Drilling and reaming
For holes with small diameters, drilling is often a good option. This is also
the case if molded-in holes would require expensive slides in the mold.
A standard high speed drill used for metals with a 118° nose angle can
normally be used, but special drills for plastics may allow faster production
rates. These drills are characterized by smaller nose angles, smaller helix
angles and larger flutes, for better chip removal, and a larger back clearance
to minimize friction.
Note, whereas many plastics require a positive rake angle, drills for Xantar
PC must have a rake angle of 0-5° for a scraping rather than a digging action.
The table below gives some guidelines for drilling conditions. The values
shown are only a rough indication, as optimal conditions depend on the
specific polymer grade and the fillers used. A lower feeding speed must
generally be used for drills with small diameters.