With the VL 5, EMAG has created a customized solution that makes a positive impression in handling the heavy stresses exerted on the tools and machine during hard turning. One example is its machine base made of Mineralit, a polymer concrete with a vibration resistance eight times better then cast iron. “A vibration resistant machine leads to an improved surface finish on all workpieces it machines, which also leads to an improvement in tool life,” says Peter Loetzner, CEO of EMAG. The vertical design is another feature that ensures an economical process, with the work spindle and the workpiece located above the tool. This offers suitable chip flow conditions, with the material removed being taken out of the machine by a chip conveyor. All guideways are located above and away from the machining, keeping them safe from any chips or dirt. This increases the component accuracy and reduces the maintenance effort.
Another important quality feature of the vertical turning centers from EMAG is their integral automation. They all use a conveyor belt with prisms that hold the raw parts in place. The conveyor belt moves the workpieces directly into the pick-up station, where they are picked up by the work spindle and then machined. Workpiece changeovers are very fast, because the distance traveled between the loading and machining position is only 550 mm. This leads to a massive shortening of the time between machining processes.
The possibilities offered by hard turning on the fully automated, vertical turning machines from EMAG is best shown by the example of a gear production for a sub-supplier to the automotive industry. The VL 5s run by the customer produce a total of eight different gears for a dual-clutch transmission system. Following the hardening process, the workpieces are pre-turned on the machine, to remove the hardened top layer. This is followed by a synchronous ring being welded onto the workpiece away from the VL 5. The workpiece is then returned to the EMAG machine and finish-turned. Before the customer had the VLs, he performed comparable operations on grinders.
“This company started investing in the VL 5 machines for their hard turning process, because the investment costs were so much lower,” adds Loetzner. “Hard turning on the VL 5 is in no way inferior to the old grinding process; and the machining times are noticeably shorter,” he explains further.
When can hard turning successfully replace the grinding process in the machining of a component surface? “That depends on a number of factors. One important factor is the desired surface texture. We help guide our customers and give them our opinion on the best way to proceed,” explains Loetzner, “and when hard turning is possible, it often becomes first choice.” Apart from lower investment costs, many users are also impressed by the elimination of the grinding operations. On the VL, the turned part can be finish-machined in a single setup. It is no longer necessary to take it to another machine for finishing. The result: the output level of the whole production increases considerably.
The turning specialists from EMAG have already delivered a total of 3,500 VL machines. The know-how this has provided is something the new user also profits from. “Our design team familiarizes themselves with customer demands. This ensures that the strengths of our machines are targeted on what is required by customers.” The types and numbers of components that can be produced on these vertical turning machines are very diverse. Toothed components, such as gears and crown wheels, can be produced with the same efficiency as bearing rings. “The system can be adapted to suit any batch size and is very impressive with its short cycle times and high component quality. If the VL 5 allows you to eliminate a whole process stage, the user will be able to enjoy an unbeatable cost advantage,” emphasizes Loetzner.