Soldering little components

snipped-for-privacy@zekfrivolous.com (GregS) wrote in news:guhhdb$p18$ snipped-for-privacy@usenet01.srv.cis.pitt.edu:

I use a binocular magnifier that clips onto my glasses. Use non-magnetic SS tweezers,keep them clean and free of flux residue. I've read of othes using a dot of superglue to hold down the part before soldering,never tried it.I've put a dot of solder on one pad and reflowed it while holding the part to the board,to tack down the part before soldering the other pins.

--
Jim Yanik
jyanik
at
kua.net

before.

How's your iron? You got a nice small point? I have no particular issues with 0201 parts. Get some fine solder. Put solder on one pad on PCB. Put the 0201 down, put some flux, use the iron to reflow the solder that's there. Do the other pin with the fine solder.

0201 is getting pretty small for hand assembly, but it's doable with enough magnification for old eyes. I agree, use a soldering iron instead of a hot air gun.

In production, we don't spot the solder onto the first pad, just put down a drop of flux. The tinning on the part and the component will reflow sufficiently to hold the first end while you solder the second end, then go back to the first.

Angle-ended tweezers are great for larger parts (0603) but when they get to 0402 or smaller I just lick the sharpened end of an orange stick or wooden swab handle and use it as a pick-and-place tool.

I usually wear magnifiers regardless just for close viewing. I then put on a headband magnifier over the glasses, probably can get up over X4. The microscope works fine, but those huge irons and solder strands look scary. I now find after mounting a small cap, its polarized and they didn't specify orientation. I can't see the anode band without using the microscope. Try again. I have soldering iron needle tips which are working well on the WRS3000.

greg

I use a ground off hypo needle and rubber ball. Squeeze the ball, place tip on part, release the ball, place and solder.

Sometimes you have problems with air leaking past the part. So dip the end of the needle in PVA and blow out the residue. Alow to dry before use. You only need to dip a couple of mm, otherwise it runs down the needle and blocks it.

--
Best Regards:
                     Baron.

Oh, we have the same station. The tips I use now are the

They are fine enough to allow me to solder MLF packages, and stubby enough so that there isn't too much of a heat loss.

I have one of those, but I'm using one twice the length. One I wore to death was similar to yours with a bigger tip. It was the workhorse. I still get a chuckle looking at that .6 mm resistor. I'll have to try to measure it because i think its smaller.

greg

measure it

The thing with the skinny long tip is that the pointy bit is too cold, not enough heat makes it there. Also, it is mechanically fragile, I have a small bin full of these tips with bent, broken, or the plating's coming off. I really want to try a Metcal RF iron but we're running a tight ship these days.

Good grief. How much thermal mass do think an O201 component has? Besides, with a pointy (as opposed to screwdriver) tip, you don't solder with the point. You use the conical faces to heat component and pad, with the tip sticking out past the joint.

How much thermal mass do you think a 1/8-inch thick 22 layer board with 11 power planes and blind vias has? With the top layer 3 mils away from the first 1oz ground plane and vias in pad? Look, just because you're a hobbyist repairing TVs on one layer PCBs, doesn't mean we all are. And there's more in life to solder than 0201 parts, did you know that? How about a nice CASON part with a thermal pad 10 mils away?

You're fired.

I get along well with 0603. I paint the edge of my left index fingernail with rubber cement. I put the 0603 part onto my bench surface, and land the fingertip near the part, with the edge of the glue-painted nail over it.

Then I roll my finger into a more-vertical direction to get the part glued onto the edge of my fingernail.

After that, I land my fingertip on the board, so that dolling my finger into a more-vertical direction puts the part on the board where it goes.

I tack one end of the part onto the board with a well-tinned very-sharp-pointy-tip soldering iron of 15 watts (One with suitable temperature regulation and higher power should do no worse).

Then I properly solder the other end of the part to the board.

The step after that is to properly solder the first end of the part to the board.

This takes some practice. You will probably want magnifying glasses or a "magnifier stand". I find +3.5 or +3.25 diopter reading glasses slipped on over my bifocals barely sufficient.

I have done a few boards this way with dozens of 0603 parts (1608 metric) and one 0402 part (1005 metric).

I got prototype boards from Express PCB - and I soldered/stuffed them myself. I needed someone to pep-talk me into doing this. That someone ended up being one who uses a different method that did not work well for me, and used parts as far as I know no smaller than 1206 (3216 metric).

My experience suggests that manufacturing cost increases when part size gets smaller than 0603 (1608 metric). It appears to me that need to use smaller parts is where there is premium worth paying to use smaller parts, especially for the awfully tiny 0201 (0603 metric). The two larger sizes of teeny-tiny SMT parts that I have dealt with are flea-size!

- Don Klipstein ( snipped-for-privacy@misty.com)

Interesting technique ! I have to try that.

--
Best Regards:
                     Baron.