I made a series of container boxes for a ham radio buddy. He needed them for his “go-kit”. A rapid deployment case containing a portable radio and everything needed to put a short wave station on the air from remote locations.
He enjoys operating radio from federal and state parks. I assume almost any established park qualifies for POTA (Parks On The Air) Its a good reason to pack up ones radio gear and go operate from a remote location.
Everything needed packed into one case makes certain nothing is missing or forgotten. It’s why the case is called the “go-kit”.
What I designed and 3D printed are organizer boxes and special brackets to hold radio gear for travel and help position gear when operating.
Black was the color of choice and I had several spools of that color PLA (PolyLactic Acid) on hand.
I created three container boxes with removable lids and several mounting brackets and adapters for holding radios and video screens in operating position.
It all worked well for a couple of weeks but then I received a report that the plastic boxes were all warping out of shape. The Go-Kit is stored in the trunk of the car and evidently the Texas heat has encouraged the container boxes to take on strange new shapes.
The boxes are fairly large and I originally designed them with 3mm thick bottoms, tops and side walls to save space and weight. I didn’t consider storage in a hot automobile trunk.
Walls that thin should have been designed with ribs and gussets to resist warping. But that would have greatly reduced internal space. The equipment brackets are designed much heavier and ARE well ribbed and braced. No problems at all with the supports warping. Just the warping with the thin walled boxes.
I experimented with ASA and ABS plastic for the replacement boxes. Both materials warp excessively during test printing. I discovered I can not print the size boxes needed with either ASA or ABS.
I made another test print with PLA+ which is a new higher temperature PLA with much less tendency to warp. 225C print on a 70C build plate. I am now reprinting all the boxes with 5mm walls and double print +45/-45 degree infill pattern. Twice the previous infill and very high rigidity. A real strong and true honey-comb infill. More than double the amount of PLA+ for the same size boxes. They are also twice the weight. Can’t escape that when warp-free results are required.
Print time is also nearly doubled as well. But that is not an issue. It is what it is.
There is a very small loss of useable storage space with the thicker walls and that too is of little concern. I had to be very careful in the re-design where I could “steal space” for the added wall thickness. The packing case did not get any bigger, so the container boxes had to lose some internal volume.
Only one container box had a critical inside dimension. The one labeled "KEY" that holds the paddle key for morse-code sending. There was space to expand that case on the exterior dimension.
Lesson learned here. Sometimes one cannot think of all the factors when creating a new design. It was a learning experience that will not be lost in future designs and revisions.
