Cleaning Trays: This is how to clean reusable trays

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?

In most cases, production sites sort trays that need to be cleaned and place them at a collection point where they are picked up for workpiece carrier cleaning. The trays are then cleaned either in-house or by an external service provider. Industrial washing systems are used for this purpose. The designs of the washing systems are as varied as the items, workpiece carriers, and components being cleaned. In simplified terms, the washing process usually involves the following steps:

• Pre-sorting
• Removal of foreign objects (e.g., labels)
• Multi-stage washing process as required, e.g.:
  • Pre-wash zone
  • Ultrasonic
  • Spraying
  • Immersion degreasing
  • Injection flood washing
  • High-pressure water jet technology
• 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 returned to the production cycle immediately.

Plastic and trays are exposed to particular stresses during industrial cleaning. We will take a closer look at these in the next section.

What must the tray withstand during cleaning?

• Solvents
• Chemicals
• Mechanical high-pressure water
• High temperatures

Effects on the tray during the washing process

What workpiece carriers have to endure during the washing process naturally depends on the degree of contamination, the type of dirt, and the required hygiene standard. Solvents are used to remove grease, oil, or paint. Chemicals that remove residues can also have an aggressive effect on the surface of the tray. Mechanical high-pressure water can affect delicate contours, and drying processes expose the tray to high temperatures.

Cleaning trays: Cleaning techniques

The ultrasonic washing system is a gentle method for cleaning workpiece carriers. Even containers with the most stubborn residues can be cleaned without the use of aggressive cleaning chemicals. During ultrasonic cleaning, the workpiece carrier is placed in a bath that is set into vibration by sound waves. This creates positive and negative pressure in the cavities of the liquid, generating tiny bubbles. When the bubbles burst, this movement pulls the dirt off the surface.

Drying can be carried out using vacuum technology. Drying processes for sensitive components are carried out using warm air circulation systems or contactless, antistatic air cleaners. The possibilities are endless.

How your tray survives many washing processes unscathed

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

1.) The right choice of material

Reusable containers are generally made from thicker materials to ensure that the tray remains stable for months or years of use. In addition, properties such as

• impact strength
• hardness
• and resistance

to various substances. What will the tray come into contact with and what solvents will be used to clean it? Only plastics that are non-reactive with the relevant substances and are resistant to them are selected.

Although using high-quality plastic and thicker material is more expensive initially, the investment quickly pays for itself. A high-quality tray needs to be replaced less often and retains its stability and quality. Reusable trays therefore make sense not only from an environmental point of view, but also for economic reasons.

2.) Observe design must-dos with regard to tray cleaning

The design of the tray depends on the environmental influences it has to withstand – including during workpiece carrier cleaning. Trays can be reinforced where high mechanical and dynamic stresses occur, and thin spots in cavities must be avoided. More complex tool designs support a long service life.

Special features and post-processing support the cleaning of the tray. Plastic trays can be equipped with water-repellent edges. Holes can be milled into the bottom of the cavities or mold cavities so that water can drain off easily.

3.) Involve cleaning service providers

The design is most efficient when the internal or external cleaning service provider is involved from the outset. To avoid unwanted chemical reactions, there are two approaches:

Cleaning agent used

Ask your service provider to specify the cleaning agent they plan to use. formary checks the data sheet for compatibility with the plastic used.

Plastic used

formary will provide the service provider with a cleaning agent recommendation for the plastic used. The service provider will check the compatibility of the cleaning agent with their equipment. If you develop your tray with us, formary will be happy to handle the communication. We know that it is worthwhile for your project to draw on the combined experience of plastics and cleaning experts.

Tray cleaning – ask the right questions and get the perfect product quickly

Design your workpiece carrier for production with subsequent workpiece carrier cleaning now. You can find this configuration in the formary configurator under “Fine tuning & handling” and “Washability.” Learn more about the design of deep-drawn parts in our blog post “Release of design data” or in our design guide.

Configuration of the washing process in the formary product configurator

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