Chinese vacuum tweezers for SMT?

I have one. The handpiece and hose are pretty clunky, and the vacuum pump is seriously loud.

I put the pump on a soft pad to damp out the vibration, which helped a lot, but I still mostly use tweezers for SMT assembly.

Cheers

Phil Hobbs

I got a nice vac tweezer setup, and I find that I don't use it. I use curved-tip stainless medical-type tweezers mostly.

If you were pushing parts into solder paste, it might work. I'm mostly doing small protos and rework.

There are manual p+p rigs, with X-Y guide rails. We used to use them for small-batch production.

Okay, I'll try the $2x ones and see if I hate them. If I hate them I'll check out good ones at the next trade show.

That's the idea. Though maybe technique is more important than the tools (stick the strips down or something). Especially SOT-23s (but parts in general) seem to land on the wrong side more than 50% of the time and when the tweezers get sticky they don't want to let go.

Don't like the curved ones- the straight ones from VOMM Germany are nice- not too fine, not too coarse.

Yes, too much, but thanks.

--sp

How costly are those (manual p+p rigs)?

I keep a pump bottle of IPA next to the soldering station anyway. There is enough IPA on the top to dip the tweezers in to cut the flux on the end of the tweezers. It becomes second nature to wipe the tweezers off, just like wiping soldering iron before use.

I like angled (offset, bent, whatever) tweezers. They grow feet, though, so I use whatever the other engineers haven't walked off with.

I generally use flexible straight tweezers, with a really small binder clip up near the closed end to provide micro-adjustable closing force. That way I rarely drop things when I change my grip on the tweezers. Sliding the clip up and down the tweezers lets me hold 0402s or SOICs easily.

Cheers

Phil Hobbs

I don't hold parts long enough to slide the clip. I generally throw the part down on the board, then pick it up again and move it into place.

I'm often placing a lot of the same size parts at a time, so it helps a lot. Try it sometime.

Cheers

Phil Hobbs

mikeselectricstuff has a few tips and tricks

-Lasse

Yup, that's what I use for rework and one-offs. Occasionally a part flies off the tip of the tweezers, or a part sticks to the tweezers. I demagnetize the tweezers by passing it inside the loop of an old-fashined Weller soldering gun when that happens.

Jon

I really doubt they give much benefit, unless maybe you have really shaky hands. I do lots of 0805 parts by hand for prototypes and rework. 0603 is getting down to where I need a microscope, and I would not want to do anything smaller. But, I also do quad flatpack chips down to 0.4mm lead pitch by hand. Definitely do that under a microscope.

I see these manual P&P on eBay for $1500, and can't imagine why anyone would buy such a thing. I think once you'd done manual P&P for a week, you could do it 3X faster with tweezers that using the horrible machine.

Jon

Just to be clear, you don't slide the clip very often--just when you're switching the size of the parts. You open the tweezers by squeezing gently from the edge (90 degrees to the opening/closing motion). That forces a bit of the pad of your finger into the space, releasing the holding force. It's super fast and a very natural action. That's why the micro-adjustability is so useful.

Cheers

Phil Hobbs

They can be very cheap, e.g. less than EUR10o

I haven't tried it, but it looks plausible - and there will be minimal fettling getting software to work and BOMs in sync with correctly positioned components. In other words, KISS and "approriate technology".

I find that my hands steady out amazingly under a microscope.

I can't imagine assembling surface mount without, and I kinda wish I had a better one (maybe one that doesn't lead to neck strain -- that'd be cool!)

Thanks, some good tips there- now I'm sorry I threw out the sacrificial PCB drilling material my last stencil came packed in.

--sp

Resting the heels of your hands on the bench helps a lot.

I got a used Mantis (the original model) some years ago for about $1300 including both the 4x and 8x lenses. Well worthwhile. You have to be a bit taller for it to be comfortable--probably anywhere over five feet ten.

Cheers

Phil Hobbs

Yeah, VERY strange phenomenon! I can't imagine how that actually works, seems like the magnification would make it at least APPEAR to be worse. But, you can rest your nose or whatever against the eyepieces, so maybe that helps stabilize your head. if your head is stable, that has to help keep the shoulders stable, and that's where your arms are attached.

Also, I rest my forearms on the table that helps stabilize my hands.

I can do 0805 passives and SOIC parts all day with no assist. But, if I'm going to be doing a lot of those, I will sometimes use a magnifying visor, just to keep my eyes from having to focus so close. Without, after a while, I can't focus at a distance to read or use a computer screen.

For any work finer than 0805 / SOIC, then I definitely go to the stereo zoom microscope. If the scope is on a higher than normal bench (or you lower your seat a bit) the scope can actually be very comfortable. I sometimes do manual assembly or inspection/rework of high density stuff, and can do a whole day at the microscope without much neck or other strain. But, I set up these workstations carefully to get everything at just the right position.

Jon

I have not ever done any surface mount assembly, so these comments are likely to be way off the mark. But it seems to me that one could use a scanner to get x-y slides. Possibly use the stepper motor drives from a scanner too.

Thompson made a x-y table for machining. It could be used several ways. One was with a template to position the table. They also had solenoids which would lock the table position when activated. Seems like that would be helpful.

Also the mechanism and software for a three D printer could probably be used with some changes for a automated pick and place.

Dan

There is an open-source harware/software project called openpnp on googlegroups. They have hashed this to death, but the big difference between what they are doing and a commercial machine is error recovery. My Philips CSM84 can recover from a huge range of errors and just keep going. I don't think openpnp can handle much in the way of errors without manual intervention. Picking up parts with vacuum leads to some parts getting tumbled as they come out of the carrier tape. The vacuum sensors detect the less-than-normal vacuum and it tries again.

Jon