For suitable pulleys, brass bushings, and double wide linear bearings, did you try Misumi? They're a really good supplier, IMO. stratmaster458 - As far as I can tell Ultimaker really hasn't disclosed an actual bill of materials, which rather severely strains the definition of 'open source', seeing as it is very difficult to actually source parts equivalent to the ones they used. I was hoping toby jbayless - General New Machines Topics
There's actually no need for a servo, if you use two print heads and are willing to lay down parallelograms instead of squares. I mentioned idea like this a while ago but I haven't tested it yet. Hoping to get around to that this year... It should be extremely easy to make this kind of nozzle. The slicing software will need to be changed; that would take the most work. But the algorithm itselfby jbayless - General
Ah, cool! That's a neat stepper motor cam-attachment; where did you find that?by jbayless - Plastic Extruder Working Group
I think it's still a good idea to find 8mm rod for them, if you can. The lifetime of the bearing will likely be shortened by using 7/16" rod, because the bearing won't have its proper preload.by jbayless - General Mendel Topics
Hi, I'm just posting this here for posterity, since I don't plan to pursue it (at least, for quite a while). Stratasys' print heads have a mechanism for swapping between two filaments with a single drive motor. Here's a plan for a variant of Wade's extruder that can swap between an arbitrary number of filaments with a single drive motor. The image below shows the view from two different angles.by jbayless - Plastic Extruder Working Group
Tool changing is a good solution for multi-material printing, like switching between plastic and support material. But I don't think it works well for colour printing. The main problem with this approach is that even with six different nozzles, you can still only print in six different colours. Even a crude 16-colour printing would require 16 nozzles, and 16 different spools of plastic... The proby jbayless - General
Hi everyone, Just wondering if anyone who has an Ultimaker, or was involved in its design, could give me a hand with this. I'd also be happy to hear from other Bowden cable users. I'm designing a bowden feed for my Repstrap right now, and I'd like to use quick-fit couplings (or something similar), and choose an appropriate feed tube. I noticed that the Ultimaker uses these kinds of couplings anby jbayless - Reprappers
GreenAtol - You're right; the fact that today's precision equipment was built, generation upon generation, from less precise machines and hand tools is the best argument against critics who claim that self-replicating machinery will lose precision with each generation. Alex Slocum's lectures are good reading in general, and the third unit covers a couple of those methods. One of the ways that pby jbayless - General
As a compromise, what if an extruder were set up with two motors - a large, torquey, stationary Nema-23 frame motor, and a small lightweight Nema 14 frame or smaller on the print head? Although it would be a more expensive setup with two motors, it might be an interesting option for a high performance system. I'll take a look at the math and see if this actually is a sensible proposition or if iby jbayless - General
I agree with all of the above, and I'd also add, any application that is safety-critical. I would not be overly concerned about alignment because after many cycles, the gear teeth will wear down at the 'high points' and the contact area will gradually increase to its maximum. In general the torque capacity of the gear will increase in proportion to the height of the gear. There are engineeringby jbayless - Mechanics
Since PLA is so heavily dehydrated I would assume that it doesn't absorb much around 2.4 GHz. But if there's no data available, it would be a good idea to test it yourself before committing to something critical. I downloaded that IEEE article through my university; send me a PM if you need a copy.by jbayless - Polymer Working Group
In addition to those listed above, Misumi ships internationally and has a good range of metric parts.by jbayless - General
CdnRepRap's advice is good; I'd just add that you could also bring photographs of the printer, and tangible printed parts in with you to an interview. One of the ways I got hired for my first internship was by bringing photos of a little Stirling engine I'd built. I'm not sure that's what did it but they asked me questions about that project, and as a second-year university student my formal educby jbayless - General
I think the main obstacle is that plastics like these are usually not available as a filament in small quantities, so it's hard to do experimentation. If you can find a company that will supply filaments of such plastics, then I'm sure there would be many volunteers with RepRap machines willing to test them out and report back on their experience. =) Otherwise, we might just be waiting for granuby jbayless - General
I suppose I'm more concerned about straightness and repeatibility. Although aluminum extrusions are quite straight, it can't compete with centerless ground steel shafts. In my opinion straightness is important for a reprap, where print layers can be as thin as 0.2mm. JIS tolerance requirements for aluminum extrusions allows for 0.1mm deviation in flatness, 1 degree of twist per 300mm length, andby jbayless - General
Maybe, although I don't trust aluminum extrusions as a bearing surface. My guess is that almost all of their mechanical components are sourced from Misumi. The pillow block bearings in the T-Rep 3 would then be one of these: Misumi pillow block bearingsby jbayless - General
I'm a senior mechatronics engineering student. I joined the project specifically because it was open-source. Also, if it was not open-source, it would probably have been very difficult for me to become involved with, on the development side.by jbayless - General
I purchased copper foil tape from McMaster-Carr (76555A711). It is available with or without conductive adhesive. I was able to solder to it with no difficulty, and when I measured the connection through the adhesive, it looked like a short circuit. (Even if there is a resistivity, it's over a very small distance and a fairly wide area).by jbayless - General
Ultimachine is different than Ultimaker. Ultimaker's axes layout allow it to be very fast. I think it effectively holds the print speed record so far. To my knowledge it's not available yet for retail.by jbayless - General
Markus Amsler Wrote: ------------------------------------------------------- > You probably meant 30mm/sec which at 209 Hz > results in 0.14 mm. So I doubt there's any benefit > of higher rates. No, I did mean 30 cm/sec, which is the speed that the ultimaker extrudes at. Without a doubt, RepRaps will be pushing past that speed before long.by jbayless - General
Hi HereinCS, The second pulley is an idler pulley, so it gets mounted to a ball bearing. Depending on the type of pulley, you can either have the ball bearing inside the pulley and have it spin on a fixed axle, or mount the pulley directly to a shaft and have the shaft supported by bearings. The choice of which one will depend on what kinds of parts are available, and what is more convenient forby jbayless - Reprappers
The efficiency of converting electrical energy to heat with a Peltier junction exceeds 100%. But as Wade pointed out, it's really not worth the cost to use them this way in most applications. Maybe if you were trying to run a battery-powered reprap it would be worthwhile.by jbayless - General
Yes, thanks to you I've become a big fan of Shinko Sellbic. I wonder if they'd accept job applicants from overseas.by jbayless - Shape Deposition Manufacturing Working Group
The limitation is that layers will regularly need an edge that contacts the conveyor belt. So you couldn't print, for example, a very long cone.by jbayless - General
Yeah, the 'floor' would need some way of disconnecting once the model has been securely anchored to the belt by enough printed layers. As for makeme's issue, that could be resolved either with a constant force spring used to counteract gravity on the vertical axis, or by flipping the whole printer sideways (eg. mounting the printer to a wall instead of on a table), so that gravity once again pulby jbayless - General
That sounds like a big improvement. If the current command rate is 209 Hz, and the axis is moving at 30 cm/sec, that means that it travels a distance of 1.4 mm between recieved commands. At 1798 Hz, that's 0.17 mm between commands, which is definitely much better! Go for it, and good luck!by jbayless - General
That's a very neat suggestion. When you print each vertical slice, you'll have to make sure that the bottom filament adheres both to the printed object behind it, and to the conveyor belt. It would take some precision, and perhaps the nozzle would need to be cut with a bevel. The conveyor belt would become the new "z" axis, since it would move slowly and in only one direction. The other two axesby jbayless - General
Hi, To me this sounds like a really good idea. But it's hard for me to judge its merits, because I don't know what the current RepRap communications are doing 'under the hood'. Would you be willing to explain how the current setup works?by jbayless - General
IMO the main advantage of using filament is that it's a cheap way to get precision. You know that for a filament of cross-sectional area A, advancing it by a distance D will extrude a volume of plastic equal to D x A. If you make a granular extruder like that, you won't be able to benefit from a geometrical relationship like that anymore. Then you will need another system to control the flow ratby jbayless - Plastic Extruder Working Group
For the "long gears" idea, you might be interested in products like McMaster-Carr 6847K11. Known as "gear stock" or "gear rod", it's basically a long bar with the cross-section of a spur gear. They're solid steel and fairly large (13 mm dia) so deflection might not be a major problem, assuming that it's mounted well with bearings on either end. My main concern with this approach would be slidingby jbayless - Plastic Extruder Working Group