Think about sculpting and designing your own boxes and utensils to carry food. As amazing as it sounds, it would require us to think about food-safe materials to prototype with 3D printers.
There aren’t too many 3D printing materials that are food safe, but one of them is PETG. It is widely considered foodsafe in the 3D printing community and can be coated with an epoxy resin to increase its effectiveness. PLA is foodsafe for single-use plastics. Filament can be bought at food-safe quality levels.
3D printers use plastic materials as a source to print. All the plastics that come under the food safe category can’t be used for printing. The polymers used in 3D printing should possess some properties like being a thermoplastic, high strength with low flexibility, suitable print temperature, minimal shrinkage, etc.
Polymers that satisfy these properties and become suitable for printing include, commonly known plastics such as PLA, ABS, etc. All the above mentioned properties reduce our spectrum of finding suitable food safe printing materials, very narrow. But that doesn’t rule out the option.
What Does Food Safe Mean?
For something to be food safe, a generalized view would be to summarize it as a material that meets all the requirements which are determined by the intended use and will not create any food-safety hazard.
It can be further elaborated as materials that obey the following guidelines produced by the FDA and EU.
The material that holds the food should not:
- Impart any color, odor or taste
- Add any harmful substances into the food which includes chemicals, saline or oil
- Be durable, corrosion-resistant, good absorbent and safe under normal use conditions
- Gave sufficient weight and strength to withstand repeated washing
- Have a smooth finish which is easily cleanable without cracks and crevices
- Be resistant to chipping, pitting, distortion and decomposition
The option we are left with is to know the purpose of the object to be designed and to use a material accordingly. If the object is not used under high temperature, PET based plastic can be used to print as most of the water bottles and tiffin boxes are made from it.
PLA can be used to make objects that are subjected to short term food contacts like cookie and pancake molds. If you want to go for the extreme you can use ceramic, which has proven over centuries its place in the kitchen.
Before knowing more about the material used, we need to know a bit about how a 3D printer works and all the processes involved in it to get a better grasp on the material requirements and why specific materials are required.
What Makes a Material Suitable for 3D Printing?
We can’t use just any normal plastic material to do 3D printing. Most commercially available desktop 3D printers use a method called ‘fused deposition modelling’ (FDM). These types of printers print by extruding the thermoplastic material to be printed and setting it in the desired shape.
The extruder is often a nozzle that heats up and melts the polymer. This process gives us an idea of what material to use. The key element here is temperature and we need materials that can be modified with this property.
The workable temperature for the material should be in a range that can be produced in home appliances. This gives us some options to choose from.
When it comes to materials used for 3D printing, there are plenty of options to choose from. You can choose the material according to your needs.
The materials used can be classified into engineering grade like PEEK, commonly used thermoplastics like PLA, resin based materials and composites are materials that are created by combining two materials to get the best properties of both.
Composites stand apart from the rest of the materials as it is mainly used for prototyping with metals and it is a vast category of its own.
Popular Materials & Whether They Are Food Safe
Commonly used desktop FDM printers use materials like PLA (polylactic acid), PETG, or ABS plastic. These materials are fed into the printer head in the form of a filament or wire. These polymers are thermoplastics.
Thermoplastics are materials that have the property to soften when heated and harden when cooled. This process of heating and cooling can be done multiple times without destroying its chemical or mechanical properties.
This allows materials falling under this category, a suitable agent for molding and 3D printing.
Other than PLA, PET-G and ABS which more commonly used, other options available which can be used in FDM printers are nylon, PVA, TPU and a variety of PLA composites made with powdered wood, ceramics, metals, carbon fiber, etc.
PLA (Polylactic Acid)
It is one of the most sold 3D printing materials available in the market. It comes as the default choice when considering a desktop 3D printer which is FDM.
It is cheap and requires low temperature to print. It does not require a heated bed. If you are wondering what a heated bed is, it is the platform in which the print head prints onto. In some cases a heated bed provides more adhesion of the printing object onto its surface.
PLA is derived from processing sugarcane and corn. Hence it is eco-friendly and biodegradable. For printing with PLA, you require a printing temperature that falls in-between 190-220°C. Another key feature about PLA is the fact that it is also renewable.
The temperature for printing PLA gives us an understanding of what purpose it can be used where its food safe. This material should only be used in low temperature handling.
In an experiment conducted on PLA by James Madison University (JMU), PLA was subjected to various temperatures and pressures and found that PLA as a raw material is food safe.
When PLA is subjected to the hot nozzle of the printer, there is a chance of inducing toxic material into it while printing by the nozzle. This scenario is only applicable only is the nozzle is made of any toxic materials like lead.
It can be used to make cookie cutters and other food related objects that have short period of contact time with the food material. An interesting fact about PLA is that it sometimes produces a sweet scent while printing, depending on the brand.
The PLA I recommend is Overture PLA Filament (1.75mm). Not only does it have an incredible amount of high reviews on Amazon, it is clog-free with great dimensional accuracy and is widely known as being premium quality in the 3D printing world.
ABS (Acrylonitrile Butadiene Styrene)
It is a strong light weight thermoplastic that can be used for 3D printing.
ABS plastic is known for its toughness and impact resistance. It is an established material when it comes to industrial use. ABS popular in the toy industry and it is used to make LEGO building blocks.
ABS in its melted form produces a strong odour while printing. ABS plastic is known for withstanding much higher temperatures compared to rest of the printing materials.
The extruding temperature of ABS plastic is found to be around 220-250°C (428-482°F) This makes it a preferred choice for external and high temperature application.
Even though it has a higher withstanding temperature it is not considered food safe.
The reason for this is ABS plastic contains toxic materials that should be avoided from contact with food. The chemicals in ABS can leach into the food it is in contact with.
PET (Polyethylene Terephthalate)
This material is usually considered as an alternative to ABS plastic with an added bonus of being food safe. It has a wide range of industrial applications with food and water.
PET is a polymer widely used in the manufacture of water bottles and food carrying containers. Unlike ABS it does not produce any odour while printing. It requires a lower temperature for printing and does not require a heated bed.
The printed form of PET is prone to weathering and it can lose its properties. This can be avoided by storing the printed material in an area with less humidity.
PET-G (Polyethylene Terephthalate Glycol-Modified)
This is a modified version of the PET with glycol. This modification of PET makes it a highly printable material. It has a high temperature carrying capacity. The printing temperature of PET-G is around 200-250°C (392-482°F).
PET-G is strong and flexible at the same time. This material is well known for its smooth surface which can wear off quickly. While printing, it does not produce any odor.
It requires a good bed temperature to hold the object onto its surface. PET-G is known for its transparency and weather resistance. PETG is considered to be food safe. Its weather resistance property makes it a suitable material for designing jars and gardening equipment.
For clear PETG there is one brand and product that sticks out as a top player in manufacturing. That filament is YOYI PETG Filament (1.75mm). It uses raw materials which are imported from Europe, with no impurities and they have a strict guideline on overall quality.
It is officially FDA-approved as food-safe so this is a great choice if you want a food-safe 3D printing material in your arsenal.
Not only will you get no bubbles while printing, it has ultra-smooth technology, no odor and precise precision for consistent prints time after time.
Once you purchase this filament, you’ll be glad to know that their customer service is top notch and offer a free return within 30 days, which you would hardly need anyway!
Surprising to many, ceramic is also used for 3D printing. It stands in a category of its own, as it requires printers that are designed to handle the material in the form of wet clay with other minerals.
The printed product from the printer as such is not in its finished form. It should be put in a kiln to heat it and solidify. The end product does not have any difference from the normally produced ceramic objects.
It will exhibit all the properties of a normal ceramic dish. Hence it can be used as a food safe material for a long term, but it does take a little more than just your 3D printer!
Things to be Considered After Selecting the Right Material
Bacterial Growth on 3D Printed Surface
One of the main things to consider while using 3D printed objects to handle food is bacterial growth. Even if the print looks smooth and shiny, in the microscopic level the print would contain small cracks and crevices which can hold food particles.
This is due to the fact that the object is built in layers. This way of building can create small gaps on the surface between each layer. These gaps containing food particles become an area for bacterial growth.
The 3D printed object should not be brought in contact with food items like raw meat and egg which contains high amounts of harmful bacteria. Hence if you are planning to you a 3D printed cups or utensils for long term use in its raw form, it becomes harmful for food consumption.
One way to prevent this is by using it as disposable temporary use utensils. If you are really into using it long term, then the best way is to use a food safe sealant to cover the cracks.
Using a food-grade resin is a good option. If you are using an object fabricated with PLA, it is advisable to use Polyurethane, which is a thermosetting plastic to cover the object.
Washing in Hot Water or a Dish-Washer Can Cause Problems
Another thing to be considered while using 3D printed objects is that, it is not advised to wash the object in hot water. You should have thought this might be a solution to solve the bacterial problem.
But it simply doesn’t work as the object will start to lose its property by time. Hence these objects can’t be used in dish-washers. Brittle plastics like PLA can deform and crack while washing in hot water.
Know the Food Grade Quality of the Filament While Purchasing
While purchasing the filament of a suitable material for printing, there are a few things to be taken into account. Every filament for printing comes with a safety data sheet about the material used in it.
This data sheet will contain all the information regarding the chemical properties. It will also give information on FDA approval and food-grade certification on the product if the company has undergone it.
The Problem Can Still Lie With the Nozzle
FDM 3D printers use a hot end or extruder to heat and melt the printing material. The most widely used material for making these nozzles are brass.
Brass nozzles have a high chance of containing small traces lead in it. At the heating stage this lead can contaminate the printing material, making it unfit for being food safe.
This problem can be avoided by using a stainless steel extruder. I’ve written a post comparing Brass Vs Stainless Steel Vs Hardened Steel for a better understanding of this.
How Can I Make Material More Food Safe?
There is a product called Max Crystal Clear Epoxy Resin on Amazon which is designed just for coating 3D printed PLA, PVC and PET to make it food safe. Its described as being FDA compliant, impact resistant, waterproof, low toxicity and resistant to acids.
This epoxy resin gives a clear coat to your printed part and has execellent adhesion to materials such as wood, steel, aluminum, soft metals, composites and much more, showing how effective this product is.
The MAX CLR A/B Epoxy Resin is FDA Compliant coating system suitable for brief-use direct food contact. It is in accordance with CFR Title 21 part 175.105 & 175.300 which covers direct and indirect food contact as a resinous adhesives and polymeric coatings.
The viscosity of this product is similar to a light syrup or cooking oil. You can choose to either pour it into place or apply with a brush where it takes around 45 minutes to work and cure the material at room temperature.
Hopefully this answered your initial question and gave you some useful information on top of that. If you’d like to read more useful posts about 3D printing check out 8 Best 3D Printers Under $1000 – Budget & Quality or 25 Best 3D Printer Upgrades/Improvements You Can Get Done.