Other Materials
Thermoplastics are difficult to machine because they have poor thermal conductivity. This creates heat that builds up in the cutting zone, which degrades the tool life and locally melts the plastic. Once the plastic melts, it just flows around the cutting edge instead of being removed by it. Machinability can be improved by using high lubricity coolant and keeping the cutting area free of chip build up.
Composites often have the worst machinability because they combine the poor thermal conductivity of a plastic resin with the tough or abrasive qualities of the matrix material.
The machinability of rubber and other soft materials improves by using a very low temperature coolant, such as liquid carbon dioxide. The low temperatures chill the material prior to cutting so that it cannot deform or stick to the cutting edge. This means less wear on the tools and easier machining.
Read more about this topic: Free Machining
Famous quotes containing the word materials:
“In daily life what distinguishes the master is the using those materials he has, instead of looking about for what are more renowned, or what others have used well.”
—Ralph Waldo Emerson (1803–1882)
“If our entertainment culture seems debased and unsatisfying, the hope is that our children will create something of greater worth. But it is as if we expect them to create out of nothing, like God, for the encouragement of creativity is in the popular mind, opposed to instruction. There is little sense that creativity must grow out of tradition, even when it is critical of that tradition, and children are scarcely being given the materials on which their creativity could work”
—C. John Sommerville (20th century)