Turning a chore into a pleasure

A Swiss contract manufacturer’s CNC machine tool can be equipped, operated and programmed especially quickly and easily thanks to Sinumerik 828D. The production of highly complex turned parts is now a regular part of the company’s work.

The programming and production of individual parts

Water pipes and alphorns have one thing in common: both ­require turned parts. Wirox GmbH in Meiringen, Switzerland, develops and produces such turned parts. However, in the past, the effort required to produce complex individual parts was so high that it was more of a chore than a pleasure for managing director Roman Willi and his team. Purchasing a Leadwell LTC-25 iLM equipped with the Sinumerik 828D CNC changed all that. “I now enjoy every challenging task. Thanks to this machine and its control system, I now no longer need to think about much of what used to take up a huge amount of time,” ­explains the plastic technologist and machine mechanic.

Faster programming

While some customers come to the machine shop with a finished construction drawing, others have only a vague idea in mind. These clients often do not know what information is required for the construction, which is why Willi must first ask the right questions. “I first had to find out for myself what is important in alphorn construction,” says Willi. He creates many parts on the machine control system directly during the programming, without go­ing through a CAD/CAM system. This is where the advantages of the ShopTurn work-step programming and the extensive visual representation possibilities of the user interface Sinumerik Operate come into effect.

If programming errors slip in, they are shown in the 3-D simulation and in the sectional drawings and can be eliminated in time. The Wirox managing director knows that it is quite unconventional to program his customers’ ideas directly on the machine. On the Sinumerik CNC, however, this works flawlessly and also saves a great deal of time.

Helpful cycles

The machine control system provides standard cycles for many applications, such as plunge turning, for example. These cycles simplify the procedure and considerably reduce programming times. “Plunge turning is a technology that was previously used only rarely in practice, as there was a lack of functioning cycles. But since we have had the Sinumerik-controlled machine, we use this machining method regularly, because the cycle works perfectly,” explains Willi. Tools designed especially for plunge turning have three cutters: one for grooving and two side cutters for longitudinal turning. For this rea­son, they replace several standard turning tools at once. Willi opted for a special tool from the A4 tool range from Kennametal.

Greatly reduced workload

Since the Leadwell turning machine has been in operation at Wirox, the production of various parts in no particular order has become very simple. The operators adopted a majority of the ISO programs that already existed beforehand (G-code). As the programs for Wirox stock items now remain saved under the item number on the machine along with all the necessary information, Willi and his team have constant access to them without any need for an expensive IT solution. Once the item number is selected, the machine is ready. Using the Save Setup Data function, the offset data of various clamping tools and workpieces are also saved in the control system along with their various zero points. It is therefore possible to quickly equip the machine tool and clamp and change parts at any time.

Purchasing a single machine made it possible to greatly simplify many processes on Willi’s shopfloor. The straightforward machine operation is the most important change: “With this control system, I am repeatedly made aware that real thought has gone into what the operator needs,” concludes Willi.

Plunge turning in Sinumerik Operate

In addition to standard ISO turning, additional processes such as grooving and plunge turning have now become established. Previously, the productive use of this turning technology failed because of complicated programming, but Sinumerik Operate offers a plunge-­turning cycle that greatly simplifies the programming. The tool used for plunge turning has three cutters: a main cutter for transverse machining (depth infeed) and two side cutters for longitudinal machining.

During roughing, the material is removed gradually in the depth and not in a side­­- ways direction; this is gentle on the tool and very effective at removing the chip volume. During smoothing, which can be per­for­med with the same tool, the lateral load on the tool is naturally very low (depending on the selected allowance). As before, only the contour of the turned part needs to be traced.

By selecting parameters in the stock remo­val cycle, the user can specify whether a conventional method or plunge turning is used. Sinumerik Operate automatically calculates the tool’s steps and movements in accordance with the cycle. Plunge turning is available in both ShopTurn and programGuide.