The present invention relates to a process for the preparation of urea powders, novel urea powders, compositions comprising them and the use thereof as thickening agents, in particular in lubricants, such as so-called polyurea greases. In the device, a phase shifter controls voltage applied to a capacitor in accordance with a control signal outputted from a phase control unit and adjusts the capacitance so as to shift the phase of a carrier generated by an oscillator. The first flex spline meshes with the first circular spline and the second flex spline meshes with the second circular spline at two, preferably more meshing engagements. A transportation system transports the two or more components from the kitting facility to the build cell and transports the product to the boxing facility, whereby the product is assembled, configured, and tested in the build cell and packaged at the boxing facility.