Polishing Process: Micro Machining Process

MMP, which stands for micro machining process, is a proprietary superfinishing method for metallic parts that delivers consistent, repeatable results using a finely controlled automated process. MMP uses highly engineered finishing media in combination with environmentally friendly chemicals and a mechanical process to create a system that can accurately remove from 1 to 40 µm while achieving more finely controlled surface finishes than other methods. MMP does not leave any contamination on the part being processed.

The first step in MMP is to evaluate the three key components that comprise the finish of the unprocessed surface: undulation, primary roughness and secondary roughness. The next step is to understand the customer’s desired finish of the processed surface. Taking into consideration the above pieces of information, the type of material and the geometry of the part, a specific MMP process is selected. Due to the way MMP works, the process is able to achieve finely controlled modifications to one or more of the three components that define the finish, thus giving unprecedented control over the final surface finish of the part.

As an example case study that highlights the advantages of MMP, a European plastic molding company was having problems with a set of 300 high precision injection mold cores (see Figure 1). They found that MMP increased the performance of their injection molds by creating roughness profiles developed specifically to improve part removal from the molds, thus eliminating suction effects and chemical adherence, while still maintaining the fine details and exact size of the components.

For the above mold core case study, MMP provided the following improvements over traditional mold polishing methods: leadtime was reduced from four weeks to one week; mold polishing cost was reduced by 44 percent; more consistent size and finish across all parts was observed; less frequent mold clogging resulted in a significant reduction in mold cleaning frequency; and, the customer realized ongoing cost savings from a 13 percent improvement in injection molding cycle times.

The micro machining process is typically used for two applications: SuperPolishing, which makes it possible to automate the traditional polishing process and SuperBrightning, which generates new topography of the surfaces. One of the advantages of the MMP process, particularly within the SuperBrightning area, resides in its ability to give the surfaces new micro-structures, which are able to fine tune the surface performance for a specific function or use.

MMP shows its technical superiority in many different applications, including the following:

• Tools and Dies: Signifi-cantly increased tool life by accurately polishing, deburring and honing the cutting edges, as well as preparing an advanced surface finish promoting better PVD and CVD coating adhesion. Can also improve the surface finish of the PVD coating itself, without removing the ultra-thin coating.
• Aerospace: Complex geometries, such as airfoils. MMP delivers finely tuned surface finishes that are consistent across the entire part, without removing excessive material or altering critical geometries.
• Medical Implants and Components: MMP uses a contamination-free process to produce surfaces with increased resistance to corrosion and wear, and reduced friction.
• Luxury Goods: Jewelry and timepieces have typically relied on hand polishing, but MMP produces superior results at much lower cost.

While there are many polishing processes on the market today, MMP stands alone for its ability to produce consistent, repeatable results with an extremely fine degree of control over the amount of material removed.