I'm gonna print more printers
Friday, September 18, 2009 at 12:31AM Since I got my machine working properly (as opposed to the rather half working way it used to be working that I assumed was just the way things were) I've been printing parts like crazy. I'm at this moment doing a multpile print, where I print two objects with one press of a button. Once this print is done, I'll have all my Y axid bearing mounts. Oh, and kudos to VIk for redesigning the reprap mounts to make it all much easier to build.
My current findings.
1. The fan is not needed for most small parts. In fact the fan causes huge problems with construction in that it makes parts not bond properly, the side effect being that they will warp very easily as well as tend to detach during printing, but not having the fan running this is avoided. By adding in a cooling time, but not using a fan, the needed cooling is taken care of.by simple contact with the air.
2. When printing, a fill rate of .75 can produce parts that are very very hard. Also useful to know is that by setting the build nozzle size in skeinforge you can alter the strength of parts. Major settings that really alter the strength are.
-The build speed, setting it above your extrusion speed really causes problems with inter-layer bonding. It looks the same as having temperature set too low, but isn't. (According to Simon Kirkby, he had the same effect from when his machine was set to too low a temperature)
-The nozzle diameter setting. Although this would appear to be a physical setting that you just set and forget, it's basic that the higher your nozzle setting then the fast you build, but weaker you find the resulting materials. If the nozzle is set big then the head rises just enough for the material to spread and when it does it tends to spread out a little, this makes it bond much better then just having the edge of the filament touching.
-Setting to a high temperature doesn't really hurt things, especially when I built my machine to have an ultra rugged resistor heater. A resistor heater is a little more bulky, but is basically much easier to use when heating, given I'm pretty sure that the larger surface area that contacts the melt chamber gives the whole thing lots of energy when operating. Wrapping the whole heater in PTFE (AKA teflon) really helps the thing work well. In order to get higher temperatures, you simply need to mess around a little bit with the firmware heat sensors. You'll find that the original values supplied with reprap gen 3 firmware might be a little off. Simply adjust them a little by getting the mython program on the site and tweak the values a little so that it generates numbers that mean that a certain reading of resistance is assumed to be a reading that is a bit lower. As long as you remember that a reading of 220 is really a readying of 235. This helps you get around the max value of 255 temperature that the firmware has(It probably could be gotten around, but given this is the max of a power of 2, I'm worried it'll cause problems with overflow.
3. The use of the Old solarbotics GM3 (though the one that came with my reprap seemed to have been mis-sized vs a normal gm3.) Has the problem of not lasting very long. Fortunately, while the motor quickly burns out, the gearbox works fine ever after multiple motors have gone through it. I'm still printing a new extruder as a high priority though. I've worked out how to jerry rig new motors pretty fast though, so it shouldn't be a problem in the near future, I bought a dozen new motors anyway online for like $2 each.
Reader Comments (4)
Are you useing the 6V motor or the 12V one? I find the 12Vmotors (with a black end cap) last much much longer.
I'm using 6V ones(getting the 12V needs me to call solarbotics instead of use their site according to the forums, I'm in AU and I get by without one for now anyway), but I bought some old 12V motors from a hobby show which I disassembled and used the end cap off of, it's worked really well for the last week or so great.
what kinda power source are you using? 6V or 12V?
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