5-Axis machining for Mold and Die
More companies are investing in 5-axis technology for milling mold & die components. Part of this is certainly because of the growing numbers of different models of 5-axis machining centers becoming available in the marketplace. As with many other advanced technologies, new entries into the market place have brought innovation providing high functionality for lower costs. One such example is from the camera phone video below. This was from the IMTS 2012 exhibit trade show, and shows a Hurco iSeries mill performing smooth 5-axis movements on a part that had truly a mirror finish.
Simultaneous vs Positional 5-Axis
When discussing 5-axis, it is usually a good idea to expand on what we mean. 5-Axis simultaneous is when rotations and linear movements can happen at the same time (simultaneously) while milling. This is what you see in the video above.
5-Axis Positional, sometimes referred to as 3+2 machining, is when the mill rotates into an angular position, then mills with linear moves only. It does not rotate while actually milling.
From a practical standpoint, most all 5-axis simultaneous milling machines can also do 3+2 axis machining. However, not all 3+2 axis milling centers can do 5-axis simultaneous.
Why 5-axis for Moldmaking and Diemaking?
3+2 axis machining has been common in mold and die machining for some time. Especially when programming for slides in a mold, where this was the only way to mill that particular area. However, for simultaneous 5-axis milling, there are some real positive reasons why you would choose to invest in this technology, these are:
- To mill deeper into a part easily, allowing you to use fewer, or no, EDM burning operations.
- To mill more of the part with short tools, providing better finishes and shorter milling times.
For example, in the sample part below, this lifter pocket has very small radii at the bottom of the pocket. One would need to either mill it in 3-axis with a small diameter tool, which has a long shank, or they would need to mill several electrodes and EDM burn the material away. The problem with milling it in 3-axis is that the length/diameter ratio of the tool is very much out of line, and the tool would vibrate, if one could be found at all. The problem with burning it is you still need mill time to make several electrodes, then the time to burn it in.
In the end, the pocket can be milled in 5-axis, all the way to the bottom, quicker, and with a better finish, than other methods. This is one typical reason for utilizing simultaneous 5-axis for milling some parts.
Additionally, 5-axis programming can allow you to use shorter tools, mill more of the part, and provide better finishes and shorter mill times.
For example, the part below can be milled in 3+2 axis to utilize short tools. However, to mill the complete thing, it may take Eight separate 3+2 angled cuts, and you may run into blending issues. All milling machines are accurate when rotating to some tolerance. Blending multiple 3+2 cutterpaths may not provide as good of a surface finish as using one simultaneous cutterpath across the whole part.
Additionally, the 5-axis cutterpath can utilize optimum lead or lag angels for better cutter contact and less variation in finish resulting from milling with the tip of the cutting tool.
5-Axis CAM software for Moldmaking
So what does your CAM software need for 5-axis machining of Molds and Dies?
First it needs traditional 5-axis functions. For example rolling, swarf milling, 5-axis engraving, etc. But then it also needs an easy way to mill an entire part, with a short tool, and be completely collision free of the tool and holder.
This is exactly what the Auto-5 Module in WorkNC does. It takes any 3-axis cutterpath, and allows you to convert it to 5-axis simultaneous cutterpaths, so that the tool and holder automatically avoid collisions. This allows you to mill deeper into pockets, and also allows you to easily finish with shorter tools. The benefits of a module like Auto-5 are:
- It automatically does tool holder collision avoidance to keep collisions from happening. And automatic avoidance is better than just collision checking.
- It is easy to program 5-axis. If you can make a 3-axis cutterpath you can make a 5-axis cutterpath just as easy, and almost as quickly.
- It has intelligence built in to consider the machine kinematics and limits, especially rotational limits.
During the show, we can demonstrate the benefits of 5-axis machining for mold and die machining, as well as the benefits of the Auto-5 automatic machining module.
Looking at buying a 5-axis mill? We created a short pdf slideshow of things to consider when shopping for 5-axis mills. The tips in this paper can save you some headaches later. Simply click the button below: