Compared to High-Efficiency/Dynamic Milling and 2D Profile Milling
In this detailed instructional video, we look at how high-feed profile ramping around an outside 2D profile compares to the cycle times for traditional 2D step-down profile milling and high-efficiency/dynamic milling.
Live-action video is shown of the high-feed ramping on a Haas 40-taper VM2. We'll talk a little bit about the pros and cons of each approach to help you decide what works best for your shop. Just interested in the high-feed live-action footage? Scroll down for a short clip.
2D Profile Milling
2-dimensional profile milling has traditionally been done using an X-Y axis profiling routine, with a step-down in the Z-axis for each pass around the part profile. As such, time is lost during the lead-in and lead-out for each pass. Additionally, the cutting tool encounters undesirable shock on the entry and exit moves, shortening tool life.
High-Efficiency Milling
More modern methods include high-efficiency (dynamic/volume) milling, which utilizes solid carbide end mills applied with a very light radial width of cut and a heavy axial depth of cut, using higher than normal speeds and feeds made possible by the light radial engagement of the cutting tool.
High-Feed Ramping Footage:
This approach is very effective where it can be used, but is limited in total depth by the flute length of the cutting tool. It also carries a high initial tooling cost for the solid carbide end mill. Once the end mill has been used, it either must be discarded or re-sharpened (and re-coated), requiring re-programming to a smaller cutting diameter. This approach also creates exclusively radial tool pressure, which is a problem when milling at long length-to-diameter ratios.
High-Feed Ramping
High-feed ramping is a seldom-used approach that solves all of the problems that are encountered with both the traditional 2-D step-down method and high-efficiency milling. By starting above a workpiece, but directly on the finished part profile, we can execute a constant ramping motion while simultaneously milling around the finished part profile. The depth of cut per pass is light (generally < .060"), but the feed rates can often exceed 300 IPM.
Due to the extreme metal removal rates of this process, cycle times are shortened dramatically versus traditional 2-D milling, and they are typically on par with or faster than high-efficiency milling. Due to the cutting forces created in high-feed milling, tool pressure is primarily axial (into the spindle), creating stability for long-reach milling applications that would be problematic for side-milling techniques. This means that part profiles can be machined even to depths of 2x-3x diameter with no changes in speeds & feeds.
Given the low cost per edge of indexable carbide milling tools, this approach is very cost effective – especially when compared to the cost of solid carbide end mills – and doesn't require size changes after indexing.
In summary, high-feed ramping provides:
- Very fast metal removal rates
- Simple programming (2-D ramp)
- Long-reach capability with no performance loss
- Low-cost indexable carbide inserts (inexpensive cost/edge)