Desktop 3D filament printers have spread among different categories of users, whether amateurs or professionals. And the most common filament is PLA Polylactic Acid for its ease of use and its environmentally friendly print, in the 3D printing process for extrusion filament / thermoplastics, the hot end Extruder raises the temperature of it to obtain the appropriate viscosity for its flow through the Nozzel, the nozzle is then moved from place to place within the print space by the 3D printer movement system to gradually extrude an entire object layer by layer as the filament moves inside The printer is through the hot end and the nozzle, it is under the control of the printer through the commands of the G-CODE file, so its behavior is controlled by its temperature and flow velocity controlling, but once it leaves the nozzle, and the deposition process begins, it becomes out of control, leaving its properties easily affected by environmental factors. Because of its soft state, it helps ease the control of the forces of gravity and pulls its strings down, causing deformation Its layers. It is therefore of utmost importance to ensure that it does not move or deform after leaving the nozzle. This is done by returning it to its solid state as soon as possible, and here it appears the importance of cooling. Keywords: Statement of the problem: The quality of 3D PLA prints produced by fused filament fabrication printers was affected by the cooling process during printing. Importance: The importance of the research lies in showing the effect of cooling on the quality of 3D PLA printed parts and showing methods of controlling it to improve the quality of 3D printed models. Objectives: The research aims toidentify problems in PLA printed models related to cooling and improve its quality by adjusting part cooling. Research Methodology: The research depends on the descriptive approach and the experimental method in applying solutions and observing the results. Main results:The most important results of the research are that cooling is one of the important factors affecting the quality of models printed with poly-lactic acid filament. Cooling is closely related to the problems of wrinkling of protruding parts, deformation of bridges and accurate ends of models, as well as problems of dimensional accuracy. And the design of the air distribution duct attached to the part cooling fan affects the print quality.