Best practice: How do I 3D print a food-safe component?

An increasing number of companies are advertising food-safe materials and offering more and more materials for processing and packaging in the food industry. But the public eye is also increasingly focused on the plastics that come into contact with food and how they can potentially affect consumers’ health.

What exactly does food grade mean? In the European market, the EU Directive 10/2011 regulates food conformity of plastics. The standard deals with the requirements for objects and more specifically, plastic materials that come into contact with food. The materials are tested under extremely unfavourable conditions of use that can realistically be anticipated.

These tests involve a risk assessment with regard to the toxicity and possible migration of plastic elements or certain chemicals to foodstuffs or substances that people eat. A migration limit specifies the maximum amount of a substance that may reach given foodstuffs.

In the American market, the FDA (U.S. Food & Drug Administration) regulates the permissibility of plastics for the food industry. Both standards include detailed lists on the permissible substances that can be found in foods. It is worth taking a look at the relevant Declaration of Conformity for your material, where the specifications for the use of your plastic substance are noted.

The right conditions for printing food-safe components

How can you 3D print a component that meets the requirements of EU 10/2011 and FDA? Here are a few tips on correct filament storage, printer maintenance and cleaning, as well as printer settings before printing. Our experience with the tribo-filament iglide I150-PF serves as the basis for these tips.

Important requirements for processing the filament

The material should be stored in a dry place and protected from the environment. In addition, it should be taken out of the packaging, protected from dust and it is essential that it is dried before printing. Drying prevents moisture contained in the filament from degrading the material and creating air pockets when melting in the nozzle. This process ensures that the surface finish and quality remain up to par.

Information on drying filaments can be found in the processing instructions. A good rule of thumb is that the drying temperature should not exceed the maximum application temperature of the plastic, but also should not damage the plastic reel. Drying of the filament is easily possible in a standard household fan oven, but also in a drying air oven specially designed for this purpose.

Another important requirement is regular maintenance and cleaning of the printer. Basically, all parts that come into contact with the filament should be free of residue. This includes in particular the extruder sprocket and the pressure nozzle. The desktop 3D printer manufacturer Ultimaker provides some cleaning routines for its devices that can also be applied to other devices. In addition to the sprocket and nozzle, a clean print bed is also essential; we recommend using a cleaned glass plate with either no adhesive or a food-grade adhesive.

• About the general cleaning routine for filament printers
• About the general cleaning routine for Ultimaker 3

Setting up the 3D printer correctly

The print settings should be selected in the slicing software, for example, the Ultimaker Cura, so that the surface of the object is as tight as possible. This tightness is achieved by lowering the printing speed and adapting the line width to the nozzle diameter. This allows unevenness in the component surface and reduces gaps in the cover layers. Before and during printing, the material must also be protected from dust, which is why a closed installation space is recommended.

Furthermore, we recommend not to produce food grade components in multi-material printing together with other, non-food grade materials, as mixing of the materials cannot be completely ruled out. Accordingly, the support material should either be food grade or the same material should be used as support material.

Food grade 3D printing at igus

With the tips mentioned here, igus has already been able to achieve food conformity according to EU 10/2011 several times, for example with iglide I150. In doing so, we have also achieved food compliance for the manufactured 3D printed component, which is significant compared to other food-compliant 3D printed materials.

This blog post provides tips on food-compliant 3D printing polymer components, but is not a substitute for necessary knowledge on the application side as to what the food compliance requirements are in a specific application. Depending on the application and requirement, tests on the specific component may also be necessary. In addition, we always recommend that you check the declaration of conformity carefully for the application, as there are major differences in approved foodstuffs, temperatures and the approved contact duration.

igus already implements more than 1,000 new applications per year in the food industry with a wide variety of products, such as plain plastic bearings, linear bearings and rails, 3D printed components and more.
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