Die cleaning

Safe and automated cleaning of extrusion dies

Die cleaning is an essential part of the aluminium extrusion process. After production, aluminium residues remain in the extrusion dies, which therefore have to be thoroughly cleaned before they can be used again. PCA designs and builds complete installations for cleaning aluminium extrusion dies with NaOH, with particular attention to safety, automation and operational reliability.

How does it work?

What is die cleaning and how does it work?

In aluminium extrusion, aluminium is pressed through a die under high pressure to produce profiles with a specific shape. Over time, aluminium residues remain in the die. These residues must be removed so that the die can be used correctly and safely again.

Die cleaning is usually carried out with a heated NaOH solution. The caustic soda dissolves the remaining aluminium, after which the die is rinsed with water. In a conventional process, this often involves manual handling, moving dies between different baths and exposure to chemical hazards.

PCA starts from a different principle: cleaning and rinsing take place in a single process tank. The liquid is kept in motion to speed up the cleaning process and ensure it runs uniformly. Buffer tanks also allow pre-heated liquids to be used, making the process faster and more consistent. In addition, the process tanks are kept under negative pressure so that no vapours can escape during the process.

PCA has developed a turnkey system that increases the speed of the cleaning process and drastically improves working conditions. At the heart of the installation is the intelligent management of liquids and vapours.

When should you choose die cleaning?

An automated die cleaning installation is the right choice when aluminium extrusion dies need to be cleaned frequently and safety, process control and continuity are important.

Die cleaning is the right choice if you want to:

remove aluminium residues from extrusion dies in a controlled manner;
give operators maximum protection against contact with NaOH;
prevent vapour formation in the production hall;
automate and standardise the cleaning process;
be less dependent on manual handling;
use NaOH and rinse water as efficiently as possible.

A PCA die cleaning installation is an important step towards improving the working environment and making production more efficient and reliable.

A safe installation tailored to the extrusion process

Safety is central to the design of a die cleaning installation. NaOH is a highly caustic substance, and hydrogen vapour is released during the cleaning process. The installation is therefore designed so that operators do not come into direct contact with the chemicals during the cleaning cycle.

The process tanks are fitted with extraction so that they are kept under slight negative pressure. Depending on the application, the extracted vapours can be treated further with a droplet separator, gas scrubber or other air treatment system. This ensures no vapours are released into the production environment and the installation is fully ATEX-compliant.

PCA builds the complete installation around the cleaning process. This includes the process tanks, buffer tanks, pipework, pumps, valves, instrumentation, heating, extraction, automation and PLC control. The installation is tailored to the customer’s existing working methods, such as die dimensions, basket type, available space and the required number of cleaning cycles per day.

Process control, reuse and operational reliability

A well-designed die cleaning installation does more than simply dissolve aluminium. It must control the entire process: cleaning, rinsing, buffering liquids, extracting vapours, monitoring temperatures and reusing liquids as efficiently as possible.

PCA works with buffer tanks so that hot NaOH and rinse water are available whenever they are needed. Contaminated rinse water can be reused internally to make up or dilute NaOH, reducing the volume of liquid to be disposed of. Used NaOH can also be used for several cycles as long as the solution remains sufficiently active.

In which applications is die cleaning indispensable?

Aluminium extrusion

Die cleaning is indispensable for companies that produce aluminium profiles by extrusion. After production, dies must be cleared of aluminium residues so that they can be properly stored, inspected, repaired or used again.

FAQ: frequently asked questions about die cleaning

How often does the used NaOH need to be replaced?

That depends on the number of dies cleaned, the amount of aluminium that ends up in the bath, the NaOH concentration, the temperature and the required cleaning speed. As more aluminium dissolves in the bath, the free alkalinity falls and the cleaning capacity decreases.

PCA’s many years of experience can help your company optimise your installation and operate it as efficiently as possible.

Can PCA optimise an existing installation?

Yes. PCA can analyse the existing cleaning process and identify where improvements are possible. This may concern safety, extraction, automation, tank layout, liquid circulation, NaOH reuse or rinse water management.

Depending on the situation, an existing installation can be modified, or (partially) replacing the old installation may be the best solution when safety and automation are the priority.

Is a PCA die cleaning installation flammable or explosive?

Hydrogen gas is produced when aluminium is cleaned with NaOH. Because hydrogen is a flammable gas, this must be taken into account when designing the installation.

PCA takes the necessary measures to make the installation ATEX-compliant. These include well-designed extraction, adequate ventilation, appropriate instrumentation and components suitable for the applicable ATEX zone. The electrical control and safety systems are also tailored to the installation’s risk assessment.

Experience the new standard in die cleaning.

Want to improve safety and speed up your process? Our experts design an installation that fits your production hall exactly.

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