In a perfect world, materials printed through a circular stencil aperture would be column-like with a flat top. When you look closely at a printed flux deposit you will notice 3 distinct characteristics of real-life printing.
1) A peak on the trailing edge of the deposit. (The left side of the profile view shown above.)
2) An insufficient amount of flux at the leading edge of the deposit. (The right side of the profile view shown above.)
3) Sloping edges caused by the removal of the stencil and slump. (Both sides of the profile view.)
Understanding and controlling these printing defects will help you achieve your desired transfer efficiency.