Which type of milling involves the cutter moving against the direction of the feed?

The type of milling that involves the cutter moving against the direction of the feed is known as up milling. In up milling, also referred to as conventional milling, the cutter rotates against the direction of the workpiece's feed. This means that the cutting teeth engage with the material at the bottom of the cut, leading to a gradual increase in the width of the cut as it progresses.

This method creates a more significant force on the cutter and the workpiece because the cutter's rotation opposes the feed direction, which can lead to a rougher surface finish compared to down milling. However, it is advantageous in various operations, especially when dealing with materials that may chip or fracture easily.

In contrast, down milling, where the cutter moves in the same direction as the feed, will typically produce a smoother finish and potentially greater tool life due to the way the cutting forces are distributed. Planing and shaping are processes that operate differently from milling entirely, further distinguishing why up milling is the correct answer in this context.