When we think of 3D printed objects, the first thing that comes to mind is often something small and hard. That’s because most filaments harden as they cool and set, so your designs will be functional and durable. Although the most common 3D printing filaments, such as ABS and PLA, make solid and stiff objects, other filaments can maintain elasticity and offer a surprisingly supple stretch.
It’s possible to 3D print with soft plastic if you have the right filament, such as TPU and TPE. These flexible resins come in varying hardnesses and usually offer the strongest, softest, stretchiest 3D prints. Though most printers will print soft plastic, you may need to add a flexion extruder.
This article will tell you about soft plastic filaments and teach you how to identify them. I’ll also tell you about the challenges of printing with soft plastics and offer some pro tips on getting a perfect, smooth, flexible print.
Can You 3D Print Soft Plastics With Any 3D Printer?
Printing with flexible filaments is exciting and fun. However, if you haven’t worked with soft plastics before, you may find that they’re also quite challenging to work with.
Printing with soft plastics takes some specific settings and finesse, although it’s possible with almost any printer.
It’s possible to 3D print soft plastics with any 3D printer, although some specific extrusion models may have more difficulty printing flexible filaments. Be sure to check with your 3D printer manufacturer’s instructions before attempting to print soft plastics.
For example, Bowden tube 3D printers may have more challenges when printing with soft plastics. That’s because soft, flexible filament has the limpness of a wet spaghetti noodle. As a result, extruders may have difficulty pushing this slick filament out of the hot end, and if you use the wrong print settings and tension, you may end up with a jam or completely failed print.
However, when you print soft plastic filaments with a 3D printer, using a flexion extruder can help.
Extruders made for flexible filaments like this Diabase Flexion-Rep2 (available on Amazon.com) are fantastic for getting high-quality, soft 3D prints from any extrusion printer. They have grippier parts in the extruder, helping to keep the filament flowing evenly.
So, if you want to print with soft plastics regularly, getting an extruder that can handle slick, flexible filaments will surely pay off in the end.
In addition, the only other major constraint when using an extrusion printer is the hot end temperature when considering a filament. Try to choose a filament that melts at a temperature that your printer can achieve.
How Can You Tell if a 3D Printing Filament Is Soft?
Determining the softness of a filament is a lot more challenging than it seems at face value.
Most filaments are rated on the Shore durometer scale, which measures how well a material “bounces back” after pressing a hard, pointy sensor into its surface.
So, the Shore durometer value measures both how flexible the material is and how well it holds up to stress.
This measurement uses a number and letter rating to measure how soft, flexible, and durable a polymer or plastic is. The lower the number and letter rating, the softer the filament.
To tell if a 3D printing filament is soft, check its Shore durometer rating. Most filaments either have a 00, A, or D hardness on the Shore durometer scale. 00 materials are the softest, A-level materials are of medium-softness, and D-level materials are generally more rigid.
However, this measurement gets more complicated with the addition of numerical ratings. For example, this Gizmo Dorks Flexible TPU Filament (available on Amazon.com) has a Shore durometer of 95A. That means it has similar flexibility to hard skateboard wheels or grocery-cart wheels.
However, the Dialabs X60, the softest filament on the market today, has a Shore hardness of 60A. That means it has the same hardness as a tire tread or hard rubber eraser.
So, always check out the filament or resin’s shore hardness before you buy it to determine whether it’ll achieve the softness you want from your 3D print.
The Best Soft Plastic Filaments and Resins for 3D Printing
Let’s look at some of the best soft plastic filaments. I’ll also give you a ballpark range of Shore durometer ratings and melting temperatures, but please remember that each product’s specs will vary depending on the manufacturer.
- TPU is a fantastic filament for stretchy, flexible items. Although it’s soft, it’s also incredibly durable, and I’ve even had success with printing epoxy resin molds from this filament. Its Shore hardness usually ranges from 60A to 75D, and it has an average melting temp of 185º to 220ºC (365º to 428ºF).
- TPE is one of the softest filaments, with its average Shore hardness falling between 75A to 98A. It has a rubber-like consistency and usually melts at a temp of 190º to 250ºC (374º to 482ºF).
- SLA, DLP, and LCD Flexible Resins. Soft plastics aren’t just for extrusion printers! 3D printing resins can achieve outstanding softnesses of as low as 30A, but they can also reach incredible hardnesses.
Other materials such as nylon and polyester may also be flexible, so keep an eye out for Shore hardness ratings next time you’re shopping for filament.
Tips for Printing With Soft Plastics
- Slow down the print speed. It takes a while for your extruder to feed flexible, slippery filaments into the hot end. So, slow down your print speed by about half to keep a steady flow of filament coming out.
- Disable printer retraction. Refraction is a setting that lifts the nozzle from the print, reducing the chances of forming bubbles or over-extruded artifact spots. However, when printing with slimy, stretchy filaments, retraction won’t help since the melted filament will stretch more, leaving lumps in your print.
- Create a seamless design. Reducing the number of times your nozzle will jump from spot to spot can reduce stringing and potential artifact spots. So, try to give your print a seamless design that your printer can recreate without lifting the nozzle at all.
- Bake prints to reduce stringing. Soft plastics are stretchy and stringy, which often means you’ll have stringing and noticeable layer lines on your models. Bake your printed object in the oven at a low temperature (about half of the filament’s melting point) for about an hour to reduce these minor errors.
For more tips, be sure to check out this fantastic video from Maker’s Muse on YouTube:
It’s possible to 3D print with soft plastic, and there are many soft filaments and resins you can use. They all have different Shore hardness ratings, so go with the lowest number and an A or 00 rating to find the softest one.
When printing with soft plastics, be sure to adjust your printer settings and optimize your design since some extrusion printers may have difficulty handling softer filaments.