Cleaning Trays: This is how to clean reusable trays

Cleaning trays - Key points at a glance

• The design and material selection of plastic trays should consider the cleaning process from the start.
• Industrial cleaning processes expose trays to high stresses such as heat, chemicals, and water pressure.
• The right material selection, robust construction, and involvement of cleaning experts are crucial for a long service life of the trays.

→ In our 3D Tray Generator, you can add drainage holes to the tray to optimally equip it for washing processes.

How does tray cleaning affect design?

The cleaning of used plastic trays and workpiece carriers usually takes place at the end of the production chain or is even completely separated from the production process and carried out by external service providers. Trays are usually designed with a focus on the production process they are intended to optimize. 

Nevertheless, it is important to consider tray cleaning right from the start of development. That's why you can specify washing processes in the configurator when you make your inquiry.

How is a tray cleaned industrially?

Usually, production sites sort out trays that need to be cleaned and place them at a collection point where they are picked up for workpiece carrier cleaning. The cleaning of the trays then takes place either in-house or at an external service provider. Industrial washing systems are used for this purpose.

The cleaning process in the washing system

The designs of washing systems are as diverse as the cleaned articles, workpiece carriers and components. In simplified terms, the washing process usually includes the following steps:

1. Pre-sorting
2. Removal of foreign objects (e.g. labels)
3. Multi-stage washing process according to requirements, e.g.:
   • Pre-wash zone
   • Ultrasonic
   • Spraying
   • Immersion degreasing
   • Injection flood washing
   • High-pressure water jet technology
4. Drying process

The latter is particularly important for delicate electronic components where residual moisture can quickly lead to corrosion. After the professional cleaning process, the reusable workpiece carriers can be immediately returned to the production cycle.

What does the tray have to withstand during cleaning?

During industrial cleaning, trays are exposed to particular stresses. The choice of the right material and design must withstand these influences. Here are the most important factors:

• Solvents and chemicals: These are used to remove grease, oils or paints and can have an aggressive effect on the tray surface.
• Mechanical high pressure: Water jets can damage delicate contours.
• High temperatures: Drying processes, as is common in industrial cleaning, expose the material to high temperatures.

What cleaning techniques are available?

In addition to standard washing processes, there are gentler techniques such as ultrasonic cleaning.

• Ultrasonic cleaning: In this method, the workpiece carrier is immersed in a bath that is set into vibrations by sound waves. This creates tiny bubbles that, when they burst, loosen the dirt from the surface. Aggressive chemicals can often be avoided this way.
• Drying: Drying can be done via vacuum technology. Drying processes for sensitive components are carried out using warm air circulation systems or contactless, antistatic air purifiers. The possibilities are diverse.

How your tray can survive many washing processes unharmed during cleaning

Since we have already designed many thermoformed trays and workpiece carriers that are suitable for industrial cleaning systems, we can tell you what matters.

1.) The right material selection

For reusable containers, thicker material gauges are generally used to make the tray stable for months or years of use.

Important properties include:

• Impact strength
• Hardness
• Resistance to chemicals and solvents

Only plastics that are not reactive with the cleaning agents used are suitable. Although high-quality plastics are initially more expensive, they quickly pay for themselves through longer service life, stability and consistent quality.

2.) Design must-dos for cleaning-resistant trays

The design should be adapted to the environmental influences of cleaning:

• Reinforcements at heavily stressed areas
• no thin spots in cavities
• more complex tool designs for longer durability

Additional features facilitate cleaning:

• water-repellent edges
• drainage holes in cavities and form nests

3.) Involve cleaning service providers early

The design is most efficient when the internal or external cleaning service provider is involved from the start. To avoid unwanted chemical reactions, two approaches can be taken:

• Starting from the cleaning agent: Service provider names the planned agent, formary checks plastic compatibility.
• Starting from the plastic: formary recommends suitable agents that the service provider validates with their system.

This way, unwanted reactions can be avoided and the tray can be optimally prepared for reusable application.

Conclusion: Cleaning begins at the tray design stage

For plastic trays to reliably survive many industrial washing processes, cleaning should not only be considered at the end of the production process. It is crucial that material selection, wall thicknesses, geometry and additional features such as drainage holes are already adapted during design to the subsequent stress from chemicals, temperature, water pressure and drying.

This early planning particularly pays off for reusable trays: the tray remains stable longer, cleaning quality is improved and failures in the production cycle can be avoided.