The definition of high speed is different depending on who you ask, especially considering how fast cutting tool technology is evolving. Regardless, all these concepts apply whether you’re trying to get up to 10,000 RPM or up to 30,000 RPM. But the importance of these concepts is amplified more and more as the speed increases. The faster you spin, the more exaggerated any mass irregularities become and any speed harmonics present in the system will become increasingly excited. This translates into vibrations which, in turn, cause poor runout, surface finish, and ultimately wasted money spent on scrapped parts and equipment damage. Symmetry is your best friend at high speeds. Shrink fit holders, hydraulic chucks and high-performance collet chucks are typically the best examples of well-balanced tool holders because, by design, they’re symmetrical. They’re also generally slim – most of the mass is concentrated near their centerline. And since we’re on the topic, it may be time to ditch the trusty sidelock endmill holders you’re used to. Mechanical milling chucks improve on endmill holders in every capacity (except for perhaps axial tool pullout), so they are the preferred alternative. This includes better balance. In fact, our MEGA DOUBLE POWER chuck is a mechanical chuck that has been specifically designed for higher speeds. This chuck, along with all other MEGA chucks we offer, have had all surfaces ground to a mirror finish. At high enough speeds, even slight anomalies in body concentricity
and tolerancing) callout for shafts and holes, so boring head balance is crucial especially for those situations. At the very least, standard boring heads are usually pre-balanced for a diameter somewhat near the middle of their diameter range. If it’s a rigid, reasonably short bore, this will suffice. When higher speeds and longer boring bars are needed, we offer a family of auto-balancing heads, designated EWB. These heads are well- balanced throughout their diameter range, because of a clever counterweight design inside the head that automatically adjusts a counterweight as you adjust the diameter. Taper considerations Equally as important as the tool holder body is the taper. In most cases, you’re stuck with the machine spindle taper you already have. But, if you’re in the market for a new machine and feeling the need for speed, it may be time to consider something with an HSK spindle. HSK was developed in the 1990s specifically to combat problems that conventional steep tapers encounter at high speeds. The spindle taper will expand more than the holder under high centrifugal force because of differences in stiffness, which causes the tool to “sink” in the Z-axis. HSK was innovative in that the drawbar
come into play. Grinding all surfaces ensures that this factor is removed from the equation. They also make use of a notch-less nut, giving a perfectly cylindrical surface on the exterior, as opposed to the hexagonal or notched nut that you commonly see.
Clamping Screw
Clamping Screws
Balancing Ring
Balancing Scale
Balancing act When it comes to fine boring tools, balancing can be a very serious issue. Single-point finish boring heads are fundamentally unbalanced because of their asymmetry and special care is required to ensure that they perform as expected. To say that bores are tolerance-sensitive features is an understatement, and this unbalance can easily scrap a part if you aren’t careful. Running a boring head as fast as it can go should always be the goal, but progressively worse, unbalance can be introduced to the system as an unwanted byproduct. An unbalanced boring head can be very deceptive, because it will frequently bore your diameter within spec. Yet, upon further inspection, you will find that you have created an oval-shaped bore rather than a circle-shaped one. Circularity/cylindricity is a common GD&T (geometric dimensioning
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