Page 45 - 2021 Connectivity Components: Everything but the Connectors eBook

Cutting-tool life
To overcome the difficulties with quality, users often employ tools with more aggressive cutting angles. Unfortunately, in the machining of unleaded brass, these tools quickly lose their cutting edge, drastically reducing the tool life to a few tens of minutes. This raises the cost of producing the piece to the point of unprofitability and dramatically affects the efficiency of the entire system.
» An example of cutting-tool with evident signs of wear.
Overheating of the material
Connectors often have areas with thin walls, and if the tool cutting edge is not perfect, the material in these areas can overheat. This thermally affects the material to the point of making the produced part inoperable (the annealing of the material makes it lose its elasticity). Tests have also highlighted new lubrication parameters. For some machining operations it was necessary to adopt lubrication through the tool, which can be easily retrofitted on modern and flexible transfer machines.
Long chips
Long chips create skeins and dams that prevent their evacuation and tend to pile, making automatic production impossible. The tool must be shaped to avoid long chips, and chip breakers must be used.
Mikron Machining has carried out numerous tests in collaboration with Mikron Tool, determining the best parameters to achieve high quality, without losing productivity. Mikron Tool has developed processes for the successful use of lead-free tools with specific cutting geometries and spirals for this material. Tests have shown that the oversize between roughing and finishing operations is important in order to guarantee the connector tolerances and a good tool life without overheating the thin connector walls.
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