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Air Conditioner (Con't)

With the hose fittings in hand, I decided to go ahead and bite the bullet and buy a hose crimping set instead of running back and forth to a hydraulic line supplier. I fabbed the high and low pressure lines and installed them to the firewall....pretty straightforward.

Next was to figure out the vents for the unit. Like I mentioned earlier, I decided to not opt for the Sure-Fit system since I didn't like their vent styling. My plan was to develop my own and I wanted to see if I could design and fab a vent that used the center dash louvers that usually have a speaker in them. A year or so ago I bought a fairly cheap but capable 3D printer and my plan was to use it to make the vents and any special ducts.

The first things that I needed done were to figure out a software package to use to model the vent and to verify that I could replicate the contour needed to match the dash. I settled on FreeCad for the modeling software since it was “free” and it seemed to be close to the software that I have used for years in my job. It took a little ”googling” to figure out some things but I got it done. I also took my contour gauge and made a small cardboard template so I could measure the contour more easily.

I them put the measurements into the software and created a 3D surface. I then used the surface to create a test solid in the software that I then printed to make sure that I was heading down the right path before I got in too deeply. The surface matched well and then I kept slowly developing and testing my concepts. I didn't want to make wholesale changes to the software since it did seem to struggle a bit with parametric updates. I ended up making several prints out of cheap PLA material to validate the design. The final design is shown on the silver and red part (my PLA filament ran out mid print so I used what I had laying around).

With the design validated, I then had to decide what filament to use for the final part. ABS would have been nice but my printer isn't really set-up for printing ABS so I decided to use some high temp PLA with glass fibers. I had to change out the nozzle to print with the more abrasive material but that wasn't too hard to do. I then printed the 3 separate parts in black HT-PLA-GF filament as shown.

The high temp filament has pretty good properties at elevated temps but to make it even better I had to anneal the parts. To do that I packed them tightly in a container with table salt (to keep deformation down) and heated them to 215 degree F for about an hour to anneal the parts. I also had to upscale the parts about 1.5% to account for shrinking.

With the parts printed and annealed, I could assemble the 3 components together. I went ahead a sealed the interface with RTV (although it was probably unnecessary) and bolted them together, painted the shiny screw heads black and then installed it along with the center trim to see how it looked. I then ran the hoses from the evap so I could see how they fit and to make sure I have space for other things.

Next task is to do the same thing for the outer two vents.