Die corrections at the aluminium extrusion plant
Find out how die corrections can save time and cost in the extrusion industry by making defective dies re-usable.
The die tooling of an extrusion press
The core tooling component in extrusion is the die. The aluminium billet is heated and extruded through the die to get the desired shape of the product. Additional tooling is required to provide sufficient rigidity to the die against the pressure applied by the ram of the extrusion press (Figre 1).
Figure 1 – The die tooling of an aluminum extrusion press [1]
Die corrections
Why correct the extrusion die?
A proper condition of dies and tooling is crucial for good product quality and plant productivity. Die failures leading to rejection result in production down-times. The replacement of the scrapped dies further adds to the cost and time. Die corrections make defective dies re-usable and so avoiding its unexpected rejection.
Die corrections are of two types:
Pre-service corrections:
- Carried out on new dies after the initial trial runs, before putting them in regular service.
- Focused on adjusting the geometry or feed design, in case minor adjustments are needed.
Post-service corrections:
- Are done every time the die is dismounted after being used for extrusion.
- Focused on correcting the flow, damage and wear, fractures, deflections, and loss of hardness.
An extrusion die corrector
The die-shop technicians who perform die correction operations are called die correctors.
- Manage the die resources and are usually responsible for preparing the die assembly, performing trial runs, repairing, and maintaining the dies and related tooling.
- Must possess a high level of technical skills and knowledge about aluminium extrusion.
- Mst be capable to select a proper die correction.
Major principles of die correction
- Corrections should be usually carried out at the back end of the die. Working at the front end can reduce the die life.
- A particular die should be corrected by one specific corrector, as he is familiar with the die.
- All corrections must leave sufficient room for corrections in the future.
- All correction details and design changes must be properly documented [1].
Source:
1. Die Defects and Die Corrections in Metall Extrusion / S. Z. Qamar, T. Pervez and J. Ch. Chekotu, Metals, 2018, 8, 380