This will probably be the end of my posts to this topic (crazy nozzle ideas). I was trying to find existing materials that were tubes with inside diameters of 0.5 mm (or less). There appear to be a large number of extruded ceramic tubes that meet that description. There are several different ceramic materials that I saw in my searches with different properties for thermal conductivity (high to lby TC - General
Indeed. Some of the development boards have started to integrate USB to JTAG intefaces. From what I have seen these are all based on the FTDI FT2232 chip. This approach eliminates the need for an external JTAG probe for debugging. If you are doing "bare metal ARM development" (installing your own tools - Eclipse, GNU tools, etc.) then you will also be interested in OpenOCD for connecting theby TC - Controllers
This stuff also looks interesting... TCby TC - General
Here is some application info re: graphite ferrules that shows some of the common mechanical parts associate with their use (nuts, etc.): These items were pretty randomly chosen by me. There could be more relevant documents available. There seem to be many vendors. I haven't had a chance to read any of this yet, and I don't really know if this graphite ferrule stuff is of any use, or not.by TC - General
I didn't keep track of the various web sites I visited, or the prices I saw. But here is one... $28.31 qty. 10 I'm pretty sure that I saw a site with a package of 2 for under $10. If these would work and a simple way for mounting them could be found then it could simplify construction of the extruder. There seem to be some standard mechanical components for these (nuts, etc.) but I didn't haby TC - General
Here's another one... Try searching for "graphite ferrule 0.5 mm id", or whatever diameter you want. Here's one example (look at the image)... Good for up to 450 degrees C. Apparently, these "ferrules" are used in Gas Chromatography equipment. They seem to come in multipacks, there are multiple vendors, and they appear to be relatively inexpensive. I wonder if these could be used in the eby TC - General
Graham, RE: SD connectors... this Wiki page is pretty good... But it doesn't tell the whole story. If you still are interested in having SD capability then the simple thing is to look at the implementation from an evaluation board schematic. I'm not that familiar with development boards for ST Microelectronics devices so I can't make a specific suggestion. However, I did look at a number ofby TC - Controllers
Graham, RE: JTAG... don't overlook it. While you don't need it to load code (you can load via a UART as you pointed out) you will likely want JTAG for development (debug). I would recommend that you at least put the footprint for the standard JTAG header on the board even if you don't insert the connector. That way, if you get into trouble you can always add the connector. TCby TC - Controllers
In general, any ARM Cortex microcontroller is pretty compelling with many vendors and many product to choose from. In my opinion, the LPC17xx family is the best of the lot however. The MBED approach is great for people that are new to developing code for microcontrollers or those that don't want to get bogged down installing development tools, etc. MBED simply takes the pain out of it. Youby TC - Controllers
Mike, Meeting of the minds! You described what I had in mind really well. Using a 2-sided board would make it simple. Fat (low-resistance) etch on the bottom, serpentine etch for the heat zones on the top. However, this would require multiple vias to stitch the top and bottom traces together (to carry the current). But my hunch is that it is all workable as you described. TCby TC - General
The heated extruder bed captured my interest enough that I've been thinking about various approaches. Specifically, I've wondering about the use of a PCB withlong etch traces as the heater. Today, I ran across these two sites after a search and I thought they would be of interest here (I did a quick search of the forum and I don't think they were previously posted): More generally, I can'tby TC - General
Newbie here... as I learn about all things RepRap and Mendel in particular I keep having to remind myself of one thing - BUILD ONE. Only two words but they are both important. BUILD - it is way to easy to get distracted by thoughts about the design and ways to make it better, etc. Just build it using the wisdom embodied in the current design(s). Forget about making it better, or making it your oby TC - General