The nozzle of a 3D printer, like any element that is in contact (friction) with another material, presents a wear with the use, which as we mentioned in the previous article, varies depending on the material of the nozzle and the type of filament that be used. To detect when the wear is accused we will resort to 2 simple techniques:
When the wear is very sharp, it is detected in the tip of the nozzle with the naked eye, as seen in the following image.
Image 1: Comparison between nozzles
It can happen that, even having all the correct printing parameters, the 3D model without imperfections and the nozzle in good condition with the naked eye, internally is worn and causes malformations and bad surface finishes in the printed pieces due to the turbulent flow of the plastic by the inside of it.
In order to apply this method we will have to have the nozzle technical drawing of the 3D printer that we are using, a document that most manufacturers have available for download on their website. In this case we are going to use the Nozzle E3D v6 drawing.
Image 2: E3D-Online nozzle V6 technical design. Source: E3D-Online
The measure that we are interested in is the "C" that represents the length of the exit perforation of the filament after the extrusion cone. The wear should never be more than 80 % of the total length of "C", since if the wear is closer to the inner cone, the 3D prints will be of poor quality, or even impossible to make. To check this value we have to remove the nozzle from the HotEnd, measure the total length and apply the following formula:
Image 3: Nozzle wear formula
As shown in the drawing, the total original length of the Nozzle E3D v6 is 12.5 mm, for the model with 0.40 mm "C" diameter it measures 0.60 mm. In this case, the total length of the nozzle is 12 mm, so by applying the formula above we obtain that the percentage of wear is 83 %, which indicates that it is necessary to replace the nozzle por uno nuevo.