Airbus Overhead Panel

My Objective

• Design and create a functioning A320 overhead panel running MFS2020
• Must resemble real panel closely
• Must be backlit
• Must be under $500
• Must be aesthetically pleasing
• Must only require MBHS engineering workshop

https://youtu.be/73LFoqpkXww?si=5P_5TVTbJtoJyflX

For this project, Hobby Tech Gear generously provided all files for inkscape to cut and engrave that only require slight modifications. I will provide all files necessary at the end of each part.

https://youtu.be/73LFoqpkXww?si=5P_5TVTbJtoJyflX

The panels were an extreme joy to make, although a lot more challenging than I first anticipated. There was a lot of trial and error involved, keeping in my mind my budget and goals. Had I had an unlimited budget the panels might have come out perfect, but I settled for what I believe is very good quality with some slight imperfections. 

The primary design behind the panels is a 3-layer stack of acrylic. The bottom one being a clear, black painted sheet to block light from coming through the back, while the middle one is also clear, used as a diffusing sheet and for general structural strength, while the top sheet is the paint finished and engraved sheet, inn a opaque white acrylic. This allows for LED strip to be placed in the bottom layer and bleed through the middle layer diffused and then into the top layer through all of the engravings, lightning them up. There will be 15 panels per layer for a total of 45 panels when complete. I'll include a drawing for visual aid.

I started by purchasing a 7328 Opaque White Acrylic sheet. This will be for the top layer and run about $60 for a 24 x 48” sheet. To complete the top panel you'll need just one of them and you'll be left with a little bit extra if you cut it right, to be able to test on. 

To start take your white acrylic and place in the Trotec Laser. We are going to begin by cutting out the holes for switches and the general shape for each of the panels. Push the acrylic to the top left corner and open up inkscape. You'll notice the file contains the entire project overwhelmingly laid out on the screen. Begin by clicking Objects/ Layer and Objects. This will open up your most used tab for this project. Select the panel you will be cutting from the dropdown and right click to hit Hide/Show all other Layers. This will hide all panels but the panel you wish to cut. Next, if cutting the top panel, hide all of the engravings by clicking the hide icon next to each of the engraved parts until you are left with a cut file. Then follow Mr. Wendorff’s guide on how to cut on the laser.

Note: Keep the production film on all of the acrylics while cutting to avoid smoke burn!

Once you’ve cut all 15 panels out using the same method for the top layer, you are ready to cut out the second and third layers as well. These are slightly easier since you don't have to worry about hiding the engraving as there isn't one. These you will cut out on large Clear Extruded Acrylic Sheets much more easily available at a local Home Depot. I picked up a single 48 x 72” sheet for about $70 which is all you need plus some. Once you repeat the cutting process you should be left with 15 white opaque panels and 30 clear panels.

For this step, it will require much patience as waiting for the paint to dry is by far the most important step or you will end up wasting paint, precious acrylic, and time. The paint can sometimes be tricky to get right and also very expensive depending on availability but is definitely worth spending the extra money to get the right thing the first time. I made the mistake of trying to cheap out on local paints that were not acrylic based midway through my panels and paid for it significantly. 

Essentially what you will be doing is; on the top layer white acrylic, take an acrylic primer and spray each panel several times to create a base for the top coat and and a thick film to block out light. Then you will cover with a top coat in airbus equivalent color (the aerosol color code is RAL 7031) and let it fully cure and dry before moving on (about 4 days minimum). The Airbus color can be quite expensive because it ships from out of country and there really isn't many alternatives. You'll want to match with the same companies Acrylic Enamel Base-Coat Primer as well. I highly recommend getting 2 of each cans as you will be needing it and only have to pay the shipping cost once. Total on paint is about $100 after shipping and tax.

Begin by taking a large piece of cardboard and placing your panel in the middle of it in a well ventilated area. Next spray the Grey Primer liberally until the entire top of the panel including the sides and inner holes is coated. Wait about a minute and repeat about 4 times. Once your primer is thick enough to block out all light from the back, wait 5 minutes and grab your Top Coat. Spray the Top Coat very minimally so that some of the primer is barely visible through the top coat. Since the primer is a lighter grey, it will create a perfect mix when combined with a thin top coat. Allow your finished panel to dry for 4 days minimum. Next grab your clear bottom panels and spray the underside of all 15 semi-gloss black. (about $5 at Ace). Try to avoid the inner holes on these.

This step is by far the most tedious and the most rewarding step of the project. It will require a lot of trial and error on your part. I have done a lot of the testing myself which should hopefully help some, but every project is different and this is where your engineering skills will come into play.

The main idea behind engraving the top panels is to remove enough material that you get all the way through the paint, but not too deep that your engravings aren't visible without backlighting. You want your text engravings to be fully white and visible in daylight whilst flat on a table and also crystal clear and bright when placed in front of a flashlight. You will be working with Inkscape and Job Control to create the perfect settings for your piece of acrylic. I had various methods that I used to engrave my panels which I will describe, but there are plenty of alternatives that are potentially better and more consistent.

To create the perfect settings you are going to need some fully painted test material as well as uninterrupted access to the laser for the entirety of your work session. Begin by exporting a simple text engraving into Job Control (read Mr. Wendorff’s guide on how) and place the test material in the laser to adjust for your heights. Once complete, autofocus and begin adjusting values. The 3 values to be messed with are P or power, V or speed, and the squiggly which is PPI. Try different combinations and print them on your test material until you have your desired engraving, and save those values. These are your engraving settings. 

(Note: To allow engrave lines to show up in Job Control make sure to select all lines and click Path/Object to Path and Stroke to Path)

Next, you are going to take some of your less expensive clear acrylic and place it in the printer for a large scale test. Open up Inkscape and select the panel you are engraving. Hide everything but the thicker engrave lines. This is where your engineering skills come into play. The biggest issue with engraving is lining up the engraving perfectly on your painted acrylic. There are many methods to accomplish this but I decided to create a sort of stencil. To achieve this I placed a piece of plywood down and compensated for the height difference, then engraved the outline of the panel as a light cut so that I could line up the panel with the etch and then engrave in the same spot. On the inkscape side of things you have to unhide the outer panel cutline and color it a non-action color (like blue) so that job control knows to respect that line when engraving. From there run the job and hope that it comes out lined up.

Once you are happy with your method of lining up the engraving and everything is squared, you can attempt to engrave on your final panels. Grab your opaque white acrylic and repeat your same process with your engraving settings from the previous step and cross your fingers for the best. One important thing I discovered is that if you lay painters tape over the entirety of the panel before engraving and decrease your speed slightly, you will get rid of the smoke stains. Make sure if you decide to do this you retest your settings though and make sure that you don't overlap the tape on the panels or else it will mess up the print. If your panels came out aligned then congrats, now just do it 10 more times (4 panels don't get engraved). Don't forget to put them all together at the end and take some pictures! 

One thing you may notice in the picture is the green lines inside of the wider engrave lines on 3 of the panels. To accomplish this I picked up some green fluorescent model kit paint and filled the lines up with a fine paintbrush. You can tape off the surrounding if you are worried about getting paint everywhere. 

Korry Witches are a type of momentary/latching switch that are only found in Airbus model aircraft. It is essentially a switch with a light up led display that can be adjusted to indicate on/off functionality.

To start, I grabbed a premade fusion file of the 3D printed prototype off of Hobby Tech Gear whom was previously mentioned and used it as a reference. I ended up scouring the internet and local hardware stores for some 3/4x1/32 inch tubing which would end up acting as the casing for the part but failed to find it anywhere in the US. I ended up settling for 1/16 inch tubing which forced me to downscale the whole unit.

I uploaded the file to Fusion and began the tedious process of downscaling every corner and side dimension of the actuator to compensate for the new 1/16 inch size frame.

Finally I was able to export the file to Cura and the print machine for manufacturing. You will end up needing 116 total Korry switches to replicate the amount in a real overhead panel. You are shooting for the finest print possible so that later when it comes to the movement between tubing an filament, there is little resistance and friction. This may take longer but in the long run is most definitely worth it.

Next we will begin constructing the PCB portion of the unit. I found the most cost effective and fastest way to finalize these pieces, was by cutting small 1x1" squares of a regular copper solder board. These would allow you to feed the switches through the center with good alignment as well as provide a stable frame/base and allow for movement of the LEDs. If you have the money and time, the next step up would be custom ordering Specially made PCB that fits your design. Hobby Tech Gear has an in-depth process on his, but for my needs, the budget option was sufficient.

Next we will insert the two LEDs on opposite ends of the PCB board, in a way that will fit precisely into our actuator. In between the LEDs will sit our switch that will be soldered in via the six prongs as centered as possible. I found it easiest to solder the resistors onto the LED before feeding them through the board so you can tell where the wires will catch on the actuator and make adjustments accordingly. Then you can superglue the PCB onto the underside of the aluminum frame to fit it into place.

For this part of the process, we will create an overlayed display that will bleed light from the LED through our custom-made indicators. Much like the panels that bled light through the opaque part, we will use clear acrylic which will be engraved to etch a white underlayer. This process is much easier than the panels since instead of manually lining up the acrylic, you can simply use the precut scrap as a jig. Hobby Tech Gear has yet more files for use that streamline the project, so I highly recommend checking out those. Cut out you 1x1 inch acrylic pieces with the laser using the same steps as the panels. Make sure to try cutting all squares equally distant and on the same piece of material. This will make it much easier later.

Once your acrylic squares are cut out, save the scrap as we will use it as an alignment jig. Spray-paint the squares on one side in a glossy acrylic black and wait at least 4 days to dry before proceeding. Then place all your painted squares back in your material jig for realignment in the laser. Proceed with engraving the indicated text on all of the squares with the exact same settings you used for the panels. When finished you should have black glossy squares with white etched engravings (about 116).

Finally attach your acrylic indicator to your actuator in the printed slot with any type of string adhesive. As a final touch of realism, I purchased an inexpensive car window tint to place over the indicator so that the engraving is only visible when lit and hidden while off much like the real airbus. At this point you should have 116 completed Korry switches and are ready for the next phase of the process. Congrats!