Source code for scripts.g_code_osc_fn

#!/usr/bin/env python
"""\ : demonstration of creating an oscillatory motion represented as a G-code using a simple function

This is a fully self-contained script, i.e. it does not require any special libraries.

This emits a NC program with speeds faster than the grbl defaults.  Please issue
the following commands using a terminal emulator to set the non-volatile


Afterward, the $$ command should show these entries:
  $110=2000.000 (x max rate, mm/min)
  $120=500.000 (x accel, mm/sec^2)


# Redefine the print function to be compatible with Python 3.  This is a good
# practice even if we are using Python 2.
from __future__ import print_function

# Import the standard math functions into the current namespace.
import math

# Define a few useful functions to emit lines of G-code.

[docs]def emit_prelude(output): """Emit a header of G-code commands to reset the machine modes to a known standard state, including the following: G21 units are mm G90 absolute distance mode G17 select XY plane for arcs G94 set units/mm feed rate mode G54 use default work coordinates """ output.write("G21 G90 G17 G94 G54\n") return
[docs]def emit_rapid_move(output, x_position): """Emit a single-axis rapid move to the given location at the maximum speed. The position precision is limited to three decimal places. :param x_position: target position in mm """ output.write("G0 X%.3f\n" % x_position) return
[docs]def emit_move(output, x_position, speed): """Emit a single-axis move to the given location at the given speed. The precision is limited to three decimal places. :param x_position: target position in mm :param speed: motion rate in mm/min """ output.write("G1 X%.3f F%0.3F\n" % (x_position,speed)) return
[docs]def curve(time, frequency = 0.2, magnitude = 2.0): """Return a single-axis position value representing a position on a curved path at a given time. :param time: time in seconds :param frequency: rate in cycles/second (Hz) :return: position in mm """ # Some elementary functions and calculus: the sin function accepts an argument in radians; # one complete cycle takes 2pi radians. return magnitude * math.sin(time * frequency * 2 * math.pi)
#================================================================ # The following section is run when this is loaded as a script. if __name__ == "__main__": # Specify the name of the NC G-code file to generate. filename = "" print("Writing output to %s" % filename) # Open the file and begin writing out G-Code. with open(filename,"w") as output: emit_prelude(output) # specify the time step for each path segment in seconds dt = 0.2 # specify the magnitude of the oscillation in millimeters mag = 2.0 # specify the initial frequency in cycle/sec (Hz) f0 = 0.2 # compute the initial time and position t0 = 0.0 x0 = curve(t0, frequency = f0, magnitude = mag) freq = f0 # rapid to the start point emit_rapid_move(output, x0) # iteration to compute a fixed number of samples duration = 60 for i in range(int(duration/dt)): # keep speeding up by adjusting the frequency freq += 0.005 * dt # compute the time and position of the next sample t1 = t0 + dt x1 = curve(t1, frequency = freq, magnitude = mag) # Estimate the feed rate in mm/min. The move command expects speeds # in mm/min, so the mm/sec rate is scaled by 60 sec/min. feed_rate = 60 * abs(x1 - x0) / dt # Keep the feed rate from getting too low. if feed_rate < 20.0: feed_rate = 20.0 # Generate a move command to the new position, using the feed rate # so that the move should take dt seconds. emit_move(output, x1, feed_rate) # update the time and position for next cycle t0 = t1 x0 = x1