RepStrap
General
this repstrap is a bit different: it doesnt use any of the usual reprap electronics or sourcecode on a microcontroller.
the gcode is generated like usual via skeinforge or similar tools but emc2 and some shell and python components take control of parsing it and doing the magic.
the dc-motor as visible in the pictures for the classic darwin-style extruder we currently use is driven by a dc-motor driver based on this: http://reprap.org/bin/view/Main/DC_Motor_Driver_1_1
also in the same box are 2 tip122 transistors which switch gnd for 2 supplies in open collector mode.
the whole thing is deadlocked with and-gates (inline in the 'step' and the pwm lines for the transistors) with the other 4 inputs of the and-gates driven from a 'charge-pump' <add schem>
the chargepump gets a 'rectangular ac signal' on one input. if its missing the output goes low. if it hangs high, the same. see it as an electronic dead-man switch driven by emc2
its based on some caps, diodes, more caps and 2 or 3 transistors. i'll add a schematic soon.
for some pics of our extruder head see blogposts about reprap
uses:
- EmcArduino for measuring temperature (means the voltage)
- HeatingPlate
configs: http://yamato.hyte.de/tmp/repstrap_roh.tgz (for now, will move that somewhere here)
Status
- works somehow
Todo
- does one really need/want a 80mm fan to force-cool the object?
- build stepper-direct-drive and compare it against our geared worm-drive
- try geared motor as direct drive.
- fix heater-pid-loop Dgain
- clean up code
- Documentation / pictures / howto
References:
More
Attachments (14)
- repstrap_total.jpg (142.5 KB) - added by roh 15 years ago.
- repstrap_first_part.jpg (87.5 KB) - added by roh 15 years ago.
- repstrap_pulling_fibre.jpg (117.8 KB) - added by roh 15 years ago.
- repstrap_nozzle.jpg (100.4 KB) - added by roh 15 years ago.
- repstrap_thermic_break.jpg (118.1 KB) - added by roh 15 years ago.
- repstrap_up.jpg (93.5 KB) - added by roh 15 years ago.
- repstrap_printing_1.jpg (79.8 KB) - added by roh 15 years ago.
- repstrap_printing_2.jpg (99.3 KB) - added by roh 15 years ago.
- repstrap_printing_3.jpg (75.1 KB) - added by roh 15 years ago.
- repstrap_mounted_closeup.jpg (141.5 KB) - added by roh 15 years ago.
- repstrap_controller_back.jpg (115.9 KB) - added by roh 15 years ago.
- repstrap_controller_pcb.jpg (154.5 KB) - added by roh 15 years ago.
- repstrap_controller_front.jpg (94.5 KB) - added by roh 15 years ago.
- repstrap_controller_open.jpg (147.3 KB) - added by roh 15 years ago.
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