Project Front Panel

Faceplate mock-upMy electronics based projects most often end up in a box of some sort. with related knobs, LEDs or displays showing on a front panel. Over the years I have tried a number of different ways to make these panels look nice, and I think I have finally found a method that looks professional and I am happy with.

Project CaseMost of my projects end up in boxes made up of a top and bottom half, with removable ends. In the past I would have cut and drilled these panels to fit my hardware, and labelled the panel.

Early on I was using transfer letters, rubbed on the plastic box and then sprayed with a varnish top coat to make it durable. Often the letters weren’t straight or equally spaced (blame the operator’s skill!), or the varnish slightly melted the letters, which all detracted from the overall look.

Then I found this blog describing a method using printed sticky labels. This allowed for precise alignment and it looked better than the rubbed letters, but to me it still looked like a printed paper label …

Recently I worked out a method using thick clear acrylic sheet (Perspex) and my ShapeOko CNC machine to make new end panels that look professional without being too complicated. This method also allows me to incorporate clear windows (eg, for LCD displays), that were previously a real pain. Because the panel is painted, it can be customized to any color combination.

Here are the basic steps which can be adapted to suit your own tools and work flow:

1. Design the Panel and generate the G-Code

Click to enlarge
Click to enlarge
Design the front panel in a CAD or similar program. Start by defining the outline to match the size of the curent plastic insert. I use Vectric’s Cut2D software as it allows the generation of G-Code paths (the next step) directly. The design only needs to include the outlines for the display windows, holes, text and the panel itself.

Once the design is completed, flip it left to right, as all the machining takes place from the back of the panel. The picture shows the design at this stage.

Next comes the generation G-Code files. How you do this will depend on your workflow, but the basic files that need to be created are to machine:

  1. An outline of the panel so that one or more panels can be cut from the larger acrylic sheet. I used a 1mm spiral bit for this operation.
  2. A pocket the size of the panel to use as a jig to position and re-position the panel. I used 1/4″ router bit and then squared up the corners.
  3. The outline of any clear windows that need to be created for displays to show through. I used a 30° V bit and a depth of 0.2mm, which was enough to cut through the paper protection of the acrylic sheet.
  4. An engraving of the text. My setup used the 30° V bit and a depth of 0.8mm.
  5. The cutouts for knobs, switches, etc. I used a 1mm spiral bit.
2. Manufacture the Panel

Use the CNC machine to cut out one or more panels as a batch. For the first time through this process, I would recommend at least 3 panels, as there will be some trial and error.

Click to enlarge
Click to enlarge
Next machine the pocket. In my setup a piece of MDF was bolted to the machine bed and the CNC allowed to do its job. This was for me the longest part of the job but it made the rest of the setup much more repeatable. The photo shows the jig ready to be used – the pocket has been created and a few holding screws with washers have been screwed into edges.

You will need to create a spot on the jig that will become your ‘repeatable’ zero point so that you can realign the CNC if you need to. Not all operations are done in one session and it is likely that the machine will be turned off in between. You can see my zero 10mm to the left of the bottom left corner of the panel.

Click to enlarge
Click to enlarge
Next is cutting through the protective covering layer on the acrylic, creating a mask to stop paint getting on the clear window areas. If you don’t need windows, you can clearly omit this machining step.

Click to enlarge
Click to enlarge
Now remove the panel and peel off the protection layer but leaving the window masks still on. Spray paint the exposed acrylic with a color of your choice – my panel is black. Once the paint is dry, preferable overnight, re-mount the panel in the jig.

Click to enlarge
Click to enlarge
Run the G-Code that engraves the text into the painted surface, change cutting bit and run the G-Code to create all the cut outs. Results with my panel are shown in the photos – still on the jig and when cleaned up and backlit to show the etched text.

Click to enlarge
Click to enlarge
3. Finish the Panel

Panels Reverse Side Click to enlarge
Panels Reverse Side
Click to enlarge
There are a few options for how the panel can be finished. The first method I tried was to spray paint the back of the panel with a different color (red), so that the newly exposed text would show through the front of the panel. This worked well but I had accidentally damaged the black layer in one spot and the red showed through.

Panels Front Side Click to enlarge
Panels Front Side
Click to enlarge
Next I tried just filling in the color in the letters, using white correction fluid (Tippex, Liquid Paper, or similar), as I had no white paint handy. For an improvised solution, this worked surprising well.

A third option might be to light the text from the back of the panel with one of more LEDs.

If you look closely, the red letters are not as crisp as the white ones. For the red panel, I experimented with a 0.8mm flat mill instead of the 30° V-bit. The V-bit definitely produces cleaner results.

Once the new paint is dry, remove any window masks from the reverse side of the panel and all of the protection layer from the front side. The panel is good to go!

Click to enlarge
Click to enlarge
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