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Is It Safe To Drink From a 3D Printed Cup?

Thanks to 3D printers, owners can create a lot of products – cups included. So, you might be wondering: is it safe to drink from a 3D printed cup?

It is safe to drink from 3D printed cups as long as they’re made with food-safe filaments. Finishing the cup food-grade material will help protect it from bacteria that may invade the surface.

Read on below to learn more about the substances you should use for 3D printing. Likewise, I have some other tips that could keep your 3D printed cup safe for frequent use.

Safe Materials To Use for 3D Cup Printing

When it comes to printing materials that come in contact with food or drinks – such as cups – it’s vital to choose the right kind of material. 

That’s because some contain chemicals that are harmful to health. On the other hand, some filaments can break down when exposed to liquids or certain temperatures. 

Because of these circumstances, it’s best to use the following materials for 3D cup printing:

Polylactic Acid (PLA)

pla filament

PLA, a material derived from corn starch, is the commonly used filament in 3D printing. It’s considered safe because it contains lactic acid, a substance found in the body. For one, it’s primarily found in the red blood cells and the muscles. 

PLA also doesn’t produce any untoward reaction when it comes in contact with food or beverages. However, it can only withstand a maximum of 60 °C (140 °F) before melting. 

Despite this drawback, the Centers for Disease Control recommends using PLA over other printing materials. One such example is the hazardous filament acrylonitrile butadiene styrene.

Polyethylene Terephthalate Glycol Filament (PETG)

PETG is another one of the few food-safe filaments for 3D printing. They’re easy to use, although some versions get soft when exposed to a temperature of 100 °C (212 °F). 

That said, a PETG cup shouldn’t be used for consuming hot drinks. 

Food-Safe Resins

Most 3D printers often use powder or filaments such as PLA and PETG. But for making cups, using liquid resin proves to be another safe option.

With this, you can easily shape ceramics – as well as other filaments. 

When it comes to using resins, it’s crucial to choose a food-safe variant. Likewise, you should make a point to cure it before use.

Ceramic

Often used in fine china, ceramic is another printing material you can use for 3D cups. It’s strong, nonporous, and heat-absorbing, thus making it perfect for hot beverages.

The only drawback to using this is that it’s not as widely available as, say, PETG. 

Should you be able to find one, it wouldn’t be able to yield a ‘detailed’ design – especially if you’re using a printer with a paste extruder. 

Metal

If you have a metal 3D printer ready to use, you’ll be glad to know that you can use various materials for your cup. Metal, aluminum, stainless steel, and tin are food-grade mediums, after all. Because 3D printed metal is entirely nonporous, you don’t have to worry about stray germs taking up residence in your new cup.

Finishing 3D-Printed Cups

In 3D printing, finishing is the process of smoothing the object’s surface. Not only will this make your cup look flawless, but it can also make it ‘safer’ for use. 

For best results, make sure to finish your 3D cups with any of the following substances:

Polyurethane

After printing your cup, go and dip it in a polyurethane resin bath. This liquid plastic will create a layer that acts as a protective shell. 

Polyurethane resins are clear, so you don’t have to worry about your design. Add to that; it can make the colors look more vibrant. 

When it comes to choosing a polyurethane finish, opt for a substance that’s thin and runny. This will help cover all the microscopic holes on the surface brought about by 3D printing.

As always, don’t forget to read the manufacturer’s warning label before using it. 

Note: Finishing your cup in polyurethane is the best way to make your cup food-safe, especially if you didn’t use the recommended above for your project. In this case, it’s best to coat your cup twice – better to be safe than sorry! 

PLA Smoothing

While PLA is suitable for making cups, the 3D printing process can leave the surface porous and prone to bacterial colonization. 

Because of this, it’s best to subject your cup to a process called PLA smoothing. As the name suggests, it smoothens the surface of the PLA – thus sealing the holes from invading microbes. 

Tips for Maintaining 3D Printed Cups

Just like the cups you bought from the store, your printed cups will need some care and maintenance. This will keep it safe from deterioration – so that you can use it for the months to come.

Hand Wash Some of Your Cups

Some substances, such as PLA and resin, can deteriorate quickly due to the agitation and high temperatures of a dishwasher. It would be best to wash these cups manually in your sink with warm water and a mild antibacterial soap. 

Whatever you do, be sure you keep your printed cups clean as the smoothing can wear off over time and turn your printed cup into a bacteria breeding ground. 

Be Careful When Using the Dishwasher

plastic cups in dishwasher

Ceramic and metal cups made from tin, aluminum, or stainless steel are dishwasher-safe. However, it would be best if you placed them on the top rack. This should keep them safe from the rough movements in the dishwasher.

If you’ve finished your cup with polyurethane, ensure that the product is safe for dishwasher use. Depending on the manufacturer’s instructions, you may need to coat the cup with a certain thickness. 

Store Your Cups Well

3D cups and other 3D-printed objects should be stored in a cool and dry area. 

For best results, place your cups on a closed shelf to prevent dust contamination. Keep them away from the stove and other heat sources that could melt the material. 

To improve the longevity of your 3D cups, make it a point to alternate use. Drink from one item today – and another one tomorrow.

Final Thoughts

3D cups are safe to use as long as they’re made from PLA, PETG, resin, ceramic, or metal materials. 

Finishing the cup will keep it safe as well. This will help smooth the pores – thus keeping the microbes from penetrating the surface.  

Proper maintenance will help as well. It’s best to hand wash PLA and resin cups, while other cups should be placed on the top rack of the dishwasher.