A mirror-like surface requires the total elimination of all surface roughness. MMP Technology is capable of achieving such finishes by selectively filtering out successive levels of roughness without changing the basic form of the surface.
The diagram below demonstrates how MMP Technology categorizes the different levels of roughness.
Using MMP Technology to obtain mirror-like surfaces offers a number of advantages but also has some limitations.
MMP Technology maps a surface as a collection of different frequencies of roughness. It then removes only the targeted frequency ranges, moving from the highest frequencies to lower ones. As a result of this extremely precise approach, MMP Technology achieves mirror-like surfaces with far less material removal than traditional cutting action polishing processes
Limiting the material removal to specific frequency ranges gives MMP® Technology other benefits that differentiate it from classic polishing processes. Since the frequencies of roughness MMP Technology removes are significantly higher than the frequencies of the underlying form of the part, the resulting mirror-like finish leaves edges sharp and fine details undisturbed, meaning that MMP Technology is very well suited to creating uniform mirror-like finishes on complex geometries.
However, since MMP Technology is an isotropic (homogeneous) treatment, if obtaining a mirror-like surface requires removal of form errors (i.e. low frequency), MMP Technology may not be a good solution. Defects in the form of the part will require localized removal of material, and probably a lot of material relative to the amounts MMP Technology typically removes. In general, if a part requires non-homogeneous removal of material (i.e. changes to the actual shape of the part), MMP Technology is not likely to be the best choice.
Mirror-like polishing is often required in medical implant and instrumentation applications, and plastic injection molding.
For medical and injection molding applications the emphasis is more focused on maintaining tolerances.
Often times MMP Technology is the best path to a mirror-like finish for these applications because of its ability to preserve complex geometries while still delivering a uniformly polished surface. MMP Technology broad material and coatings compatibility is another benefit in these applications, and in many cases MMP Technology also delivers shorter, more predictable lead times at lower cost.
MMP Technology also creates mirror-like finishes on MIM and/or CIM parts, provided the initial surface is free of porosity.
In conclusion, depending on the applications and markets, the mirror-like surface produced by MMP Technology is often the best choice due to low material removal, the ability to preserve the initial shapes and designs, an improvement of technical properties of the surface, reproducibility and homogeneity, accessibility to complex shapes, and superior lead times and overall cost.