## 2 3D Printing Methods--Information Essential for Designing Layout Plans
### Environmental Conditions for Machines and Devices for 3D Printing, Important for the Layout Plan  
Machines and devices for 3D printing must be provided with appropriate environmental conditions, which should be taken into account when designing layout plans. In addition, access to various media is necessary: electricity, compressed air, cooling water, or protective gas. In addition to the main machines that print a given element, a number of devices are also used that support the entire process so additional space should be allocated for them. For research work, it was assumed that the 3D printing devices used in the newly built plant--along with appropriate auxiliary machines--will be the devices offered by EOS GmbH:  
* FORMIGA P 110, using the SLS method [34], and
* EOS M 290, using the SLM method [35]. 3D printing machines and devices have strictly defined environmental conditions during operation, and the requirements relate to the permissible temperature in the room and relative air humidity. Separate requirements apply to the storage environment for the powder used in the SLS method. The specification of the mains connection includes the values of voltage, its fluctuations and frequency, the necessary mains protection, and the type of connection. The specification of the compressed air connection includes its consumption, operating pressure, minimum, and maximum pressure, compressed air temperature, its quality (including water and oil content), and the type of connection. All these information and requirements must be considered by the layout plan designer [36]. The key information in developing layout plans, however, are the dimensions of the machines as well as their weight. The main dimensions of an exemplary SLS device are shown in Figure 1a,b. Figure 1: Main dimensions of an exemplary SLS device, dimensions in [mm]: **(a)** Front view of machine; **(b)** Side view of machine [34]. Manufacturers of 3D printing machines and devices also provide detailed information on the recommended distances from walls and other objects and the location of individual types of media, which is important for designers of layout plans (Figure 2). 3D printing devices that use a laser to sinter metal powder have specific requirements that must be met in order to ensure the correct operation of these machines. These requirements relate to the permissible temperature and humidity of the ambient air. During the SLM process, heat is released, which must be collected by a cooler operating in the system (e.g., air-water), hence, the requirements for the quality of the cooling water (e.g., pH value, chloride content, temperature, and minimum flow). An important role is also played by the shielding gas circuit filtering system (most often this gas is argon), which effectively collects the smelting contamination; a suitable place for it should be provided on the layout plan. During the operation of the SLM device, the noise emission at the level of approx. 70 dB (A) should be taken into account, which is also a factor that the designer of the layout plan cannot underestimate as the vicinity of a working 3D printing device can be troublesome in this respect. The power supply connection is particularly important for this type of 3D printing machine, due to the high energy demand of the laser sintering metal powder, the rated powers reach significant values so it is necessary to check these requirements with regard to the parameters of the power connection each time. Manufacturing Processes Implemented in SLS and SLM Technologies, Determining the Necessary Number of Machines  
For computational purposes, a hypothetical production plan was assumed; the production processes of two types of products will be carried out on 3D machines: product X manufactured in the SLS technique and product Y manufactured in the SLM technique. The production plan assumes the production of 20,000 pieces of product X and 23,000 pieces of product Y per year.