A comprehensive collection of 3D printing tricks – Part 3

In this part we’ll take a look at the most common materials you can use for 3D printing and how to compare to each other. I’ll discuss the most important features and problems of each material and I’ll also look at a few methods that should help you get that first layer right as well as some methods to fight warping.

Choice of material, layer adhesion and warping

The material

The choice of the right material is crucial for a good result. Use ABS or PETG for strong, functional parts and PLA for weaker but more detailed parts. Due to the strong odor of ABS, as well as other problems like warping, I wouldn’t recommend using it any more. Even though, PETG is harder to use properly, it’s definitely worth the hassle because it’s less likely to warp or to get knocked off the print bed during longer prints. Anyway, let me go over these three options individually:

ABS is good for strong, functional parts. It usually prints at a high temperature somewhere between 220 and 240 degrees celsius. If you have a heated bed, it should also be turned on pretty high. I usually go with 75 to 80 degrees celsius. The biggest two problems when using this material is the strong odor and the warping that can easily occur during longer prints.

PLA should be used for more detailed prints where the finished part doesn’t necessarily have to be strong. It prints with a temperature of roughly 170 to 190 degrees and a heated print bed running at 60 degrees celsius. It still emits a noticable odor when printing, but it’s way less unpleasant. Because the material is often made from starch, it emits a somewhat sweet smell when printing. However, you should really not extensively breathe that stuff in.

PETG is my personal favorite for all kinds of prints. Even though, it prints at very high temperatures starting at 235 degrees celsius, it never warped in any print I made. If you heat the print bed up to 75 degrees celsius, you get the best results, at least from experience. However, the material is fairly hard to handle and your printer needs to be perfectly set up. You should pay close attention to the print bed. It has to be almost perfectly level and the Z-Offset must not be too large or too small, otherwise your prints will constantly fail and the nozzle might get clogged.

Getting the temperatures right

Just as described above, the temperatues vary a lot from material to material. Pay attention to the notice that’s usually included with the material and try to use the temperature that the manufacturer recommends:

Figure 6: Note the sticker on the spool for the recommended temperatures

Just one last trick here: If you have problems getting the first layer to stick, even with a perfectly clean print bed, try increasing the bed temperature by five degrees (celsius) and try to printing again.

Furthermore, I recommend that whenever you get a new spool of material (especially when you try a new manufacturer) you print a small object and slowly increase the temperature during the print. Start with the minimum and end with the maximum. When the print is done, carefully inspect the part and determine at which temperature the results were the best.

Methods to make your prints stick

There are several methods here but I tried a few of them and I’ll discuss how they worked, starting with the worst:

Somebody once recommended that I try to dissolve a tablespoon of sugar in some water and spread a thin layer of the mixture on the print bed. Once the water evaporates, a sticky coating will be stuck to the bed and the prints will easily stick to that. Let me tell you: That absolutely didn’t work. Everything inside of the printer was messed up and the prints didn’t stick down at all. Don’t try that.

The same trick exists with water and salt. I haven’t tried it myself due to the fatality of the previously mentioned method. However, I can imagine that this one actually works.

Special coatings for the print bed are an alternative too. I can’t guarantee that every single one of them works perfectly fine but the one I tried once did the trick. However, they are pretty expensive and you can usually only use them a certain number of times before you need to replace them.

The glue stick method is pretty common and I used it myself for several years. However, recently I stopped doing so as I noticed that it only messed up the printer, especially the alignment of the bed and the Z-Offset because it always added to height of the bed. Furthermore, each layer leaves some residue that builds up over time and cleaning that off is not fun at all. Therefore I can’t recommend using that method anymore.

My new second favorite method is using some hair spray. However, be careful when using this method. Only spray a very very thin layer onto the printed bed and make sure that the aerosol doesn’t stay in the printer. If you have an enclosure, let it air out a bit before starting the print. The bed will still be sticky but I personally don’t want a 240 degree hot part close to some highly flammable aerosol.

My new favorite method is simply having a spotless print bed. Most materials will stick to the bed as good, if not even better, without anything applied to it as long as the bed is (almost) perfectly level and clean. The Z-Offset also has to be just right. The material should not be simply laid down, it needs to be squished onto the bed ever so slightly. However, the nozzle has to be far away so that the material can easily be extruded.

How to prevent warping

First of all: Why do prints warp? The warping happens due to uneven cooling of the printed parts. When a fresh layer of hot material gets put down on the top, the bottom layers have already cooled down. Therefore, they move towards the hot area and then warping occurs. This is even more problematic for long prints and large objects. Furthermore, the warping gets more extreme when the first layer doesn’t stick down very well.

The easiest method is to use a material that’s less prone to warping. However, if that’s not possible or you simply don’t want to use a different material, there are a few methods you can use to prevent (extensive) warping.

The first trick is to make sure that the bed temperature is high enough. Try increasing it in small steps (5°C for example) if your prints don’t stick well. However, with PLA, for example, the opposite can be the case: If your print bed is too hot, the material won’t solidify and it stays very soft and sticky. That will allow the material to stretch upwards easily.

You can also lower the infill percentage of your print. Try not to go higher than absolutely necessary. Full infill prints are much more prone to warping

Another method is using brims, as discussed earlier.

You may also increase the print speed. This will make sure, that the print doesn’t take too long. However, this method has problems on its own, for example decreased precision.

My last method to prevent warping: You can also change the orientation of the printed part. If the largest area is on the print bed, warping is more likely to happen than on smaller surfaces. However, you should always note the tips from earlier regarding the orientation of the object.

Summary

If you have problems with warped parts, try the methods discussed in this article. If you’re using ABS, you should also try PETG. Switching from ABS to PETG is not easy but you’ll never want to go back to ABS once you know how to use PETG. If you don’t want to (or can’t) switch to a different material, you can always try a different combination of the discussed methods.

Table of contents

Part 1 – Basics, Maintenance and Cleaning
Part 2 – 3D modelling, slicing, and printing software
Part 3 – Choice of material, layer adhesion, and warping (You are here)
Part 4 – Removing the printed parts (Not published yet)
Part 5 – After-print cleanup and storage conditions (Not published yet)
Part 6 – Short summary and cheat sheet (Not published yet)

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