Eliminate the bottleneck In some cases, you’ll find that your spindle is the part of the chain that’s holding you back. Fortunately, there also exist alternative, after-the-fact methods by which to increase the maximum speed of your spindle. Spindle speeders, as their name suggests, are specialized holders that aim to do this. They really shine in applications that involve very small and monotonous work, and especially in larger spindles where you wouldn’t otherwise be able to ramp up the speed very high. Basically, it’s possible to retrofit your conventional 40- or 50-taper machine into a high-speed micro machining center, without the cost of buying an entirely new machine. They’re available in a variety of different flavors, but the function remains the same: to significantly increase RPM and cut down on time-consuming cycle times. Whether it’s electric, hydraulic, pneumatic, or spindle-driven, each version has its pros and cons. Personally, we find that spindle- driven and pneumatic (air-driven) spindle speeders cover all of our
fingers go inside of the thin-walled taper and expand outward to clamp. Unlike steep tapers, high speeds are encouraged because they aid the clamping mechanism and proper seating. Moreover, all HSK holders have flange contact in addition to taper contact as part of the standard. This eliminates the dreaded sinking phenomenon. Past 35,000-40,000 RPM, an HSK spindle becomes one of your only remaining options. You can also remedy this unwanted Z-axis movement by using BIG-PLUS tooling, which is the same flange contact principle applied to steep taper holders like CAT or BT. In addition to preventing Z-axis sink, you will see huge gains in rigidity, given that you have a BIG-PLUS spindle. What most people don’t know is that many machine tool builders already include BIG-PLUS spindles as a default feature, so there’s a good chance you have one and don’t even know it. This may be easier than making the big leap to HSK. A word of caution: be careful not to confuse BIG-PLUS with the dual contact claims that are running rampant throughout the market. Keep in mind that only licensed tool holder manufacturers have the tools and gages to make true BIG-PLUS holders. Anyone can claim to have dual contact tooling with practically no proof. BIG-PLUS is not an international standard, so to be safe, use tooling clearly marked with “BIG-PLUS Spindle System – License BIG DAISHOWA SEIKI,” otherwise you can seriously damage your spindle. All BIG DAISHOWA tooling comes with true BIG-PLUS, so for our customers, this is never an issue.
bases. Spindle-driven speeders are really the only preferred option for situations in which you’re trying to increase your output up to ~20,000 RPM (ours are designed with a planetary gear system that multiplies your input spindle speed by 4-6x). At the same time, you maintain high torque transmission since it’s mechanically driven, and you can still use relatively large diameter tooling. In a perfect world, gear-driven systems would be used for all high-speed situations for this very reason. However, some applications call for speeds in excess of 100,000 RPM (think of a dentist’s drill) and you can imagine that even the most impeccably oiled and designed gear system would start to melt well before that point. This is where some other method of power transmission is required, like an air turbine. Air-driven spindle speeders provide the fastest speeds of any type by far and utilize ceramic bearings to withstand the high heat caused by internal friction. BIG DAISHOWA’s Air Power Spindle system, for instance, can reach speeds up to 120,000 RPM.
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