Severeal weeks ago I completed my new Thing-O-Matic. Well, the MakerBot firmware doesn't limit acceleration. There are several firmwares which do. I already tried to use SJFW - but successless so far. I found hints to Marlin and Repeater but before I start to build them I want to be sure that my next approach will work. So... Does anybody run such an accelerating firmware on a MakerBot Thing-O-Mby Howie - Firmware - experimental, borrowed, and future
> A 5 milliwatt beam focused down to about .4mm and > assuming 100% absorption could heat the surface of > an aluminum plate under the beam to several > thousand kelvin. This is just taking into account > thermal conduction of the plate. Add in radiation > effects (a T^4 term), you get limited to about > 1300K. Wow! Could this mean I could solder copper plated PCB using a grby Howie - Laser Cutter Working Group
I am even anxious when using office laser pointers that are said to be safe. I remember a TV show in the early days of 'party-lasers' where the camera was hit by a green laser leaving a colored spot on the image. Oh, and I just came across an inexpensive and finished device: Watched one of the viedos where a guy ignited a match and burned a whole into some black plastic... Very instructive asby Howie - Laser Cutter Working Group
Okay. But have a look at Howieby Howie - Laser Cutter Working Group
Well, the interesting point is that signal strength of the head depends on speed of movement over the tape. This is probably not very constant. Howieby Howie - Mechanics
I remember this as the PU-foam trick I've seen some twenty years ago at the Chemistry section of Deutsches Museum, Munich. Take a few mililiters dialcohole and a diisocynid (sp?) - and you get polyurethane. For first tries use a large container you don't need anymore! The chemical reaction also produces CO2 making foam out of the PU filling the container. Problem here is to guard the height ofby Howie - Plastic Extruder Working Group
Recently, there was a discussion about FireballCNC. At their mailing list someone mentioned Zenbot. Does anyone here know this device? Looks interesting - although not that cheap and without motor driver. Howieby Howie - General
> IN that article, it talks about them reducing the > temperature required to just about room > temperature Right. He also writes about 1,000 psi which is more than 70 bar. tells for CO2 a critical temperatur of 304.4 K and critical pressure of 73.8 bar. In summer, CO2 can be made supercritical at room temperature... However, I am also concerned about the pressure. 73.8 bar seem quiteby Howie - General
Alter Schwede! - as we say in Germany. :-) I just looked around a bit and found that there are materials with even friendlier critical temperatures and pressures. E.g. Chlorine at 417 K and 8.14 bar. Yes, I would do these experiments outside wearing a mask... CnH2n+2 are also interesting. They are inflammable (explosive at pressure under consideration) but not toxic. However, increasing n meansby Howie - General
Yeah, I also thought about using a pasta machine to produce 'plastic sheets'. At a kitchen store I found out that the one they offered are adjustable from .3 mm to 10 mm or so. I am still dreaming of trying Instructables' potato plastic (plastic made from starch). Since pasta dough is just a different kind of starch based plastic I will try the lubrication proposed for intended use of the deviceby Howie - Plastic Extruder Working Group
Regarding the potato - sorry, starch plastic, have you also tried the HCl / NaOH variant? Idea is to use hydrochloric acid instead of vinegar and netralising it with sodium hydroxide. Look here: No, I've not yet tried any of those two methods. But I'm curous anyway. The non-vinegar recipe has the advantage that no odor would disturb my wife. ;-) Howieby Howie - Polymer Working Group
Pasta dough... also fully degradable... Reminds me of the article about starch plastics: Howieby Howie - Paste Extrusion Working Group
Fascinating! looked around a bit and found this page: Lots of stuff there. Search for 'z-drive'. Then you'll see that it works with magnets. At first sight it looks like a regular linear motor. Interesting question is how they got the coils that flat. Howieby Howie - Plastic Extruder Working Group
Just found this site: They offer 240 mW at 650 nm Sony DVD burner laser mounted in MinMaglite housing for $189. Is this for real? Would you recommend it? Buy it? Any other application for this 'dangerous toy'? I am a mechanical newbie - so please tell me how do I use such a beast (focus it) for laser cutting? Howieby Howie - Laser Cutter Working Group
Demented Chihuahua Wrote: ------------------------------------------------------- ... > Cigarettes dipped in formaldehyde is called sherm > and is smoked to get hi. You won't find it but at Uh! formaldehyde (methanal, as it is called today) is a carcinogen. Well, cigerettes are carcinoges, too. And they smell as bad... Anyway, assure clean and fresh air if you work with it. Or even wear mby Howie - Polymer Working Group
> ... for images with very low distortions you need > telecentric cameras, whats pretty expensive, or ... > The images have nearly no distortion and a very Umm, yes. You're right. Very pretty images! Actually, with 'distortion' I meant bendings due to irregular shapes of the lens. E.g. if the front and back shapes are a bit excentric or if a lens isn't exactly mounted in optical axis..by Howie - 3D Scanners, Book Scanners, and Optics
I also thought about using some camera. But what about distortion? I would expect the pixels on the sensor chip to be aligned in a pretty accurate rectangular pattern. But the lens is just a set of glass blobs converting straight lines to curves. A colleague told me about a former project where they used images taken with such cameras for geographic mapping and they had to calibrate individuallyby Howie - 3D Scanners, Book Scanners, and Optics
First the disclaimer: In my opinion you should not build shielding goggles! They are too dangerous! If you burn your retina you might get in trouble. Buy professionally ones. They are safe. Anyway, if you still want to try... I remember a recommendation at the last recent total solar eclipse visiting western Europe. Look thorugh a CD. You won't see very much, but you look through a thin layer ofby Howie - Laser Cutter Working Group
Well, 25.4 mm/inch, 400 dpi and 18 pixels give a total field size of 1.143mm. The sensor has 18 x 18 pixels. If we print a position encoding at 100 dpi we could use 4 * 4 = 16 bits per scanned image plus one pixel row / column as separator. If we use 8 bits for x and 8 bits for y we could encode a total square of 292.608 mm. If we only use it for a single axis then limits would probably be largby Howie - Controllers
Ummm... sorry, Viktor! I missed that you changed the string (or rod) arrangement from vertical to horizontal. Thought about it over the weekend. This is an ingeniouw approach! My plan to build such a device is getting much clearer now. Seems that I will buy some Meccano parts to build a prototype... Howieby Howie - Mechanics
Viktor: I am a computer scientist grown up in the era of 8bit microprocessors. Writing a program that takes (x, y, z) and gives string moves is easy. Building a machine is kinda tricky... Conclusion: I like your idea very much! Actually, I also thought about using tapes for z-control. This would handle only one degree of freedom. But the direction of the tape would not change. Image 'Seil-Tripby Howie - Mechanics
Hi Viktor, > ... could it be, that it's an dot/comma-reading - > e.g. $28,000 for 28 US-Dollars instead of > $28.000,00? if I remember correctly I saw something like $28,406,42. The length of the number also took my attention. In my opinion too many digits to be cheap. > When i order small parts, then it's mostly in the > range of 50 to some hundred Euros, dependant of Well, I'by Howie - Reprappers
graymushroom Wrote: ------------------------------------------------------- > Thomas, did you change the units used in the > dimensions to millimeters? It's to the left of the > 'Upload' button and the default is 'Inches'. That > might account for the high price. Just a > thought... Yes, I did that. I even suspected the smaller size to be the reason for the high price. Well, doesnby Howie - Reprappers
Well, one point I want to make clear. Seems that there are Reprap _builders_ and Reprap _users_. Lessay in terms of self-mounted furniture. Some people spend weekends with shopping for tools and parts, then even more weekends sawing, painting, and screwing stuff together. They want to _build_ a shelf, table, whatever. Other people visit the next shop of a certain Swedish company, buy complete kby Howie - Reprappers
Well, I'm caught. I have to build a Darwin! However, I tried Alpha Prototypes' online quote by giving them an STL file of a single clamp and they gave me a price over $28,000. Gosh! This doesn't really match the $400 for a complete Darwin... What's wrong here? How can I order the parts at a reasonable price? Or can even somebody here help me by printing the parts on their own Darwin? Looking fby Howie - Reprappers