„„„ x0,y0 _________________ ________________| ^ |________________ | ________________| | L |________________ | ________________|v <-----------------------> L „„„ # Import numpy library (numerical computation) and matpotlib (generate plots from data in lists and vectors) import numpy as np import matplotlib.pyplot as plt # Definition of variables # independent variables L = 30 # scaffold length (mm) D = 1.75 # filament diameter (mm) d = 0.400 # extruder nozzle diameter (mm) dist1= 1 # distance between lines of the first layer (mm) dist2 = 2 # line spacing of second layer (mm) nz = 4 # number of layers ts = 1200 # traverse speed (mm/min) fr = 800 # printing speed (mm/min) flow = 1 # extrusion multiplier E_extruded = 0 # initialization of extruded length (mm) h = 0.2 # layer height (mm) # Dependent variables n1 = int(L/dist1) # number of turns per horizontal layer n2 = int(L/dist2) # number of turns per vertical layer w = 2*h # extrusion width A= (w-h)*h + pi*((h/2)**2) # cross section of extruded filament # EXTRUSION FUNCTION # extrusion volume calculation for a given length (L) def extrusion(L): ext = L*(A*4)/(pi*(D**2)) #source: Slic3r return ext # FIRST LAYER # assign vector (x, y, z), initial position P0 = [100-L/2, 100-L/2, h] xpos1 = [] #1D array—storage of x values for g-code ypos1 = [] #1D array—storage of x values for the g-code extr_l = [] #1D array—storage of the extrusion values for the g-code # GENERATION OF XY POSITIONS ypos1.append(P0[1]) # initial position Y for j in range (0,int(n1/2)): # generate positions in X for n1 laps xpos1.append(P0[0]) xpos1.append(P0[0] + L) xpos1.append(P0[0] + L) xpos1.append(P0[0]) for k in range (1,2*n1-1): #generate Y positions for n1 turns if (k % 2) == 0: ypos1.append(ypos1[-1]) # Y position (k= even number). else: ypos1.append(ypos1[-2] + dist1) # Y position (k= odd number). # G-Code generation and text file creation # Write a .txt file with the values obtained and the G-code format for each position: file = open(“gcode.txt”, “w+”) extr_l.append(0) print(‘G0 F{:.0f} X{:.3f} Y{:.3f} Z{:.3f}’.format(ts, P0[0], P0[1], P0[2])) for o in range(1,len(xpos1)): extr_l.append(np.abs((xpos1[o]-xpos1[o-1]) + (ypos1[o]-ypos1[o-1]))) E_extruded = E_extruded + extrusion(extr_l[o])*flow print(‘G1 F{:.0f} X{:.3f} Y{:.3f} E{:.3f}’.format(fr, xpos1[o], ypos1[o], E_extruded)) file.write(‘G1 F{:.0f} X{:.3f} Y{:.3f} E{:.3f} E{:.3f}’.format(fr, xpos1[o], ypos1[o], E_extruded)) # Save and close file file.close # Generate XY positions for a scaffold with ‘nz’ layers for i in range (1,nz): # Generate XY positions for even layers. if (i % 2) = = 0: P2 = [100-L/2, 100-L/2, (i + 1)*h] xpos2 = [] ypos2 = [] ypos2.append(P2[1]) ypos2.append(P2[1]) for j in range (0,int(n1/2)): xpos2.append(P2[0]) xpos2.append(P2[0] + L) xpos2.append(P2[0] + L) xpos2.append(P2[0]) for k in range (1,2*n1-1): if (k % 2) == 0: ypos2.append(ypos2[-1]) else: ypos2.append(ypos2[-2] + dist1) file = open(„gcode.txt”,”w+”) # ‘w’ for write, the ‘ + ’ to create the file if it does not exists extr_l.append(0) print(‘G0 F{:.0f} X{:.3f} Y{:.3f} Z{:.3f}’.format(ts, P2[0], P2[1], P2[2])) for o in range(1,len(xpos2)): extr_l.append(np.abs((xpos2[o]-xpos2[o-1]) + (ypos2[o]-ypos2[o-1]))) E_extruded = E_extruded + extrusion(extr_l[o])*flow2 print(‘G1 F{:.0f} X{:.3f} Y{:.3f} E{:.3f}’.format(fr, xpos2[o], ypos2[o], E_extruded)) file.write(‘G1 F{:.0f} X{:.3f} Y{:.3f} E{:.3f}\n’.format(fr, xpos2[o], ypos2[o], E_extruded)) file.close # Generate XY positions for odd layers else: P3 = [100-L/2, 100-L/2, (i + 1)*h] #100-L/2.5 xpos3 = [] ypos3 = [] xpos3.append(P3[0]) for j in range (0,2*n2-1) if (j % 2) == 0: xpos3.append(xpos3[-1]) else: xpos3.append(xpos3[-2] + dist2) for k in range (0,int(n2/2)): ypos3.append(P3[1]) ypos3.append(P3[1] + L) ypos3.append(P3[1] + L) ypos3.append(P3[1]) file = open(„gcode.txt”,”w+”) # ‘w’ for write, the ‘+’ to create the file if it does not exists extr_l.append(0) print(‘G0 F{:.0f} X{:.3f} Y{:.3f} Z{:.3f}’.format(ts, P3[0], P3[1], P3[2]) for o in range(1,len(xpos3)): extr_l.append(np.abs((xpos3[o]-xpos3[o-1]) + (ypos3[o]-ypos3[o-1]))) E_extruded = E_extruded + extrusion(extr_l[o])*flow2 print(‘G1 F{:.0f} X{:.3f} Y{:.3f} E{:.3f}’.format(fr, xpos3[o], ypos3[o], E_extruded)) file.write(‘G1 F{:.0f} X{:.3f} Y{:.3f} E{:.3f}\n’.format(fr, xpos3[o], ypos3[o], E_extruded)) file.close # GENERATE PLOT ax = plt.figure().gca() plt.axis(‘square’) plt.ylim(80, 120) plt.xlim(80, 120) #plot the final g-code values (green, red, blue)) ax.plot(xpos3,ypos3,’g’) ax.plot(xpos1,ypos1,’b’) plt.show()