Machining with transfer machines and CNC machining centers: features, applications and differences

Transfer machines and CNC machining centers: how they work

To understand the differences between these two technologies, it is useful to start with how machining operations are organized.

Machining with transfer machines

In a multi-station transfer machine, the component moves through different stations, each designed to perform specific machining operations. In rotary transfer machines, workpieces are positioned at the loading/unloading station and progressively transferred from one station to the next with each rotation of the indexing table.

The key feature of this configuration is the ability to perform different machining operations simultaneously on multiple components, distributing the machining cycle across several stations. This operating principle makes transfer machines particularly well suited for high-volume production.

Transfer machines represent a significant part of Brawo's machine fleet and are used across the Group's manufacturing facilities, alongside machining centers, CNC lathes, and flexible manufacturing cells.

Machining with CNC machining centers

In CNC machining centers, the component is secured in place and undergoes various machining operations using tools controlled by a computer numerical control system. The machine controls the required movements along its axes and uses different cutting tools throughout the machining cycle to perform the specified operations.

Unlike the multi-station approach used by transfer machines, machining operations are generally performed sequentially on the component. This results in a different organization of the production cycle and its associated cycle time.

Alongside transfer machines, Brawo also uses CNC machines and machining centers in its production facilities. All these systems are supported by tooling design using CAD/CAM software and solid modeling. Cutting tools and workholding systems are also designed and manufactured in-house within the Group through Emmebi.

What types of transfer machines does Brawo use?

Brawo's machine fleet includes transfer machines with different configurations, distinguished by the arrangement of their stations, machining units, and workpiece handling systems. These include transfer machines with vertically or horizontally oriented rotary indexing tables, as well as machines equipped with fixed machining units or units mounted on cross slides, a configuration used in flexible transfer machines.

Another distinguishing factor is how the workpiece is handled during the machining cycle. Transfer machines can be configured with rotating vises, rotating clamps, or no rotation. The number of stations also varies depending on the machine configuration: Brawo's equipment includes machines with 7 to 12 stations.

These features do not necessarily represent separate machine configurations. Brawo's transfer machines can combine several of the solutions described within a single machine, resulting in a diverse range of equipment with different configurations and design characteristics.

How to choose between transfer machines, CNC machining centers, and flexible manufacturing cells

Choosing between transfer machines, CNC machining centers and flexible manufacturing cells starts with the component's characteristics and production requirements. At Brawo, the main factors considered include production quantities, number of machining operations, required tolerances, machining angles, and component material.

Among these factors, production volumes, precision and repeatability have a significant impact on machine selection. Cycle time, on the other hand, plays a different role: it is primarily a consequence of the technology selected based on the component's specifications and production requirements.

One of the main differences between these technologies is productivity. The multi-station design of transfer machines allows operations to be distributed across multiple stations, with several components machined simultaneously. In CNC machining centers, operations are generally performed sequentially on the workpiece. This difference in cycle organization affects the machine's production capacity and machining times.

The choice of technology is therefore based on a comprehensive evaluation of these parameters, with the goal of identifying the machine best suited to the component's specifications and production requirements.

How do costs and operator-to-machine ratios affect the choice between transfer machines and CNC?

Costs are also evaluated in relation to the entire production process. Generally speaking, a transfer machine requires a higher initial investment and setup cost than a single CNC machining center. However, its high productivity tends to make it easier to spread these costs over a larger number of components, particularly as production volumes increase.

The cost of an individual machine is therefore not enough to determine which solution is more economical. Other factors include setup requirements, productivity, cycle times, and production organization. Brawo also considers the operator-to-machine ratio.

In CNC machining centers, where cycle times are generally longer, an operator often does not need to remain continuously at a single machine: one operator can therefore oversee multiple CNC machines. Transfer machines, on the other hand, typically require an operator to be present due to their higher production rates.

A comparison between transfer machines and CNC machining centers must therefore consider the overall balance between investment, production volumes, productivity, and operator utilization, evaluating these factors in relation to the specific production requirements.

Precision machining: the Brawo approach

Brawo integrates machining operations into its manufacturing process to produce components made of brass, aluminum, and other non-ferrous metals, combining transfer machines, flexible manufacturing cells, and CNC machines according to the workpiece's characteristics and production requirements.

These machining technologies are supported by engineering expertise and in-house tooling management. Through Emmebi, a Group company, cutting tools and workholding systems are designed and manufactured internally.

Brawo's engineering team develops CAD/CAM programs in-house for tooling design and everything required to industrialize a new product, from component and tool design to machining process planning and simulation, covering both forging and machining operations.

This approach enables Brawo to support customers from the development and industrialization stages through to component machining, matching component geometry, production volumes, and manufacturing requirements with the available technologies.

Do you have a component to develop or industrialize? Contact Brawo to assess its manufacturability with our technical team.