Tuesday, September 27, 2011

Aikido Pre-Amp Project - Part 4

Works continue on chassis design...

We will take up where we left in part 3 where we gone as far as determining the required chassis dimension of such,
PCB chassis dimension :141 x 293 x 100mm (H)
                                         ~5-1/2" x 11-1/2" x 4" (H)
PSU chassis dimension : 121 x 293 x 100mm (H)
                                         ~4-3/4" x 11-1/2" x 4" (H)
Aluminium is the material of choice.

Determine Type of Chassis & its Construction Method
Nothing in my junk pile match the sizes required, not even aluminium metal containers or kitchen utensil which I can improvise.... :(

Instead, I found some 300 x 500 x 2mm thk aluminium sheets which sits on a shelve all by themselves.. These will be suitable for folding a chassis per sheet with some tweaks in the chassis dimension.
Before any further a do, I need details of the press brake that will be folding these chassis for further number twitching in the previous development drawings. A disappointing trip to my friendly neighbourhood sheet metal fabricator reviews that the smallest bending radius is 9mm which is IMHO too coarse for folding chassis with a million-dollar-look

 "Desperation is the mother of innovation"

More stock check on what are at my disposal, with a pinch of copy cat & a whole load of cheating... The following drawings appear progressively...

Don't know how you will coin it. Borrowed from wood joinery technique; Its basically a 3D jigsaw puzzle with tabs & tab holes.  Tabs & tab holes are employed for locating the panels in relation to each other accurately. They will be spot welded at the tab joints to ensure good electrical & rigid structural bonding.

While I was at it, conveniently added some perforation on the PCB chassis top panel to facilitate ventilation path while preserving the rigidity of the penal. No opening on the side panel as I'm too tired to do so...

Keen eye readers will notice by now that both PSU & PCB chassis are identical in size.

So, I cheated... .Uniformity is the current excuse of choice for my laziness... I am sticking to it.. :)

After burning more man hours on touching up the design with further detailing such as optimising material utilisation; The nested penal layouts were born.

I reckon this will be the eventual construction drawing... but I do expect "unforeseen" circumstances.

The next on the list is to put the design aside to simmer for a couple of days (maybe weeks) while I can go on with my day job. We will know if there are any need for further tweaking by then...

Before I switch off the PC, here are the summery,

External : 140(W) x 290(L) x 100mm(H)
                  ~5-1/2" x 11-3/8" x 3-15/16"
Internal  : 124(w) x 274(l) x 98mm(h)
                  ~4-7/8" x 10-25/32" x 3-7/8"

~Panel material~
2mm thick Alum Plate which is approximately 14Gauge.

~Construction method~
CNC machined panels with tabs & tab hole, held together by TIG spot weld.

Wire brushed, with natural colour Anodised.

Another 10 man hour burnt....

Now I can stop staring at the monitor & rest....

...........PART 5 PREVIEW...........

It will be physical! 

No comments:

Post a Comment