Live tooling increases a CNC lathe’s capabilities and elevates the final product’s precision. It’s a cornerstone of modern production. But mastering the intricacies of live tools requires a comprehensive understanding. Monitor feed rates, minimize tool stick-out, and adhere to best practices to maximize the lifespan of live instruments.
As mentioned in the first paragraph, live tooling allows a CNC lathe to perform milling operations on a workpiece while rotating. The machine can eliminate the need to send the workpiece to another device for secondary machining, set it aside, and then return to it. It saves time, reduces cycle times, and improves overall part quality. The live tool system uses a specialized holder to hold the cutting tool. This holder fits into the live tool spindle of the lathe and allows a machinist to change instruments without having to stop or restart the machine. The holder can also be adjusted to a certain angle, depending on the desired application, and the computer in the CNC lathe controls the tool as it moves. Manufacturers use a live tooling lathe in various applications, including milling, drilling, tapping, and threading. These operations allow the CNC machine to produce a complete, finished part in one setup, reducing both cycle times and the risk of errors. Having the right live tooling system in place is critical to the success of any shop. However, many shops must be more careful with maintaining these systems and wasting money on an expensive investment.
Live Tool Holder
A live tool holder, sometimes a driven tool attachment, allows CNC turning machines to perform milling operations while the workpiece remains stationary on the turret. It allows shops to reduce the number of setups needed for complex parts and enables machinists to serve a wide range of operations they might otherwise need to send out for completion. When selecting a live tool holder, it’s essential to consider the machining conditions a shop can expect. For example, if a machine is subject to high cycle or high volume production, thermal growth of the holder’s bearing can occur, leading to offsetting deviations and compromising workpiece tolerances. The same goes for machining exotic alloys with high coolant pressure, which can cause the holder to crack or burn up.
Most new CNC turning centers come with a small assortment of live tools. Still, it’s worth checking with a tooling supplier to see what universal types they can supply for unique setups or machining configurations. Also, ensure the holder can run with wet or dry lubrication, as some manufacturers may recommend one method over the other.
Tang-style BMT tool holders, for instance, are often lauded for their rigidity due to their bolted design. These are typically matched to the turret’s outer faces with a pattern of keyways and a cam-lock drawbar mechanism that connects with a servo motor.
Live Tool Turret
A live tool turret (a driven rotary turret) performs various machining processes while the workpiece spins in the chuck. A servo motor powers the turret and can be configured with VDI or BMT-style tool holders. Each VDI-style tool holder has a serrated shank that fits into a mating hole on the turret plate. When tightened with a wrench, this fixes the tool in place. This system has many advantages over other types of holders and quickly makes tool changes.
In contrast, the BMT-style holder has a collar with keyways under it that engages a matching tang on the servo drive. It enables BMT-style turrets to support a broader range of tool shank sizes. The collar also allows the holder to be tightened while operating, avoiding damage to the disk inside the turret. Whatever the type, an excellent live tool turret can significantly improve a machine’s productivity by allowing secondary operations, such as gear hobbing and production of squares and flats, to be moved into the lathe. However, these systems require careful planning and proper maintenance to ensure accuracy and precision. Follow best practices for mounting the holder to the turret and the tools to the holder, and these systems can deliver years of productive use.
What is a Live Tool Spindle?
A live tool spindle adds milling capability to a lathe, allowing users to drill, tap, bore, and perform other operations on workpieces that they could only turn. It is essential because it eliminates the need to move parts to a separate machine for milling, which often increases turnaround time and can result in scrap if the operation needs to be done correctly.
When selecting a live tool spindle, look for one with combined bearing and gear technology to ensure maximum stability and rigidity. Look for hardened gears, ground, and lapped-in sets for optimum contact and minimal runout. Choose one with a servo motor that can deliver more power than a standard spindle, resulting in greater cutting intensity and tool life.
The type of work a shop does will also play a role in its selection of live tooling. For example, shops that produce large and deep-pocket components will require a more rigid system than a smaller job shop. Also, a shop that makes a family of products may need quick-change systems to facilitate offline tool presetting. At the same time, another that does small runs and one-offs can benefit from a longer-lasting design that offers better stability and tolerances. Prospective lathe purchasers need to evaluate the tooling needs of their shops just as they have assessed the machines themselves.