Koneistusterissä

Koneistusterissä, often translated as "machine reaming," is a machining process used to enlarge and finish existing holes to precise dimensions and smooth surface finishes. It is an economical alternative to drilling a larger hole or performing a full milling operation when a hole already exists but is slightly undersized or has a rough surface. The process involves using a reamer, a multi-fluted cutting tool, which removes a small amount of material from the walls of the hole.

Reamers are designed with multiple cutting edges that rotate and advance axially into the workpiece. The flutes of a reamer are typically straight or helical, with a slight taper at the lead end to help guide the tool into the hole. The primary function of a reamer is to achieve a high degree of accuracy in both diameter and roundness, as well as to produce a superior surface finish compared to drilling alone. This makes koneistusterissä particularly useful in applications requiring tight tolerances, such as in the assembly of precision components, bearings, or shafts.

The choice of reamer material, such as high-speed steel (HSS) or carbide, depends on the workpiece material and the desired production rate. Speeds and feeds for koneistusterissä are generally lower than for drilling to ensure a good surface finish and tool life. Proper lubrication is also crucial to prevent tool wear and improve chip evacuation. While often performed on milling machines, koneistusterissä can also be done on lathes or with specialized reaming machines.