What happens when it breaks? If it's all plastic it will, due to a phenomenon called stress relaxation, it's just a matter of how long. That unibody is going to make repairs hard, if one part breaks then it's going to hard to replace it.by Gene Hacker - General
Here's an interesting study on the environmental impact of solid freeform fabrication processes. Of course they assume that the parts produced are for prototyping are immediately discarded and it's quite old. Turns out FDM is the best and worst of all freeform fabrication processes(it's the absolute best if you do recycling). Unfortunately they don't compare these processes to conventional manufaby Gene Hacker - General
By 240 C do you mean 240 degrees Celsius? ABS's melting point is ~105 degrees C so this seems dangerously high.... Also why are you heating up Acrylic to >0.5*it's melting temperature(~130 degrees C)? Acrylic might permanently deform under load at this temperature. Printing on something that's an insulator isn't really a good idea...by Gene Hacker - General
We could just use the plastic burnout process to do investment casting. Here's a guide from Stratasys on how to do it. www.fortus.com/uploadedFiles/North_America/Downloads/Application_Guides_(All)/AG-InvestmentCasting-0109.pdf Though its best to burn the plastic out at very high temperatures to minimize the production of toxic gases. The PLA(PCL?) melt out process that Vik uses might be better iby Gene Hacker - Kartik M. Gada Humanitarian Innovation Prize
So why is the end that holds the nut on a flexural mount? Why isn't it a continous plastic piece?by Gene Hacker - Look what I made!
Here's another cool bendy pneumatic actuator: And a way for sensing how far a pneumatic muscle has contracted: One might use quantum tunneling composite(metal particles in an elastomer) to do the contraction sensing: That tentacle setup looks like it would be ridiculously hard to control, not only would the inverse kinematics be hard, but things would start to get pretty interesting when yoby Gene Hacker - General
So why don't we make the belt out of magnetic sheet that is used to make refrigerator magnets and have something ferromagnetic on the bed? I really think the heated bed is going to be too expensive(cost and power wise) for the Gada prize, so problems with heating shouldn't be an issue. Or maybe we can get the benefits of the heated bed with sufficiently elastic material on the bed(bed contractsby Gene Hacker - Kartik M. Gada Humanitarian Innovation Prize
I think a plaque might be cooler than a certificate. So why not have some reprap core team members sign their signatures on piece of paper, scan the paper in and turn the signatures into lifted text on a 3d printed plaque. Or why not get the signature data directly from a digital pen and turn it into G-code to run the machine? Increase the size if printing plastic or put a pen as the tool head toby Gene Hacker - General
The problem with the z and y combined axis and independent x axis is that when you're printing really big things you have to move all the material that was printed. The mass of a full build volume is probably more than the mass of the x-axis and y-axis combined. Now when you want to print a bunch of parts in one go this becomes a problem.... It's also hard to do a conveyor belt part ejector on aby Gene Hacker - General
So getting back to the whole printed rack and pinion idea. The problem with rack and pinion is that we have to move the relatively massy y axis stepper motor with the X axis. More mass means more inertial forces on the rack(if we're aiming for a print time of less than 10 days we're going to have to go fast!) Anyone have an estimate of how much mass the x axis could have?(the mass of darwin's x-aby Gene Hacker - General
Now how do we make the rollers? It seems like it'd be pretty hard to print a bunch of low friction bearings for each roller.by Gene Hacker - General
I can see acouple problems with using cams for information storage, 1. We have to store a lot of information(especially if you want to store the movements for an entire print), the cams might end up being very very large. 2. Analog control systems need to be made to high tolerances, otherwise they will be inaccurate and produce inaccurate parts. It'd be much better to use something digital for iby Gene Hacker - Plastic Extruder Working Group
One thing we're going to have to take into account is inertial forces. As the extruder goes around the turns doing the raster scan or sharp corners it's accelerating a fair amount. At 128 mm/s the extruder's experiencing 6 g of acceleration as it goes around the raster scan turns(print speed doesn't change throughout the print?). 0.001(m/mm)*((128 mm/s)^2)/(0.5*0.5mm(width of filament))=65.5 m/s^by Gene Hacker - General
Thank's theOtherRob, glad to see it in the wiki. On computer vision, perhaps I should redesign the mount to accomodate a webcam and make it mendel compatible...by Gene Hacker - Pick-and-Place Electronic Assembly (and robots!)
I don't think so, the curta requires parts made to fairly high tolerances, if we're going to build a curta we're either going to have to increase print resolution or print a larger curta. [1.bp.blogspot.com] We might be able to build a Long Now Clock computer, as it's digital so it won't need to be made to high tolerances.by Gene Hacker - Let's design something! (I've got an idea ...)
Why don't we try 'teleporting' something from one RepRap meeting to the other? IE someone 3d scans in an object at one meeting, destroys it, then sends the 3d scan data to another RepRap meeting all the way across the world? Also something like this: www.roboticsproceedings.org/rss05/p16.pdf Or this(part of this was 3d printed, we should beg for files): might be worth considering for RBS. Howby Gene Hacker - General
I have no idea about the wear quality, but all that matters is that it last long enough to make more than 1 copy of itself(I hope to integrate this part into a printable stepper motor I'm designing). A thread reinforced belt is a must, I learned a while after I designed this bearing about something called stress relaxation.(http://en.wikipedia.org/wiki/Stress_relaxation) Stress relaxation would cby Gene Hacker - Let's design something! (I've got an idea ...)
Babbage difference engines and other mechanical analog computers require parts made to fairly high tolerances(if it's out of tolerances it will make errors!), so any mechanical computer we consider making should be digital. The Zuse mechanical computer might be worth reproducing: We could try printing fluidic logic elements(no moving parts!) and use those to make a computer, in fact Forrest Higby Gene Hacker - Let's design something! (I've got an idea ...)
For more on punched card control systems and mechanical replicators see this: Fluidic logic is used in fighter jets? I've heard of it being used as part of a helicopter control system, and even missiles but not fighter jets. Though there have been fluidic jet engine control devices. Do you have the link to that information? I've been looking into using fluidics too. Currently I'm designing aby Gene Hacker - Plastic Extruder Working Group
What type of steel? High carbon or low carbon steel?by Gene Hacker - General
Cool, how far away from production is it and where do you get the filament(ink)?by Gene Hacker - General
No, never seen how real pick and place machines work. Visual recognition of component parts would also automate things more, no need to carefully align parts in a parts tray. Might a webcam work? Another option might be to use one of those cheap USB microscopes, the one I have has some fairly decent resolution.by Gene Hacker - Pick-and-Place Electronic Assembly (and robots!)
The best place to get mylar is walmart or a camping store in the form of space blankets. Also would love to hear more about his inflatable wing.by Gene Hacker - RepLab Working Group
Cool could you make a driver for an epson printer head? Epson printer heads are piezoelectric, which means you can shoot a larger variety of stuff through them, like stuff that is either flammable or alive. Epson heads can also be cleaned, which is good if something goes wrong.by Gene Hacker - General
Here's a rotary rolamite bearing I designed: It's primarily designed as a replicapable alternative to skate bearings.by Gene Hacker - Let's design something! (I've got an idea ...)
First off, how would we make aerogel with reprap? We definitely couldn't do so in a one step procedure. Second how would we get the supercritical CO2 drying apparatus necessary to turn gel into aerogel?by Gene Hacker - Plastic Extruder Working Group
Well it might be possible to use fluidic muscles to do fine positioning of the extruder if the extruder's/toolhead's absolute position could be be determined accurately. I want to use a fluidic control system as opposed to an electric based one is that we can currently print one using just plastic.(IE it's easier to replicate) Ferrofluidic actuators offer an interesting possibility in that it mby Gene Hacker - Mechanics
Viktor, they still have printers that use bars of wax as ink. They are known as solid ink printers, and can have very good print quality. Also, they are available at decent pices secondhand. Modifying one into a 3d printer might be a bit of feat though...by Gene Hacker - Mechanics
My thoughts: WOW! Reminds of giant CNC milling machines they use to make nuclear reactor containment vessels.by Gene Hacker - General