I’ve mentioned a few places in these forums that I spend good amount of time working on projects for others. (Coworkers, Neighbors / Friends) This is one of those projects…
Compared to some of the projects I have shared here, this project was less ‘free hand’ and more driven from an initial CAD model. In modeling, I did stick to flat pattern / wire frame CAD just because it is so very fast for this kind of work.
The photo below looks liek there are segments all over the place. That is just an artifact of capturing the graphics. You’ll see below, the parts came out smooth and ellipsoid right off of the cnc.
And right away, it was out to the garage to the plasma table side of the AVIDcnc:
This is 16Ga Mild Steel.
The design has many many more pieces, so immediately after the plasma cutting above, I switched over to the spindle side of the AVIDcnc. I use a quick drilling program to drill some holes (needed for the stock) all the way down into the spoil board. With these in place, I can simply screw the part down to fully support it while cutting.
Screen snapshot of a program used to convert the G-Code .
This first material is the UHMWPE that I am using as a light defuser. It doesn’t show very well in the photo below, but the material stock is 24in x 24in and there is a piece of 3/4MDF lined up underneath it, so I’m not screwsing into the main clamp down board.
I’m using pretty thin UHMWPE so lots of screws go into this for holding it down.
I use a stubby ER-16 straight shank adapter to hold the smaller drills. The ER16 collet sets I use cover the full range of sizes in-between each next collet so this works well for holding odd-sized jobber drill shanks.
And next it was time to put it to use in some acrylic. There are three different colors and two thicknesses of acrylic to be cut for this project.
Why the crazy shape? You’ll see this further below, those cut-outs around the edge are so that this part will fit around the weld beads I’m going to put it.
In the CAD system, the following parts were manually nested to fit on this plate of 3/16in steel.
After generating G-Code, I often use a 3’rd party utility, like the one shown below, to verify the tool path and look for hiccups. This is mostly a quick anity check to make sure I haven’t missed something obvious.
After this there is a little ‘post-post-processing’ to convert the G-Code my legacy CAD system spits out into something that is ‘plasma-aware’. This includes setting material thickness, voltage, amperage, travel speed, touch-offs, pasuses for pierces, etc. It is incredibly nice to have a program that automates all this or lets one change it on the fly without having to look all of that up in the Hypertherm manuals.
Out on the plasma table side of the AVIDcnc this is loaded into Mach and machine is ready to run.
Is this cool or what? Nope, never gets old!
But wait, there’s more… After this I needed to cut some perforated stainless for one of the layers. I was a little nervous given how thin the material is, needing to drive the cut to higher and higher travel speeds, while having the torch heigh controller and the high-frequency re-start kicking in and out.
I put my hand on the Z-axis while this was running and I could feel the THC bobing it up and down, but the travel speed was so very high it just felt like a vibration. (no diving)
you can see that same odd outline / pattern, mentioned above, repeated here. I’ll share more on this below. The part came out great!
It is always fun during a project to stop and take stock of how thing are shaping up. I just stacked some of the pieces on top of each other in this photo. This is one of my favortie photos in the whole design.
No rest yet, there is plenty left to do, so it was back to the spindle side of the AVIDcnc to cut some more acrylic… It is a little hard to see but this one is screwed down as well…
And then it is time for some clean-up prep and welding. I spent a little extra time with the angle grinder to ‘break’ all the hard edges on the front faces to put a small bevel across the top side of these parts. It helps them throw light later after powder-coating.
And then right on into welding. Nothing fancy here, just a whole lot of, “rinse and repeat.”
I’m not showing all of the welding steps here, but this gives one an idea… Below, a large number of additional tack welds have been used to attch the neon support ring.
The snippet below shows a compressed / cutaway view of the steel needed. The faux neon is in the upper right and the remainder of blue and red are LED strips…
Here you can see some of the structure has been welded in for the center section. I made a little jig to hammer form that steel into a perfect matching elipse. It came out better than I had expected. The jig is still in place, in the photo, below.
The other piece that shows in the photo below explains why the design such a strange outline on many of the pieces cut, above. Before welding, I set the stainless piece in place and traced that outline pattern. This showed me where I could and could not place weld beads, since the stainless (and later acrylic & UHMWPE) need to sit flat when screwed to the front of the sign.
The highlight rings for the letting sit forward from the front of the sign. (quite a bit more than shown below). What I’ve done here is put the attachment screws in their various holes in the steel. I’ve gone in and put a drop or two of C-A glue on top of the head of each one and then set the lettering outline on top of them and left them to sit / dry. This is thickened C-A glue with filler, so it can take a while to dry. (I just left it over-night.)
With that, they are ready to weld up. This first image shows how the super glue holds the screws in the precise location to line up with the holes in the sign,from the step above.
One of the fixturing pieces used is not showing in the photo below. I have three pair of 10" long locking forceps. I clip each one to the screw (spread 90-deg apart) and rest the loops / handles against the welding table. The trick to welding these is to get in and out with the exact right amount of heat. That C-A glue is going to let go just above 400 deg and the part needs to hang out for a few seconds as the weld pool solidifies. The extra forceps just provide a little insurance the screw won’t tip over if the weld timing / application of heat isn’t perfect.
With that part of the fabrication out of the way, it was time for powdercoat and paint. I used high temperature tape to mask off the back during powdercoating. The back will be treaded wtih an acrylic white paint to help with lighting in a later step.
Wait, blue? Isn’t the part red in the final? I made a few variations of blue and red acrylic and powder coated parts. I started with one color scheme in mind but my daughter helped me see the error in my ways.
In the image below, you can see I’ve got some high temperature tape protecting the threads on those 6-32 mounting screws.
Before and after the reflow process in the oven. The picture below at night under a flourscent light in the garage, really does not do this justice.
And finally, some assembly…
The screws from all the letter outline rights come all the way through to the back and sandwich everything together. I use electronics washers with every other tooth kicked up / down to retain the nuts.
I’m using a rubberized edge protector on the back edges to help it keep from scraping up the wall over the next ~30+ years…
And then some LEDs are layered in…
Hahah, my camera stands identically zero chance of taking the above photo. I’ve got the exposure cranked way down but the blue light easily over-saturates the sensor.
And lastly the faux neon was added. This was another piece I struggled with. With the colors blue, red, silver and charcoal already in the design, I almost went with a violet for the faux neon, but as you can see, I went with red to repeat the color from the center.
Drum roll please…
The sign is sitting on a 3M blue anti-static mat and all that blue light from the LEDs, purposefully made to light up the wall and make this thing pop again over-saturate the image, so much so, that the red lighting in the middle of the sign barely shows in this photo. In person the eye is drawn right to it.
This project I finished up just a few short weeks back and not long after that last photo was taken the sign was boxed up and on its way across the country to my friend’s workshop. This was a fun project.