Sizing presses from Frey re-press sintered parts

Sizing presses from Frey repress sintered parts
Marginal Column
Sizing presses handle complex sintered parts at up to 315 bar – and at the highest safety level.

Sizing presses handle complex sintered parts at up to 315 bar – and at the highest safety level.

The ABPAC compact standard unit can be tailored to suit customer needs.

The ABPAC compact standard unit can be tailored to suit customer needs.

The electric servo motor of SHA only provides the power needed.

The electric servo motor of SHA only provides the power needed.


March 2016


Sizing presses from Frey bring sintered components into their final form. Electro-hydraulic plug-and-run axes from Rexroth provide help.

An increasing number of components in the automotive industry are created by pressing metal powder alloys in molds. This way, complex components that were subject to time-consuming machining processes in the past, can be manufactured in a cost-efficient manner. Sizing presses made by the Bavarian company Frey & Co. in Lenggries-Fleck are designed to re-press the components after they have been sintered. “This step is necessary because a minimal amount of deformation always happens during sintering. We compensate for this with calibration and simultaneously compress the material structure”, explains Kaspar Waldherr, technical director at Frey. To make this cold forming process possible, axial presses from Frey work with a pressure of up to 315 bar. For the new KA series, the company is implementing newly developed plug-and-run ­solutions from Rexroth for the first time. These are ready-to-use, autonomous axes that combine the proven functions of servo drives with the high power density of hydraulics.

Economical and quiet

“We always have phases in the manufacturing process when the cylinders are idle. Central hydraulic units would continue to run”, according to Waldherr. Compared to conventional solutions, the servo hydraulic axes (SHA) have a reduced power consumption because the electric servo drive constantly adjusts its engine speed to the power requirement of the pump. Controller-related throttling losses disappear, the cooling

requirement is reduced. “What we are able to save there is remarkable and exceeds our initial expectations significantly.” Furthermore the SHA is significantly quieter due to the encapsulation of the pump in the control block. Due to the fact that central hydraulic power units also need to continue operating during process interruptions, in order to maintain pressure in the system, there's a permanent high noise level in the workshops. “The three SHA are much quieter when in operation and silent when they are idle”, the technical director explains.

In terms of the controller, Frey uses standardized IndraDrive servo converters and combines them with the Motion Logic System IndraMotion MLC from Rexroth. The drive and control software includes a special SHA library, which automatically takes into account all the peculiarities of fluid technology. Because hydraulic tasks are done by means of servo drives, the engineering also includes all established functions – such as the regulation of the axis and drive-based safety technology via the control unit. Frey can therefore construct the axial press according to the EN ISO 13849-1 that it achieves the highest performance level e (PL e) within the standard. This maximum protection against errors and incorrect operation is necessary for man and machine safety because the machines are also loaded by hand. “Manual loading is intended for small batches. Safety is the top priority here”, says Waldherr.

Compact and without reservoir

The machines from Frey also score points due to their compactness. The mechatronic combination of hydraulic and electric drive technology makes this possible – it works with very small amounts of oil and thus needs no separate reservoir. “Once it was necessary to have a reservoir with more than 1,000 liters of oil. We don’t need that any more, even if additional hydraulics are still required for peripheral processes. We can forego oil changes and also save ourselves the expensive structural measures to prevent leaks”, explains Waldherr. In the axial press, other peripheral functions with relatively low power requirements are hydraulically powered, in addition to the three servo-hydraulic axes. For this, Frey uses the new, compact ABPAC standard units from Rexroth, which can be tailored to suit customer needs.

Frey introduced the first press in this series late 2015 at the ceramitec in Munich. Quick installation with significantly less hydraulic piping, less noise emissions, lower energy consumption, as well as improved environmental protection are good reasons why Frey will continue to use Rexroth technology in the future.