Printing Polycarbonate for Production
This video shows the EVO making 48 individual polycarbonate pieces over a period of 40 straight hours. For a desktop 3D printer this is a formidable accomplishment. In fact, the EVO is the only desktop 3D printer capable of printing large batch polycarbonate parts
a. These parts, referred to as “tensioners” are used in the feeder component of the EVO to guide filament into the hot end. Rather than injection molding the tensioners, it is more cost effective to 3D print them in polycarbonate, a strong and temperature-resistant thermoplastic.
b. 3D printing avoids tooling, setup, and a host of additional costs related to conventional manufacturing. There are a number of additional benefits to 3D printing the tensioners:
i. Speed: The design can travel straight from design software, i.e. SolidWorks into production.
ii. Complexity: It would be difficult to capture all of the intricate details of the feeders in a conventional mold.
iii. Adaptation/Iteration: As the feeder design is iterated to work better with new applications, such as carbon fiber, it can simply be revised, reprinted and retrofitted into existing machines, without necessitating tooling changes.
iv. On-site manufacturing: Able to produce end-use products in America
2. Mechanical Durability and Advanced Software Make It Possible
The key to achieving large polycarbonate 3d prints is a solid combination of mechanical durability and advanced software features. The parts are made over the course of 40 hours, where the chamber is kept at a constant 70C, the print head at 300C and the heated bed at 162C.
a. The elevated temperatures over this extended period of time are unheard of in the desktop 3D printing space as they create an inhospitable environment for machine componentry. However, at Airwolf we have perfected high-temperature componentry, printing with polycarbonate since 2014 with the HDx.
The latest 3D printer model, the EVO has an aluminum frame to withstand heat while ultra-strong polycarbonate windows reinforce the frame, insulate the heated, and provide an uncompromised viewing angle for the user to observe the build.
a. Maintenance-free linear guides ensure that the print head acts in a repeatable motion, hour after hour for nearly two (2) days straight. Further, the CNC’d aluminum hot ends, and silicone-insulated stainless steel bed ensure that the machine will be able to sustain such prints for thousands of hours in the future. Finally, the enclosed chamber heaters are designed to continuously keep the chamber at 70C and higher for the polycarbonate builds.
On the software side, Apex 1.6.0 is designed to perform many tasks without the user’s input. To put it simply, all the user needs to do is set the parts on the bed and multiply the instances. In this case, there are 24 instances of the polycarbonate tensioner to be printed.
a. Once the parts are on the build plate, the customer simply selects the material and whether he or she would like to heat the chamber for the build. Apex will automatically default polycarbonate to precise settings.
b. Unbeknownst to the user, Apex is performing an extraordinary number of calculations in the background to ensure that the part is printed to the absolutely optimum precision and speed possible.
c. First, Apex will look to the material selected and determine the approximate temperature range, print head, bed, and chamber for best printing performance.
d. Apex will then look at the quality and nozzle selections to determine the appropriate layer height. For smaller nozzles, Apex will set finer layer height to take advantage of the fine printing capabilities. Similarly, for finer quality settings, Apex will lower layer heights to optimize surface finish. Apex uses quality and nozzle diameter together to determine these values.
e. Apex also looks at the number and size of parts and determines the optimum speed to print. For instance, if there were only a couple parts on the bed, Apex would slow the print head down to avoid layer bulging and excessive heating. Here, because the plate is nearly full, the print will be performed at top printing speed to complete the job in a reasonable time.
f. Similarly, Apex will adjust the temperature of the print head and heated bed according to part size. For smaller parts, both temperatures will be carefully lowered to avoid overheating the part. Conversely, when printing larger plates such as the one here, bed temperatures will be increased to prevent warping and in connection with the higher print speeds mentioned above
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