... the water disperses nearly immediately in the powder and evaporates quickly if heated, so it's not enough for sintering-inhibition ... the salt crystalizes out, so a thin coating of nano-salt-crystals separates the wetted particles, even if they melt under the IR-heater ... An LCD-mask is only usefull if the LCD isn't affected by the heat from the IR-source and don't block the radiation on tby VDX - General
Hi Alex, ... check the german forum, especially "Hi German RepRappers, where are you located?" - i know there are some reprappers in Berlin too ... *** EDIT: checked the posts and noticed that the German forums had mainly suffered from the "Umlaut"-bug ... many posts are truncated after the first occurance of a special sign ... and nobody managed to repair the truncation So maybe ask your queby VDX - General
Hi Alex, ... if you can assemble the model from two parts (legs and upper body) then tis wouldn't be a problem. Bigger 'overhangs' are a bit tricky but some guys solved this too with supporting cobweb-structures ...by VDX - General
... there were some related discussions, don't know where ... you need only 5 axes, as you can replace any 6th by rotating one of the others ... snd yes, a 5-axis-RepRap would be a big advantage, but the software is a really big venture tooby VDX - General New Machines Topics
Hi Sebastien, > VDX mentioned that he had done some work on a > related subject, and might be up to putting it in > the wiki. ... i'm really busy now, but here is a related discussion and atached images with some of my then developed and used tools ... mabe helpfull?by VDX - General
... i think the idea behind RepRap was to create a system capable of building most (if not all) of its own parts with an affordable cost, so anyone interested in the technique could participate. The idea is not unique (most CNC-routers can do the same), but it was based around FDM with DIY-plastic (PLA) for reducing the basic costs and an ecologic meaning ... but you need some 'vitamines' as eleby VDX - General
... by the way - if you already have a cutting/sintering laser, you can combine the mask-sintering method by applying an IR-heater and cutting the masks with the laser. But there are some really hard to realize preconditions: - for the masks you need a material which you can cut with the laser, that withstand the heat from the IR-source and is cheap enough for highcount masks per part. For plasby VDX - General
... inkjet printimg and areal sintering is much faster than fabbing with FDM or laserspot, but you are limited by possible materials and final stability. Masks are made from heatresistant and/or reflective material and you have to cut every changing layer or combine single elements as in oldstyle Gerber photoplotters. With laser you have much higher temperatures, so you can melt/fuse any materiby VDX - General
... not water, it's called "Inhibition Sintering" and you print with a salt-water mixture - the water evaporates, the salt remains and "inhibits" the melting/sintering of the 'contaminated' area. When heating the surface with an IR-heater, the clean powder melts and the salt crystals prevent the fusing in the printed lines ...by VDX - General
... beside SLS there is another sintering technique called "Selective Mask-Sintering" - here you rise your powder-bed as with SLS but then you place an optical mask on the powder-surface and activate an areal IR-heater above the mask, so only the powder not covered by the mask melts. I would atach the PDF-file, but it's 3MB, so i cant upload ... here the (maybe temporary) link to the (German) PDby VDX - General
... the most promising omnipotent technology is laser-sintering - here you haven't mechanical forces, so your mechanics can be lightweight, but have to be really accurate. And you can make any shape from every material you can melt/sinter with the laser. The only problem is the fabrication of the laser source, here only CO2-tubes with extrenal mirrors and a high-volt PS are in the DIY-range, alby VDX - General
Nyarlathotep Wrote: ------------------------------------------------------- > > Slightly off topic has anyone discussed the > > fundamental stumbling block of extruding a part > > that will stand the temperature of extruding > the > > same material. How are we ever going to make an > > extrusion nozzle?! > > > Well, single-material isn't a design goal.by VDX - General
Hi Adrian, its really interesting stuff and give some ideas for meso-/macro-scale-fabbing with 'vanishing' materials I know similar 'macro'-systems with a soldering bit vanishing styrofoam - my father made his mountains for a model-train with this methode. I remember a post in the forum where someone modelled wax-blocks with a heated needle sucking the molten wax away ...by VDX - General
... the main difference are the fumes - some plastics are extreme toxic and carcinogenic when burned away ... remember Seweso/Dioxinby VDX - General
Hi Bob, rhmorrison Wrote: ------------------------------------------------------- > > Even the badest ones, ... > > > Is that proper English English because it's > certainly not proper American English! ... this is more like "German English" - sometimes i have similar issuesby VDX - General
... or adopt this behaviour as "RepSpam"by VDX - Russia RepRap User Group
... a word for "all files in one place" - i'm actually posting/blogging and updating my diodelaser-work ... As i was asked for more informations in complete separate forums (and languages), i started with a 'multi-places'-blogging: - so i actually have to update all relevant infos here in english and german, on the wiki in two language versions too and aditionally in a german CNC- and a specificby VDX - Plastic Extruder Working Group
... i'm following the f@h-project as long as RepRap ... As you can see, the f@h had a highly optimized start, a strict roadmap, mainly closed development ... and a relative small community RepRap on the other hand was/is much more imperfect, a bit 'shaky' and a really good candidate for 'repstrapping' with materials you have at hand or in your scrapery ... and the community 'explodes' in a neby VDX - Plastic Extruder Working Group
... um die Dioden mit einem 'richtigen' Laser zu vergleichen, habe ich mit dem Faserlaser bei 1Watt Leistung mit einer einfachen Fokussierlinse und einem Spot von etwa 30 Mikrometer Durchmesser (mit Strahlaufweiter wird der Spot kleiner 10 Mikrometer) parallele Linien mit 2mm Abstand über die vorher gelaserten Buchstaben gezogen: Die Schmelzspuren sind zwischen 40 und 80 Mikrometer breit - icby VDX - Laser-Ecke
... to compare i engraved the same material with the fiberlaser at 1Watt CW and a single focussing lens - so the spot was around 30 microns in diameter (with beamexpander the spot will be below 10 microns). The trays have 2mm distance and measure between 40 and 80 microns in width. I think the surrounding material melts and retracts, so the molten tray is much wider than the original laserspotby VDX - Laser Cutter Working Group
... here is an old post about embedding prefabbed structures and such ... or try the search with "embedding" and "All Dates" set ...by VDX - General Mendel Topics
Hi Marcus, > > and/or > > you embedd some rods or fibres for the needed > > rigidity. > > Way ahead of you. > The parts already have added support-structures. > > For some flat parts I´ll add additional ones as > they flex too much for my linking > (unfilled). ... have you constructed/fabbed the support-structures or embedded aditional insets from metal,by VDX - General Mendel Topics
Hi Marcus, ... hotglue (mostly EVA) is really elastic, so a harder filling material would be better ... and/or you embedd some rods or fibres for the needed rigidity. But anyway - excellent workby VDX - General Mendel Topics
Hi Marcus, ... have you already tried with infilling the parts with some 2K-epoxy for getting higher stability? I think with your shelled parts and solidifiyng critical objects after printing with epoxy the building time and the overall costs per set can go down dramaticallyby VDX - General Mendel Topics
... i don't see any real benefit either You can get complete single motor-drivers below $20 (i remember seing some singlechip-drivers even below &10) which need two pins per motor (DIR, CLOCK) and you can drive two or more motors synchronous so your mechanic is much faster/accurater than with only a single axis moving per timeframe ... The advantage of a discrete transisitor-array over a sby VDX - Controllers
... anbei zwei Photos von Folienschneidtests mit 1Watt bzw. 2Watt und 500mm/min Vorschub. 1 - 1Watt: zum Testen der Mindest-Anforderungen - die Gravierspur ist 0.25mm breit, die Löcher haben etwa 0.28mm Durchmesser und entstehen beim Start/Ende einer Linie oder eines Kreisbogens wegen des etwas langsameren Vorschubs 2 - 2Watt: glatter Schnitt mit einer Fuge von etwa 0.28 bis 0.3mm Breite - dby VDX - Laser-Ecke
... atached two photos where i cutted black plastic foil with 1 Watt power at 500mm/min for testing the min-limits and with 2 Watts for a clean cut. The carved tray in the first image is 0.25mm wide, the holes were melted at the start/end of lines and curves, where the moving speed was a bit slower. The holes and through-cuts have a width of 0.28 to 0.3mm - for a thinner cut i need a much betteby VDX - Laser Cutter Working Group
... for what More problems and misbehaviour than cost saving ...by VDX - Controllers
... with the naming conventions: - a RepRap is mainly built with printed parts (self-Replicating Rapid prototyper) ... all other systems should better be named RepStrap And for the accuracy: - my CNC-mill has an accuracy of 0.0125mm in halfstep-mode and corresponding better with microstepping - the repeatability of the XYZ-position is depending of the mechanical setup and even with high microstby VDX - General
... für in den Vertrieb gebrachte elektronische Komponenten dürften die allgemeinen Bedingungen gelten (TÜV/GS/CE, Elektronikschrottverordnung/Rücknahme), unabhängig davon, ob die Platinen geätzt oder gedruckt wurden. Die Frage ist eher, was du in der Richtung mit dem RepRap anders machst oder was für Kunden du hastby VDX - Altes Forum