Production and processability for future square shank tool holders

Abstract: The square shank tool holder is one of Sandvik Coromants most common products. The tool holder has been manufactured the same way for 25 years without changing tolerances. However, it is predicted that tighter tolerances will be required in the future to maintain competitiveness.   The purpose of the thesis was to study how today's square shank tool holders can be made straighter and to what price it can be done. The tolerances allow too much convexity and concavity which might lead to unstable products. To find where in the current production flow the greatest impact occurs, the production flow was studied and then a common square shank tool holder with high production volume was followed through the production flow.   The tool holders were measured with a CMM after each station and analysis showed that the hardening station has the largest impact on the tolerances. This lead to six experiments using different manufacturing methods and the results were compared to see what production flow that allowed the best tolerances and lowest cost.   The results lead to two optional ways of manufacturing since they showed better results with a production economic perspective. Option 1 includes manufacturing in hardened material and Option 2 includes a grinding process.   The production flow for Option 1 is to first harden the blank followed by the manufacturing processes. By moving the hardening processes to the beginning of the production flow, the shape changing is prevented and the final product becomes straighter and obtains a smooth and aesthetic surface since the hardening process creates a rough surface. The production time is increased by CON% and the production cost is increased by CON%. The bottom side flatness tolerance of the final product is reduced by CON%.   The production flow for Option 2 is to first manufacture the shank followed by hardening. After the hardening process the tools get surface grounded on the bottom side and the outside. By grinding the tool holder, it becomes straight and the surface flatness obtains a tolerance of CON mm. The production time is increased by CON% and the production cost is increased by CON%. The bottom surface flatness tolerance of the final product is reduced by CON%.   The advantages of Option 1 are that the final product becomes better and it is easy to apply in the current production flow. The advantages of Option 2 the surface becomes very flat and the tool holder is more competitive.   By choosing any of these two options, Sandvik Coromant will achieve a straighter and more competitive final product.