4 axis CNC machining 2020: an authoritative guide
Introduction of 4-axis CNC
The fourth axis machining is an interesting and important subpart of the CNC milling world. If you are new to CNC, your first impression may be that axis 4 is used in the same way that a rotary table is used for manual machining. Indeed, there are many projects where someone will manually convert the rotab to the 4th Axis. While there is some truth to this idea, it is largely incorrect. Most of the manual machining of the 4th Axis work is about the characteristics of cutting along the ARC, which is difficult to accomplish by manual machinery. With CNC, cutting along the ARC is easy-that's what the G02 and G03g codes are for. In some cases, we use the fourth axis for continuous machining-in other words, we want the tool to be machined when the fourth axis is rotated. But there are many other applications.
4 axis indexing access
The first thing discussed is the term "indexing" . The fourth axis is usually used in either the "scale" or the "continuous" mode. When dividing, cutting is not performed until the fourth shaft has stopped (usually locked with some kind of brake) . In fact, some types are called "indexers" that can only be used to index in fixed degree increments, and can not be continuously rotated to any desired position. In contrast, "continuous" refers to the processing of parts as they rotate. For example, create Cam Cam Angles. You might wonder why you want everything but continuous processing, but endure it? There are many useful ways to use indexes. In addition, you will need more advanced CAM software to program continuous machining. It's very powerful, but you can do a lot with indexes alone (and probably most of the fourth axis) . The fourth shaft moves each tooth into place, stops, and the cutter moves back and forth until the tooth is complete. They index the next tooth. Gears are an extreme case, because if we can't index teeth, it's hard to imagine how to make gears. However, in many simple cases, indexes can also be very useful. Suppose you have a part that looks like a throttle body and has holes on all sides. You can build fixtures and make a bunch of settings, one on each side. Alternatively, you can use shaft 4 to scale the sides so that more than one shaft can be machined in a single installation。
The 4 axis is used for more parts
Horizontal machining centers are more productive than vertical ones, they say. One reason is that the chips are more easily anchored to a horizontal surface, because gravity helps rather than pushes them further into more difficult holes. But another reason is that almost all horizontal mills have a 4th Axis tombstone structure
Fourth axis continuous machining
Now there are some strange things: the fourth axis of continuous processing can also be called "fourth axis contour processing. ". Continuous processing has two advantages. First, you can machine shapes that would otherwise be impossible or very difficult. Without continuous processing, the closest thing is to index as many places as possible and use the 3D outline tool path to try to get the job done. This can be surprisingly effective, but rarely as powerful as true sequential processing. The second advantage is the use of a circular tool when copying. The disadvantage of the ball is that the closer you get to the tip, the slower the flute rotates. This may sound counterintuitive, but think of the cue as a series of concentric circles of different heights. The circle near the tip is smaller and has a shorter circumference, but rotates at exactly the same speed as the larger circle. So, the tip moves more slowly. Conceptually, the exact tip doesn't move at all, because it's a circle with a radius of zero.
Conclusion
Axis four can be a powerful addition to your CNC arsenal. It can do all new types of processing, and it can make existing jobs run faster and require fewer settings.