How do you design these days?
in [Design]
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From: krw on 1 Jan 2010 20:35 On Fri, 01 Jan 2010 23:35:41 +0000, Raveninghorde <raveninghorde(a)invalid> wrote: >On Fri, 01 Jan 2010 13:40:38 -0600, krw <krw(a)att.bizzzzzzzzzzz> wrote: > >>On Thu, 31 Dec 2009 19:16:58 +0000, Raveninghorde >><raveninghorde(a)invalid> wrote: > >SNIP > >>> >>>The current oven is made by TWS Automation in Italy and is pre RoHS. 2 >>>guys can move it. >>> >>>http://www.zen88234.zen.co.uk/photos/tws.jpg >> >>Oh, a small thing! How many zones? Our current oven is five zones. >>We're told we should have at least seven and preferably nine for RoHS, >>where the temperature profile comes dangerously close to the maximum >>the components can handle. The idea is to soak the board in five or >>six zones, then spike the temperature in one or two. Balancing the >>soak and spike gets iffy with only five zones. >> > >From memory 4 zones. It was fine with real solder. We still had problems with real solder, but I think those would have been solved by now. Except, perhaps, the interboard connectors. The real problem there turns out to be mostly a pick-n-place issue and an inventory issue (they have 6000 or some stupid number of the wrong parts). It was still much better with real solder. >>>It was OK after moving to RoHS but I am packing bits tighter and using >>>larger SMT parts such as 12mm square inductors which suck up the heat. >> >>Whihc indicates to me (certainly not my area of expertise) that the >>soak isn't getting it done. >> >>>I had a guy going through test failures today. I saw a big pile with >>>the same fault. I was told the oven was killing SOT-223 transistors. >>>First I had heard of it. Some one will die on Monday. >> >>;-) >> >>>When I found the LED problem all LEDs where replaced on existing >>>boards, about 600. They are now put on by hand which is a PITA but I >>>know they are reliable. >> >>That is one problem we haven't had. Sounds like your temperature >>profile is way too high. We did kill aluminum capacitors at one time, >>but fixed that by getting rid of them. > >I think the problem is inadequate pre heat. So the guys are pushing >the temperature too high at the soldering stage. Unfortunately even >that isn't enough to compensate for the poor pre heat. Four heat stages may not be enough. They're telling us that five is really iffy for our boards. One is pretty large, though. >I just had to put my money on the table and replace it. > >The next step is to upgrade the pick and place. Even with second user >kit that will be real money. The pick and places are again TWS >Automation but we need better. 0603 is a struggle so I don't go below >0805 but more importantly more and more ICs are too fine pitch and now >with Altera BGAs on the horizon... We can do 0603s, BGAs down to .8mm, and QFPs down to .5mm, without issues. They're going to barf when I demand 0402s, though. The BGA pitch really cramps my style too. Actel has a very limited package selection with a pitch that large (they like .5mm and .4mm) so I'm more or less being forced into Altera. Not that I mind Altera, but I don't like to be in a position without an alternative. It's good to have them fight over your business. ;-) >>>Now I know I have boards out there with suspect transistors:( >> >>Not a good feeling. >> >>>I had to get LEDs put onto aluminium backed boards elsewhere as there >>>was no chance of this machine coping. >>> >>>The new beast, 1.3 tonnes, is a second hand Ersa Hotflow-5 made in >>>Germany and cost about twice as much for the new TWS one, �12k. >>> >>>http://www.zen88234.zen.co.uk/photos/hotflow.jpg >> >>That's more the size I'd expect. I don't recall what we're using. >>Again, I'm not an IE. >> >>>Spec here: >>> >>>http://www.zen88234.zen.co.uk/hf5.pdf >>> >>>We had to upgrade ventillation and electrics for another �2k. >> >>AIUI, our line came with the building. ;-) We are seriously >>considering a new oven because of our problems. I'm told that there >>is all sorts of surplus equipment available out there. > >It's either keep the kit reasonably up to date or pull out of the game >as far as I am concerned. We really don't need the bleeding edge but it's getting hard to buy anything else. We don't keep the line busy (test and rework is the bottleneck) but the owner doesn't trust contract manufacturers. But you're right, you have to ride the wave, though perhaps not at the leading edge.
From: Joerg on 1 Jan 2010 21:30 krw wrote: > On Fri, 01 Jan 2010 23:35:41 +0000, Raveninghorde > <raveninghorde(a)invalid> wrote: > [...] >> I just had to put my money on the table and replace it. >> >> The next step is to upgrade the pick and place. Even with second user >> kit that will be real money. The pick and places are again TWS >> Automation but we need better. 0603 is a struggle so I don't go below >> 0805 but more importantly more and more ICs are too fine pitch and now >> with Altera BGAs on the horizon... > > We can do 0603s, BGAs down to .8mm, and QFPs down to .5mm, without > issues. They're going to barf when I demand 0402s, though. The BGA > pitch really cramps my style too. Actel has a very limited package > selection with a pitch that large (they like .5mm and .4mm) so I'm > more or less being forced into Altera. Not that I mind Altera, but I > don't like to be in a position without an alternative. It's good to > have them fight over your business. ;-) > 0402 is a problem? Then it's high time to either upgrade the equipment or contract out. >>>> Now I know I have boards out there with suspect transistors:( >>> Not a good feeling. >>> >>>> I had to get LEDs put onto aluminium backed boards elsewhere as there >>>> was no chance of this machine coping. >>>> >>>> The new beast, 1.3 tonnes, is a second hand Ersa Hotflow-5 made in >>>> Germany and cost about twice as much for the new TWS one, �12k. >>>> >>>> http://www.zen88234.zen.co.uk/photos/hotflow.jpg >>> That's more the size I'd expect. I don't recall what we're using. >>> Again, I'm not an IE. >>> >>>> Spec here: >>>> >>>> http://www.zen88234.zen.co.uk/hf5.pdf >>>> >>>> We had to upgrade ventillation and electrics for another �2k. >>> AIUI, our line came with the building. ;-) We are seriously >>> considering a new oven because of our problems. I'm told that there >>> is all sorts of surplus equipment available out there. >> It's either keep the kit reasonably up to date or pull out of the game >> as far as I am concerned. > > We really don't need the bleeding edge but it's getting hard to buy > anything else. We don't keep the line busy (test and rework is the > bottleneck) but the owner doesn't trust contract manufacturers. But > you're right, you have to ride the wave, though perhaps not at the > leading edge. Why doesn't he trust them? I really never saw any hardcore problems, most of my clients contract out. In many cases full turn-key. The only situation that I could imagine where in-house assembly makes sense is if you do super confidential stuff. Even high volume doesn't necessarily justify it because then you can get some really sweet deals in Asia. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Michael A. Terrell on 1 Jan 2010 22:19 krw wrote: > > On Fri, 01 Jan 2010 18:12:35 -0500, "Michael A. Terrell" > <mike.terrell(a)earthlink.net> wrote: > > > > >Jim Thompson wrote: > >> > >> On Fri, 01 Jan 2010 16:17:30 -0500, Phil Hobbs > >> <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >> > >> >On 1/1/2010 3:56 PM, Joerg wrote: > >> >> krw wrote: > >> > > >> >>> Why are pin numbers an issue? You never probe from the backside of a > >> >>> board? The spatial transform is pretty ingrained in me and I spent a > >> >>> decade doing processor design (no PCB stuff). > >> >> > >> >> > >> >> Until one fine day you have one of those Supertex high voltage chips. > >> >> Some weirdness happens on the prototype boards, must be a software > >> >> issue. It's always software. Has to be. Hmm, let's see how that looks on > >> >> the old breadboard. Grab probe, lemmee see, serial data out was, uhm, > >> >> umpteenth pin from upper left ... POP ... *PHOOMP* > >> >> > >> > > >> >How dull your life would be without fireworks, though. ;) > >> > > >> >Cheers > >> > > >> >Phil Hobbs > >> > >> Indeed! I haven't had a "fireworks" event since ~1980. > > > > > > I wonder if Joerg demands at least one fire extinguisher in all his > >design contracts? :) > > Yeah, but he returns it, fully tested. Aka: EMPTY? -- Greed is the root of all eBay.
From: krw on 2 Jan 2010 01:05 On Fri, 01 Jan 2010 22:19:16 -0500, "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote: > >krw wrote: >> >> On Fri, 01 Jan 2010 18:12:35 -0500, "Michael A. Terrell" >> <mike.terrell(a)earthlink.net> wrote: >> >> > >> >Jim Thompson wrote: >> >> >> >> On Fri, 01 Jan 2010 16:17:30 -0500, Phil Hobbs >> >> <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >> >> >> >> >On 1/1/2010 3:56 PM, Joerg wrote: >> >> >> krw wrote: >> >> > >> >> >>> Why are pin numbers an issue? You never probe from the backside of a >> >> >>> board? The spatial transform is pretty ingrained in me and I spent a >> >> >>> decade doing processor design (no PCB stuff). >> >> >> >> >> >> >> >> >> Until one fine day you have one of those Supertex high voltage chips. >> >> >> Some weirdness happens on the prototype boards, must be a software >> >> >> issue. It's always software. Has to be. Hmm, let's see how that looks on >> >> >> the old breadboard. Grab probe, lemmee see, serial data out was, uhm, >> >> >> umpteenth pin from upper left ... POP ... *PHOOMP* >> >> >> >> >> > >> >> >How dull your life would be without fireworks, though. ;) >> >> > >> >> >Cheers >> >> > >> >> >Phil Hobbs >> >> >> >> Indeed! I haven't had a "fireworks" event since ~1980. >> > >> > >> > I wonder if Joerg demands at least one fire extinguisher in all his >> >design contracts? :) >> >> Yeah, but he returns it, fully tested. > > > Aka: EMPTY? "Ayup, it worked as designed!"
From: krw on 2 Jan 2010 01:26
On Fri, 01 Jan 2010 18:30:50 -0800, Joerg <invalid(a)invalid.invalid> wrote: >krw wrote: >> On Fri, 01 Jan 2010 23:35:41 +0000, Raveninghorde >> <raveninghorde(a)invalid> wrote: >> >[...] > >>> I just had to put my money on the table and replace it. >>> >>> The next step is to upgrade the pick and place. Even with second user >>> kit that will be real money. The pick and places are again TWS >>> Automation but we need better. 0603 is a struggle so I don't go below >>> 0805 but more importantly more and more ICs are too fine pitch and now >>> with Altera BGAs on the horizon... >> >> We can do 0603s, BGAs down to .8mm, and QFPs down to .5mm, without >> issues. They're going to barf when I demand 0402s, though. The BGA >> pitch really cramps my style too. Actel has a very limited package >> selection with a pitch that large (they like .5mm and .4mm) so I'm >> more or less being forced into Altera. Not that I mind Altera, but I >> don't like to be in a position without an alternative. It's good to >> have them fight over your business. ;-) >> > >0402 is a problem? Then it's high time to either upgrade the equipment >or contract out. We'd need new feeders for the P-n-P machine. Not a huge deal but they're having too many problems now. When we start using any real FPGAs 0402s will come with them. I've already been warning them. ;-) >>>>> Now I know I have boards out there with suspect transistors:( >>>> Not a good feeling. >>>> >>>>> I had to get LEDs put onto aluminium backed boards elsewhere as there >>>>> was no chance of this machine coping. >>>>> >>>>> The new beast, 1.3 tonnes, is a second hand Ersa Hotflow-5 made in >>>>> Germany and cost about twice as much for the new TWS one, �12k. >>>>> >>>>> http://www.zen88234.zen.co.uk/photos/hotflow.jpg >>>> That's more the size I'd expect. I don't recall what we're using. >>>> Again, I'm not an IE. >>>> >>>>> Spec here: >>>>> >>>>> http://www.zen88234.zen.co.uk/hf5.pdf >>>>> >>>>> We had to upgrade ventillation and electrics for another �2k. >>>> AIUI, our line came with the building. ;-) We are seriously >>>> considering a new oven because of our problems. I'm told that there >>>> is all sorts of surplus equipment available out there. >>> It's either keep the kit reasonably up to date or pull out of the game >>> as far as I am concerned. >> >> We really don't need the bleeding edge but it's getting hard to buy >> anything else. We don't keep the line busy (test and rework is the >> bottleneck) but the owner doesn't trust contract manufacturers. But >> you're right, you have to ride the wave, though perhaps not at the >> leading edge. > > >Why doesn't he trust them? We're a small company and up until recently, very seasonal (almost all income was in a three-month window). I'm told the worry was a that large, more "important", customer might bump our production at a CM. A month late and we wouldn't be set back a month but a year. The company couldn't survive that so we build our own; insurance. >I really never saw any hardcore problems, >most of my clients contract out. In many cases full turn-key. The only >situation that I could imagine where in-house assembly makes sense is if >you do super confidential stuff. Even high volume doesn't necessarily >justify it because then you can get some really sweet deals in Asia. The problem is that it's *low* volume and very seasonal. If we did a couple hundred systems a year it was a lot. We've recently added higher volume products (still only 2-5K per year) in a year-round market. This helps the production situation but the original market/products still have the same issues. |