Posted by Jerry Avins July 8, 2003
Al Clark wrote:
> > Jerry Avins <jya@ieee.org> wrote in news:3F0AE1B4.9614B6F5@ieee.org: > > > Kenneth Porter wrote: > >> > >> Jerry Avins <jya@ieee.org> wrote in news:3F03A9C0.8C7949FA@ieee.org: > >> > >> > I use a binocular erect-image microscope with about 2.5" clearance. > >> > I bought the body on eBay for about $40, refurbished it and mounted > >> > it, using an old 1.25" eyepiece focuser meant for a Newtonian > >> > telescope. A pair of 10X WF about doubled the cost. It's also great > >> > for removing splinters. > >> > >> Which of course points to the other common practice of fine hand work > >> under a microscope: Surgery. Which I'll leave to folk with steadier > >> hands than mine! > >> > >> -- > >> Kenneth Porter > >> http://www.sewingwitch.com/ken/ > > > > A pair of 3X clip-on Gallilean telescopes is another gadget I use a > > lot. It focuses about about 11 inches past my nose, much further than > > a plain magnifier of the same power, so I can use it while silver > > soldering. (I have a lightweight torch with a mouth bit that puts the > > flame at the right spot, allowing me to use both hands on the work. > > The whole get-up makes me look like a bug-eyed dragon.) > > > > Jerry > > Jerry, are these the eyeglass attachments that my dentist uses? He said > they are expensive? What do they cost and where do you buy them? They > look like they might work well for soldering 0805 parts, SO ICs etc. H > > -- > Al Clark > Danville Signal Processing, Inc. > -------------------------------------------------------------------- > Purveyors of Fine DSP Hardware and other Cool Stuff > Available at http://www.danvillesignal.com
I got mine from Edmund Scientific years ago. Last I looked, they now sell only monoculars, and I have one of those too for around $40. It screws into a holder that is a pain. (With a Gallilean telescope, the eye relief is negative, so the closer you get to it, the larger the field of view.) I made a nut with the same thread as the holder, and one of these days, I'll drill a cheap plastic lens and mount it. Doing it twice requires a lot of cut and try to get the convergence right. Your dentist's probably has optics not much better than what I've got. The cost is in mounting them with equipment that can get it right most of the time, and a surcharge to cover those times when it needs done over. Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Posted by Al Clark July 8, 2003
Jerry Avins <jya@ieee.org> wrote in news:3F0AE1B4.9614B6F5@ieee.org:

> Kenneth Porter wrote: >> >> Jerry Avins <jya@ieee.org> wrote in news:3F03A9C0.8C7949FA@ieee.org: >> >> > I use a binocular erect-image microscope with about 2.5" clearance. >> > I bought the body on eBay for about $40, refurbished it and mounted >> > it, using an old 1.25" eyepiece focuser meant for a Newtonian >> > telescope. A pair of 10X WF about doubled the cost. It's also great >> > for removing splinters. >> >> Which of course points to the other common practice of fine hand work >> under a microscope: Surgery. Which I'll leave to folk with steadier >> hands than mine! >> >> -- >> Kenneth Porter >> http://www.sewingwitch.com/ken/ > > A pair of 3X clip-on Gallilean telescopes is another gadget I use a > lot. It focuses about about 11 inches past my nose, much further than > a plain magnifier of the same power, so I can use it while silver > soldering. (I have a lightweight torch with a mouth bit that puts the > flame at the right spot, allowing me to use both hands on the work. > The whole get-up makes me look like a bug-eyed dragon.) > > Jerry
Jerry, are these the eyeglass attachments that my dentist uses? He said they are expensive? What do they cost and where do you buy them? They look like they might work well for soldering 0805 parts, SO ICs etc. H -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com
Posted by Jerry Avins July 8, 2003
Kenneth Porter wrote:
> > Jerry Avins <jya@ieee.org> wrote in news:3F03A9C0.8C7949FA@ieee.org: > > > I use a binocular erect-image microscope with about 2.5" clearance. I > > bought the body on eBay for about $40, refurbished it and mounted it, > > using an old 1.25" eyepiece focuser meant for a Newtonian telescope. A > > pair of 10X WF about doubled the cost. It's also great for removing > > splinters. > > Which of course points to the other common practice of fine hand work under > a microscope: Surgery. Which I'll leave to folk with steadier hands than > mine! > > -- > Kenneth Porter > http://www.sewingwitch.com/ken/
A pair of 3X clip-on Gallilean telescopes is another gadget I use a lot. It focuses about about 11 inches past my nose, much further than a plain magnifier of the same power, so I can use it while silver soldering. (I have a lightweight torch with a mouth bit that puts the flame at the right spot, allowing me to use both hands on the work. The whole get-up makes me look like a bug-eyed dragon.) Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Posted by Kenneth Porter July 8, 2003
Al Clark <dsp@danvillesignal.com> wrote in 
news:Xns93AC5F400B1DFaclarkdanvillesignal@66.133.130.30:

> BGAs are certainly a reality and if you want to build DSP boards you > better get used to them. Of course, there are suppliers that would love > to save you the trouble ;-)
For those lurkers who don't know, Al's company makes nice little PCB's with the BGA DSP pre-mounted along with memory and other support stuff, and the signals brought out to convenient connectors. The boards are still very compact and the pricing was quite reasonable for incorporation in products with small runs. This actually wasn't the first time I saw this kind of product. I'd been evaluating the PowerPC at one point and there's a German company making similar boards with Motorola high-integration BGA PPC's. Their approach is to standardize the connectors and sell various combinations of processor boards and I/O boards to plug them into. -- Kenneth Porter http://www.sewingwitch.com/ken/
Posted by Kenneth Porter July 8, 2003
Jerry Avins <jya@ieee.org> wrote in news:3F03A9C0.8C7949FA@ieee.org:

> I use a binocular erect-image microscope with about 2.5" clearance. I > bought the body on eBay for about $40, refurbished it and mounted it, > using an old 1.25" eyepiece focuser meant for a Newtonian telescope. A > pair of 10X WF about doubled the cost. It's also great for removing > splinters.
Which of course points to the other common practice of fine hand work under a microscope: Surgery. Which I'll leave to folk with steadier hands than mine! -- Kenneth Porter http://www.sewingwitch.com/ken/
Posted by Eric Jacobsen July 4, 2003
On Wed, 02 Jul 2003 23:33:58 -0400, Jerry Avins <jya@ieee.org> wrote:

>Steve Underwood wrote: >> >> Al Clark wrote: >> > Steve Underwood <steveu@dis.org> wrote in >> > news:bduvmg$pm1$1@hfc.pacific.net.hk: >> > >> >>Al Clark wrote: >> > >> > Where did cleaning come in? Reballing is a process that remakes the BGA >> > contacts. >> > >> > Profiling determines how fast the board heats, etc. for correct reflow. >> > You only do it once for a given assembly type. If you did 6 identical >> > boards you wou profile one and place 6 (cost = $80 + 6*$65) >> >> OK, a confusion of terms. I understand what you mean by profiling now. >> >> > Unless you have parts on both sides of the board, parts are not glued. >> >> Are you refering to QFP or BGA? QFPs are routinely glued by the robots >> so the board is less susceptible to shaking as it passes through (maybe) >> several other robot and shakey conveyer belt steps. I wish people >> wouldn't use that concrete like red glue, though. It makes changing QFPs >> a real pain. Perhaps that is the intention! >> >> > When I hand solder a QFP, I place a small amount of solder on a corner >> > pad. I then heat this pad with the QFP pins absolutely perfectly aligned >> > on the board. I then flip the board 180 degrees, and solder the opposite >> > corner. The rest of the pins are then soldered in a kind of controlled >> > bridging approach. FLUX IS YOUR FRIEND!!! >> >> In production environments the girls (its usually girls) tend to use a >> soldering iron with a bit the whole width of one side of the QFP. In 4 >> goes (i.e. one on each side) they can put a QFP in place very >> accurately. Messing around with corner pins is just for people like us, >> who don't do this often enough [actually one in a while is often enough >> for me :-\ ] >> >> > My technician uses a x-acto knife to help slide the part, I use tweezers. >> > In all cases, this is done under a microscope. >> >> I can't image being able to solder with a microscope. I can't remember >> seeing someone try. Doesn't the lens get in the way? Even low power >> microscopes come quite close to the object. Doesn't it fog with flux, too? >> >> > Its been a long time since I laid out pcbs on a light table with tape. I >> > remember when plated thru holes were troublesome. >> > >> > Now even a "down & dirty" house can etch 5/5 multilayer boards (5 mil min >> > trace, 5 mil clearance). >> >> They always seem to get them bubble free too. Most places used to give >> you a few bubbles a few years ago. >> > >> >>>BGAs are certainly a reality and if you want to build DSP boards you >> >>>better get used to them. Of course, there are suppliers that would >> >>>love to save you the trouble ;-) >> >> >> >>If you want to build practically anything above the simple MCU level >> >>you'd better get used to them. >> > >> > What's a DIP? This term seems vaguely familiar..... >> >> Cheese DIP? Lets go for a DIP? They seem familiar..... >> >> Regards, >> Steve > >There are some pretty nice skinny DIPS around. > >Jerry
I used to have some PALs that were DIPs... ...actually think I still do... ;) Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
Posted by Jerry Avins July 3, 2003
Al Clark wrote:
>
...
> > I use a microscope that has a range of 7x - 30x. The microscope is > mounted on a boom stand. With a bit of practice you learn exactly where > your hands are under the scope. There is a real incentive for learning > this skill quickly since the tip of the soldering iron is maybe 700 > degrees F. Soldering is best done with the microscope set to 7-8x. > Sometimes, I inspect the connections at 20-30x, especially if I have > identified a problem. > > Clay is right that the focal length should be long. There are optical > systems for this purpose aimed at electronics that are very nice, I use > an old Baush & Lomb which is OK. My tech uses an Olympus that is better. >
... I use a binocular erect-image microscope with about 2.5" clearance. I bought the body on eBay for about $40, refurbished it and mounted it, using an old 1.25" eyepiece focuser meant for a Newtonian telescope. A pair of 10X WF about doubled the cost. It's also great for removing splinters. It has two powers, about 7.5 and 15. It's good enough. jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Posted by Jerry Avins July 3, 2003
Steve Underwood wrote:
> > Al Clark wrote: > > Steve Underwood <steveu@dis.org> wrote in > > news:bduvmg$pm1$1@hfc.pacific.net.hk: > > > >>Al Clark wrote: > > > > Where did cleaning come in? Reballing is a process that remakes the BGA > > contacts. > > > > Profiling determines how fast the board heats, etc. for correct reflow. > > You only do it once for a given assembly type. If you did 6 identical > > boards you wou profile one and place 6 (cost = $80 + 6*$65) > > OK, a confusion of terms. I understand what you mean by profiling now. > > > Unless you have parts on both sides of the board, parts are not glued. > > Are you refering to QFP or BGA? QFPs are routinely glued by the robots > so the board is less susceptible to shaking as it passes through (maybe) > several other robot and shakey conveyer belt steps. I wish people > wouldn't use that concrete like red glue, though. It makes changing QFPs > a real pain. Perhaps that is the intention! > > > When I hand solder a QFP, I place a small amount of solder on a corner > > pad. I then heat this pad with the QFP pins absolutely perfectly aligned > > on the board. I then flip the board 180 degrees, and solder the opposite > > corner. The rest of the pins are then soldered in a kind of controlled > > bridging approach. FLUX IS YOUR FRIEND!!! > > In production environments the girls (its usually girls) tend to use a > soldering iron with a bit the whole width of one side of the QFP. In 4 > goes (i.e. one on each side) they can put a QFP in place very > accurately. Messing around with corner pins is just for people like us, > who don't do this often enough [actually one in a while is often enough > for me :-\ ] > > > My technician uses a x-acto knife to help slide the part, I use tweezers. > > In all cases, this is done under a microscope. > > I can't image being able to solder with a microscope. I can't remember > seeing someone try. Doesn't the lens get in the way? Even low power > microscopes come quite close to the object. Doesn't it fog with flux, too? > > > Its been a long time since I laid out pcbs on a light table with tape. I > > remember when plated thru holes were troublesome. > > > > Now even a "down & dirty" house can etch 5/5 multilayer boards (5 mil min > > trace, 5 mil clearance). > > They always seem to get them bubble free too. Most places used to give > you a few bubbles a few years ago. > > > >>>BGAs are certainly a reality and if you want to build DSP boards you > >>>better get used to them. Of course, there are suppliers that would > >>>love to save you the trouble ;-) > >> > >>If you want to build practically anything above the simple MCU level > >>you'd better get used to them. > > > > What's a DIP? This term seems vaguely familiar..... > > Cheese DIP? Lets go for a DIP? They seem familiar..... > > Regards, > Steve
There are some pretty nice skinny DIPS around. Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Posted by Al Clark July 3, 2003
"Clay S. Turner" <physicsNOOOOSPPPPAMMMM@bellsouth.net> wrote in
news:T7MMa.5048$Sy1.78@fe02.atl2.webusenet.com: 

> > "Steve Underwood" <steveu@dis.org> wrote in message > news:bdvu5a$nqq$1@hfc.pacific.net.hk... >> I can't image being able to solder with a microscope. I can't >> remember seeing someone try. Doesn't the lens get in the way? Even >> low power microscopes come quite close to the object. Doesn't it fog >> with flux, too? >> > > Hello Steve, > > I have had the priviledge of soldering under a microscope. And I know > quite a few others who do it that routinely with TQFPs. The trick is > to use a scope with a very long focal length objective. This will give > you several inches of working space. This trick has been exploited for > years in macrophotography so as to have more working room. The 6x > objective gives somthing like 4 or 5 inches of working room. The > scope I used is set up so you look horizontally into the unit and your > work is underneath the unit. This takes a little getting use to.
I use a microscope that has a range of 7x - 30x. The microscope is mounted on a boom stand. With a bit of practice you learn exactly where your hands are under the scope. There is a real incentive for learning this skill quickly since the tip of the soldering iron is maybe 700 degrees F. Soldering is best done with the microscope set to 7-8x. Sometimes, I inspect the connections at 20-30x, especially if I have identified a problem. Clay is right that the focal length should be long. There are optical systems for this purpose aimed at electronics that are very nice, I use an old Baush & Lomb which is OK. My tech uses an Olympus that is better.
> > A few months back I was was at a client's where they do quite a bit of > work with BGAs, and they had a neat optical camera that could see > three rows of balls on a soldered BGA. The head of the camera was > about a 1/4 inch wide and would be manouvered about by having the > board on a translation table. Their production engineer showed me a > bunch of stuff about their manufacturing capability, and I was duly > impressed. I had done a BGA design for them, and they were building > it. BGAs are not for the home assembling environment! I've heard many > claims that BGA soldering has better reliability than TQFP soldering. > Of course this assumes one possesses a full production type of setup. > > Clay > > >
The house I use for BGAs have many years experience as a rework center for Silicon Graphics. They have individual screen stencils for most BGAs which is great for prototyping. You can equip a bench for 1-2K dollars (or euros) to solder most SMT parts. BGAs are SUBSTANTIALLY more expensive. I can't see ever having our own equipment for this purpose. -- Al Clark Danville Signal Processing, Inc. -------------------------------------------------------------------- Purveyors of Fine DSP Hardware and other Cool Stuff Available at http://www.danvillesignal.com
Posted by Clay S. Turner July 2, 2003
"Steve Underwood" <steveu@dis.org> wrote in message
news:bdvu5a$nqq$1@hfc.pacific.net.hk...
> I can't image being able to solder with a microscope. I can't remember > seeing someone try. Doesn't the lens get in the way? Even low power > microscopes come quite close to the object. Doesn't it fog with flux, too? >
Hello Steve, I have had the priviledge of soldering under a microscope. And I know quite a few others who do it that routinely with TQFPs. The trick is to use a scope with a very long focal length objective. This will give you several inches of working space. This trick has been exploited for years in macrophotography so as to have more working room. The 6x objective gives somthing like 4 or 5 inches of working room. The scope I used is set up so you look horizontally into the unit and your work is underneath the unit. This takes a little getting use to. A few months back I was was at a client's where they do quite a bit of work with BGAs, and they had a neat optical camera that could see three rows of balls on a soldered BGA. The head of the camera was about a 1/4 inch wide and would be manouvered about by having the board on a translation table. Their production engineer showed me a bunch of stuff about their manufacturing capability, and I was duly impressed. I had done a BGA design for them, and they were building it. BGAs are not for the home assembling environment! I've heard many claims that BGA soldering has better reliability than TQFP soldering. Of course this assumes one possesses a full production type of setup. Clay