Of course the most attractive part of this is that it would be possible to develop the film to have an exact grating/pattern on it. Using that together with optical sensors and DC motors would allow for fine movement. We might need to glue the film on a non-stretching backing, but that seems a problem that should be easy to solve. -Geertby GeertB - Reprappers
Slanted extrusion is key to do higher quality overhangs without support, and also would be useful to increase finish quality of many objects. We're only scratching the surface of what we can get out of our machines when we improve the software. Also, there really is no reason why the Z should add processing delays in the common situation where it is unchanged. For one thing, while parsing the Gcby GeertB - RepRap Host
Yes, I use it all the time. MeshLab imports these and exports STL. You can also do any simple rotation/scaling/translation at that time. My workflow: Brain -> Sketchup -> *.dae *.dae -> Meshlab -> *.stl *.stl -> Skeinforge -> *.gcode *.gcode -> ReplicatorG -> MakerBot Works very nicely. As with any 3D software, it is important to keep objects clby GeertB - RepRap Host
MDF is flatter, more uniform and therefore less likely to bend. For the build platform that is an advantage.by GeertB - Mechanics
People at MakerBot are doing this right now, and went through the process of trying out different PLA formulations. The first batches have proven less than ideal (yellowish color or too brittle), but if the current batch turns out right, they'll order a ton or so of it and it will be for sale from them. They have more information on their site, so you can learn from their mistakes. -Geertby GeertB - General
Typically, you can reverse the ABCD cable from the stepper driver to the motor (it might not fit exactly right, but will be OK). Then you can figure out a better solution later.by GeertB - RepRap Host
Just send me a PM, and attach the STL files of the parts you want printed. -Geertby GeertB - Wanted
Great! I'm sorry to say I won't be able to make it this month (and possibly the next), but I'll definitely would like to join for upcoming meetings! -Geertby GeertB - New York City RepRap User Group
You can buy it at Makerbot for 1340 GBP, which is just a third. Flight would add another 300 GBP or so, and you'll probably have to pay some extra charge for overweight luggage and customs, but you'll still come out ahead. Alternative is to have Makerbot ship it via UPS (split in two packages) or DHL for about 800-1200 GBP. Even though cost almost doubles, it would still be far cheaper to get iby GeertB - Wanted
The obvious solution is to get together with another Reprapper and split costs. I'm in for 50 624's. I'll pay half of your shipping costs, plus the full cost of shipping it (using regular postal mail) to me. Please send me PM if interested. -Geertby GeertB - Mechanics
Completely agree that the software should be built with a strict focus on driving the hardware. However, I also thing that with smart programming and scheduling, it should be possible to do a whole load of processing on the AVR. Key is to use the right abstractions. For example, never use floating point. Directly parse decimal numbers in scaled integers scaled just right (16 bits with 0.01mm resoby GeertB - RepRap Host
Using a web-based proprietary tools seems as far from open source and GPL software as possible. The Arduino environment uses GCC as compiler, and the Cortex chip is supported by GCC as well. No need for proprietary software. The main issue in porting the Arduino environment and Wiring language is to port the libraries and essentially implement a small abstraction layer for the board. Going to aby GeertB - RepRap Host
I make a living writing free GNU GPL software. The company I work for sells this software, with first class support, for a yearly licensing fee that is well out of range of any hobbyist. There is NOTHING wrong with charging whichever price the market will bear for free software. You have no legal restrictions. The free is free as in "free speech", not "free lunch". One will quickly realize that oby GeertB - For Sale
No, you don't want short bars, but continuous filament ("lasdraad"). It seems they're just not listing it on their website, but they'll likely sell it, given that they do sell a "lasdraadafrolinrichting". Just give them a call. -Geertby GeertB - General
Nope, had the same thing. However, somebody from Ponoko contacted me (I left the orange safety area border in) and noted that the scaling was wrong. However, given they they provide the templates, I think they should ensure they have been tested with Inkscape to give properly scaled output. I have no idea what's going on here. In the email conversation I did get the idea that they themselves mosby GeertB - Plastic Extruder Working Group
Use rotating mirrors and an optical sensor on the printing head and one on a fixed reference point. Then you can time the duration between hitting the fixed sensor and the head sensor, and then compare that to the duration of an entire period. By using a pyramid made of 4 flat mirrors, and a 6000 rpm motor to spin this assembly, there would be 400 sweeps per second. So, 90 degree sweep is 2500 miby GeertB - General
There wouldn't need to be a switch. Just a couple of extra products. Given that there is a lot of overlap (extruder parts, electronics, stepper motors, rods etc), there might not be much involved to increase sales volume. -Geertby GeertB - Mechanics
The 624 bearings are $99 per 100, see . That's pretty cheap. Now, if only MakerBot would carry Mendel hardware packages... They'd have the volumes to get prices down to reasonable levels. -Geertby GeertB - Mechanics
Ehmmm... 300 mm/sec. This is, like, 50 times the speed of a McWire? -Geertby GeertB - Mechanics
I'm working on modifying the firmware in a couple of ways to allow for better control: * Use internal 1.1V reference to measure low voltages * Use higher resolution for accumulating sensor readings * Directly control these high resolution readings rather than rounded degrees Celsius. * Use an automatic test in ReplicatorG to calibrate heater settings and store constants in EEPROM. The nice thingby GeertB - RepRap Host
I'm using the MakerBot "plastruder", and their 100KΩ thermistor. Here are the relevant lines of the conversion table: // Thermistor lookup table for RepRap Temperature Sensor Boards (http://make.rrrf.org/ts) // Made with createTemperatureLookup.py (http://svn.reprap.org/trunk/reprap/firmware/Arduino/utilities/createTemperatureLookup.py) // ./createTemperatureLookup.py --r0=100000 --t0=25 --r1=0by GeertB - RepRap Host
Hi Nophead, I hoped you'd chime in. I previously noted you're using simple use on/off control, but the crucial difference is that you're heater was switching with a period of about 2 seconds, while mine has a period of about 45 seconds, and Tim's is on the same order. Both my nichrome and thermistor directly touch the brass barrel, so the Kapton tape should not be a factor. The nichrome is wounby GeertB - RepRap Host
Hi Tim, Very funny coincidence! I've been doing exactly the same thing last night with my CupCake (#180). I came to the same conclusion wrt. lack of resolution in heater resolution for the D part of PID control. I changed the firmware to not return the average of a number of samplings, but rather the sum. However, it turns out that the analog input signal from the thermistor does not have enougby GeertB - RepRap Host
I don't quite see the reason why a parent machine can't build all parts for a machine with bigger build area. There is no fundamental problem. That said, I think it is useful to keep thinking about "bootstrapping" issues. You can tell I'm a compiler guy. When using the word "compiler", I refer to a programming tool that takes source code written using a programming language (such as Ada or C) anby GeertB - General
Yes, should be doable. I've been programming Sketchup a bit recently. Using Ruby (which turned out to be easy to learn) it is straightforward to generate useful object directly from code. I've put together most of a CupCake using Sketchup in order to learn from the design and make my own modifications. Similarly, it should be straightforward to slice using Sketchup and Ruby. Basically, you use aby GeertB - 3D Design tools
Hi John, I'm afraid this won't really be suitable, because you cannot continuously feed at a fixed rate. Also, I don't see how this is any simpler than the current pinch-wheel design which is in production use. Additionally, there is a huge gap between concept and practice... -Geertby GeertB - General
Great to hear! Could you maybe post some more details (here a picture might indeed equal a thousand words) on how you got things working? -Geertby GeertB - Mechanics
The approaches may be opposite, but they clearly are complimentary. The goal is to limit temperature differences, which is best done by keeping the whole object somewhat warm, while quickly cooling newly extruded material. Keeping the whole object warm also requires less heat from the extrudate to meld with it, possibly allowing a lower extrusion temperature (at the nozzle tip, not necessarily iby GeertB - General
FWIW I think the L297 is one of the big limitations of the stepper board as soon as you want to go beyond simple half stepping. A cheap AVR chip can be programmed to do the same (albeit with slightly different pinout) and would allow things such as dynamically switching between full stepping/half stepping, reducing current when idle and delayed last step to reduce resonance. -Geertby GeertB - Controllers
Don't worry about driving current. It's rarely a good idea to drive steppers at maximum rated current. While the motor is actually moving at any reasonable speed, induction and back EMF will cause maximum current that you'll be able to drive through the motor to drop to only a fraction of the rated current. High current are mainly relevant for holding torque, but you'll have that plenty anyway. Lby GeertB - Controllers