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.
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.
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.
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 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:
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