Hi Mychaela, Let me see how my machine can keep this kind of tight margins. I'll make an initial design and see how does it look like.
A couple of notes. Would it be possible to extend the spacer by 1 mm outside of the LCD footprint? On the inside at the bottom legs it will be just 0.4 mm wall for the pin, with +/-0.1 mm precision it is too close. I was thinking that making a notch instead of a hole would be a better option. This way I can have reasonable margins on outer side. Will send you address shortly, having a sample on hands would be very helpful for the initial iteration. -Serg On Fri, Jun 1, 2018 at 1:51 AM, Mychaela Falconia < mychaela.falco...@gmail.com> wrote: > Hi Serg, > > > Can you make a handmade drawing of the spacer right over the page 6 of > the > > attached document? Just want to make sure that I understand the > description > > correctly. > > I printed that drawing page out on paper, marked it up and scanned my > marked-up version: > > https://www.freecalypso.org/members/falcon/lcd/KD020C_ > drawing_marked_up.pdf > > I used a blue highlighter to mark where the spacer would go onto the > back of the LCD module. I also made two arrows with a pen to point > out a feature of the original drawing which can be easily overlooked > if you don't have a physical part in front of you. > > Basically I want the legs of the spacer to extend far enough to include > the lower alignment pin, i.e., when the spacer is fitted to the LCD > module, both of the module's alignment pins should go into corresponding > matched holes in the spacer. There is no exact constraint on how far > the legs can extend past that lower alignment pin, but there would be > no use in having them extend significantly past that lower pin: it is > not shown directly in the drawing, only hinted by the two little lines > I have pointed out with arrows, but the profile of the back of the > module thins out just a tiny bit below those little lines, hence if > the legs of the spacer were to extend the full 51.4 mm height of the > module, there would be a gap between the lower ends of these legs and > the module frame. This is why I said originally that the length of > each leg should be about 41 mm - going just below the lower alignment > pin, but no further. > > Also note from the highlighted drawing that when the LCD module is > mounted with its tail folded under, the wide part of this tail (the > part that's 34.58 mm wide according to the drawing on the left) will > extend a little bit into the area where the lower alignment pin > resides. This detail imposes a tight constraint on the width of our > spacer legs: they cannot be too wide or else there would be no room > for the folded-under tail to go in between. But our spacer legs > cannot be too narrow either, as they need to be wide enough to fully > incorporate the holes for the alignment pins to go into. > > According to the original drawing, the diameter of each alignment pin > is 1.00 mm, and the distance from the centre of each pin to the edge > of the module frame is also 1.00 mm. The implication is that the > distance from the outer edge of the module frame to the inner edge of > each alignment pin is 1.50 mm, giving us the lower bound on the width > of our spacer legs. The upper bound is 1.90 mm, the margin left by > the wide part of the folded-under tail as given in the tail drawing on > the left. As you can see, it is very very tight. I asked for 1.7 mm > width as the middle of our tolerance window. > > > I can make few samples. > > I would greatly appreciate it. Because it is so difficult to do this > mechanical design going only by email verbiage and awkward drawings, > if you are serious about helping with this project, I would be glad to > send you one of my LCD samples so you can have an actual target LCD > module in your hand to first properly visualize what is needed, and > then to test-fit what you have 3D-printed. If you are willing to do > it, please resend me your current snail mail address off-list. > > TIA, > Mychaela > _______________________________________________ > Community mailing list > Community@freecalypso.org > https://www.freecalypso.org/mailman/listinfo/community > _______________________________________________ Community mailing list Community@freecalypso.org https://www.freecalypso.org/mailman/listinfo/community
