Since 2009, the main patents for portable 3D printers have expired, and 3D printing has developed into an industry of its own. Therefore, 3D printers are one of the decisive products of our time.
Currently, 3D printers are used to create almost everything you can think of, such as instruments, camera equipment, medical models, phones and personal technical accessories, home decoration, toys, and fashion. Its applications are almost endless. In theory, 3D printing can make any solid object. Although some technical limitations hinder the printing of specific sizes and specific materials, scientists have been researching to rapidly improve capabilities.
The most popular type of 3D printing is Fused Deposition Modeling (FDM), also known as fuse manufacturing. The working principle of fuse deposition modeling is that when the plastic filament goes up, down or over the specified XYZ coordinates, it passes through the nozzle Melt and squeeze a roll of plastic filament.
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Use the FDM process to create a product like this:
·Using CAD software to generate three-dimensional models.
·The CAD model is exported as a stereo lithography file (.stl format), and then imported into the slicing software.
· The file is divided into layers, and a specific tool path is generated.
· The design is sent to the printer.
Depending on the size and complexity of the part, the part can be produced by additive manufacturing in minutes, hours or days.
Create heat for 3D printing
After all, fused deposition modeling is about heat. 3D objects are made by melting, shaping and cooling plastic.
Several key components of FDM printers can generate and manage heat:
·Extruder.
·Printing bed.
·Layered cooling fan.
Studying each one carefully will explain how they affect the printed results.
Extruder. The extruder is where most printer technology is located. It consists of a cold end and a hot end, where the cold end pulls the filament through the system, and the hot end melts the filament when it is extruded.
Inside the hot end of the extruder is a heating block. Usually, it is made of aluminum and heated by a heater box. When the filament passes through the heat pipe and reaches the nozzle, the heating element melts it.
There is also a radiator fan in the extruder. This cooling element helps prevent heat from entering the extruder parts that need to be kept at a lower temperature.
Another component worth mentioning in the extruder is the thermistor or thermocouple. This piece can sense and help regulate the temperature of the hot end.
Print the bed. The printing bed is the surface on which filaments are deposited in a specified shape during the printing process. Most printing tables are heated to prevent the plastic from cooling too quickly and causing the product to warp. The print bed is usually kept somewhere between 122 and 212°F (50 to 100°C). The specific temperature requirements depend on the type of filament used.
Some printers do not have a heated bed. The materials that these machines can print are limited. Likewise, the material may not stick to these beds, and the melted part is more likely to be ejected from the middle of the printing.
Layered cooling fan. The layered cooling fan cools the plastic after leaving the nozzle. This element helps the created product maintain its shape when printed.
Controlling heat: dealing with heat-related issues
Since 3D printing relies heavily on heat, any temperature issues can easily disrupt the entire process. Common problems encountered in 3D printing include:
·High temperature creep.
· Twisting and bending.
· Melted or deformed fingerprints.
· There are cracks on the side of the higher print.
·Bend near the bottom of the printed matter.
· Vague or undefined first layer
Due to the unsatisfactory temperature, manufacturers may encounter such problems.
With the continuation of 3D printing research and development, sophisticated technology advances to provide more precise control of higher temperatures, resulting in high-quality printing and difficult-to-handle materials.
High temperature creep. When heat is irregularly diffused through the hot end of the extruder, thermal creep occurs. When the filament cools during the extrusion process, heat will rise into the thermal barrier tube. This will cause the filament to heat up and expand too quickly, and stick to the wall of the thermal barrier tube. Thermal creep can cause clogging and stop printing, which is difficult to remove.
Therefore, the design of the thermal barrier tube often helps prevent thermal creep. Grooves or wires in the tube help prevent heat from entering spaces that shouldn’t. In addition, some precautions can be taken to prevent thermal creep. First, add ceramic insulating tape around the heating block. Second, avoid letting the printer heat up when not printing. Third, avoid using low-end filaments that will expand irregularly. Finally, if possible, be sure to remove the filament after printing.
Twisted and bent. Too fast cooling of the plastic after extrusion will cause the product to warp. Because the plastic shrinks slightly as it cools, rapid cooling will cause the plastic to bend as it hardens.
Keeping the plastic just below the melting temperature on the printing bed can prevent warpage. If warping occurs, it is likely that the temperature of the press bed needs to be increased.
Melted or deformed printed matter. It looks loose when it is designed because it is too hot. FDM printing requires a good balance between the temperature that provides good flow and the temperature that ensures rapid solidification.
To correct a print that looks melted, adjust the temperature setting. First, make sure that the temperature is within the proper parameters of the material. Next, try to lower the nozzle temperature by 9°F (5°C) each time.
There are cracks on the sides of the higher print. Sometimes, when the 3D printer produces higher fragments, cracks appear between some of the higher layers. This is because these layers are too far away from the heat of the print bed. After extruding, the filament cooled too fast and did not reach the proper viscosity. This can lead to small spaces or cracks between layers.
To prevent the filament from cooling too quickly, try increasing the extruder temperature by approximately 18°F (10°C).
Curved or bent near the bottom When the weight of the model is pressed against the bottom layer that is not sufficiently cooled, it will bend or bend.
This deformation of the bottom layer can be remedied by ensuring faster cooling. This can be achieved by lowering the temperature of the print bed by 9°F (5°C) until the desired result is achieved.
Blurred and undefined first layer. Sometimes, the first layer becomes very fuzzy. When this happens, the angle does not seem to be defined, and the filament lines look rough. This is usually due to the printing bed being too hot, which causes the plastic to lose its shape.
The solution to this problem may be quite obvious. It may be necessary to lower the print bed temperature by 9°F (5°C) each time until the desired result is achieved.
Material temperature limit
There are several options for the filament. The filaments come in different colors, textures and effects, from glowing in the dark to the appearance and smell of wood. An important part of mastering the use of these different materials is to understand the specific temperature requirements of each material. Failure to pay attention to these parameters may cause any of the temperature-related problems already mentioned.
The higher the temperature, the greater the possibility. When the 3D printer can maintain a higher temperature during the production process, there are more filaments to choose from. However, working at higher temperatures requires the specific technology of a 3D printer.
For example, the hot end of the extruder is usually composed of metal and polyether ether ketone (PEEK) or polytetrafluoroethylene (PTFE). Although PEEK and PTFE provide excellent insulation, they limit the hot end temperature to not more than 464°F (240°C). However, when using an all-metal hot end, the temperature can be effectively maintained above 572°F (300°C). This opens a door to the use of various materials.
New developments in FDM technology have paved the way for higher temperatures during 3D printing. Last year, a 3D printer manufacturer introduced a series of high-temperature printer components that can allow the hot end temperature to reach over 752 degrees Fahrenheit (400 degrees Celsius). The print bed on these devices can reach temperatures above 392°F (200°C).
With the continuous development of 3D printing research and development, sophisticated technology will continue to provide more precise control for higher temperatures. These advancements are producing high-quality prints made from materials that are difficult to process. We are very happy to see the future of 3D printing.
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