That is interesting. I suspected that they of course had to have a pretty radicle motherboard design to fit all that good stuff into one small little unit. I wonder what the manufacturing costs of a round mobo would be? Becuase I would think that it would require a change to the fab process, obviously.
There really would be no difference in cost of a round or square mother board (I used to work at a board fab house). No change required in the fab process whatsoever. The costs would come from the design side, trying to fit everthing on that little board.
No doubt they make use of a double sided board because they are standard, but it may be possible they went to a multi-layer board to fit all the circuitry on the board. Hard to say.
Boards are fabbed on a sheet of Fiberglass like material with a copper coating on one or both sides depending on needs (single or double sided), I won't go into depth on multi-layer unless someone really wants me to, but it is essentially sandwiching multiple layers together in one sheet.
This initial board is sent to auto drill machines that drill out the necessary holes and tooling holes. They try and pick the best sheet size to get the most boards out of one sheet (like IC's on a platter).
Then they are sent to a machine that roughens up the copper surface.
Next (in the process we used) the boards went through and electroless copper process. Using various chemicals to treat the board through a long line of chem baths you finally but the board in a cuperous (is that right?) bath that deposits copper on the panels and on the inner surfaces of the drilled holes. The boards are then washed and dried.
They then have a film applied to them and are put in a machine with a "template" of the circuitry placed over them and they are exposed. The exposure is actually in the places you DON'T want the circuits, this makes the film harder. The boards are then run through a machine that dissolves the unexposed film off the board revealing the copper surface that you want to have the traces/circuits and holes that need to be plated.
The boards are then micro etched to give them a better surface to electro-plate onto. The boards are put in a bath of copper sulfate and there are bars of copper hanging in the tank on bars conducting current. The boards hang on another bar inbetween the copper bars and also has current passing through it. The correct settings are determined for voltage (which is very low) and amperage (which is very high) to get the correct amount of copper to "flow" from the bars to the boards thru the solution without "burning" or over/under plating.
There are lots of things that can be done next but here's what is probably done on these boards. They have a layer of solder (tin & lead if I remember) added on top of the copper in the same manner as above (electro-plating).
They then run thru a machine that uses some heavy duty amonia and other chemicals to eat of the exposed hard film and the thin unprotected original copper layer underneath the film. Leaving you with your circuits in tact made of copper and the small solder layer on top.
Then you run them thru a stripper that removes the solder layer and leaves only the copper traces. The boards are washed (all throughout the above procedures too). Washing usually consists of going thru multiple water baths.
The boards are then covered with the familar green (or other color) covering you see on them (why can't i remember what it's called) and then silkscreened.
Next my guess is they use the hot air leveling process for adding solder back on to the copper traces that are still exposed (not covered by green stuff and in the holes so later you can solder your components and wires to the board). A layer of flux is added to the boards as they are heated and then put in a machine that quickly dips them into a molten solder pot, pulls them out and hits it with many blowers to blow off all the excess and keep the holes from clogging. This is a thin layer of solder.
If gold tabs are needed the board will go through a line that applies it to the desired areas much in the same way the electro-plating line adds copper (well not really, but too much detail to go into).
Next your boards go back to the drills that use router bits to route out the individial boards which are then most likely electrically tested to see if there are shorts, etc... and I think that's about it. Been about 9 years since I worked there but now I am on the Mfg side (putting the components on the boards).
Hope this little tutorial helps (and was accurate)
<strong>What would they ROUTER?</strong><hr></blockquote>
I guess I wonder what you're asking? I thought I was pretty clear
[quote] Next your boards go back to the drills that use router bits to route out the individial boards which are then most likely electrically tested to see if there are shorts, etc... and I think that's about it. Been about 9 years since I worked there but now I am on the Mfg side (putting the components on the boards). <hr></blockquote>
In other words the panels which contain the boards go back to have each individual board contained in the panel cut out using ROUTER bits on the drill.
Definition: Router
NOUN: One that routs, especially a machine tool that mills out the surface of metal or wood.
There really would be no difference in cost of a round or square mother board (I used to work at a board fab house). No change required in the fab process whatsoever. The costs would come from the design side, trying to fit everthing on that little board.
<hr></blockquote>
There is, in fact, additional cost per board due to the amount of board (in between all the round boards) wasted. That is, you can fit more (electrically identical) square boards on a sheet than you can round boards. Just draw some adjacent circles on a piece of paper and look at all the "stars" of wasted space.
[quote]
No doubt they make use of a double sided board because they are standard, but it may be possible they went to a multi-layer board to fit all the circuitry on the board. Hard to say.
<hr></blockquote>
I guarantee that the board is at least a 6 or 8 layer board. They probably have the components packed together quite tightly (on both external sides). There would be no way to route all those signals on only the top and bottom of the board.
[quote]
The boards are then covered with the familar green (or other color) covering you see on them (why can't i remember what it's called) and then silkscreened.
<hr></blockquote>
Soldermask. Green is most common. Handspring likes black, I've seen red, clear (white) and blue.
[quote]
Next my guess is they use the hot air leveling process for adding solder back on to the copper traces that are still exposed (not covered by green stuff and in the holes so later you can solder your components and wires to the board). A layer of flux is added to the boards as they are heated and then put in a machine that quickly dips them into a molten solder pot, pulls them out and hits it with many blowers to blow off all the excess and keep the holes from clogging. This is a thin layer of solder.
<hr></blockquote>
Actually, I believe a solder paste squeege is used these days. Kind of like screenprinting a t-shirt, a mask is used and tiny balls of solder and flux (paste) is spread across the board, only coming in contact with the board where there are holes in the mask.
[quote]
Next your boards go back to the drills that use router bits to route out the individial boards which are then most likely electrically tested to see if there are shorts, etc... and I think that's about it. Been about 9 years since I worked there but now I am on the Mfg side (putting the components on the boards).
<hr></blockquote>
The "router" basically cuts individual Printed Circuit Boards out from a panel of say 4 or 6 boards.
KidRed.... I simply thought that it MAY also have uses in future products as well.. As I suggested....
It could provide an example for future case designs... for the G4/G5 for instance..... The way Apple designed the iMac G4 suggests that they are far more open to form rather than function........ and have the technolgy to achieve it in say a spherical form factor.
Soldermask, Soldermask, Soldermask..... How the heck could I forget the name. Yes we made other colors too, but over 90% were green.
[quote] Actually, I believe a solder paste squeege is used these days. Kind of like screenprinting a t-shirt, a mask is used and tiny balls of solder and flux (paste) is spread across the board, only coming in contact with the board where there are holes in the mask. <hr></blockquote>
You must be thinking about surface mount part placement here. Where the solder and flux are laid thru a screen to the locations necessary for part placement, the boards are then placed in the surface mount machine. Parts are then automatically grabbed and placed and the boards are then baked to heat the solder and flux to "fuse" the parts into place.
The problem is that unless there is already a solder base for these parts to go on (the pad) the bond will be poor and parts can fall of or the solder can crack.
That is why almost all bare boards that ship from a board fab house to an assembler have solder on the pads and in the holes and not just the bare copper.
The board house I used to work at did this one of two ways. One was to use the solder that was put on the copper to protect while the film was being etched off:
[quote] There are lots of things that can be done next but here's what is probably done on these boards. They have a layer of solder (tin & lead if I remember) added on top of the copper in the same manner as above (electro-plating).
They then run thru a machine that uses some heavy duty amonia and other chemicals to eat of the exposed hard film and the thin unprotected original copper layer underneath the film. Leaving you with your circuits in tact made of copper and the small solder layer on top.
<hr></blockquote>
After the film was removed and the board cleaned the board was ran thru a machine that heated the boards and melted the deposited solder down and then quickly cooled which leaves a nice shiny solder over the copper circuits. This process has more impurities in it though.
So the other way was to remove that small (i think .04mils) layer of solder, then soldermask the boards. All of the pads and holes that are not covered by soldermask (and some are taped of that are exposed as required, mostly tooling holes) need to have solder applied to them, we had a machine (HAL) Hot Air Leveler that was used to apply this solder. The board is ran thru a machine that applied hot flux and the board is entered into the HAL, I hit a foot pedal that dropped the board into a molten vat of pure solder and it immediately shots up will passing thru high pressure air nozzles that blow off all excess and clear the holes. This layer is extremely thin but makes the bonding process of solder parts to the board much easier.
Now that being said it is quite possible that they have come up with a new solder/flux paste for surface mount that bonds fine with copper and eliminates the need for a layer of solder at a board house, but what you mention sounds very similar to how we surface mount parts to the board.
Also there is a purpose to covering the copper on these boards as it tarnishes extremely easy which makes it impure and copper pits a lot easier than solder, generally I've only seen the "fingers" or end connecters (as in where a PCI card plugs in) as being the only part that isn't coated with solder and that is because the copper gives you a better electrical connection. Most of those are either solder or gold plated too though.
Comments
No doubt they make use of a double sided board because they are standard, but it may be possible they went to a multi-layer board to fit all the circuitry on the board. Hard to say.
Boards are fabbed on a sheet of Fiberglass like material with a copper coating on one or both sides depending on needs (single or double sided), I won't go into depth on multi-layer unless someone really wants me to, but it is essentially sandwiching multiple layers together in one sheet.
This initial board is sent to auto drill machines that drill out the necessary holes and tooling holes. They try and pick the best sheet size to get the most boards out of one sheet (like IC's on a platter).
Then they are sent to a machine that roughens up the copper surface.
Next (in the process we used) the boards went through and electroless copper process. Using various chemicals to treat the board through a long line of chem baths you finally but the board in a cuperous (is that right?) bath that deposits copper on the panels and on the inner surfaces of the drilled holes. The boards are then washed and dried.
They then have a film applied to them and are put in a machine with a "template" of the circuitry placed over them and they are exposed. The exposure is actually in the places you DON'T want the circuits, this makes the film harder. The boards are then run through a machine that dissolves the unexposed film off the board revealing the copper surface that you want to have the traces/circuits and holes that need to be plated.
The boards are then micro etched to give them a better surface to electro-plate onto. The boards are put in a bath of copper sulfate and there are bars of copper hanging in the tank on bars conducting current. The boards hang on another bar inbetween the copper bars and also has current passing through it. The correct settings are determined for voltage (which is very low) and amperage (which is very high) to get the correct amount of copper to "flow" from the bars to the boards thru the solution without "burning" or over/under plating.
There are lots of things that can be done next but here's what is probably done on these boards. They have a layer of solder (tin & lead if I remember) added on top of the copper in the same manner as above (electro-plating).
They then run thru a machine that uses some heavy duty amonia and other chemicals to eat of the exposed hard film and the thin unprotected original copper layer underneath the film. Leaving you with your circuits in tact made of copper and the small solder layer on top.
Then you run them thru a stripper that removes the solder layer and leaves only the copper traces. The boards are washed (all throughout the above procedures too). Washing usually consists of going thru multiple water baths.
The boards are then covered with the familar green (or other color) covering you see on them (why can't i remember what it's called) and then silkscreened.
Next my guess is they use the hot air leveling process for adding solder back on to the copper traces that are still exposed (not covered by green stuff and in the holes so later you can solder your components and wires to the board). A layer of flux is added to the boards as they are heated and then put in a machine that quickly dips them into a molten solder pot, pulls them out and hits it with many blowers to blow off all the excess and keep the holes from clogging. This is a thin layer of solder.
If gold tabs are needed the board will go through a line that applies it to the desired areas much in the same way the electro-plating line adds copper (well not really, but too much detail to go into).
Next your boards go back to the drills that use router bits to route out the individial boards which are then most likely electrically tested to see if there are shorts, etc... and I think that's about it. Been about 9 years since I worked there but now I am on the Mfg side (putting the components on the boards).
Hope this little tutorial helps (and was accurate)
EDITED----------------------------------------------------------------------------------------------
I should have used a spell checker
[ 01-10-2002: Message edited by: Slacker ]
[ 01-10-2002: Message edited by: Slacker ]</p>
<strong>What would they ROUTER?</strong><hr></blockquote>
I guess I wonder what you're asking? I thought I was pretty clear
[quote] Next your boards go back to the drills that use router bits to route out the individial boards which are then most likely electrically tested to see if there are shorts, etc... and I think that's about it. Been about 9 years since I worked there but now I am on the Mfg side (putting the components on the boards). <hr></blockquote>
In other words the panels which contain the boards go back to have each individual board contained in the panel cut out using ROUTER bits on the drill.
Definition: Router
NOUN: One that routs, especially a machine tool that mills out the surface of metal or wood.
There really would be no difference in cost of a round or square mother board (I used to work at a board fab house). No change required in the fab process whatsoever. The costs would come from the design side, trying to fit everthing on that little board.
<hr></blockquote>
There is, in fact, additional cost per board due to the amount of board (in between all the round boards) wasted. That is, you can fit more (electrically identical) square boards on a sheet than you can round boards. Just draw some adjacent circles on a piece of paper and look at all the "stars" of wasted space.
[quote]
No doubt they make use of a double sided board because they are standard, but it may be possible they went to a multi-layer board to fit all the circuitry on the board. Hard to say.
<hr></blockquote>
I guarantee that the board is at least a 6 or 8 layer board. They probably have the components packed together quite tightly (on both external sides). There would be no way to route all those signals on only the top and bottom of the board.
[quote]
The boards are then covered with the familar green (or other color) covering you see on them (why can't i remember what it's called) and then silkscreened.
<hr></blockquote>
Soldermask. Green is most common. Handspring likes black, I've seen red, clear (white) and blue.
[quote]
Next my guess is they use the hot air leveling process for adding solder back on to the copper traces that are still exposed (not covered by green stuff and in the holes so later you can solder your components and wires to the board). A layer of flux is added to the boards as they are heated and then put in a machine that quickly dips them into a molten solder pot, pulls them out and hits it with many blowers to blow off all the excess and keep the holes from clogging. This is a thin layer of solder.
<hr></blockquote>
Actually, I believe a solder paste squeege is used these days. Kind of like screenprinting a t-shirt, a mask is used and tiny balls of solder and flux (paste) is spread across the board, only coming in contact with the board where there are holes in the mask.
[quote]
Next your boards go back to the drills that use router bits to route out the individial boards which are then most likely electrically tested to see if there are shorts, etc... and I think that's about it. Been about 9 years since I worked there but now I am on the Mfg side (putting the components on the boards).
<hr></blockquote>
The "router" basically cuts individual Printed Circuit Boards out from a panel of say 4 or 6 boards.
It could provide an example for future case designs... for the G4/G5 for instance..... The way Apple designed the iMac G4 suggests that they are far more open to form rather than function........ and have the technolgy to achieve it in say a spherical form factor.
Soldermask, Soldermask, Soldermask..... How the heck could I forget the name. Yes we made other colors too, but over 90% were green.
[quote] Actually, I believe a solder paste squeege is used these days. Kind of like screenprinting a t-shirt, a mask is used and tiny balls of solder and flux (paste) is spread across the board, only coming in contact with the board where there are holes in the mask. <hr></blockquote>
You must be thinking about surface mount part placement here. Where the solder and flux are laid thru a screen to the locations necessary for part placement, the boards are then placed in the surface mount machine. Parts are then automatically grabbed and placed and the boards are then baked to heat the solder and flux to "fuse" the parts into place.
The problem is that unless there is already a solder base for these parts to go on (the pad) the bond will be poor and parts can fall of or the solder can crack.
That is why almost all bare boards that ship from a board fab house to an assembler have solder on the pads and in the holes and not just the bare copper.
The board house I used to work at did this one of two ways. One was to use the solder that was put on the copper to protect while the film was being etched off:
[quote] There are lots of things that can be done next but here's what is probably done on these boards. They have a layer of solder (tin & lead if I remember) added on top of the copper in the same manner as above (electro-plating).
They then run thru a machine that uses some heavy duty amonia and other chemicals to eat of the exposed hard film and the thin unprotected original copper layer underneath the film. Leaving you with your circuits in tact made of copper and the small solder layer on top.
<hr></blockquote>
After the film was removed and the board cleaned the board was ran thru a machine that heated the boards and melted the deposited solder down and then quickly cooled which leaves a nice shiny solder over the copper circuits. This process has more impurities in it though.
So the other way was to remove that small (i think .04mils) layer of solder, then soldermask the boards. All of the pads and holes that are not covered by soldermask (and some are taped of that are exposed as required, mostly tooling holes) need to have solder applied to them, we had a machine (HAL) Hot Air Leveler that was used to apply this solder. The board is ran thru a machine that applied hot flux and the board is entered into the HAL, I hit a foot pedal that dropped the board into a molten vat of pure solder and it immediately shots up will passing thru high pressure air nozzles that blow off all excess and clear the holes. This layer is extremely thin but makes the bonding process of solder parts to the board much easier.
Now that being said it is quite possible that they have come up with a new solder/flux paste for surface mount that bonds fine with copper and eliminates the need for a layer of solder at a board house, but what you mention sounds very similar to how we surface mount parts to the board.
Also there is a purpose to covering the copper on these boards as it tarnishes extremely easy which makes it impure and copper pits a lot easier than solder, generally I've only seen the "fingers" or end connecters (as in where a PCI card plugs in) as being the only part that isn't coated with solder and that is because the copper gives you a better electrical connection. Most of those are either solder or gold plated too though.