You and your team have worked hard on a new production-ready FDM design with intentions of avoiding the purchase of a costly mold. From feature strength and tolerances through functionality and aesthetics, everything looks great on your computer screen and expectations are high. Next, you run it through some default parameters within your slicing software, press print, and walk away, right? This critical step is often taken for granted. If you overlook design and file processing upstream, you may experience unexpected results or settle for poor quality that will not survive your required finishing process downstream.
In order to achieve that ‘injection-molded finish’, a sound part structure is essential. Here is an example of a part build that was not optimized, leading to warping and separation. By reorienting the build path, the gaps created by the default raster parameters were filled and strengthened. The part is now stronger and porosity was eliminated to take on the appropriate finishing needs.
Left: Raster gaps (before); Right: Gaps eliminated (after); Fix: Reorienting Build Path
In addition, critical geometries such as mating surfaces and load-bearing features may not achieve sufficient density or detail. Here you can see that a critical mating feature was essentially glossed-over in the printing process due to printer limitations in the initial build orientation. By rotating the build, you can build the appropriate contours and accurately print the desired feature.
Left: Poor print orientation, lack of detail (before); Right: Proper orientation, accurate detail (after); Fix: Adjusting Build Orientation
Another consideration is wall thickness. There will be instances where default parameters will leave your walls hollow. During support removal in traditional dunk tanks or baths, this space will allow solution and contaminants to get in between your build material, leading to a weakened or damaged part. During design, the interior wall can be thickened or the contours can be rotated to eliminate those gaps. Additionally, if you are subject to porous part builds, an automated PostProcess spray solution like the BASE or DECI that was used to finish the parts shown here will avoid the ‘soaking’ effect that can cause support material within hallowed walls to swell and cause damage.
This example FDM part (click for full screen) that was printed with the intention to be finished with injection-molded quality was achieved in two steps with a combination of PostProcess’ automated, intelligent solutions – 1) one minute of technician attendance time in the DECI Support Removal solution to finish a batch of 16 parts in 1 hour process time, and 2) five minutes of technician attendance time in the NITOR Surface Finish solution to finish a batch of 50 parts in 6 hours process time. The combination of PostProcess’ proprietary chemistry, highly engineered hardware, and AUTOMAT3D® software creates a complete solution that allows for just minutes of touch time instead of what would have previously required many hours of manual technician labor.
By including the above design practices into your process, you will set your part up properly for the required finish. Without these design considerations, you will find yourself hard-pressed to achieve that ‘injection-molded’ finish you are striving for. And when you are ready, contact PostProcess for a complete automated finishing solution to take your additive manufacturing workflow to full production.
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