Monday, February 14, 2011

 

Printing small holes in small features



In which your narrator discovers an out-of-the-box method of making small holes for pinned hinges in small features.








Do you want to read more?


Saturday, February 05, 2011

 

RepRap Calculator

I recently started to do simple tool for RepRap related calculations. Mainly because often someone ask me how to count something on IRC, now I can link them to this tool. It's simple page with calculations via Javascript, so its runs in your browser even if you are offline.



The calculator is here http://josefprusa.cz/RepRapCalculator.html or on Github https://github.com/prusajr/RepRapCalculator.

So far It can count these few things, but if you have idea what more it can do lemme know in comments
-Motor stuff
--Precise calibration
--Steps per mm - leadscrew
--Steps per mm - belt
-Convertors
--mm/s to feedrate
--Feedrate to mm/6
-Extrusion
--Flow rate multiplier for layer height change

 

Thermocouple vs Thermistor

I originally wanted to just calibrate the thermistor table I used in my FW, since I remember that Camiel from Mendel-parts was moaning that his table was horrible and it affected his prints, I now just guess that his table wasn't made for his thermistor. I used one generated exactly for my thermistor by createTemperatureLookup.py from SVN. So I crated fake heater with both Thermocouple and Thermistor and written small sketch in Arduino to generate table, BUT I did want first to simply try how imprecise it is. Then I was shocked, both readings were pretty close, actually biggest deviation was 3°C. You can see the graphs under and also download the Arduino sketch and sample data.

My verdict, is that both technologies are good for heaters and heatbeds, the precision is mainly affected by mounting on heater. Also be careful to use precision resistors for thermistor circuits, thats all :-)

Code and data can be downloaded on RepRap wiki.






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