In many flashlights they are just pressed down by the reflector, or adhesive is used under the board, this is especially common for 16mm boards. 20mm boards are sometimes screwed down. The holes in the board may best be somewhat wider than the used screw, to have some wiggle room to center it under the reflector. Thinking of that, it may be a good idea to not make countersink holes.
I thought so too. With countersunk holes, the free play is limited. Itâs also easier to isolate the screws from the board (CDTP limitation).
You know what Djozz? âCDTPâ is popularized by you! You were the first to use that term, AFAIK
- The (three) designs are 90% ready for upload, only holes/slots placement left. I also design another aluminum square DTP 30mm x 25mm linear 3535 single/triple config exclusively for use with LEDIL STRADA and SHELLY
- ASAP in early February. But please, please, donât take it tightly. Iâve been trying my best to be a faster designer/provider, yet still not fast enough for BLF.
Will TRY to bring them here at approximately USD 3 - 4/pcs
No, plain washer still expose the screw thread to possibly contact to the MCPCB body
You have to at least use waisted/flanged washer to insulate both the screw head and the thread body, otherwise youâll screw it. But flanged washer will need bigger holes. Normal clearance fit for M3 x 0,5 is 3,2mm. With flanged washer you have to open up to 3,8-4mm minimum hole diameter.
With plastic screw you can save the precious surface area and simplify installation. Plastic screw comes in wide variety of materials and designs.
Decided to follow standard âstarâ shape, though mine is rounded to make centering easier if necessary.
I still havenât heard about optic holes for the 20mm. Should I just leave it blank? So everyone can just drill themselves?
I prefer to leave it blank, since in this CDTP design, anode/cathode surface area is of high importance.
So the +trace is one large pour over the entire surface with just a clearing for the -pad which is a small connection the size of the solder pad going down to the core?
(Iâm not familiar with single led optics so I canât advice on the holes)
Ever wondering why this budget friendly Sn96,5Ag3,5 with superior thermal conductivity 78 W/M.K is not so popular?
Hereâs the answer: http://www.psma.com/ul_files/forums/leadfree/aim_lead_free_guide.pdf
The short answer is it has somewhat troublesome wetting ability. Not a good thing for automated soldering. But for us who really likes to spend hours just to get perfect reflow, this should not be a major problem. The jump from ~50 W/M.K to 78 W/M.K is indeed worth the hassles.