CNC Machining – Space
In providing machined components for the space market, most machining (metal removal) requires using CNC machine tools. As the space market expands, there is a continued demand for better tolerance control, coupled with improved surface finish callouts. In the past, the CNC equipment used to produce these parts was two-axis (lathes) and three-axis (milling). Many of the more complex shapes were produced using a combination of these machines along with multiple setups. With advances in control, servo, and tooling technology, we can now accomplish 4- and 5-axis simultaneous machining. Having this 5-axis ability has significant advantages creating complex machine shapes.
Traditional CNC machines move in two linear axes (X and Z) for lathes and three linear axes (X, Y, and Z) for machining center. The term “5-axis” refers to the number of directions in which the cutting tool can move and cut simultaneously. On a 5-axis machine, the cutting tool moves across the X, Y and Z linear axes, as well as rotates on the A and B axes, to approach the workpiece from any direction.
The ability to precisely move the workpiece without removing it has distinct advantages over conventional three-axis machining. Here are some benefits of five-axis CNC machining:
Tool Life Improvement
Improved tool life and cycle time is a result of tilting the tool/table to maintain optimum cutting position and constant chip load.
The Ability to Machine Complex Shapes
The major (and most well-known) advantage of five-axis machining is the ability to machine complex shapes. The additional movement creates machining angles and arcs for the cutting tool and for chip relief that were only previously possible with a multitude of special fixtures or additional setups.
Reducing the Number of Machine Setups
Five-axis machines can machine nearly every visible surface, excluding the bottom or clamping area. This ability significantly reduces the need for multiple setups or special fixtures. In some instances, it reduces the number of setups to one.
Relational Accuracy
Tolerance stack up (imprecision) is one of the results and challenges every time you have to move the part for re-fixture. Once a part comes out of the machine, precise alignment is lost. By using the same “zero” or “home” location, feature-to-feature accuracy is improved.
3+2 Axis Machining
There are parts that can only be machined with simultaneous 5-axis movement. Not all 5-axis parts require 5-axis simultaneous machining. Some 5-axis parts are best machined with a 3+2 movement.
In 3+2 machining, the fourth and fifth axes are used to locate the workpiece (or cutting tool, depending on the type of machine) in a fixed position. In these scenarios, there is no need for all five axes to move simultaneously.
The same tool paths could have been achieved in a three-axis machine, but only after loading and unloading between multiple setups, fixtures, or machines. The five-axis machine increases uptime, decreases human error, and eliminates the need for special fixtures. For parts with features or holes on multiple faces or angles, 3+2 machining is the clear choice.
Improved Surface Finishes
Using the rotating fourth and fifth axes, the part can be orientated to bring it closer to the cutting tool. If the part can get closer to the cutting tool, then the cutting tool can be shorter. A shorter cutting tool is less susceptible to vibration at higher cutting speeds, which directly impacts surface finish.
As technology advances, so does the market’s expectations for higher quality products at competitive pricing. To meet this challenge, Intrex has made significant investments in 3-4-5 axis equipment, as well as in systems software to oversee and control our entire manufacturing process.
We would welcome an opportunity to speak to you about addressing your supply chain needs. Contact Intrex today.
