Feasibility of automating the production of carbide-tipped milling cutters

Abstract

It is intended that this thesis describes, analyses and appraises the various techniques of automating the brazing of tungsten carbide tipped tools. It also investigates the control of parameters for the intended future automation of the helical forming of the tips prior to being brazed. The first part involved performing a feasibility study into the various techniques of brazing, commonly available, that is, vacuum, furnace, induction, torch and bath brazing, and assessing the merits of each for the adaption to brazing tungsten carbide tips to tool bodies. The techniques were viewed in conjunction with the filler metal alloy, jigging arrangement, braze temperature, atmosphere, joint configuration and design, plus any mechanical properties that may be affected during the braze cycle (eg. cracking of tips due to different coefficients of expansion). The second part of the thesis begins with a review of the production of helical tungsten carbide tips leading to experimental work undertaken to measure the parameters of the manual method (i.e., force, displacement, temperature), utilising a "Macsym" measurement and control system. A considerable amount of work was done to allow such parameters to be measured in hostile conditions (i.e., in an induction heating environment where RFI was present, and in conditions heavily affected by graphite dust). The experimental techniques used to solve these problems are discussed.Finally, graphs were plotted for Force versus Displacement and Force, Displacement, and Temperature versus Time for the various tests performed. The study shows that brazing of tungsten carbide cutting tool scan be automated using a torch brazing method, with pre-placement of filler in a modified tool body design. Automation of the helical forming of the tips is very much dependent upon the efficient control of the difficult to measure parameters, although not impossible.