Futaba 3UCP 3D printed battery cover

Last year I purchased a couple of Futaba 3UCP transmitters on eBay that were missing their battery covers.  Here are pictures of one of them, front and back.

Futaba 3UCP 3 channel 2 stick transmitter (front)

Futaba 3UCP 3 channel 2 stick transmitter (back)

Futaba 3UCP battery compartment

Both transmitters were in good condition with only minor blemishes from usage.  The single major problem with each of them was the missing battery cover.  Apparently, the original owner was using some sort of larger battery pack and misplaced the covers over the years of owning them.  The seller, who seemed to be a clearance house company, searched for them to no avail when asked about them.  Knowing the covers are practically impossible to find, and with no response from Futaba support, I bought the radios anyway at a reduced price due to the missing covers.  The hope was that I'd find some hole-in-the-wall place online or eBay auction with covers for sale at some point.  I knew this would be unlikely, but worst case, these units could be useful as spare parts for my somewhat large collection of 3UCP transmitters if anything ever went wrong with them.

Here is what the original battery cover looks like:

Original Futaba 3UCP battery cover (front)

Original Futaba 3UCP battery cover (back)

After studying the OEM cover in detail, I decided it might be worth trying to see if I could create a 3D model of the battery cover and have it printed in plastic by a company like Shapeways (http://www.shapeways.com).  Having practically no experience in 3D modeling and design, I asked people on the TamiyaClub forum what they use for design software.  One person suggested using Rhino, but the trial version lasts 90 days and the full version was US $1000.  Although I figured I could create the battery cover in under 90 days, I would ultimately be left with nothing to use after that point in case I wanted to create other things for printing and I really didn't want to spend any money if at all possible.  In the end, I used Blender (http://www.blender.org) because it was free and appeared to have a fairly large user base, including many helpful tutorials on Youtube. Blender also seemed to be fairly powerful with many features that could allow my 3D models to become more complex as my skills improved.

After 10 hours of measuring the original battery cover, reading and watching tutorials and playing around on my own, I finally had the first version of the cover ready.

I created an account on Shapeways, uploaded the model and ordered it in strong and flexible plastic dyed black.  After a week and a half, it was delivered to my door.

Incredibly, it fit into place and actually snapped shut with a very nice clicking sound much like the original part!  I had to file down the top two corners because I forgot to round them in the 3D model, but I was amazed that my very first try at 3D printing actually worked and was completely useable.  The printed cover certainly wasn't perfect - it had gaps around the edges and did not contour perfectly with the transmitter back cover, but with some tweaking I was sure I could make it look and function even better.  

For version 2, I added some rounding to the two corners that I had missed and widened it so the door wouldn't show such large gaps on the sides and top.  I also pulled the bottom rear curved part back a little bit to make it larger than a 90 degree angle in order to more closely mimic the original door contour.  I had missed these things during my initial measurements and modelling.  I uploaded version 2 to Shapeways, ordered it, and waited another couple of weeks.  Here is version 2:

The second version functioned better and looked much nicer than version 1 when installed. The width was now perfect and the overall fit was much tighter, but I still wanted to make a couple more minor tweaks to the door in order to get it to fit more closely like the original part.  I increased the size of the rear stubs so the rear part of the door wouldn't lift as much and show a gap, added material to the hook part of the front barb so the door wouldn't pull down as much and leave a gap and finally enlarged the "OPEN" text so the 3D printer could have an easier time with it.  Upload, order, wait.  Here is version 3:

The third version fit very well with the same pleasing "click", but the looks were not quite as "clean" as the second version.  By clean, I mean it didn't quite fit snug at the top and sides like version 2, which had practically no gaps.  I do not know why this happened, because I did not modify those dimensions in version 3.  Also, it looks like a different model or brand of 3D printer created version 3 because the plastic looks and feels slightly different.  This may explain why the fit isn't the same as version 2.

At this point I thought I was playing within the realm of the resolution of the 3D printers themselves, so further attempts at refining the door might result in something that no longer functionally fit depending on which 3D printer created the part.  I decided that version 3 would become the final product.  3D printing is very different from a mold where each part comes out exactly the same.  Some variation is to be expected each time an object is printed, though it is usually very minor.

I created a store on Shapeways and enabled the ability for others to purchase it for themselves.  If you have a Futaba 3UCP transmitter that is missing its battery cover, you can now order a 3D printed one on Shapeways by clicking here.  Please note that the 3UCP battery cover is unique to this model and does not fit any other Futaba transmitter.