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Discuss any sort of mechanical stuff here: positioning systems, gears, extruding methods, etc.
Re: Powderbed Machine - 14 years ago
You could also buy a Mercury Vapour (aka High Intensity Discharge aka Metal Halide) bulb, but you would need to find one which does not have a UV filter. I see a couple on bulbs.com for cheap that fit standard edison sockets, though you'd need a fixture with a proper ballast. There are black light flourescent bulbs available too, but I can't find any over 60W. (Although, 60W of UV only miby NuclearNerd - Powder Printing and Selective Laser Sintering
Re: Powderbed Machine - 14 years ago
I was thinking halogen, yeah. You can get a 300w floor lamp from walmart for like $20. It's my understanding that halogen bulbs throw off a lot of UV. (you might need a more specialized UV bulb, but this would be a good start. I'll look for a cheap way to measure the uv flux)by NuclearNerd - Powder Printing and Selective Laser Sintering
Re: Powderbed Machine - 14 years ago
Great John. I would suggest you perform the following simple test: Load a test picture into the photo frame. Get a 300W floor lamp (or shop light). Remove the UV filter (piece of glass) from the lamp. Set the photo frame a few inches above the light (you'll have to find a distance that doesn't get too hot). Turn the whole contraption on and check back every couple of hours. See if the iby NuclearNerd - Powder Printing and Selective Laser Sintering
Re: Photo Reactive Resin - 14 years ago
Reading the linked website, it looks like the latter. Solarez is an "initiator" for catalyzing polyester (or vinylester), much like MEKP. A Polyester/Solarez mix could work for stereolithography, but the Solarez site says it takes 3 minutes of UV exposure to cure, which would make for very slow printing.by NuclearNerd - Polymer Working Group
Re: DIY Photopolymer machine - 14 years ago
HereinCS Wrote: ------------------------------------------------------- > I'm curious, why do people use halogen projectors > for these processes rather than LED? Is it the > brightness or color spectrum? Because the resin cures with UV (or near-UV) wavelengths of light. Halogen bulbs emit tons of UV. LEDs emit hardly any. I've also heard that UV damages the liquid crystals in an LCby NuclearNerd - Polymer Working Group
Re: Autodesk Inventor Fusion - 14 years ago
Thanks for the pointer. I downloaded it today. It looks good - kinda like a parametric version of Sketchup. The downside is it runs dog slow on my machine, which has a pretty top-spec graphics card. So I'll keep using Solidworks until they speed it up or my computer gets faster.by NuclearNerd - 3D Design tools
Re: LOM RepRap? - 14 years ago
Regarding thermal printer ribbons - the economics look even worse than laser printing. The rolls of wax are relatively cheap, but the ink is only 4 microns thick, so it would take quite a few to build any significant height. I also found another commercial LOM casualty (to neighbor the Helisys and Solido graves). The Japanese company Kira used to sell a LOM printer that joined paper sheets usby NuclearNerd - Mechanics
Re: On the Fly Powder Printing Bed - 14 years ago
Quotemartinprice2004 As the head moves across a little powder is deposited, a roller follows it, then a heated plate only slightly above the powder which raises the temperature to the transition point. The heater could be 5mm wide in Y, but long in X so the powder has time to rise in temperature Behind the heated plate is a laser panning back and forth 5mm taking the powder where needed to the meby NuclearNerd - Powder Printing and Selective Laser Sintering
Re: The rebirth of the peristalic pump? - 14 years ago
Hi Loan. Great work! You might be interested in Kraftmark's "fabEpoxy" material for your extruder. They've engineered an epoxy blend with low shrinkage and very long "pot life" specifically for 3d printing. If you can pump it, you should be able to make very high strength parts. I'd be interested to see how it works! http://www.kraftmark.biz/kraft.fabepoxy.htmlby NuclearNerd - Paste Extrusion Working Group
Re: Alternative to timing belts - 14 years ago
I see it has been discussed here briefly, and someone's mocked it up. I'm still interested to hear if people would find it valuable enough to warrant a bit of R&D.by NuclearNerd - Mechanics
Re: LOM RepRap? - 14 years ago
Quotemakeme If you made a LOM Reprap could you still call it additive manufacturing? Seems like that's subtractive, with all the associated waste of materials. Yeah, I definitely think LOM is on the border. For instance, Solidica makes (made?) a sweet little aluminum foil LOM machine, but it ends up looking a lot like a machining center. On the other hand, if you include the "wasted" supportby NuclearNerd - Mechanics
Alternative to timing belts - 14 years ago
Question: do the timing belts used in the reprap x/y/z axes present problems for anyone in terms of cost / sourcing or performance? If so, a cable reel like the following might be of interest. I think something like that could be printed relatively easily. The only potential issue might be the (small?) error caused by the cable movement along the reel.by NuclearNerd - Mechanics
Re: LOM RepRap? - 14 years ago
One more thought before bed: With wax paper, the melting point is low enough to a thermal printing head to selectively bond layers before or after cutting. Actually now I'm trying to think of a way to use thermal transfer printing to lay down wax layers without the need for laminates. You'd need some sort of aborbant scaffold (tissue?) that could draw the wax from the ribbon, made from a mateby NuclearNerd - Mechanics
Re: Printing methode for 'endless' objects - 14 years ago
Seems workable to me, especially as the Mendel extruder appears to work fine at odd orientations. I think jbayless' suggestion of a rigid vertical "floor" is a good one. If you were hoping to make this an "endless" printer, you'll have allow the "floor" to disconnect from the belt and slide along a table with the emerging model. The friction from pushing the model out along a floor might caby NuclearNerd - General
Re: LOM RepRap? - 14 years ago
For completeness: 40 lb "basis weight" wax papercosts only $60 for a 18" x 1200' roll. It's hard to find an actual thickness, but it's probably between 0.007 and 0.01", or 0.15-0.2mm. That gives a build volume of 12" x 12" x 12", or about 1/5 the cost per cubic inch of plastic sheet. I'm hesitant to recommend using wax paper because it's probably won't have the surface finish, strengtby NuclearNerd - Mechanics
Re: LOM RepRap? - 14 years ago
I've spent a little time looking for cheaper film. The Quotehttp://www.mcmaster.com/#catalog/117/3565/=b7e77q cheapest is by far LDPE (visqueen), usually as window or other "self-adhesive" (statically charged) film, anywhere from 0.002 to 0.010" thick. You can also get LDPE film in a nice sized roll for laminating machines, but it's a little more expensive. PVC (vinyl) rolls exist too, but thby NuclearNerd - Mechanics
Re: LOM RepRap? - 14 years ago
... price is still going to be an issue though. The cheapest thermoplastic sheet is LDPE. You can get a 1000' roll of 0.002" thick sheet from home depot, which equates to a build volume of about 10"x10"x10", for $60. With LOM, you have to pay for that whether you use the whole build volume or not. Better thermoplastics like HDPE, PVC, Polypropylene, and ABS are even more expensive. I suppby NuclearNerd - Mechanics
Re: LOM RepRap? - 14 years ago
albanetc Wrote: ------------------------------------------------------- > > As far as DIY developments, I'm not aware of any, > except for Viktor's efforts and my "paper > prototyper" project which has been on hold for a > while: > > I was planning to cut paper with a knife and glue > it using 3M spray adhesive, repeat for every > layer. Ideally I'd like to be ableby NuclearNerd - Mechanics
Re: Rapid Prototyping with Epoxy? - 14 years ago
Quotevdx . all curing ingredients are costly - especial when low viscouse, so it can be ink-jetted Costly is relative I suppose. Epoxy resin & hardener is about $6/lb, which isn't much more than the abs used by and FDM reprap, and about 10 times less expensive than UV-curable SLA resins.by NuclearNerd - Polymer Working Group
Re: Rapid Prototyping with Epoxy? - 14 years ago
I know about stereolithography, but this is different. What I'm describing is something closer to what z-corp does with plaster, only using the two parts of epoxy as the "powder" and the binder. UV-curable resins are very expensive, and aren't as strong as epoxy. The acid / sodium silicate thing is interesting too - but I think it's pretty brittle isn't it?by NuclearNerd - Polymer Working Group
Re: Rapid Prototyping with Epoxy? - 14 years ago
I'm digging up an old thread here, but I had an idea which might have legs. What if you combined epoxy with the powder printing approach described here. What I'm envisioning is a bed of resin, perhaps mixed with filler to reduce costs and increase the viscosity. An inkjet printer would deposit hardener in the desired cross section. Finally the build table would drop and a blade would spreadby NuclearNerd - Polymer Working Group
Re: Electrostatic Sintering? - 14 years ago
Here's another obstacle - toner isn't the only consumable in a laser printer. The photostatic drum wears out too. I did some research and found that typically the drum and the toner are both replaced after about 3000 pages at "5%" density - At about 0.01mm thick, that's only a few mm thick of build material per $50 cartridge. That's not exactly economical!by NuclearNerd - Powder Printing and Selective Laser Sintering
Re: Electrostatic Sintering? - 14 years ago
Thanks again Markus. I've almost got enough enthusiasm to start hacking something up. I searched the archive and saw that this has been discussed a little before, although they envisioned using the toner transfer method you suggested upthread. I'll PM jdoll and see if he got anywhere with it. So step 1 is to get toner transferring from a laser printer drum to a build space, either directly orby NuclearNerd - Powder Printing and Selective Laser Sintering
Re: Electrostatic Sintering? - 14 years ago
Traumflug Wrote: ------------------------------------------------------- > LOM uses the paper as the build material while > with toner transfer, it's just a (reusable) > transport medium. None of the paper is intended to > end up in the final part. OK, I understand now. Kind of like those iron-on t-shirt transfer sheets you can buy for your printer. If we can't solve the charged-mby NuclearNerd - Powder Printing and Selective Laser Sintering
Re: Electrostatic Sintering? - 14 years ago
Actually, I've built such a machine a few years ago. With one drum only, but it was capable of doing a print. Great post Traumflug. It's really cool to hear about your experience with this. I figured that getting the toner off the roll would be tough. We would need to keep the part at a static potential greater than the roll. Maybe we could connect the build table to a Van De Graaf generatorby NuclearNerd - Powder Printing and Selective Laser Sintering
Re: Electrostatic Sintering? - 14 years ago
QuoteWith an automated powder-bed and SLS you can make nearly the same with a single powdered material and the layer thickness can be varied much more ... True, but the surface quality of SLS printing suffers because of the porosity of the sintered part. Here I'm suggesting a method that allows us to densify each layer more compactly using heat and pressure from the fuser. When you combine thby NuclearNerd - Powder Printing and Selective Laser Sintering
Electrostatic Sintering? - 14 years ago
Hi all. I'm just digging into rapid prototyping and I've caught the bug. I can't wait to build my first reprap. Here's a thought for a (possibly?) novel method for 3d printing. The idea is to use the guts of a laser printer to deposit 2d layers of toner. Here are the details. I'd love to know if you think there's anything to the idea: * Take apart two laser printers (or one colour laser prby NuclearNerd - Powder Printing and Selective Laser Sintering