Before we move from system to system through the main topics of desktop 3D printer anatomy, let's focus briefly on the process of starting a print. This may be best served as an overview of printing before diving into each area individually. Loading Materials. We're going to jump to the extrusion system to start our preparation with a preliminary step that takes place just before we print the part, loading the print material. Before the 3D printer is ready to execute our printing request, we need to load the filament we will use to fabricate the object. This sounds obvious but, you'd be surprised how many busy 3D printer operators forget to check how much material they have left on their machine and don't look to see if the nozzle mounted on the machine matches their filament. Today, I'm going to take it easy and just select the Ultimaker silver PLA that I typically use to print this little robot character. I'll check that I have the correct core installed, and get started. At this point, if I wanted to shift to another nozzle size, or we're setting the machine for the first time, I'd go through a different process. I'd go through a process of removing and installing a new core and/or running a manual build plate calibration process to confirm that everything is at a great baseline for printing. Cleaning the build plate. Here's another moment where the mechanical system meets the extrusion system. If you don't confirm that you have removed the last printed part from the build plate, along with any detritus, the chances of the tool head blissfully plowing into a printed object is very high. Your 3D printer needs you to take a second and clean and prep the plate for the new print, or the results from broken tool heads to part slipping off the plate will be on you. Because I've selected silver PLA and because borosilicate heated glass plate for this machine is already suited for printing PLA with no extra films, coatings, or glue required, I just need to confirm that the plate is clear of parts, cleaned of residue from past print jobs, and free of the natural oils from fingers touching the glass surface. Now, let's head to the control system, interactive interface subsystem next. Now, we are ready to start the specific job in the control system, starting with the interactive interface subsystem. The interface is typically the primary control you use to calibrate, operate, and service your printer. In some cases, it compliments the computer control the device, and in other cases, it replaces computer control entirely. When you are ready to run a job on your 3D printer, your first steps are here at the front of the machine. The core components of the interactive interface subsystem are the display itself, a way to see what options you are activating, as well as other additional information posted by the system about its temperature printing progress and job file options. The control buttons, your physical point of contact with the electronics. A Java file delivery process, typically an SD card, USB drive, or USB or Ethernet cable. The means for getting the job files queued for fabrication. An interface menu or other UI strategy that an operator can navigate to achieve intended goals. Maintenance utilities, usually within the interface menu itself which allows an operator to update firmware, perform initial or additional calibration stages, and manage materials, loading, unloading and profile settings, and other aspects related to the baseline of the machine. I use the interface to load materials, to install silver PLA, and now we're ready to run our print. We navigate through the print menu to locate our file and select it. Many times, this is the last physical intervention you will have with the machine, until you collect the final print; minutes, hours, or even days later. But we're going to explore in greater detail what happens next, and the systems, subsystems, and components involved. Control System. While the interactive interface subsystem might be the system you interact with physically, and the one that provides you evidence, as to what processes are taking place in the machine, the control board locked away in the base of the machine, is really the one calling the shots during the printing process. Because the control board electronics coordinates all power signal motion and cooling, all of these other elements of the control systems deserve their own separate consideration as parts of the portrait of the control board electronics. Any discussion of the control board subsystem may end up overlapping significantly with the other elements within the control system. In terms of anatomy, I'd say that the main board electronics behaves a bit like the heart brain and circulation system. It touches on just about everything that happens. When we select and activate the print job in the interface, this action triggers the control board to start the printing process unspooling a series of actions across the electronics, from diverting power to preheating, for the heated bed and tool head, to reading through the initial pre-print commands and settings in the G code file and/or onboard in the firmware. The interface only plays the role of the messenger. Now the real orchestra tunes up and is poised for action. This material requires a heated bed, so preheating of the bed and nozzle happens during this stage. The time to heat these elements depends on the environmental conditions. You can never fully predict the temperature of the electronics draw required to reach the target state. Establishing home and auto calibrating the build plate. Let's continue but now from the perspective of the mechanical system. As soon as the job is selected and activate in the print window, the machine springs into action, a combination of onboard preset actions and tasks specified in the top startup G code from the job file, trigger the mechanical system to move elements around in the operational envelope. It sets out to accomplish these two critical tasks. One, the homing of the x y z axes by moving the tool head and build platform to hit the corresponding x, y and z instops. From this point forward, the control system knows where the tool head and build platform are, and calculates all adjustments going forward from this known position. Two, the triggering of an auto leveling script that probes several points on the build plate, to make slight adjustments to each aspect of the motion telemetry. This helps to make sure that the build plate, the area that the nozzle on the tool head can access, is true to the manual calibration of the build plate. If the difference is too great to make small compensations and adjustments, the interface will display an error message requesting that the operator run the manual build platform calibration process, to improve the baseline calibration before trying again. When you bring together the results of both of these activities, the instops identifying the true zero points and the plate calibration probe ensuring that the nozzle will always be at the right distance from the physical plate, the build envelope is established and all is set for the print to begin. Now, when the right temperature and conditions have finally been met in just a few more seconds surely, here we go. Here at the end of the startup sequence, the machine goes into motion again. Moving the tool head, the build plate, purging some material and then finally heading to the starting position for fabricating the desired part. But we are going to leave the printing of the object for the rest of our grand tour through the anatomy of a 3D printer.
