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16.01.2017 12:42 Age: 3 yrs
Category: News 2017

All process steps networked to save time

Forming and hardening in a single manufacturing chain


Production line layout

The manufacturing chain developed by Landau-based Wickert combine component forming and hardening in a single work process. Using controls to network all steps in a process not only allows comprehensive component tracking, but also provides continuous process data acquisition. Comparison of this data with target values is a given in these production lines. Fluctuations in the production process are quickly detected as a result, allowing the plant operator to make a rapid response.

Manufacturing chains of this type generally comprise a component feed with a component buffer, a high-temperature furnace, and forming presses with integrated quenching. Forming and hardening are followed by component batching and the output buffer. Depending on the plant operator's requirements, a tempering furnace and a cooling section can also be integrated. The quenchant can consist of water, polymers or hardening oils.

During the combined forming and quenching process, a semi-finished metal sheet part is heated to around 950 °C in a furnace and placed in the forming press. Once forming is complete, it is then quenched in the forming tool in direct contact with the hardening agent. The forming tool is modified to allow this to happen.

This means that lower investment and reduced costs are required to manufacture wear parts for agricultural machinery in comparison with a conventional process, for example. In the standard process, the component is first formed and then, after a suitable time delay and in a separate step, placed and hardened in what is known as a quench press.

Hardening process assured

The combined process offers another advantage in the fact that components come into contact with the quenchant very swiftly, thus ensuring that quenching takes place within the designated temperature range. This usually prevents ferritic structures from forming – a particular great advantage for thin blanks between 2 and 4 mm thick.

Permanent monitoring of process data guarantees the required quality level for the plant operator, especially when producing safety-relevant components such as those for fast-rotating blades. The monitoring system in these Wickert combined production lines pays special attention to the handling time between the furnace and the forming tool until contact with the first hardening agent and also to the component temperature directly in the tool before forming.

The manufacturing chain proposed by Wickert comprises five individual processes:

1. The trimmed blanks are placed in a fully automatic handling system and fed into a heating unit, which heats the component to between about 900 °C and 950 °C.

2. As a general rule, the blanks are uniformly heated up in roller passage furnaces.

3. Forming takes place in presses with a pressing force between 1,600 kN and 8,000 kN using high-response proportional technology. The system includes hydraulic die cushions and component lifters.

4. The components are quenched with a liquid quenchant, which is channeled to the forming tool via the clamping plates with large cross sections.

5. The last step in the process is when the formed, hardened component is removed from the press. The component temperature is recorded during this stage of the process and monitored to ensure it remains within a selected tolerance range. The setting time is 1 ms (90 %).

Shorter hardening times by 50% or above

The return grooves containing the quenchant are bounded into the clamping plates to ensure a guided return flow into the filtering systems. Full filtering ensures that the system remains almost completely free of scale.

The bounded return grooves allow a typical constriction of drainage, which creates an adjustable internal pressure within the forming or hardening tools. This internal pressure offers a decisive advantage for the plant operator: the Leidenfrost effect, which produces a vapor layer, is overcome more quickly than in a hardening quench thanks to the internal pressure in tools and the constricted flow. The cooling process changes over to what is known as the simmering stage earlier and the vapor layer dissipates. This is when the quenchant first comes into contact with the component, achieving a maximum cooling effect. The result is dramatically shortened process times. Hardening time can be halved – or even more than halved, depending on the component.

Good parts guaranteed

Process-relevant data for all work steps can come together in a process engineering diagnosis and archiving system in Wickert LOG. Derived over the entire process, this information helps to optimize the system and detect any deviations in individual manufacturing parameters in good time. Components which have experienced deviating parameters can be discharged for inspection before they are returned among good parts.

The intelligent process sequence ensures that these combined forming and hardening production lines can deliver optimum product quality and time savings in the manufacturing process. They not only increase cost efficiency in the manufacture of highly precise components, but also provide traceability for quality-relevant parameters.

For further question please contact Mr. Marc Jordan, Email: m.jordan@wickert-presstech.de