3D Printer Model - Cura Slicing

After we finish building and inspecting the 3D model, the STL format file needs to be sliced to generate a Gcode (so-called "G-code") file. -The 3D printer is able to recognize the actions and parameters specified in the sliced Gcode print code file. The 3D printer recognizes the actions and parameters set in the Gcode print code file after slicing, and will eventually follow the Gcode commands in order to perform formal 3D printing, such as print nozzle temperature and print speed adjustment.

Meaning of slicing and related printing parameters

"Layer by layer processing, stacking molding" is the basic working principle of the common desktop 3D printer, that is, after the first layer (the bottom layer of the 3D model) is printed, the print head will move up (along the positive direction of the spatial Z axis) for a specified distance, then print the second layer on top of the first layer, and then move up to print the third layer ...... so layer by layer until the print is completed, each layer has the characteristics of "horizontal, equal distance, superimposed texture".

The slicing operation is equivalent to pre-layering the 3D model from the bottom to the top for horizontal "cutting", and recording the model distribution information of each layer of the plane (X-axis and Y-axis) one by one according to the serial number, which will eventually directly affect the quality of the 3D printed model, including dimensional accuracy, surface roughness and strength, etc. The main The meanings of the 3D printing parameters are as follows.

  1. Nozzle size

Nozzle size refers to the size of the print head nozzle discharge hole, i.e. the diameter of the liquid plastic filament ejected during printing, usually 0.25mm, 0.4mm, 0.6mm and 0.8mm. In general, the smaller the nozzle size (i.e., the smaller the diameter of the plastic filament), the smoother the surface of the finished print will be, but the slower the printing speed.

  1. Layer thickness

Layer thickness refers to the thickness value of a single print layer, matched with different nozzle sizes, usually in the range of 0.06-0.6mm adjustment. Under the same conditions, the thinner the print layer, the smoother the surface of the finished print, but also more difficult to shape; on the other hand, the print layer is too thick will be printed between the layers of adhesion strength is too low and reduce the mechanical strength of the finished print, or even cause the finished print fracture (print failure).

  1. Wall thickness

3D printed products are formed by the shell and the internal filling structure combined, the thickness of the shell is the "wall thickness" of the printed product. Wall thickness is divided into a single wall thickness and multi-layer wall thickness, the former is determined by the nozzle size, the latter is an integer multiple of the former, usually wall thickness is proportional to the strength of the printed product.

  1. Filling

The role of filling is to adjust the degree of solidity of the printed product, the two "extreme values" are: 0% means hollow, and 100% means solid. The current 3D printing filling is divided into grid-like, honeycomb structure, the higher the filling rate means the more solid the printed product. In general, the thin-walled 3D model or a certain mechanical requirements of the finished print is recommended to fill 100%; but this value if larger (more than 70%) must pay attention to the 3D printer heat dissipation problems (especially in the case of high room temperature), otherwise it is easy to cause the finished print shrinkage deformation or from the printing platform off and other accidents.

  1. Support

In the 3D printing, may encounter the model has a cantilever structure, especially when the cantilever structure and the printing platform angle is less than 45 degrees, then it is recommended to use support. The support can greatly improve the success rate of printing overhanging models, but it requires "extra" operations to remove the support parts from the finished print after printing, and it may produce defects on the surface of the finished print, thus increasing the difficulty of refining the model later.

  1. Wire diameter

Since desktop 3D printers control the amount of material extruded from the nozzle through the wire feed mechanism, the larger the wire diameter, the larger the amount of material extruded at the same wire feed speed. The diameter of the wire must be set based on the actual diameter of the wire used for printing, and fine-tuned from this value. Too much extrusion is likely to lead to "overflow" on the surface of the finished print, affecting the appearance; too little extrusion will lead to a lack of material hollowing on the surface of the finished print, and also reduces the mechanical strength of the finished print.

  1. Printing speed

Print speed refers to the normal work of the 3D printing nozzle movement speed, different slicing software on the basis of this will be subdivided into different working conditions when the nozzle movement speed. Reasonable printing speed is very important, printing speed is too slow, resulting in lower printing efficiency; printing speed is too fast, resulting in surface defects of the finished print, and even reduce the strength of the finished print (produce some internal hollowing phenomenon).

  1. Printing temperature

Printing temperature refers to the normal operation of the 3D printing nozzle temperature, different types of materials generally have different printing temperature, and the same type of material will vary slightly (manufacturers or production batches, etc.), are generally in the rated temperature range of the material based on experience or the results of their own tests to adjust. Print temperature is too high, easily lead to melt collapse of the surface of the finished print, or even the print nozzle material quickly carbonized and caused by clogging of the nozzle; print temperature is too low, not only will the print layer bonding strength and reduce the strength of the finished print, but also increase the difficulty of the delivery mechanism, and may even cause the print nozzle in the plastic wire due to the front "half-cured "and can not continue to spray out the nozzle and "stop work.

Second, the representative of slicing software: CURA

The core of 3D printing slicing software is the slicing engine, which is essentially an object-oriented algorithm program that can calculate and generate Gcode printing code according to the structural composition of the 3D model and the different parameters set by the user. The current slicing software is rich, such as Slic3r, Simplify3D, MakerWare, CURA, etc. Among them, the open source slicing software CURA developed by the well-known Ultimaker company is called "the standard slicing software for 3D printing", which is highly compatible and easy to learn and use. Its slicing speed is fast and the printing results are excellent, so it is recommended for beginners.

To download and install CURA, visit Ultimaker's official download section (https://ultimaker.com/en/products/ultimaker-cura-software) and click the "Download for free" button. (Download free version) button to download the slicing software UltimakerCura 3.6 for 64-bit Windows platform. The installation process of CURA is very simple, just click the "Next" button, and pay attention to check the five key installation components: InstallArduino Drivers, CURA Executable and Data File, Install Visual Studio 2010 Redistributable, Open STL Files with CURA, Open STL Files with CURA, and Open OBJ Files with CURA.

Finally, Using CURA for 3D Print Slicing

After installing CURA, the first time you run CURA, you will be prompted to set the model of 3D printer connected to your computer, so you can choose according to the actual situation.