Has anybody seen a video of this making a large piece? We have discussed moving build beds extensively and generally question the ability of a conveyor belt design being able to keep the corners from curling up, even heated. It looks great, but until I see proof that parts as big as the bed still come out without curled up corners, and there is some reliable way to automagically get the finishedby rocket_scientist - General
Tony Wrote: ------------------------------------------------------- > “…the PID can easily be done in the ATMega or > Aurdionos that we currently have, it is not > difficult to do if you are programming in C.” > -The point here is not about how easy but how > FAST. Having a poor 8-bit controller do > floating-point math, G Code processing, PID > control… I think you border onby rocket_scientist - General
Thanks for pointing that out, Rick. Work won't let me complete the checkout process, so I will order from home. I will pick up a few color variations in ABS, and some PLA and HDPE to see how they work in the glass nozzles compared to ABS. I have also been thinking bonding together a few pieces of different intrinsic colors and run it through a glass nozzle with easy view between the heater wiresby rocket_scientist - General
Yes, I just ordered some larger outside tubing. As to using stringers of soft glass mixed with boro, they strongly recommend against mixing even slightly different Coefficient of Expansion glass types in fusing and slumping. They talk about doing test runs even within a single brand in case a small difference not mentioned in the spec causes a problem. But it is possible that with the much smalby rocket_scientist - General
I wish it had PWM hardware as well. It would make a great robot-on-a-board or Underware ROV-on-a-board if it did. Running 6 to 12 PWMs in software, even with fast interrupts, could get messy. On the other hand, 16 or even 32 channel external PWM chips exist with I2C interface, so that would be easy to add. However, Tony, the PID can easily be done in the ATMega or Aurdionos that we currently havby rocket_scientist - General
Ah, I completely missed the point, aka47, thanks for explaining in detail. Yes, an additive spiral of glass is the easiest of the four or five methods I was thinking of. My only current problem is that no one seems to sell borosilicate stringers, very thin glass rods. 3mm seems to be the smallest, and that is too coarse for making the spiral. I will have to work on stretching and thinning the 3mmby rocket_scientist - General
No, the nichrome wire burns away before the glass even gets soft enough. And if you heat the glass up high enough to kepe it warm for a few seconds, it is so soft that the pull of the wire bends the whole end. I am looking into using tungsten wire, but it is 20 times more conductive then nichrome, so must either use a very thin wire, long length, or switch to high current low voltage heater (40Aby rocket_scientist - General
Looks a bit tough for my garage setup. Yes, I REALLY wish that a spiral could be cut in the glass for the nichrome. Then, the out tube of glass would easily fit over the wire. Same with making a slot for the thermocouple. I have been playing with that all day. Mostly created thermal stress cracks using cold tools, and warping the shape of the tip. A small amount of expansion at the top of the heby rocket_scientist - General
I still like just wrapping the nichrome wire around the glass for heating. Nophead, thermal stress is a critical concern with glass, but the borosilicate has ore strength and a lower coefficient of thermal expansion. While making them, I have one end glowing orange to yellow hot (working temp is around 1250C) and 5cm away I am holding it in my hand at 37C, so a gradient 24C per mm, 5 times tby rocket_scientist - General
I would also say that 3D solid freeform printing is more the commercial side, and reprap more the DIY/homebrew side Mikeby rocket_scientist - General
Peer, sorry to say that I don't have a working extruder yet, let alone a repstrap or reprap, so I can not answer that question yet. However, at this point, JBayless, Wade, Greg Frost, and mccoyn should have one or more nozzles each to experiment with, and most of them have running machines. The 4.5mm outside, 3mm inside would have to have 0.75mm thick walls, which is very thin. It might work,by rocket_scientist - General
The 6 mm thin walled tubing is too narrow for the 3mm filament to fit. I will try at some point 'blowing' the glass tube wider to accept the filament, but I am not that skilled yet. It should be easy for someone with more practice at actually blowing glass. Next time I order from Hot Glass Color, I will try a 7 mm medium wall to see if it fits better. And to see if thinner is better. Thinner willby rocket_scientist - General
Jacob, I only have ABS here, so all my tests are with plain ABS. For three of the four tests I have done so far the Katpon tape worked just fine, even at ABS extruder temperatures. They only problem was the tapered nozzle. I think I used to short a piece of nichrome, or to fine a gauge, and it mostly only covers the very tip. With glass being such a power conductor of heat, I am beginning to thby rocket_scientist - General
Want to try a glass nozzle, too? No need for PTFE or drilling. Just wind the nichrome around the tip, connect a thermocouple, and clamp the other end to your extruder base. More detailed instructions at wiki:Glass Nozzles Mikeby rocket_scientist - General
Here is a video of my second glass nozzle construction test. The fist attempt did not work because it took too long to heat the plastic inside the glass. But the second take on the video, although the lighting is poor, you can see filament coming out a decent rate with reasonable force applied. I also did a third test on the first tapered point nozzle. The results are that it was also hard to pusby rocket_scientist - General
I was originally thinking I would need a 50W model to handle the temperature derating, then released what you said. We are using them to reach and hold a temperature, not constantly dumping 50W into it regardless of how hot it already is. I think we still need some margin there, because the resistor will always be hotter then the glass, which is always hotter than the plastic, but not by the hugeby rocket_scientist - General
From reading the specs, it sounds like Arboform may be too fibrous non-uniform to extrude through a 0.5mm nozzle. It would be useful for casting parts. It is not quite as strong as ABS, and has low softening temperature like PLA, but unlike most plastics, it has a very low creep and low ultimate elongation. This would make it an adequate substitute for cast reprap parts, but I think it won't workby rocket_scientist - General
I have been wrapping extra layers of Kapton tape around the section with wires. But I agree that something more is needed. I intend to experiment with putting a second tube of glass around the heater section after all the wires and thermocouple are installed. That will not only keep more of the heat in, but protect the wiring. Mikeby rocket_scientist - General
I built up two more glass nozzles with nichrome wire and thermocouple over the weekend, in part to document the procedures for wiring and mounting the glass nozzles. Wiki Glass Nozzles I was also purchased a 40X pocket inspection microscope with 0.05mm per tic reticule to try to actually measure the diameters of each orifice. That way, I was able to select a blunt nosed and tapered point nozzleby rocket_scientist - General
It may be possible with more skill and practice, but actually, I WAS working it in the plastic region. The metal was heavy enough to try and fall out by extending the glass on the low side, and if tipped at all would just fall out. But if I worked it any colder, it would not go around the metal, just get pushed back into the rest of the glass. The bolt worked better because it was almost the righby rocket_scientist - General
The raw glass is 8mm outside diameter, but you can buy it much smaller than that. And yes, you could use a micro-pipette puller, but that looks like an expensive machine to do what I have been doing with tools on hand. Also, there have been some concerns about the strength and durability of the long drawn out tips. I have already drawn the 8mm down to about a 0.2mm orifice size, but the walls getby rocket_scientist - General
Rick, nice pics! S far, I have not made a glass nozzle that you could see past the heater coil and thermocouple, since I was attaching them with Kapton tape. I will try to make one that you can see inside and show the process. It looks like yours still uses a brass heater/nozzle at the bottom end, and a thermal break at the top. You also have nichrome wire wrapped around the glass even though iby rocket_scientist - General
Or you could try my glass nozzles. Still not reported to be working on any reprap machine, But they eliminate the soft plastic thermal break and are a one piece design of borosilicate glass from where they are clamped onto the extruder chassis to where the internal tube narrows down to the actual orifice, typically 0.5mm. Cheaper than most other designs, but so far no reports of testing beyond myby rocket_scientist - General
That is a very small orifice size! It will take forever to print a large object. Remember that in general, the time to print will go up with the cube of the reduction in orifice size. A 0.050mm orifice will take nearly 1000 times longer to print the same object, although admittedly with very high resolution and very smooth surfaces. Unless you only plan on writing a resist layer onto a pc board oby rocket_scientist - General
Looks like I can do USPS First Class International Package to Australia for the same rate as Europe. As far as I can tell, there should be no problems with the customs forms at my end. I am not as sure what happens at your end, but any duties taxes would be small. If you want to make a special request and can pay through paypal, I would be glad to put a package together for you. Mikeby rocket_scientist - General
Pity that I only saw this old post because it got spammed, but I liked the basic design of the windbelt so much I just emailed them a free patentable upgrade. The biggest problem with their current windbelt design is that it needs to be loose for low wind speed, and taught for high wind speed. So I just sent them the following email describing how to do both with a simple mechanism and no extra pby rocket_scientist - General
Nice to know that it would appeal to more than just me! Yes, if the machine scanned your foot or hand, or you held or stood on/in some clay or mold material and then had the machine scan that and make custom shoe insoles, electric razor handles, pistol grips, cooking utensil handles, etc that might help. This means that in addition to needing a way to extrude removable support material for overby rocket_scientist - General
More glass nozzles for sale for those interested in trying them out. $7 each blunt nosed, flanged glass nozzles $5 each without flange and index key glass nozzles More details in For Sale section. Mikeby rocket_scientist - General
Item: blunt nosed, flangeed, with index "key", glass extruder nozzle Item description: this replaces both the brass threaded rod and the PTFE/PEET insulator block with one simpler, smaller, hopefully more reliable part. Unlike the tappered glass nozzles, these are blunt nosed and much stronger (part #, technical specification, etc.) The glass is borosilicate, which means it is good to over 1by rocket_scientist - For Sale
Item: blunt nosed, no flange, glass extruder nozzle Item description: this replaces both the brass threaded rod and the PTFE/PEET insulator block with one simpler, smaller, hopefully more reliable part. Unlike the tappered glass nozzles, these are blunt nosed and much stronger (part #, technical specification, etc.) The glass is borosilicate, which means it is good to over 1000C, is very strby rocket_scientist - For Sale