Glued Machining Tools Result in Improved Machining Performance
Together with an industry partner, the Fraunhofer IFAM has proven that improving the properties of machining tools primarily relies on the damping ability of glue joints.
To manufacture high-performance tools, cutting edge segments are brazed onto a carrier tool made of tool steel or hard metal (WC). Hard metal and polycrystalline diamond (PCD) are often used for the cutting edge segments for machining abrasive materials or polycrystalline cubic boron nitride (pCBN) for hard machining.
How well a tool performs in machining processes is determined by the maximum possible material removal rate, the workpiece quality achieved and the tool wear. When a tool is in use, its performance is significantly limited by self-excited or externally excited vibrations. Damping these vibrations therefore has substantial economic implications for machining in industry.
Greater understanding of processes needed
Using adhesives technology as an alternative joining process in place of brazing can improve the damping behaviour of tools due to the specific material properties of the adhesive, among other things. The first indications that glued tools provide improved damping were identified during the abrasive cutting of granite. Compared with other damping methods used in machining, the damping provided by a glue joint has the advantage that it is applied directly at the source of the vibrations, making it particularly effective. Using glue is also advantageous because joining requires low process temperatures and can be easily automated.
In order for adhesives technology to be successfully introduced into the industrial manufacturing of high-performance tools, the process chain for the manufacturing of machining tools must be adapted to suit adhesives technology. This requires a much greater understanding of processes to build on the current limited knowledge. The aim of this research projects was therefore to take a closer look at and significantly improve the process chain for tool gluing.
Gluing process leads to fewer manufacturing steps
The project demonstrated that glued processing tools have significant benefits when compared with brazed components. The tools' damping properties and, by extension, their operational behaviour can be changed and strategically controlled by the glue joint geometry. In addition, gluing requires fewer manufacturing steps than brazing and reduces the distortion of components in the thermal process.