Printing a 3D model that sticks

FDM 3D printing technology uses molten filament (plastic) that is printed onto the print bed through the nozzle. For a perfectly printed model, it is crucial that the first layer of filament adheres well to the print bed. Most filaments tend to warp when the material cools too quickly, especially on the print bed. So, without proper adhesion to the bed, the filament will warp, making the product deformed and unusable. There are several ways to prevent this: the biggest benefit comes from using a heated print bed.

Temperature

Temperature is very important when making a 3D print. Without the right temperatures, it is impossible to make a good print. The filament must be melted before it can pass through the nozzle and be printed in layers. The temperature at which the filament transitions from a solid to a liquid form is called the glass transition temperature. This temperature differs per filament: for PLA it is between 60 and 65°C, for PET-G around 70°C and for ABS even between 110 and 115°C. Especially for filaments with a high glass transition temperature, such as ABS, it is crucial to have a high temperature in the printer. This can be achieved by using a heated print bed that heats the print chamber.

Adhesion to the print bed

An additional advantage of a heated print bed is that the first layers of filament on the print bed do not cool down immediately, but stay at the right temperature. This is essential for adhesion. Filament layers adhere well to each other, but not so well to another surface – in this case the glass print bed. This can be solved by setting the correct temperature for each filament. In addition, various aids are available to prevent warping of the print bed. Examples include Kapton tape (adhesion tape) or Dimaxif (adhesion spray). The popular PLA filament can be printed without a heated print bed, but more high-tech filaments like ABS, PP or PC -often used for industrial purposes- cannot be printed without a heated print bed and a closed chamber. The use of adhesion spray or tape is not sufficient, the model will still warp.

High tech filaments

The advantage of filaments with a high glass transition temperature is that as a product they are also resistant to higher temperatures. ABS is therefore often used in the automotive industry for dashboards and bumpers, for example. ABS also has a longer lifespan compared to PLA, as it is less sensitive to weather conditions, for example.

The dddrop RAPID ONE is equipped with a heated print bed and a closed chamber. This enables perfect printing with a wide range of filaments, making the design possibilities endless.

A stable printing process

The right temperature remains the code word when making good 3D prints. After all, it remains a plastic process, where temperature is an essential component. With a higher ambient temperature, a number of things will be important to keep the printing process stable. What components these are and what you can do about them you can read here.

It’s all about temperature 

The basic principle of 3D printing is that a plastic (filament) is heated to liquefy, so that the filament can be passed through the print head. The point of temperature at which the filament begins to melt is called the glass temperature. This temperature varies from filament to filament. You can imagine that the glass temperature must therefore be reached in order to lay down good print layers. The most ideal situation is when the filament is laid down and cools immediately so that it becomes solid and cannot deform. The next layer can then be printed immediately. Finding the right balance between temperature and cooling so that the filament can flow freely through the nozzle, but also solidify in time to maintain the exact dimensions of your 3D printed part, is the trick. Unfortunately, this is easier said than done. Occasionally, we have to deal with overheating. This is when the temperature of the filament stays too hot for too long, resulting in it melting away and distorting your print model. We cover the most common causes of overheating, as well as the solutions here.

Not enough cooling

A common cause of overheating is that the filament is not cooled fast enough when it is poured. The filament coming out of the extruder head can be as high as 250°C, depending on the filament being printed. For many types of filament, it is good to cool the layers immediately after depositing, this prevents deformation of the layers. The dddrop printers are equipped with multiple fans on the extruder head and in the back of the extruder head, so they can cool the product directly.  Two fans in the back of the cabinet are designed to control the temperature during the cabinet printing process. Watch out for too much cooling. There are plastics such as ABS, PA-12 & PC that cannot withstand temperature fluctuations. It causes shrinkage and makes the plastic warp.

To high extruder temperature

If fan cooling is not working (enough) you can try lowering the temperature of the extruder head to print at a lower temperature. Start with a reduction of up to 10 degrees Celsius. Note: do not lower the temperature too much, you then run the risk that the filament does not run through the extruder head because it is not liquid enough. At that point you will have to deal with a clogged nozzle.

To be (too) fast

If the layers are printed in too quick succession, there may not be enough time in between to allow the previous layer to cool sufficiently. This usually occurs when printing very small models, as the layers here are deposited in a few seconds. Again, even with a cooling fan, the layers may not be cooled down fast enough. You can choose to adjust the print speed manually in Simplify3D. You can set the software to adjust the print speed for layers that take less than 15 seconds to print. The print speed for these small layers is then automatically slowed down.

Tip: Perhaps not the most obvious option, but when printing small models you may choose to have multiple models on the board at once. The RAPID ONE has a large volume, which creates a lot of print space on the print bed. By printing multiple models at once, you create more time between depositing the different layers. The extruder head goes to the other models first before the next layer is deposited. This can give just enough time for the layers to cool sufficiently.

The advantage of the dddrop is that all filaments come with ready-made FFF profiles. These are settings that come with the filament. All cooling values are focused on the filament and calculated at room temperature. If the ambient temperature does increase, you can adjust these values at any time with, if necessary, support from our dddrop helpdesk.

Benefits of printing with a closed chamber

Purchasing a 3D printer may result in some stress in choice because there is a lot to choose from. An important difference is the construction of the 3D printer. There are 3D printers on the market without a casing/cabinet, these printers are very sensitive to the ambient temperature. There are also 3D printers on the market with a closed casing/cabinet, so the temperature is considerably better to regulate. These closed chamber 3D printers are generally more expensive, but also offer more possibilities with better print performance.

Print temperature
To be able to make a deliberate choice on which 3D printer the most suitable is for you, it is useful to find out more about the 3D printing process first. When making a 3D print, the temperature is of great importance. Without the right temperature it is impossible to make a good 3D print. The print material (filament) must melt to be able to go through the print head (nozzle) and to lay it down per layer. The temperature at which the filament changes from solid to liquid phase is called the glass transition temperature. This temperature differs per filament. The higher the temperature must be, the more difficult to realize this with an open printer. The filament will still be able to be sent through the hot print head. However when it is deposited on the print bed and it cools down too quickly, due to the ambient temperature, it is very likely that the filament will warp on the print (glass) plate or there will be delamination higher in the product.

Open 3D printers
The more simplified 3D printers are in general the open printers. These are available from around €250,-. Very accessible and great for simple prints where the material (filament) is less important. These 3D printers can only print the filaments PLA and PET-G. PLA and PET-G are totally not shrink-sensitive and can therefore be printed with an open printer.

PLA is strong and hard plastic material that cannot simply be pulled out of its context: it can withstand great forces. But in case of a hard blow or a fall, it is just glass and it will break. PLA is is therefore especially suitable for vision models and not for industrial use. Great for home, harden and kitchen experiments.

PET-G is a very strong material that is also flexible: it can be stretched twice its own length before it breaks. Thanks to the combination of strength, toughness and flexibility, it is extremely suitable for parts that move a lot and where fatigue lurks.

Heated printbed
The dddrop 3D printers are equipped with a heated printbed up to 130 ºC. This is the heating source of the printer, the hot air rises and the warm air remains in the printer due to the closed box. The big advantage of this is that the warping on the print bed is often prevented.

Closed 3D printers
When we talk about filaments such as ABS, PA (polyamide, nylon) PC (polycarbonate), carbon, metal-filled filaments or so on, the temperature really matters. These filaments have a high glass temperature. To be able to print these materials shrink-free, you really need a conditioned chamber. It is important that a kind of oven is created. Often we want a chamber that is as warm as possible, but when the chamber is too warm, the printer head gets stuck. That is why it will have to be cooled without losing too much temperature in the chamber. Is there a door open and there arises draft? That is not a problem. It does not affect your print. The ambient temperature is a lot less important. Although a room temperature is required for the standard print setting for the best results.

The dddrop printers have a closed, conditioned chamber which makes it easy to regulate the temperature. This makes it possible to print with various (high-tech) filaments.