# Case Study: 3D Modelling and Printing of a Plastic Respirator in Laboratory Conditions
## 3 Description of the 3D Printing Procedure of the Selected Object  
For processing the design of a respirator suitable for the 3D printer, the material was selected and also the time of printing was determinate. Zmorph 3D printer was used to produce the model of the respirator. Dimensions, printing technology, and software was suited. The ZMorph printer solves complex solutions for 3D printing using several materials or machining directly on the desktop. Advantages:  
Interchangeable tool heads;  
Can print thick paste as well (ceramics, dough, chocolate);  
CNC machining, engraving, two-color 3D printing;  
Print two materials simultaneously;  
Very high print quality;  
Handles high-level professional models;  
LCD display. Figure 8: Creating a hole for the possibility of attachment, bonding profiles, and moving the hole. Figure 7: Carving the outside—view from below. The ZMorph VX [17] features a rugged aluminium construction with high quality components that is designed to withstand high 3D printing speeds as well as high torque. Basic specifications of the 3D printer ZMorph VX is shown in Table 2.  
After much deliberation, it was decided to use ABS (acrylonitrile butadiene styrene) strings to make the respirator. Visible and tactile indistinguishable from PLA (polylactide) type strings. The entire respirator consists of three separately printed parts: 1. respirator body, 2. plastic filter, and 3. Filter cap. Each of these sections has been modified in Voxelizer 2.0.0. This program is recommended for the given printer and is therefore completely adapted for editing models that will be printed with the help of the Zmorph 3D printer, see Figure 9. It also offers editable settings for 2D and 3D milling, cutting, and laser engraving. It supports.dxf,.jpg, and.stl files. In Figure 8 we can see the body of the respirator designed in the program Voxelizer 2.0.0. Its position and dimensions have been adjusted so that we have enough material and so that printing does not take too long, as the Zmorph printer is not one of the fastest models of 3D printers. One such model of respirator body was extruded in approximately 80 min. The design of the entire respirator took about 180 min. After selecting the printer, the material and designing the model, a step follows, which consists of transferring the STL models to the software, where the appropriate G-codes have been read and created. After adding G-codes, there were two options for data transfer, either directly to the printer or using an SD card. Specifically, for the Zmorph printer, the SD card method was chosen. This process is no different for any type of model. The second part of the respirator model is a plastic filter. It had to be adapted in size and shape to the other two parts of the respirator so that it would fit exactly in the specified position. The task, after being placed in the body of the respirator, was to filter the air. The plastic filter went through the same process as the body of the respirator. It was designed and modified in the same software Voxelizer 2.0.0. Voxelizer also calculated the expected printing time of the two plastic filters, which was 1 h and 56 min. An alternative to printing two pieces has been chosen so that the printing area and printer performance can be used to the maximum. In the program, it is possible to adjust the position where the printout will be printed, the thickness of the printout, etc. The third and last printed part of the respirator model is the filter cover. Its task is to prevent damage (e.g., to a mechanical) unpressed filter and at the same time forms the front part of the entire respirator. A green ABS string was used to make this part of the respirator. The model also underwent thorough preparation for printing in the Voxelizer program.