$35/lb. isn't a deal - it's a steal. Normal retail price for Stratasys filament is $250 for a 2 lb. spool - dealer cost is $200. NewPerfection Wrote: ------------------------------------------------------- > Holy crap that stuff is expensive! Especially > if $35 a pound is a deal!by Have Blue - For Sale
I've seen quite a few band heaters on Ebay - here's a very inexpensive little 3/4" unit:by Have Blue - Plastic Extruder Working Group
Nifty! The idea had occurred to me as well (I sell a lot of push-to-connect fittings and Nylon tubing for paintball guns), but I wondered about the stiffness for such an application - I can easily imagine the teflon tubing stretching a bit when the filament is driven through (though adding a bit of rollback in software may alleviate this).by Have Blue - Plastic Extruder Working Group
Buback Wrote: ------------------------------------------------------- > I can imagine complex algorithms to determine > when/where to use soluble support and when to just > use regular plastic in a double-extruder machine. > what would be particularly nice would be to just > use soluble support for the interface of exterior > support and model. That way you'd only be using a >by Have Blue - General
VDX Wrote: > ... think about hollow objects with support > structures embedded in the cavities and only small > openings to crack and remove the support - here > soluble support is much more user friendly Precisely - I don't think you'd have a chance of removing non-dissolvable support material from, say, a printed ballnut/ballscrew assembly...by Have Blue - General
I think our concepts of 'desktop sized' may be skewed a little as that term can cover quite a range (and I've admittedly been playing a bit of devil's advocate). I seem to recall that Stratasys FDM machines were once advertised as 'desktop', though at several hundred pounds, I really can't take that seriously... For utter simplicity, compactness, and ease of use, no - I don't think you can beatby Have Blue - Plastic Extruder Working Group
makeme Wrote: ------------------------------------------------------- > It just seems like a granule extruder is drifting > much closer to an industrial machine than a > desktop machine. I mean, turning granules into > something else is an industrial process. Have you seen the granule based rapid prototyper Anna Bellini built as part of her thesis? (page 206: ) It's most definitelyby Have Blue - Plastic Extruder Working Group
mlagana Wrote: ------------------------------------------------------- > I got a part printed on a dimension printer today > and it used ABS for the part and support. I asked > the girl if the support was orange and waxy and > she said no it's the same. Dimension printers do not use ABS for the support material - BST machines use a high impact polystyrene for support and SST machinesby Have Blue - General
makeme Wrote: ------------------------------------------------------- > For example, in my mind the only reason to go to a > granule extruder is if you want to print a whole > lot of plastic because then the savings of not > paying for the ganules to be turned into filament > makes sense. It's a scale thing. If you're just > going to putz around at home you're never going to &gby Have Blue - Plastic Extruder Working Group
Yes, trying to find a cheaper source of filament was the primary goal, and I think use of injection mold grade plastics rather than extrusion grade will have benefits for RepRap as well (lower drive force required, and hopefully less warping on parts). Right now I'm selling my extra 5lb. spools of MG47 for $135 plus shipping, but I'm sure this can be driven down to under $100 for 5lbs. if demandby Have Blue - General
I'd be curious to try Teflon ENP plating on metal extruder parts:by Have Blue - Plastic Extruder Working Group
I'd love to be able to make my own feedstock, but had to settle for having the professionals do it for me. I had some SABIC MG47 ABS extruded into 0.070" filament and documented the process here:by Have Blue - General
Stratasys has information here: A fellow in my foundry class this past semester used the same process (though using a LEGO figurine, which is also ABS) at home with a plaster mold and ceramic kiln to make his own mold. The cast aluminum part came out surprisingly well!by Have Blue - General
galaxyman7 Wrote: > The problem is, when the melted plastic comes out, > it is full of bubbles. It doesn't come out > cleanly. Of course i could only push it through > about a half inch before the aluminum nozzle got > cooled down too much. So it could be just the > first few inches that do this. Does anyone know > why this happens? Nylon _loves_ moisture and will absorb a sby Have Blue - General
I assume this is specific to the RepRap host software? Under Mach3, I just toss in M00 for a pause when I need one...by Have Blue - General Mendel Topics
Have a look at 'Microcasting' on pages 5-6: Page 3 of this paper discusses how the process differs from welding and thermal spraying:by Have Blue - General
nophead Wrote: ------------------------------------------------------- > If it is on cold bed then it will anchor the raft > well due to the holes. This is what Shinko Sellbic did on their machine in 1997: Doesn't appear to be a heated bed - just (reasonably thin) perfboard clamped in mid-air.by Have Blue - General
jbayless Wrote: ------------------------------------------------------- > I don't think that 1.75mm geometry filament > results in lower extrusion pressures. The pressure > required to extrude will depend primarily on the > flow rate and the nozzle diameter and length. The > filament diameter shouldn't affect that. Sorry, I should have said 'force' instead of 'pressure' - you're cby Have Blue - General
Instead of splitting the G-code into two files, couldn't you just put an M00 command at the end of that layer to pause execution?by Have Blue - General Mendel Topics
Well, I'd assume you'd be able to use an IR source (as long as it covers a spectrum and is not a specific wavelength) and an IR sensitive camera (as long as it is sensitive across the entire polymer bond IR absorption spectrum from about 2500nm to 16500nm). That range is certainly way outside of what a visible light spectrometer will handle, though (you'd have to realign the lens and diffractionby Have Blue - Polymer Working Group
I doubt a visible light spectroscope will do much for you, especially as pigmentation may affect readings. Plastic analysis is done with IR spectroscopy.by Have Blue - Polymer Working Group
1.75mm extruders also allow you to run PP3DP and Stratasys filaments. I think the biggest benefit is in lowered feed pressures - this extrusion grade ABS is like trying to pump concrete through a garden hose, and it's no wonder there have been so many extruder versions to deal with stripped gears and the like.by Have Blue - General
There have also been a number of papers published on the topic (not specifically RepRap, but commercial machines) - here's one of them:by Have Blue - General
Oh, sorry, didn't check back far enough in the thread to see that you're in the UK. Hopefully you can still use it as a price point for the purposes of your report.by Have Blue - General
Try surpluscenter.com - I've gotten a number of motors from them, and they have a 1HP for $60: Of course, shipping would probably run half that for such a beast...by Have Blue - General
Shinko Sellbic has apparently done a hybrid FDM/milling machine (from 1997, apparently): They have some other neat things such as a filament-fed mini extruder head:by Have Blue - Shape Deposition Manufacturing Working Group
I came across a paper today that might be of interest - "Recycling of RP Models by Solution – Casting Technique":by Have Blue - Kartik M. Gada Humanitarian Innovation Prize
Anna Bellini did some fantastic research on nozzle geometry in her PhD thesis, and page 206 has a photo of the extruder based rapid prototyper she built: She notes that the extruder module itself was manufactured by Shinko Sellbic in Tokyo:by Have Blue - Kartik M. Gada Humanitarian Innovation Prize
The 'EvaNut' - cheap, DIY zero backlash leadscrew nuts:by Have Blue - General