Using 5 axis milling in injection mold making is so commonplace now that it has become standard in the industry. In a single setup, 5 sides of the workpiece can be machined, which saves time, money and increases accuracy. Thankfully, the days of tedious setups are mostly a relic of the labor-intensive past.
With the advanced CAD/CAM software available today, programming is relatively easy. This is remarkable, considering the complexity of the simultaneous movement of all 5 axes! There is, of course, a learning curve involved though and 5 axis milling is not to be taken lightly. This is truly a game-changer for the mold making process.
By integrating the plastic injection mold design with the programming and actual CNC machining, the chance for human error is greatly decreased, plus the modeling is more true to the design. This makes for a cleaner part with a better finish.
Justifying 5 axis milling
Making the decision to purchase an expensive machine tool such as a 5 axis milling machine is not an easy one. Considering that they easily can cost $100,000s, the ROI must be carefully analyzed.
If you manufacture injection molds with complex geometry and have sufficient volume, the answer is much simpler. But if your work is rather “simple” and low in volume, you might have a difficult time justifying the purchase of a 5 axis milling machine.
Also, having the right CNC tooling is critical to any milling operation, especially using such a precision machine tool. Typically work holding is different than convention milling and special vises or tombstones are required.
There are several companies offering these unique vises: Kurt Workholding, and Tombstone City are among the leaders.
Think outside the box
Because these remarkable machines are so versatile, you will find that you are able to machine cores, cavities, electrodes, and inserts as well. This is, of course, what can be done on a 3 axis machine, but that requires much more set-up time and programming. Plus, any time you break up a set-up, you lose precision and vast amount of time.
A good CNC programmer will quickly adapt to the change in programming, in fact, he will probably find it easier, once he becomes accustomed to the changes. Since so many operations can be done in one set-up, programming time actually goes down overall. This also presents an opportunity to gain a foothold in the industry, and it is one of the better jobs in the plastics industry.