5 Axis Machining is one of the most advanced CNC (computer numerical controlled) milling-machines; two more axis are added to the normal three to further enable the operator to manufacture more complex geometrical parts. Even though parts can be made with ease, the skill to make these parts is very advanced hence the use of CAM (Computer-Aided Machining).

5-Axis Machining Alternatives

There are currently three alternatives to achieving full 5-axis machining capabilities:

Tilting - Rotary Table

Spindle Head Attachment

Dedicated 5-axis Machining Center

There are currently more than fifteen (15) original equipment manufacturers of 5-axis machining centers sold in the U.S. These manufacturers include all of the biggest names in manufacturing technology including: Cincinnati Machine, SNK, Makino, Haas Automation, Deckle-Maho, Nicholas-Correa, Okuma, Toshiba, Mitsubishi and Zimmerman.

The majority of these machining centers are large, powerful, accurate and expensive with prices averaging well above $500,000. The least expensive 5-axis machining centers on the market today have a starting price of about $300,000. The chief draw-back of the dedicated 5-axis machines is their range of motion which is generally limited to (+/- 30°). Work pieces that require a steeper angle of cut must be manually repositioned and restarted. Also, these machines are somewhat less rigid than a 3-axis machine of the same size and class.

Tilt - Rotary Tables

Several manufacturers now produce a tilting-rotary table that can be mounted to the bed of a (3-axis) CNC machine. Simple rotary tables have been available for many years and are used extensively by small and large machine shops around the world to index parts for various machining operations.

A ‘tilting’ rotary table can rotate and tilt a part at various angles to provide machine access to many sides of the part, simulating true five axis machining.

The relatively small work surface of a tilting-rotary table places significant limits on the type of the work piece that can be mounted to it including limits of length, width, height and weight. Additionally, tilting-rotary tables are themselves very large and use much of the host machine’s working envelope. Even the largest tilt-rotary tables can reduce the working envelope of the host machine by 75% or more. Tilt-rotary tables are not suitable to hold parts during heavy cutting operations.

Spindle Head Attachments

The primary advantage of a spindle head attachment is that it can access all points of the machining center’s work envelope. The head places no limit on the size of the work piece that can be machined.

Two U.S. companies and at least one German company manufacture and sell a programmable spindle head for attachment to large 3-axis milling machines. When properly installed, these heads are fairly dependable, accurate and expensive. Because of their size and weight they cannot be mounted onto any of the small to mid-sized machining centers and are reserved for only the largest gantry type milling machines. Installation is permanent and requires custom fabrication and fitting. The price range for these head attachments is $175,000 to $300,000 plus the cost of custom fabrication and installation.

5-Axis Benefits

The Benefits of Machining with 5 Axes are:

Reduced machining time: By using a flat bottom endmill and maintaining perpendicularity to the complex surface you can step-over the full diameter of the cutter thereby dramatically reducing the required number of passes across a surface. The same principle applies to sidemilling of angled surfaces.

Better surface finish: Using a flat bottom endmill to maintain perpendicularity to the complex surface can eliminate ribbing caused by ball-nose endmills.

Eliminate multiple setups required to re-position the work-piece at complex angles.

Eliminate costly tooling and fixtures required to hold the work-piece in place.

Eliminate manual millwork and handwork required to cleanup kellered surfaces.

Machine complex parts that are not otherwise possible, including holes required to be normal to a complex surface.