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General discussions. For specific printers / electronics / fabrication methods / softwares, please see other sections.
Re: RS485 questions - 14 years ago
eustace, What country are you in? In the US, digikey seems to show no shortages, under a buck/part in quantity 1. If you're in a bind on this, send me a PM and I'll see if I can help you out.by Larry_Pfeffer - Reprappers
Re: Why print plastic when you could print liquid glass? - 14 years ago
Greetings all, This material appears to be a (very!) thin coating, rather than a bulk material. It certainly sounds interesting, but I'm always wary of announcements that are high on hype and low on details and specifics (where one could get samples, dates for production, data sheets, etc.) If this turns into a real, avaliable product, it might help reprapping by giving us a way to lower friby Larry_Pfeffer - General
Re: Why Not use Nylon? - 14 years ago
Greetings all, One of Nylon's precursors is Formic Acid. This is irritating far out of proportion to its strength as an acid. Formic acid is the major component in ant and bee venom. So, handle with *extreme* care!by Larry_Pfeffer - General
Re: Concept for negative-Z 3d printer - 14 years ago
@Eagalon, If nothing else, , I give your idea a point or two for creativity and use of an inexpensive support material. I don't know whether playdough would work well as a support material (of course I don't know that it wouldn't, either.) However, the issue of the part wandering in the horizontal is an issue, as has already been pointed out. Similarly, I think playdough springs back somewhby Larry_Pfeffer - General New Machines Topics
Re: Crazy Extruder Nozzle Idea - 14 years ago
The tip of a mechanical pencil might be so long that the extruder would have trouble creating enough pressure to pump the desired rate of plastic through it. But that's just a guess. In most of the nozzles people have made, they've gone to some trouble to make the final, small bore section be a short as possible. If you try it and it works, we can put this guess into the trash. (Figuring ouby Larry_Pfeffer - General
Re: Reprap Electronics Devolpment - 14 years ago
Larry_Pfeffer Wrote: ------------------------------------------------------- > I just found out about a low-cost board with an > LPC1768 chip, with the I/O lines broken out to > header pins. > > roducts_id=65 > > The price is right, a bit under $33 US. I ordered > a couple, along with a USB/JTAG interface (that > supports open OCD.) Of course, shortly after ordby Larry_Pfeffer - Controllers
Re: Reprap Electronics Devolpment - 14 years ago
Bruce Wattendorf Wrote: ------------------------------------------------------- > So here is what I have found so far > > NXP LPC1768 $8.70 looks like a very good > possibility. Greetings all, I just found out about a low-cost board with an LPC1768 chip, with the I/O lines broken out to header pins. The price is right, a bit under $33 US. I ordered a couple, along with a USby Larry_Pfeffer - Controllers
Re: Can't find 0.5mm Drill bit! - 14 years ago
Amazon sells sets containing #61 -- #80 (not exact 0.5 mm, but not far off) 20pc MICRO-DRILL BITS INDEX 61-80 w/ Plastic Case Warning, #80 bits break if you look at them funny. -- Larryby Larry_Pfeffer - General
Re: Q: Height of extruder nozzle above the print? - 14 years ago
Wade, Thanks so much for the picture; I *really* appreciate your taking the time and effort! With the measurement grid, that gives me a much better idea about what the plastic is doing as it's being deposited.by Larry_Pfeffer - Reprappers
Re: Argument Kills Uploads - 14 years ago
Greetings all, I agree -- argument kills both community and contributions. However, respectful discussion, and organization of information *encourages* both community and contributions. IMHO, one of the key (perhaps under-appreciated) aspects of these boards is that the volume of discussion regarding possible improvements/variations/problems often overwhelms the basic information that prby Larry_Pfeffer - Administration, Announcements, Policy
Re: Q: Height of extruder nozzle above the print? - 14 years ago
Wade, Thanks for your thoughtful comments -- and your (bonus) observation and measurement of ripples in your extruded plastic! In my planned machine, the bed moves, but the extruder does not (except during infrequent Z-height changes.) Thus, I can avoid ripples from XY motion-associated vibrations (at least, so I hope.) If I were to vibrate the tip of my extruder, I might still get a ripplby Larry_Pfeffer - Reprappers
Re: Q: Height of extruder nozzle above the print? - 14 years ago
Wade, Using the input rod diameter for a realtime control of the extrusion volume rate, would work fine so long as one is using rod feedstock to extrude. If one wanted to use polymer granule feedstock (much cheaper than rod stock) or recycled shreds, then won't be a rod diameter to measure. I was asking about nozzle height (above previous layer) as part of an idea to measure the extruder outby Larry_Pfeffer - Reprappers
Re: Q: Height of extruder nozzle above the print? - 14 years ago
Nop, Thanks for your extrusion parameters. Looks like this idea probably won't work. Back to the drawing board. (Now there's a saying in need of an update....)by Larry_Pfeffer - Reprappers
Q: Height of extruder nozzle above the print? - 14 years ago
Greetings all, I have a question for those of you getting good print results: How high is your extruder nozzle above the print surface, for good printing? Ideally I'd like to know: Material / Diameter of nozzle opening / Height of nozzle above surface The reason I ask is that I have (yet another) idea about measuring the rate of plastic deposition (so it can be controlled), but it'd neeby Larry_Pfeffer - Reprappers
Re: Mechanical Computing Working Group - 14 years ago
Julie, First off, my apologies for not reading your history of mechanical computing carefully enough. I should have caught your mention of V. Bush and his work. Much though I like the subject, history of science/technology wasn't my dissertation topic. I just wanted to add some historical and literary context to set the stage -- my dissertation research was on the design and control of cooperby Larry_Pfeffer - General
Re: Mechanical Computing Working Group - 14 years ago
Julie (and others reading), Although I think all-mechanical computing isn't really a core part of reprap, it might be useful -- if nothing else, it's pretty resistant to EMP. (Although we'd still have to replace the motors with something mechanical, as well. One aspect of mechanical computing I don't see in your summary (did I miss it?) are the mechanical analog computers, notably the ones useby Larry_Pfeffer - General
Re: Belt Versus Screw Drive - 14 years ago
FYI, in the US, this material is often called "wire rope" If you search that phrase, you'll find lots of suppliers. Note, it isn't braided, so far as I can tell, though the outer strands are often twisted. Note that the coated versions (specifically the compressibility of the coating) can have consequences to the stiffness and repeatability of drive mechanisms. Really thin wire rope is alsby Larry_Pfeffer - General
Re: RepRap future and leader (the need for) - 14 years ago
Greetings all, It seems to me that one thing that the rrrf.org was doing awhile back (until Zach split off to do makerbot), was to make it easier forwould-be reprappers to get parts and materials from a single source, such as PC boards, stepper motors, plastic rodstock, and related mechanical and electronic components. Many of these things are hard to source in small quantities, so having someby Larry_Pfeffer - General
Re: rack and pinion versus belt? - 14 years ago
Forrest, The low-backlash you report from your printable herringbone gears is great news! Given that, it may be possible to use printable rack/pinion for milling. Just as a thought experiment, assume that we could use either microstepping, or additional gear pairs to get small motions, even if the final drive gears had big teeth. (Big teeth presumed for the final "moving the table" stageby Larry_Pfeffer - General
Re: rack and pinion versus belt? - 14 years ago
Forrest, First off, please forgive me for not following your work on printable rack and pinion drive systems more closely. What software is needed to run your rack and gear scripts? Have you made any measurement of the backlash, due to the rack/pinion themselves? (That is, the back/forth motion possible when the pinion is not permitted to rotate. I realize that this will also be a function oby Larry_Pfeffer - General
Re: 35mm film driven repstrap - 14 years ago
This in not only *very* clever, it's another widely available resource for driving mechanisms. Q: Did you put the "PRINTER...." image onto the film? Could you put regular stripes on it instead? If so, such film could serve as both a drive belt and an encoder. Good work!by Larry_Pfeffer - Reprappers
Re: Open Source Reprap contract - 14 years ago
Greetings all, It's apparent that many of us have strongly held opinions on what license(s) they do/don't like. In a group effort, this diversity of opinion seems unavoidable. I'd like to point out that having different parts of the reprap "intellectual property" under *different* (sometimes conflicting) licenses makes the whole less usable -- and likely profitable only for the lawyers -- someby Larry_Pfeffer - Administration, Announcements, Policy
Re: Delta robots - 14 years ago
Greetings all, I have a question about sensing and resolution for Delta robots: What angular sensors are folks considering, and what spatial resolution do those give in/near the "sweet spot" of the mechanism (area where the kinematics are reasonably well behaved?) -- Or are folks considering some other sensing approaches? The reason I ask is that it looks to me that one needs considerableby Larry_Pfeffer - Delta Machines
A thought on the horizontal travel dimensions for Eiffel - 14 years ago
Greetings all, Earlier, I wrote: > The working envelope seems a bit bigger than strictly neccessary for PCboard > routing, but will probably come in handy. If folks are mainly interested in fabbing that uses only additive or subtractive machining on any given part, then I'm not so sure having a large horizontal workspace is critical. So, for circuit boards (which probably don't need aby Larry_Pfeffer - General New Machines Topics
Re: Introducing Eiffel 
- 14 years ago
Sebastian (and anybody else reading), I like the idea of a hybrid machine -- one that can do both additive machining (extrude plastic) as well as subtractive (route and drill PC boards.) What you've sketched out is similar to what I'm already ( *very* slowly) building. The main difference is that I bought an XY table for the horizontal motions. The links to spindle options are great. I was gby Larry_Pfeffer - General New Machines Topics
Re: Metal Mendel Build - 14 years ago
In the second photo, I see both a bar of Toblerone chocolate and a wine glass, in addition to the mill and toolbox -- that's an interesting mix in a kitchen! Good work; please keep us posted,by Larry_Pfeffer - General Mendel Topics
Re: New England meeting, sometime in the next couple months? - 14 years ago
Bill, Nice to hear from you. Most of our local msg traffic (what there is of it), is now on a google group: If you let me know your email address, I'll send you an invitation. We *try* to meet a couple times/year, but the timing has been pretty variable. Larry ursine @t gmail d0t c0mby Larry_Pfeffer - Massachusetts, Boston RepRap User Group
Re: New England meeting, sometime in the next couple months? - 14 years ago
Ben, Lurking is perfectly fine; nobody is checking qualifications or anything like that, just be reasonably polite. I'm also sending you an invitation to our google group -- that's where more traffic is going, lately. -- Larry Ben Wade Wrote: ------------------------------------------------------- > Hi, > > I do NOT have a reprap yet, and I am about 6 > months away from having tby Larry_Pfeffer - Massachusetts, Boston RepRap User Group
Re: Custom Machined Metal Mendel - 14 years ago
Thanks so much for making this set of dimensioned drawings. I haven't studied them in detail yet, but the few I opened showed exactly the sort of dimensional detail I was seeking! Thanks again!by Larry_Pfeffer - General Mendel Topics
Re: Paths toward more CPU capability, yet retain Arduino compatibility? - 14 years ago
annodomini2 Wrote: ------------------------------------------------------- > > Many Safety critical Embedded software design > standards, suggest avoiding pointers as much as > possible. It's very hard to use C without using pointers. From "The C programming Language", second Ed., p. 99 (AKA K&R 2nd, by the language designers, themselves): > In evaluating a(should beby Larry_Pfeffer - RepRap Host