One of the most often asked question is "Which type of tool should I use for my application?"

With the numerous types of end mills and routers on the market the answer can often be a challenge to find the tool which will perform the best for a particular material and application.

We have put together a quick description of the major tool types and which materials they generally give the best performance with.

This is a very basic exposition and many more considerations are possible.  We tried to make it quick and simple to point you in the right direction regarding tool selection.

Routers

Two major types of routers are Diamond Pattern Flutes and Chip Breaker Flutes. 

Diamond Pattern routers have numerous diamond-shaped blades which gently cut materials and leaves smooth sidewalls with minimal top edge burr formation.

This type of tool is great for materials that are subject to fracturing or cracking such as Printed Circuit Boards (PCB's), fiberglass, FR4, G10,ceramic tiles, marble and soapstone, cutting sheet composites

Chip Breaker routers have several (usually five) spiral flutes with numerous notches formed along their lengths.  This has the effect of cutting the chips into tiny pieces.

For materials that tend to cut in strands, the strands would wrap around other tools, obstructing the cutting surface of the tool and negatively affecting cut quality.

Instead, the strands are cut into small pieces that are easily evacuated out of the cut.

Some materials that benefit from Chip Breaker Routers include: Wood,  rigid circuit board materials.

Another consideration is tip style.  The two major types are Fish Tail and Drill Point:

Fish Tail tips gently cut into materials greatly reducing the chance of cracking or splintering.

Drill Point Tips increases penetration forces on hard / dense materials and are best for use in these materials as the Fish Tail tips are more fragile and can wear down prematurely in these materials, especially if you are plunging frequently.

End Mills

The major features of carbide end mill are: Number of flutes and tip type.

End mills have one or more cutting blades along the length of the tool.

The blades and the associated grooves are referred to as "flutes".

The material an end mill is suitable for is largely determined by the number of flutes.  In general, the more flutes the harder the material it can cut.  Conversely, the fewer the flutes, the softer the material it is suitable for.

In addition, the angle of the flute (helix) plays a role in material consideration.  Usually, larger tools with larger helix angles are better at cutting softer materials.  

The major tip types are: square end and ball nose.

Square End tools feature flutes with sharp corners that are squared off at a 90° angle.  These tools are widely used for profile cutting and can be used to plunge part-way into a material to create a pocket.

Ball Nose tools are used for 3-D contouring  and slotting a channel where a flat bottom is not required or most commonly used to produce multi-dimensional contours in molds or dies.