The 3D Printed Battery Box
Standard & with CutoutI originally designed a battery box built using custom heat formed styrene sheet for the semicircular ends of the box. All of the parts were cnc cut for accuracy, overlapping joints were used for strength. For maximum internal volume there were no internal supports inside the box. I actually assembled one box myself and made enough parts for another two. The design was workable, but manufacturing the bent ends was going to be difficult. Then along came 3D printing technology and it solved the problem (but also added some complications of it's own!) You can see the details of the original design here.
||This is the 3D
Printed Battery Box
The image links to a 3d pdf file, click on it if you want to be able to rotate the image around and examine it from other angles. (Note, the 3d.pdf file opens in a new window. If you have problems with the 3d feature you may have to upgrade to the latest version of Adobe Reader).
After 'activating' the 3d mode by clicking on the display
select a part by left clicking on it (the part will be highlighted)
then right clicking brings up a window. Follow the sequence
-> part options -> part render mode -> transparent
to make the outer parts transparent and the inner
|Instead of a door panel on the side of the
box, the entire side slides out. It's attached to the end of the box
and held on by two flat head screws.
This image, and its associated 3D .pdf file are shown with the door partially opened.
|This version of the 3D Printed Battery Box is intended to be used with my outer foot drive. Because the Scooter motors stick out into the Battery Boxes I've added cutouts to the parts to accommodate the design. In addition I've also added mounting holes that match bolt locations on the foot shell so that the battery box can be securely attached.|
|This is actually the second version of the curved end design. The first one utilized a Barrel Nut. However, in order to install the nut there was a separately printed 3D part that held the nut and then that part was glued into the curved end. Converting the design to a square nut meant that the nut trap could be printed as part of the curved end.|
|I actually cut parts to go with the
original version and got to the point of assembling the prototype when
I realized that I was hand fitting a small piece of plastic at the top
that should have been printed as part of the design.
I didn't think of doing it originally since it represents what's called a "bridge" in 3D printing terms. However, adding the curved transition makes the "bridge" easy to print reliably.
|I thought I was done designing curved ends when the one I was working with slipped out of my hands and hit the concrete floor of my workshop. To my surprise it had split along the print layers. Something that I had not experienced with other parts I've printed. This one, however, at over 7 inches in height, is the tallest part that I've printed so far. There were a few changes made so that the parts were more durable. First, I enclosed the printer to raise the ambient the parts are printed in from ~20 deg. C to ~25 deg. C. Second I increased the temperature of the extruder from 230 deg. C to 234 deg. C. This helps the layers stick together better. Finally, although it's counter intuitive, I reduced the wall thickness of the part from .125 in to .1 in while at the same time increasing the internal fill ratio from 20% to 80%. Basically it means the parts are almost solid. Internal ribs were also added to strengthen the parts. They can now survive 3 drops without any damage!|