Machining for the E-vehicle market

SW Machines machining centre for electric vehicle market part
SW Machines machining centre for electric vehicle market part

More flexibility with an extended machine concept: German machine tool builder SW says it has developed a new machining centre specialising in large-volume, light metal machining for a changing automotive market. PES reports.

The strong growth of electric vehicles is bringing fundamental changes to the worldwide automotive industry and also presents new challenges for machine tool builders. In the long term, various part categories for combustion powered cars will be reduced, as hybrid motors and battery electric vehicles (BEV) become ever-more efficient. However, the number of electric vehicle components will rise and other new parts will be created.

With continuing development of product technology in the area of high-volume, light metal workpieces, Schwäbische Werkzeugmaschinen GmbH (SW) says it is ideally equipped for these new developments in electric vehicle production.

"More and more automobile manufacturers are offering hybrid and/or electric vehicles. For machine manufacturers this means that their machine ranges must also cover machining of typical electric vehicle parts," explains Reiner Fries, managing director of sales at SW.

Suppliers are currently using machining centres that are designed for machining large motors and thus for heavy-duty machining. The drive technology of these machining centres is designed for high drive forces and is correspondingly slower and less dynamic.

In comparison to large components for vehicles with combustion engines, however, machining high-volume electrical parts is equivalent to conventional light metal machining. Highly dynamic, fast machines that can cover long sections in the shortest possible time are more suitable for this type of machining. The SW machine series with linear motors is especially suitable for these market requirements and has long been recognised in the industry as an expert in machining light metals.

SW has developed a special machining centre for processing electric auto parts: the BA W08 is designed for 4-axis and 5-axis machining of very large light metal workpieces
SW has developed a special machining centre for processing electric auto parts: the BA W08 is designed for 4-axis and 5-axis machining of very large light metal workpieces

Making light work

SW has developed the BA W08-12 to respond to these new challenges – a single-spindle, horizontal machining centre designed for the 4- or 5-axis machining of very large light metal workpieces, for example battery housings. Like all SW machines, the machining centre features a monoblock which minimises deflection and ensures optimum flow of force between the machining unit and the workpiece carrier.

The machining centre also has a weight-optimised machining unit featuring a ‘box-in-box’ design which is developed for highly dynamic machining operations in light metal applications and can be inserted into the monoblock at the rear. Linear and torque motors in the feed axes guarantee maximum dynamics and short auxiliary process times, while the gantry drive of the Y-axis ensures optimum positioning accuracy, even with eccentric loading.

Another essential component of the machining centre is the double swivel carrier which is equipped with two independent rotary axes, allowing loading and unloading in parallel to machining time.

“During machining, the double swivel carrier is hydraulically locked in a Hirth coupling and the rotary axes are fixed in place with safety clamping,” explains Mr Fries. “The geometry of the rotary axes makes it possible to load the machine at an ergonomically favourable height. If necessary, directly driven planetary modules can be attached, which allows for 5-axis machining.”

The rotary table concept together with the horizontal spindle arrangement also guarantees swarf will fall freely. Since the BA W08-12 also features sophisticated flushing in the machining area, swarf is effectively prevented from adhering to the workpiece or remaining in place where it would adversely affect quality. Since workpieces could become even larger and then not fit on the W08, however, SW is also working on an even larger machine.

“Of course, it will incorporate all the technological advantages of SW machines. That includes two pallets, horizontal spindles and linear motor technology,” Mr Fries adds.

To further increase the space for workpieces achieved by the reduction to a single spindle, SW has designed a fixture with a recess. This provides greater flexibility for the shape of workpieces
To further increase the space for workpieces achieved by the reduction to a single spindle, SW has designed a fixture with a recess. This provides greater flexibility for the shape of workpieces

More flexibility

Until then, the BA W08-12 offers a collision circle 950mm in diameter with a length of 1,710mm (500-litre volume) for holding workpieces and clamping fixtures. The travel path in the X-axis is also increased by 700mm in comparison to the two-spindle BA W08-22, which nearly doubles the range of machining for workpieces.

Depending on the workpiece design and clamping situation, the travel path can be fully utilised. To achieve even more flexibility in terms of component size and shape, SW has developed a double swivel carrier fixture with a recess that can be used to rotate especially long and wide parts horizontally.

"Thanks to the modification of our machine concept, we can meet the requirements of many new vehicle parts in the area of hybrid and electromobility," Mr Fries comments.

Since a safety separation is required between the loading and machining area, the carrier is closed by a cover that can be individually adapted in size to the shape of the workpiece being machined. The size of the carrier fixture is restricted only by the second fixture with the workpiece that faces it. This makes it possible to rotate parts up to 1,300 x 400 x 300mm (L x W x H) horizontally. For larger or smaller dimensions in length or width, the respective other dimension can change. For example, a workpiece could have the dimensions 1,000 x 700 x 300mm.

This advantage in terms of space can also be used if a company already has a BA W08-12 on its shopfloor. The Q carrier fixture for these machines can also be removed and replaced by a Q carrier with a recess so that the downtime for conversion is reduced to a minimum.

But the SW machine features more than just a high level of flexibility for large parts – a single-spindle BA W08 can even be converted into a two-spindle machine. Once the 3-axis unit is replaced, the machining centre can then also be used to produce smaller parts with high output.

Battery housing production

One of the greatest advantages of the BA W08-12 is that despite its large machining area, it has two independent rotary axes (4th axes), both of which can be fitted additionally with a 5-axis table. In the example of a battery housing, four different parts have to be processed on the machine. With the SW CNC this can be done in one clamping with four axes. Since the clamping fixtures are capable of holding the workpieces being processed on the top or bottom of the base plate, there are a total of four clamping clusters on the two rotary tables for the four components.

Most other machines that are able to process large structural parts are usually single-station machines that often do not offer the possibility of clamping parts on the top and bottom of the fixture plate. In the most difficult situations, a separate fixture will have to be constructed for each individual workpiece.

This results in a high level of set-up overheads for smaller batch sizes since the fixtures must be exchanged for each workpiece or each clamping position. For larger batch sizes with multiple clamping positions, several machines are used for machining and parts logistics between the machines is needed. Since high-volume parts are involved, the cost of the logistics in time and money is correspondingly high.

This is not the case for the BA W08-12. After completing machining – which includes milling, drilling and thread cutting for all four parts on one machine – it can be in almost continuous operation, and is thus utilised optimally. More and more complete sets of housings are being manufactured, which also allows suppliers to estimate their capacity for battery housings very accurately.

SW Machines www.sw-machines.de

Company

SW Machines

Related Articles

Environmentally friendly

Aluminium ingot manufacturer Norton Aluminium has appointed Trevor Bird as its new general manager.
8 years ago News
Most recent Articles

Renishaw highlights career pathways in engineering

There is not one singular blueprint that can lead to a career in the engineering industry. It offers a variety of roles, open to people from diverse backgrounds. To highlight the diversity of skills and experiences in engineering, global engineering technologies company, Renishaw, has created the ‘Employee perspectives’ series.
13 hours ago News

Login / Sign up