Pretreatment systems

Continuous pretreatment systems -also known as continuous spray systems- are usually used in wet chemical processes for medium and high throughput. During wet chemical pretreatment, metal surfaces are cleaned using chemicals and heat, with water acting as a carrier material. The pretreatment and cleaning of the workpieces is carried out regularly in several coordinated cleaning steps, between which rinsing processes take place.

The structure of the continuous pretreatment systems depends on the workpiece shape and size, part throughput and the material to be processed. As part of the system planning, AFOTEK, together with the chemical supplier, develops a pretreatment concept tailored to the customer's needs for cleaning parts before the surface is coated in the painting system.

Parts can be transported within the painting system or powder coating system using conventional conveyor technologies, such as a power-and-free conveyor, a circular conveyor system or the AFOTEK Shuttle Conveyor System (ASF).

Continuous spray systems are environmentally friendly, energy efficient and investment-friendly and can be implemented for a wide range of component sizes.

Chamber pretreatment systems or chamber spraying systems are primarily used in the metal industry and are integrated into powder coating systems as an upstream cleaning process. A liquid cleaning medium is applied to the workpieces to be cleaned through adjustable nozzles, which dissolves contaminants and rinses them from the workpiece.

In chamber pretreatment systems, several cleaning steps take place in one chamber. To do this, the workpieces enter one or more chambers – depending on the throughput and the required treatment steps. As part of the project planning, AFOTEK equips the spray system so that the workpieces are optimally flooded on all sides. This is made possible by an offset nozzle system. The additional mechanical effect of the spraying process means that significantly shorter treatment times can be achieved at lower bath temperatures compared to immersion pretreatment systems. In addition, the system footprint is smaller compared to immersion pretreatment systems while process control is simpler.

Workpieces with surfaces that are difficult to access are ideally treated in immersion cleaning systems. These offer the security that not only the external
surfaces but also all cavities and edges are reached. This type of pretreatment is particularly recommended for complex geometries where a spray system cannot reach the entire surface. Immersion cleaning systems are often used in vehicle construction as well as in agriculture and forestry as an upstream cleaning process in CDC systems.

AFOTEK plans and configures the entire system based on the products being cleaned and customer-specific requirements and, together with the chemical supplier, develops the best possible concept with regard to the number and duration of the process steps. The various dipping pools are usually arranged in a row or in a horseshoe shape. The size of the dipping pretreatment depends on both the workpiece size and the required treatment steps. An integrated conveyor system, for example a cycle lifter system, rounds off the automated AFOTEK immersion pretreatment process. After the pretreatment process, the workpieces can be transferred from the cycle lifter to a power-and-free system or another type of conveyor system.

In addition to lower energy consumption compared to conventional spray pretreatment systems, dip pretreatment is also characterised by high-quality corrosion protection of steel and aluminium components.