Why mould makers can’t treat cutting tool choice in isolation
Using the best possible toolpaths
Mould machining cutter paths should be optimised by correct programming to avoid placing unrealistic demands on cutting tools. For example, when machining a mould and the toolpath encounters a corner, a smooth transition must be programmed to allow for the change in direction in order to prevent a large angle of engagement which could overload the cutting tool. A good rule of thumb is to program an arc that is larger than the cutting tool’s radii. So, if a 50 mm diameter cutter is used, the program should not encounter 25 mm radii, but instead use a smoothing radius that is larger.
Programming proper arcs can be a challenge and, if not done properly, can lead to erratic toolpaths. Several current software packages can help accurate programming and an experienced programmer with an understanding of the arc of contact principle is obviously a bonus. The key is to avoid machine stop and start scenarios within the toolpath because any amount of machine hesitation when changing directions generates heat that transfers to the tool. Heat can destroy a tool’s cutting edge and coating, and must be evacuated from the cutting zone through and with the chips.
By gaining a better understanding of today’s milling techniques and tooling technologies as well as the various failure modes and failure analysis skills, mould manufacturers can experience increased productivity, reduced cycle times, better tool life and tool life consistency, improved part tolerances and appearance, superior mould surface finishes, and less wear and tear on equipment.