this problem moving between nozzle | diameters and the only reason I could think of was that it | wasn't possible for the slicer to maintain both accurate hole | diameters and the correct placement of filament relative to | previous extrusions. The STL was identical, but the parts | printed with a 0.8 mm nozzle were undersized and _only_ the | holes. My experience of this was with Cura and an Ultimaker | S5. Generally you should always start printing loose holes | and tightening them up as you go to see where the limit is. | | The simplest dimension to control is the perimeter. That can, | for most parts, be perfectly accurate because there are no | constraints on where the nozzle needs to avoid. However if | you print a hole close to the edge of a part then the printer | somehow has to lay down both an accurate edge to the hole | while maintaining suitable separation from previously printed | stuff. Essentially your design is quantised by the nozzle | diameter within the perimeter of the part (I may be wrong | here, but this seems like a simple explanation). You may have | better results if you tune your part to the printer/nozzle | you're using so that the slicer doesn't have to worry about | leaving/filling gaps that are non-integer multiples of the | nozzle size. In theory this shouldn't matter, because the | hole perimeter can also be printed first, as it's an | "outside" edge, but it doesn't always seem to work that way. | chasd00 wrote: | i've noticed things shrink a bit when the cool off ( at least | with PLA ). What i do is print, test fit, adjust dimensions, | then print again. It usually only takes one or two iterations | to get it just right. I built a deck once, designed it, | spec'd out all the materials i would need, optimized for | minimal wastage, the whole 9 yards. I learned the hard way | that in the real world dimensions are a matter of degree and | what's on the label may or may not be what you get (to a | ridiculous degree when it comes to lumber). | | I'm use to software where it either compiles or it doesn't, | it either works or it doesn't. In the real world with | physical objects it's much more a matter of "is it close | enough or not". | dekhn wrote: | Holes with interior dimensions close to the width of the | nozzle are hard and need to be calibrated if you absolutely | need to print them to size. Basically, the plastic is | "spreading" a bit wider than the nozzle tip. | | better solutions, rather than making exactly sized holes, is | to increase the number of vertical walls, make the hole size | slightly under, and use a precision drill and reamer to get | to the target size. Also, make sure you're setting your | scaling right (for example, I need to set my object size to | be 100.6% of its designed size, because PLA shrinks when it | cools). | maxioatic wrote: | Yeah this is just a thing you have to design around while | using FDM printers, as others have mentioned. I really like | melting in threaded inserts if you need threads, otherwise | use a drill bit or reamer. If you need super tight tolerances | (like CNC level tight) then a consumer grade 3D printer | likely won't get you there though. | 2muchcoffeeman wrote: | Prusa uses 3D printed parts and I'm a bit surprised just | how good the prints are. | LeifCarrotson wrote: | The slicer does maintain hole diameters, but just like CNC | milling HDPE, you should expect dimensions to change a little | after printing. If you need to have a tight tolerance fit on | something, expect to run a drill or chucking reamer through | it after printing. If it's really tight tolerances, it's easy | enough to melt or press a drill bushing or threaded insert | into an oversized hole to get fits tighter than you're likely | able to hit with a mill. | | Your expensive parts likely go through many steps before and | after manufacturing already that involve things like | fixturing the material in place, rotating it and reacquiring | datums, running taps through by hand, deburring sharp edges, | etc; you should not expect 3D printing to be as easy as | sending the STEP file to the machine and getting a complete | part out. Sanding, acetone vapor polish, drilling, reaming, | tapping, etc. are normal parts of the manufacturing and | prototyping process. | theelous3 wrote: | Just an fyi drills are not good for tight tolerances. They | cut trilobular holes, not circles. | | Reaming or boring are the route to tight tolerances. | andi999 wrote: | Which slicer do you use? It seems to be a known problem of | cura. | sokoloff wrote: | I use Cura. It's across FDM printing techniques and is | (somewhat) akin to the errors in subtractive | manufacturing. Subtractive errors/inaccuracies tend to be | of the type that remove too much material. Additive | errors/inaccuracies tend to add material. | | My models for FDM often include a "hole size | compensation" user parameter and I tweak it to introduce | an offsetting bias in through-holes. (Non through holes | tend to get heat-set brass inserts, which are more | forgiving of the 0.1mm or less radial errors.) | 2muchcoffeeman wrote: | You can print a clearance tolerance test to see how | accurate your printer is. I use a Prusa mk3s and as | accurate as it is, at best my tolerance is 0.1mm. Enough | to stop your parts fitting together. I normally build in | a 0.2mm tolerance for close fitting parts. | 0_____0 wrote: | IIRC there's a param in the slicers I've used that can fine | tune hole sizes. | roland35 wrote: | Next thing you should do is get a raspberry pi with octoprint! | Then you can drop the gcode in from your web browser :) | sanj wrote: | Gershenfeld helped coordinate a bunch of folks with COVID work | too! | gabrielsroka wrote: | Here's a complete class listing | | https://cba.mit.edu/classes | Metacelsus wrote: | See also "How to grow (almost) anything": | https://fab.cba.mit.edu/classes/S63.21/ | forgotmyoldacc wrote: | Note that the title is fairly misleading, students don't | actually do real practical labs. A random example: https://fab. | cba.mit.edu/classes/S63.21/class_site/pages/micr.... Probably | because this class was being held during COVID times. | | There's no hands on biology work. Homework consists of: | | - Find a research or journal article - Propose a technology - | Propose a methodology | | etc | | The 2019 version looks a little better: | http://fab.cba.mit.edu/classes/S66.19/S66.19/ | azinman2 wrote: | I never took this back when I was at the Media Lab and that's one | of my main regrets from that time. This class is very famous, but | I'm not sure how useful this is as an online class because as a | normal person you won't have access to the water jet cutters, | plastic mould injection machines, etc. | | Covid aside, hacker spaces were already dying out in SF. I wish | there was more push for ordinary people to become makers rather | than just consumers. | chasd00 wrote: | 3dprinters are pretty accessible but you're right about other | tools. Also, some of the tools can be pretty dangerous ( | looking at you lathes/mills ). | | IMO one of the greatest things about software development is | you can goto walmart and get $500 laptop, sit in a coffee shop, | and have access to all the tools needed to build cutting edge | high performance software of any type. It's not so easy to do | that in meatspace with physical objects. | adamsmith143 wrote: | As someone not much into this scene, how useful are 3D | Printers actually? I get the sense that they're very useful | to hobbyists or for creating prototypes but are the plastics | used suitable for production use cases? | theelous3 wrote: | Without going in to it - there is a massive range of | plastics and non plastics of varying quality, expense, and | accessibility. | | Yes, 3d printing is a legit method for production. | _Typically_ if you can have a die made for it you will be | better off in the long run with casting. Dies are | incredibly expensive however. | | Smaller runs or highly specialised and difficult geometries | benefit from 3d printing. | akamoonknight wrote: | I think to some extent it's a frame of mind thing. For | instance, my friend's vacuum broke for some reason or | another, some plastic piece that wasn't super complicated, | but was required for functionality. And rather than buying | a new one, he was able to model and print the piece that | broke and the vacuum is able to work again, but mileage in | general probably varies. | srcreigh wrote: | except for video games and deep learning | baud147258 wrote: | depends on the video game. If you target what AAA was doing | 5 or 10 years ago in term of graphical quality or even | specific style like low polygon, pixel art, 2d art..., you | don't really need the cutting edge in terms of graphic | cards. | dannyobrien wrote: | Noisebridge is re-booting pretty successfully in San Francisco | -- a break during early Covid was either well-timed or | overdetermined, because they also had to move venue due to rent | rises, but the new space is coming together, and there's a | bunch of in-person events now kicking off to celebrate the | space's fourteenth birthday: | | https://www.noisebridge.net/wiki/Noisebridge | azinman2 wrote: | Happy to see they're back! The death of maker spaces in SF | has been very sad for me. ___________________________________________________________________ (page generated 2022-03-07 23:00 UTC)