I have been fine tuning my quad copter design now and it’s seen quite a few iterations. This is number 5. It is built using G10 FR4, HDPE, 12mm carbon fiber tubes and double side 1/16″ copper clad. This quad is meant to be a simple sport flier but could easily be extended to carry a camera or FPV gear. I’m using my Aurora 9 TX as usual with the proven optima 7 RX on this one.
When I design parts for CNC Routing I use Vcarve Pro. I am very happy with this software and it has been well worth every dollar I spent on it. When I make parts to be 3D printed I use OpenSCAD the programmers CAD.
Motors and ESC’s and Props
I am using Turnigy Plush 25amp ESC’s flashed with the simon k tgy.hex you can read about it here. The motors are these Hacker Style 20-22L 924KV motors. As for props I’m using the trusted APC 10×4.7SF and 10×4.7SFP.
I have had great success with the KK version 1 controllers on both tricopters and quadcopters. I am planning to put the KK2.0 Multirotor controller in this one. I have been flying the Naza with GPS on my other hexacopter and quadcopter and absolutely love it. It is the best flight controller I have ever tried (and I have tried many). I am mounting the controller using the rubber isolation mount stand offs I bought from nghobbies.com.
The top plate is cut out of 1/16″ G10 FR4 and painted using the same Truck Bed Liner in a can that I used to paint the power distribution board and boom motor mount plates. The truck bed liner makes a nice hard surface and sticks really well to the G10 FR4 with light sanding only.
Orientation is always challenging on a quad and I found that the multicoloured arms on the DJI quads/hexas helps a lot. Normally I make the motor and frame boom mounts out of 1/2″ HDPE. I cut the shapes out on my cnc router then create a pocket and setup a program to drill the two 1/8″ holes. I tried to drill some by hand using a template and it was impossible to keep them straight. I decided to make two of the booms white and 2 of them black. This meant that I needed to make some frame and motor boom mounts out of white HDPE. I has some 1/2″ laying around from another project and used that to make the parts. The 12mm carbon fiber tubes come in black only. I used some white 1/2″ heatshrink on 2 of the booms to make them white. I left the G10 FR4 the natural yellow color on the motor mounts for these booms as I did not have any white paint.
The landing gear is made from 1/2″ HDPE. I use two 0.120″ carbon fiber rods with 4 3D printed end caps. The landing gear is unbreakable and doesn’t weigh very much.
I’ve been building multirotor copters for quite a few years now. One of the frustrating things about the build is the need to create a wiring harness to supply power from the battery to all the speed controls. I decided to try and build the power distribution into the bottom plate. The first one I built I used my CNC router to take the copper off the PCB. I didn’t like this method as it also took a little bit of the PCB material away as well. I decided to try a different method.
I used the CNC router to drill all the holes and cut the board out from the copper clad PCB stock material.
Then I spray painted both sides of the PCB with this flat black spray paint.
While I let the paint dry for about 20 to 30 min I imported the dxf vectors into the laser engraver software. I am using a 50W laser engraver I bought from an ebay vendor. the software is actually quite good. I’ll post more about it later. I setup the software to do a “scan” engrave of the areas I wanted copper removed from. I did 2 passes with the laser. The first pass was 200mm/s at 100% power and took about 25 min. The second pass was set to 450mm/s with power level of 100% and took about 12 min. The second pass helps to clean up the residue left from the first pass but might be able to skip it in the future.
Even with the second pass there is still some residue on the board.
I used some alcohol on a cloth to remove the residue. Be careful not to remove the paint. The board is now ready for etching with ferric chloride.
Here is the board after etching.
I removed the left over paint from both sides with acetone to expose the copper. It came off very easily rubbing it with a cloth.
Next I masked off the solder pads with electrical tape.
Now for the insulation coat I sprayed both sides a couple of times with black truck bed liner in a can. I lightly sanded both sides with 1500grit paper before painting. This bed liner paint provides a really hard coat. In this picture I have already removed the electrical tape to expose the solder pads.
Here is a shot of the quad copter being assembled after the esc’s and battery connector were soldered on. I used a liquid mask insulator to cover all the joints on the PCB.
In summary I’d say this was a complete success and I’ll be doing future boards using the same process.
I designed a 2 axis simple camera gimbal for use with my DJI Naza hexacopter. Here are some pics of the build. I might post it to my thingiverse account. The gimbal works well using the DJI Naza controller. I also designed the landing gear and made it using HDPE on my CNC Router. The hexacopter flies well. Here is a video.
Here is one of the first boards I made where I used the router to remove all the excess copper. This is one of the original versions of the KK board using the gyros interals from the Hobbyking 401b gyro.