This code shows how to create a 3D printable Lorenz attractor  at the standard parameter values. 
You are welcome to use this code for non-commercial purposes. If you do so, please send me an email and let me know how it goes!
Evelyn Sander, esander@gmu.edu GMU, 2016-2017

rho = 28; sig=10; beta=8/3;
TubeThickness = 0.52;
Tmax = 50;
xinit = 11.13261;yinit= 17.5124;zinit= 21.0398;

q = NDSolve[{x'[t]==(sig*(y[t]-x[t])),y'[t]==(x[t]*(rho- z[t])-y[t]),z'[t]==(x[t]*y[t]-beta*z[t]),x[0]==xinit,y[0]==yinit,z[0]==zinit},{x,y,z},{t,0,Tmax},MaxSteps->Infinity];

fig1 = ParametricPlot3D[Evaluate[{x[t],y[t],z[t]}/.q],{t,5,Tmax/2},PlotStyle->{Tube[TubeThickness,PlotPoints->Tmax],Green},PlotRange->All];
Show[fig1]

Export["LorenzAttractor.stl",fig1]