Currently showing posts tagged Plastic

  • 3D Printer Material Selection Guide

    Picture this: you’ve got a part or assembly you want to print, but you have no idea what material you need. Here’s the process we use.

    First, determine your requirements. Do this first. If you can answer these questions, it’s easy to select a filament.

    • What is the max temperature your part will be exposed to?

    • What mechanical properties will you need?

    • Do you have specialty requirements?

    • What is your budget?

    Filament Deposition Modeling (FDM) or Fused Filament Fabrication (FFF) 3D printing uses thermoplastics, plastics that can be melted and shaped without loss of engineering or cosmetic properties. This means that heat is the first thing to check.

    What is the max temperature your part will be exposed to?

    This is often the most important question to ask yourself when choosing a material. Most of the time, the print will be in your air conditioned and heated home or office and you have no special requirements, you can move on to the next question. But maybe you want to keep it in your car, or it’s used next to something warm, or you want to be able to put it in the dishwasher. Maybe it’s outside in the Texas heat.

    PLA is a great choice for the vast majority of prints, 80+% of the prints we do are in PLA. It looks great, and it comes in a rainbow of colors. However, it’s shortcoming is its lack of resistance to heat. If prints will be exposed to temperatures over 130 degF it may warp permanently. Choose another material if you require high-heat resistance. This is the most economical filament to print with. It is perfect for design and prototyping when multiple rapid design tweaks need to be made and tested.

    Amphora, n-gen, colorfabb XT, and colorfabb HT are most heat resistant materials we use. They exhibit ultra-high heat resistance. They produce beautiful glossy prints and come in many colors. They have great temperature resistance and can be used in prints that must be exposed to boiling water or temperatures above 200 degF.

    ABS used to be the most common heat resistant material.  In fact it used to be the most common material for 3D printing, but advances in plastic chemistry and alloying have produced tons of materials that have better properties and print much more cleanly. ABS is very likely to crack along layer lines due to the shrinkage of the plastic as it cools. This also can cause problems with parts that need to have tight tolerances. We no longer offer ABS.

    If heat resistance is your driving requirement then you’re probably done with your selection unless you have another special case. Next we’ll look at strength and toughness/flexibility.

    Nylon is very resistant to heat. 

    t-Glase is moderately resistant to heat. 

    What Mechanical Properties will you need?

    Plastics are different than some materials in that strength and toughness must be considered together in all situations. Does the part have to be strong? Does it need to be able to take impacts or flex?

    PLA is one of the strongest materials available at a low price point. The downside is that it’s not flexible at all, and it does not take impacts well.

    Amphora, n-gen, colorfabb XT, colorfabb HT co-polymers are also very strong. They are less brittle than PLA but still not very impact resistant. They are very resistant to cracking along layer lines when broken and exhibit more consistent strength in all directions than other filaments. Whether this applies to your selection or not depends on the geometry of the part and where the highest stress points lie. We can advise you on these factors. Available in many colors

    Nylon offers high strength with a ton of toughness and resistance to impact. It is slightly flexible in thin cross sections. It is very resistant to abrasion. Recently Nylon has become available in several colors whereas it used to only be available in natural. There are a few different varieties, so ask us if you think this might be a match but you have special requirements (see below).

    PETG/PET has properties that nicely bridge PLA and ABS. It is essentially the replacement for ABS in 3D printing. If you require strength over all other factors but still need resistance to impact this is a good choice. It is also resistant to high temperatures.

    PC (Polycarbonate) is strong, durable, and tough. It is also naturally translucent, or nearly transparent in some applications. PC is very difficult to print and is not suitable for some geometries.

    TPE/TPU are the flexible filaments. They come in different hardnesses that go from floppy to firm. They can stretch a LOT before they break. They are virtually indestructible when dropped or impacted. They are not stiff, they are similar to rubber or silicone. They do not have ultra high temp resistance but do fine in hot cars and outside.

    t-Glase is strong and impact resistant but not as much as some of the other materials. It is one of the most transparent filaments available and comes in several colors.

    Do you have other specialty requirements?

    The majority of prints don’t require a lot of special properties and the above materials will cover nearly all situations but sometimes the most popular filaments aren’t what you need. Here are a list of some other specialty filaments and their differences. Keep in mind that these are specialty filaments that are considerably more expensive than more common filaments.

    • Carbon filled high temp filaments have tiny strands of carbon fiber mixed in with a highly heat resistant co-polymer.
    • Brass/Bronze/Copper/Iron/Steel fill. These filaments have tiny particles of metal mixed into them. This causes the prints to be heavier and exhibit some of the characteristics of the filler metal. They can often be polished and can also be oxidized or patinaed.
    • HIPS/PVA. If you need a part that will dissolve in water this is the one.
    • Wood fill. Just what it sounds like. Particles of wood mixed in with the plastic. This can be sanded like wood and have a smell like wood. There are a couple different species available.
    • Laybrick. Particles of stone in the filament.
    • Ceramic fill. This is filled with ceramic material and can be fired into hard pottery. We do not currently offer kiln services.

    Believe it or not, this isn’t all the materials that can be 3D printed. There are variations that have scents infused into them. Cinnamon, coffee, cedar, beer, hemp seem to be the most popular. There are even filaments that are ESD safe, food safe, and glow in the dark!

    What is your budget?

    If you’re on a budget and don’t have special requirements then PLA is probably your best bet. It is the most economical of all the filaments we use. The second most affordable is PETG. The specialty filaments are the most expensive, and the others lie somewhere in between.

    There is no doubt that more varieties of filament will continue to be added to the already overwhelming number to choose from. Let us make it easy. If you’re still not sure what filament to use just ask. We can give you expert advice gleaned from years of turning plastic into parts.