Modeling guide for 3D printing
It is commonly mentioned in the industry that 3D printing breaks all kinds of limitations in terms of manufacturing parts. It is believed that any object can be printed and therefore there is no need to restrict or limit the models we design.
This mentality is sometimes true and sometimes false. It is absolutely true that it generally reduces the complexity of machining parts and requires less intervention or expertise from the machine operator. However, complexities arise when target prices per part or reduced manufacturing times are required. For these cases, it is important to keep in mind several strategies that help us reduce costs and manufacturing times. In addition, reducing complexity and manufacturing time also reduces the likelihood of printing process failure. Increasing yields of 3D printing supply businesses.
Below is a list of strategies to consider when CAD modeling:
Keep in mind the orientation of the part when printing. It is important to have enough surface area so that the part adheres properly to the printing platform and does not peel off. Also, the print orientation of the part should be oriented so that the direction of the greatest mechanical stress that the part will experience is not parallel to the print bed. Remember that 3D prints are generally anisotropic.
Use multiples of your printer's line width for the walls of your model. When creating borders or walls on a model, use multiples of the line width to improve printing time. In the image below, a model is shown on the left where the width of the printing line (0.45 mm) was used and multiplied by 3 (1.35 mm) to obtain 3 perimeters as a border. On the right, a 1.5 mm border was generated, so the printer has to add one more perimeter to try to approximate the modeled border dimension. Note that the two inner perimeters (marked in yellow) are overlapping each other.
Make sure that the edges are rounded and that you preserve the width of the wall. It is preferable to round edges so that the user has a better experience when manipulating the modeled piece. When adding fillets to edges, add the thickness of the edge to the distance of the fillet you are applying. In the image below, it is shown in the center when the rounding is done incorrectly (depositing additional and unnecessary plastic on the corners of the model).
Plan ahead your parts so that they do not require supports. This can be done by using angles greater than 45 degrees relative to the print bed. Several times, this will save us from having to use support material in the prints. Saving material and printing time. Sometimes, this can be easily achieved by adding chamfers on some straight edges of the model.
Take advantage of bridges for screw holes. When screwing holes or similar geometries are required and the perimeters are not supported, supports are commonly used when printing. However, a bridge can be made in the lowermost layer where the hole starts (the bridge covers the hole, but only for one layer). The rest of the layers remain with the shape of the hole. That is, the bridge ends up working as a support for the upper layers. When the printing of the part is finished, you can remove the bridge with tweezers or with the screw itself.
These are some of the tips we follow at Kenko Solutions when modeling functional parts for projects or customers. In this way, we save material and time; in addition to reducing development or production costs. Also, remember to calibrate and perform preventive maintenance on your printers to get the best results.