Still interesting to talk about, though. I had a different view of the system, especialy since it was an older unit. From my understanding of the system, it was a standard vat SLA. Vat of liquid and an X-Y galvo aiming the 100mW solid state laser from the top (looked to be CW? I'll have to check the normal modes). They improved accuracy by trading in for settling time, so it built slower.by SOI Sentinel - General
I know not everyone is thrilled with the Farnell steppers, especially state side. I poked around a bit and ran across Anaheim Automation. Anyone ever look into their capabilities? They list the prices for some stepper models right on their web site and it seems competitive. I'm personally interested in their BLDC motors. I also ran across LIN Engineering, who seem to be perhaps rebrandingby SOI Sentinel - Mechanics
The base compiler is GNU actually, downloadable for free from their support tools web site. ∂=SW006012 Few ARE in PDIP format, yes. Well, at least the more capable chips. There's about 20 variants that come in a DIP package and run at 5V. Most are thankfully motor control varieties. This generally means that you will have 3 PWM pin pairs that are specific to motor control (same time base)by SOI Sentinel - Controllers
I don't know about the original cost, but the original cut sheet on the machine is linked in the second post in the thread.by SOI Sentinel - General
Of interesting note, some mechanical parts manufacturers put out CAD files of their products as STL files. I was just digging through the CAD repository of dodge-pt.com for some 3D CAD files of their timing belt pulleys for work and found that they support a few dozen CAD formats, including STL and STEP.by SOI Sentinel - General
I don't know what's worse, that or the fact that about 50% of the links point to a personal web site hosted by my alma mater (thankfully removed).by SOI Sentinel - General
Sounds like you need Matweb. I've been using it since college (2002) to do material lookups as I go about my day (electromechanical applications engineer is probably the best term for what I do). You need to poke around a bit, but Matweb has quite a good listing of material properties. If you bore down to a specific manufacturer (as I did with HDPE + Bottle + FDA to see what's qualified forby SOI Sentinel - Reprappers
337.1nm actually.by SOI Sentinel - General
I am unfortunately in a serious financial bind right now, otherwise I might have been interested. Anyway... That machine makes me optimistic. 100mw UV solid state laser? That's the average power output for some of the homemade N2 lasers. 32L @ $0.32/cc ~ $10,000 vat price initial investment. I wonder if Fernando can educate us as to how much of a markup this is?by SOI Sentinel - General
PP/PE capacitors are probably a good possiblity. I've been personally thinking of using an HDPE backplate and a micro-silver deposition (inkjet method) to build the basis of an active electrode (I have interests in EOG systems). We have a lot of research to go through...by SOI Sentinel - General
So... we'll save the world when we develop a head-set that can do image recognition (part selection, placement verification), routing, drilling, soldering (solder paste dispensing + point heating, maybe area heating too), and part selection (vac pickup tool)? It's not unheard of, Just a little overboard at this time, and it would probably require a stiffer machine than Darwin. One issue with adby SOI Sentinel - General
Sean: I don't know if an air laser does have a signature power spike. I don't think it would make it back past the flyback transformer to where it's safe to measure. In the HV side, the electrodes are directly connected to the DC discharge capacitors along an edge in most models. You either get a spark at a hot spot or an even glow of firing. The issue is that at atmospheric the N2 max inverby SOI Sentinel - Laser Cutter Working Group
Steve, Lee's mixing up Capa with polyactic acid (PLA). CAPA is probably identical to Polycaprolactone, but either no one's asked the manufacturer or they're not telling. I believe so far the best was also the first. Adrian assembled the first Darwin directly from the instructions on the main site (check the main blog). It apparently went smoothly without any real trouble spots. I don't belby SOI Sentinel - Reprappers
Yes, that's the idea. Oddly enough, the Darwin with some mild modification would also make a good SLA machine, but with reduced capacity. You replace (or modify) the MDF board with a build platform that drops down in the center on four rods to the bottom of the current machine. Remove bottom stiffening rods (will probably have to find a replacement option). Put the vat on a slide on the bottoby SOI Sentinel - Laser Cutter Working Group
And Fernando has pretty much brought us back to a stereolithography (SLA) system, at least the one I've known in the past. A high speed laser positioning system does take some expertise and time to make, but it's not impossible. We'd need some small galvanometers and controllers, but it could be done. There are some dedicated people out there making galvos at home for their own laser light shoby SOI Sentinel - Laser Cutter Working Group
So, what's next, EDM? Anyway, my current favorite site to understand the differences in construction is this professor's personal site. Fiber optics may be the best choice for the laser, but testing will definitely be required. I'm curious about focus and energy loss. One advantage I do see is that you could have multiple lasers focused on a point or in a row, multiplying your fire rate (ifby SOI Sentinel - Laser Cutter Working Group
Here's some of my thoughts on your views Head switching and material feed: I've put a lot of thought into this one. My personal preference involves a different electrical design than we have, but it should be possible on Darwin. This means that we need to have all heads connected, powered, and talking at startup and nothing drops off the net. While hot plugging is possible, I'm not certain wby SOI Sentinel - Reprappers
I know we have a few people here that are interested in lasers, and I've put some thought into this (I blame Fernando!). I'm putting down some thoughts. The two most useful I could see being used with a RepRap is a CO2 laser and a nitrogen laser. TEA lasers actually. Google will provide a more complete answer than I can as to what that is. The CO2 version would be great for doing cutting, buby SOI Sentinel - Laser Cutter Working Group
Ack, I never remember what works where, and a lot of the motors I deal with have an additional case ground wire, so I thought all center taps were tied together from the "six wire" setup. I see I'm wrong after a little reading here and elsewhere. I tend to live and die (professionally) by PMAC three phase servo motors for motion control. Tends to warp my perceptions sometimes. A discrete FETby SOI Sentinel - Mechanics
Ack, no good. You'll have to make an entirely new driver board. Unipolars have a constant common high voltage line and switch each individual coil to ground to actuate. Bipolars change the current flow through each coil set to move. They take entirely different driver configurations to accomplish this. While one board can be made to do both drive schemes, I don't think the RepRap driver boarby SOI Sentinel - Mechanics
My wife's architecture school has one of the Z Printers. They're basically a starch-like build material and a liquid binder. Change the binder color and you get different parts colors. Horribly hygroscopic unless laquered, and the powder gets everywhere. About 10% of the models break just being extracted from the powder bed and cleaned up. The actual company doing this, Zcorp, has some veryby SOI Sentinel - General
There is at least one good reason to not do a Theta YZ layout instead of the current XYZ design given "Darwin 1.0" electronics. Taking any axis to a rotary axis will require accurate parts. Backlash becomes a more significant concern (especially if you build something that's distant from the center) as does gearing torque to get you the oomph to accelerate that interial mass of the turntable.by SOI Sentinel - General
Hmmm... uses for a RepRap that (may) simultaneously drive an industry to its knees or create one -Any game that uses collectible figures -Robo-One and related -Architectural conceptual models (my wife would kill for this) -Kids toys (and not quite kids toys, ever see what people are doing with Nerf these days?) -That blasted battery door to my TV remote that broke and now I can't even find it -Cby SOI Sentinel - General