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  1. #21
    Join Date
    Apr 2003
    Posts
    23
    Quote Originally Posted by ciccio
    Z axis again: what kind of adhesive do you think to use?
    Has the machine to PUSH the SMD over the adhesive, or just to let it drop over? This will tell me if I ( we) need a small sping or not on the Z axis.
    .....an adhesive dispenser on the same axis....no !!!!!!
    This is really R & D.
    I'm lucky to be the second builder, I can have a lot of infos from you !
    Again
    Paolo
    Hi,

    You just apply the solder paste before putting the parts on the board. The solder paste surface tension is enough to hold the components in place. No need for glue for small parts.

    You can just cut the vaccum and the solder paste surface tension will hold the part in the right place.

    My machine did not work.. I may be a bad example to follow :-) All the things I am telling you comes from experience of mounting thousands of SMD boards using simple hand tools...

    Best regards,
    Alexandre Guimaraes

  2. #22
    Join Date
    Nov 2004
    Posts
    69

    Your machine....

    You say: my machine did not work.
    This is really NOT a problem. Your first prototype is a mine of ideas and
    suggestions for a working machine: we will built it.
    ....and now some more stupid ideas of mine: why not put a pressure sensor on the vacuum tube? and a sort of potentiometer on the small compression spring on the " go down" Z axis? Just imagine:
    PICK: Z axis goes down
    Vacuum pump is ON
    pressure in the tube is low ( but not VERY LOW)
    when the needle reaches the SMD ( level does not matter , no level to program ) pressure goes VERY LOW, Z axis stops and goes
    up
    TRAVEL from PICK to PLACE position: if we loose SMD pressure goes LOW ( but no VERY LOW ), so we can have some alarm
    PLACE :Z axis goes down
    when SMD is on the PCB the small spring starts to compress, we know it from the potentiometer connected to the spring
    motor stops, vacuum pump is OFF, motor goes up, no problems with level, no level to program.
    Just an idea of mine, you know, I'm a little mad.....
    .................................................. .................................................. ....I have found the higher SMD component on the RS catalogue ( ...the Bible...)
    it seems to be :aluminium low ESR series VFC 105° Panasonic capacitor:
    the bigger ( for example 10V 470yF 0r 35V 47yF) is 10.2 mm high:
    this means we need a max Z axis travel a little more than 10.2 X 2, I will
    go for 25mm: what do you think ?
    I think Z axis with all the accessories is 90% of the machine.
    the problem is the rest is another 90%......
    Regards
    Paolo

  3. #23
    Alexandre,

    I know what you mean, hand-mounting SMT parts. I have to hand-mount 0805s, SOICs, SOT-23s, etc. on prototype boards. Once they work, we order-up a stencil, paste the panels and put them in the Zevatech FS-730s which places parts to the tune of 3 per second.

    Until that happy point it's a pair of needle-sharp tweezers, a Nikon stereo zoom low-power microscope, a Hakko 851 hot-air rework station and a very, very steady hand. Thank God for solder surface tension; it corrects a lot of near-misses.

    Mariss

  4. #24
    Join Date
    Nov 2004
    Posts
    69

    A picture, please....

    Dear Mariss, can you make us a present? Some detailed pictures of the head
    of your pick and place ? We will really apppreciate it. And any suggestion from a user is very important in this stage of developement:
    We count on you, Mariss
    Thanks
    Paolo

  5. #25
    Join Date
    Nov 2004
    Posts
    69

    3 parts per second

    ...adding a turbo and some nitrous, maybe, we can.......

  6. #26
    Join Date
    Apr 2003
    Posts
    23
    Quote Originally Posted by ciccio
    You say: my machine did not work.
    This is really NOT a problem. Your first prototype is a mine of ideas and
    suggestions for a working machine: we will built it.
    ....and now some more stupid ideas of mine: why not put a pressure sensor on the vacuum tube? and a sort of potentiometer on the small compression spring on the " go down" Z axis? Just imagine:
    Paolo
    Hi, Paolo

    The pressure sensor is how it is done in comercial machines.. I think it is a great idea but.....

    Nowadays I really became a believer in " Evolutive " development

    Lets get the thing to work and then we can add many gadgets to make it better and faster. If we sophisticate too much at this stage we will not acomplish anything real because we can talk about it during months... And besides it gets to a point when the homebrew gets so close in price to the comercial machines that it is not worth it anymore. We have to keep focus on a machine that is a replacement for hand placement but not a replacent for the great pick and place machines in the market. If the volume goes up it is better to buy a ready machine.

    I will grab a picture of my junk machine... And we can get ideas from my many mistakes...

    Best regards,
    Alexandre Guimaraes

  7. #27
    Join Date
    Apr 2003
    Posts
    23
    Quote Originally Posted by Mariss Freimani
    Alexandre,

    I know what you mean, hand-mounting SMT parts. I have to hand-mount 0805s, SOICs, SOT-23s, etc. on prototype boards. Once they work, we order-up a stencil, paste the panels and put them in the Zevatech FS-730s which places parts to the tune of 3 per second.

    Until that happy point it's a pair of needle-sharp tweezers, a Nikon stereo zoom low-power microscope, a Hakko 851 hot-air rework station and a very, very steady hand. Thank God for solder surface tension; it corrects a lot of near-misses.

    Mariss
    Hi, Marris

    Nice to see you in this thread.. Lots of real World experience with the pick and places machines combined with the best drivers for the price that I have ever heard off :cheers:

    Placing by hand is a PITA most of the times and the mistakes are inevitable. You can imagine my situation. My small company produces about 10 to 15 boards everyday with hand placement. I do not have enough money available to buy a real machine... So the easiest path available is make a machine.. My idea is to make it really easy to program and use for small runs.. Maybe even for your prototypes What program do you use to design the boards ? Can you extract a small portion of the BOM with the placement information ? So I can check if it is similar to the one I have ?

    Other function of the machine will necessarily place solder paste with a pneumatic dispenser. This way we can eliminate the need for the stencil for short runs. The pneumatic control is already working and I plan to integrate everuthing together once I have a machine that really works... And not the crap I made...

    Best regards,
    Alexandre Guimaraes

  8. #28
    Uh, maybe that's not a good idea...

    The machine is a 5' by 5' by 5' cube and weighs 3,000 lbs. It is a 3-head, gantry type machine. The heaviest part (X axis) probably weighs 100 - 150 lbs, moves at around 4 feet per second and accelerates at around 4 - 5G.

    The machine is bolted to the floor. Were it not, it would chase me all over the shop like an insane, badly loaded washing machine. You don't know fear until you have had a 3,000 lb machine come looking for you. Ask me how I know.:-)

    Mariss

  9. #29
    Join Date
    Nov 2004
    Posts
    69

    Z axis : starting point

    Here is my material for Z axis test
    We will try to build a longer axis for the " rotation " stepper, to put
    needle on the lower side and an attachement for tube in the upper.
    Paolo

  10. #30
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    Nov 2004
    Posts
    69

    Hi,....

    Hi, is there someone on this web site?

  11. #31
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    Aug 2004
    Posts
    2849
    Yes, why???

  12. #32
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    Nov 2004
    Posts
    69

    Help needed

    Quote Originally Posted by ViperTX
    Yes, why???
    Can someone help me with the following info?
    squaring station : I need info and pictures
    suction needle: internal diameter of the most used
    suction needle: what is the value of vacuum ?
    Thank you
    Paolo

  13. #33
    Join Date
    Aug 2004
    Posts
    2849
    Quote Originally Posted by ciccio
    Can someone help me with the following info?
    squaring station : I need info and pictures
    suction needle: internal diameter of the most used
    suction needle: what is the value of vacuum ?
    Thank you
    Paolo
    Vacuum is generally measure in inches of mercury. I'm not sure about the size of the pickup needles most are very tiny...in the range of an inside diameter of 0.015 to 0.03, the ends have cups that are very pliable....I suspect they are a silicone.

  14. #34
    Join Date
    Jul 2003
    Posts
    148
    I do not know if this helps or not, but I've worked with pick and place and chip shooters for over 7 years. One of the big things to consider is that on all the machines I've ever worked with the the machine will turn on the vaccum for picking up and carrying of the componet. But as the machine places the componet vaccume is reversed and the componet is helped off the nozzle with a gentle burst of air. Very important with smaller 0402's 0603, 0201's.

    Nozzle size is dictated by what your going to try and pick up. The larger the part the larger the nozzle. Nozzles material varies much between differnt manufactures as does the pattern a nozzle can have. Panasonic for some of the smaller nozzles used a diamon epozy tip that supposedly lasted longer. The opening was an "X" shape. But that was for the smaller chips. After that they went over to straight tubes. For the really large parts you could get into custome nozzles down to robotic gripper like arms for some connectors.

    Fuji, the nozzles were aluminum, but they would mushroom over time. So the switched over to stainless steel. I still have a windmill off a chip shooter. Missing a nozzle or two for it but I'll try and post a picture of it Friday. I have finals tommorrow and should be studying.

    Their use to be a company called manncorp
    Did a goggel for them. They are still in buisness. http://www.manncorp.com/

    They use to put out a brochure that had alot of closeup of their equipment and you could see how it all worked. They had a very primative machine that used a tray at a angle to center the componets. It was to primative for the company I worked for then's needs but their constant bombardment of myself with sales liturature made me atleast remember their name.

    Take a look at their site and fill out the web form so you can get the brochures for the machines. I don't think they offer the really primative SMT placer any mre since I didn not see it on their site, but a call to them might yield an old brochure.

  15. #35
    Important even for 0805's and SOT-23's.

    We were having placement problems with one of the three heads on one of our Zevatech FS-730s. Turns out the service technician found a problem with a solenoid valve that wasn't giving that little "puff" of positive pressure immediately after part placement.

    Valve was replaced, problem went away.

    Mariss

  16. #36
    Join Date
    Jul 2003
    Posts
    148
    I've seen that and the wrong nozzle being used for smaller chips. Sucks them up into the head and on some older machines you had to take the head off to get the compont out.

    are teh pictures of he CP6-4 Windmil. Think they were over $1k new.
    Attached Thumbnails Attached Thumbnails MVC-001F.JPG   MVC-002F.JPG   MVC-003F.JPG   MVC-004F.JPG  

    MVC-005F.JPG  

  17. #37
    You'll probably hate me for this but I have to say it.

    Of all the CNC projects to assume, this is the least renumerative. Before I go on, let me say when I was younger, I also designed a pick and place machine in ACAD; I still have the .dwg files to remind me.

    These are enourmously complex machines. CNC-wise they are very simple point-to-point X,Y positioners. That is where the easy stuff ends.

    Modern machines 1, 2, 3 or more heads each use laser measuring heads to detect the Z and theta axis measurements of the part you are about to place. It uses these measurements to adjust the final X,Y trajectory of the part about to be placed as well as its thickness and rotation from the pick-up point.

    Parts come on either 7" or 12" reels; lots of 7" or 12" reels. On my machine it's 40 locations in front, another 40 in the back. Each reel requires a mechanism (solenoid plunger) to index the reel 4 or 8 mm after a part pick-up. That's 80 solenoids right there.

    About the parts that are on a reel. The pocket (stamped paper tape reel) is much bigger than the part (resistor, capacitor, SOT-23). The part in the pocket can have an angular misalignement of +/- 15 degrees and an X,y error of 0.03" in either axis. When placed, the part must align within a degree and can't be off by more than 0.002".

    If you are building a machine, what are you going to do about the reel-feeders? Use Juki, Fuji, Seimens, Panasonic or your own design? Either way you will need a lot of them.

    How about ICs? Tape and reel or linear feeders? I have linear feedes on my machine and each is a work of art CNC-wise. Several servo motors and a computer in just the feeder.

    My first pick and place machine was a Manncorp EMC-97. It was a servo driven tooth-belt transmission piece of crap that gave me the grey hair I have now. It could chug along at at one totally misplaced (>0.025") part every second and a half. The machine was named Ursulla for some wicked queen by my daughter. I paid $35,000 for it to make my aquaintance.

    Not a part she was supposed to place landed even remotely near the solder pads on the board. Service techincians came and went; they pronounced that was the best Ursulla could do.

    It was my sanity or Ursulla. I chose sanity and got rid of her for $1,000 to a machinery reseller. She lasted for the longest 2 years of my life. God protect whomever she wound up with.

    For the same money ($35K) I bought a near zero-time Zevatech FS-730. A dot-com failure company that put up a $250,000 machine for near 10 cents on the dollar. Earlier this year I bought another one, similar source but a little dearer ($50K).

    Now I have two honest 15,000 parts per hour machines. When they are tooling, they put down 3 parts per second. That's for 0805s and SOT-23s. It's slower on SOICs.

    My point is this. Don't even consider making a machine that can't place a part every second and a half. If it can, have the parts land someplace near the pads. If it's even close, solder surface tension will take it the rest of the way.

    Second, don't bother unless you have thought the problem all the way through. That means laser parts measuring and how to deal with a lot of parts feeders. Without that it's a non-starter.

    I told you you would hate me for this.

    Mariss

  18. #38
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    Nov 2004
    Posts
    69

    Help. suggestions, .....

    Thanks to all, to CNCzone, to Vipertx, to Scotsss, to Alexg and Mariss for help and suggestions.
    Mariss, I agree with you: if I had to build a lot of SMD populated PCBs, then I'd buy a GOOD pick n place, or I will have it done by a company: it is the same as for good PCBs.
    But I have to build very small runs, or prototypes, so I can:
    place by hand : very very inexpensive
    buy a " hand placer" : 1500 to 5000 USD
    buy a old, useless pick and place : 500 to 10,000 USD
    buy a " useless" new machine ( say 20.000 USD + accessories)
    buy a new or recent-used machine ( more than 40.000 USD )
    PLUS feeders, nozzles, and a very expensive import, plus 20%VAT, not to say about service....
    I'm a one-man-business, and speed is not a problem for me, consider time to talk with customer, time to design a working circuit, to design a PCB, to find components, to build the PCB, to solder, to seelk-screen the box, to drill it , etc.: so to place a SMD component every some seconds is really not a problem: no need for speed.
    Of course I'm talking about prototype or very small runs, low-tech big-SMD circuits.
    Feeders: no problem, as I have to buy in any case:new machine, used machine, home-built machine.
    Precision: this is the problem! This is where I need a lot of help, suggestions, pictures, and the help of people like you ( using or trying to build) is invaluable !
    Paolo

  19. #39
    Join Date
    Apr 2003
    Posts
    23
    Quote Originally Posted by Mariss Freimani
    You'll probably hate me for this but I have to say it.

    My point is this. Don't even consider making a machine that can't place a part every second and a half. If it can, have the parts land someplace near the pads. If it's even close, solder surface tension will take it the rest of the way.

    Second, don't bother unless you have thought the problem all the way through. That means laser parts measuring and how to deal with a lot of parts feeders. Without that it's a non-starter.

    I told you you would hate me for this.

    Mariss
    No hate... Nice advice is always good to hear...

    I am making about 25 boards mostly every day with 2 people working on them using hand held vacuum pickup needles and with components in small trays already out of the tapes.. And it works !!

    I guess that my needs for a pick and place machine and Ciccio needs are not for a fast machine or one that can handle big varieties of sizes and shapes but just something that can automate a tedious and erro prone process.

    I am planning on no parts fedder at the "first phase" of the machine !! I will just cut the tapes to the right size and put them in a support over the table. I am planning on just using it for 0805 passives and SOT-23. All other sizes will be hand placed. 1 part every 3 seconds is enough for me to equal what I have in hand placement today.. And I guess that Ciccio requirements are similar to mine..

    If we keep it simple I really believe it is quite doable. If we loose track and try to make a complex machine we will just not be able to accomplish it or will end up with a cost that is the same as a commercial machine.

    In this way IMHO, we can keep the parts fedder out and just use the tape cut by hand and put inside a "container rail". This rail can be quite easily done with a mill or even with small pieces of plastic glued together.

    The pick-up head is a simple mechanism with a hypodermic needle that can be rotated and makes contact with the parts. No need for pushing the components out at low speeds. The solder paste surface tension is enough to pull the component from the needle. When placing bu hand we do not even take the vaccum out !!

    If kept simple we can get it to be a simple XY gantry with a little more complicated Z and rotation axis. It will work slowly and with low precision but it is still much better than doing it by hand.

    Best regards,
    Alexandre Guimaraes

  20. #40
    Join Date
    Apr 2003
    Posts
    23
    Quote Originally Posted by ciccio
    Thanks to all, to CNCzone, to Vipertx, to Scotsss, to Alexg and Mariss for help and suggestions.
    Mariss, I agree with you: if I had to build a lot of SMD populated PCBs, then I'd buy a GOOD pick n place, or I will have it done by a company: it is the same as for good PCBs.
    But I have to build very small runs, or prototypes, so I can:
    place by hand : very very inexpensive
    buy a " hand placer" : 1500 to 5000 USD
    buy a old, useless pick and place : 500 to 10,000 USD
    buy a " useless" new machine ( say 20.000 USD + accessories)
    buy a new or recent-used machine ( more than 40.000 USD )
    PLUS feeders, nozzles, and a very expensive import, plus 20%VAT, not to say about service....
    I'm a one-man-business, and speed is not a problem for me, consider time to talk with customer, time to design a working circuit, to design a PCB, to find components, to build the PCB, to solder, to seelk-screen the box, to drill it , etc.: so to place a SMD component every some seconds is really not a problem: no need for speed.
    Of course I'm talking about prototype or very small runs, low-tech big-SMD circuits.
    Feeders: no problem, as I have to buy in any case:new machine, used machine, home-built machine.
    Precision: this is the problem! This is where I need a lot of help, suggestions, pictures, and the help of people like you ( using or trying to build) is invaluable !
    Paolo
    Hi, Paolo

    Let's keep the feeders for a second phase... They are complicated....

    Precision is not a big problem with 0805 components and SOT-23 ! They self align nicely of you put enough solder paste on the pads. No need for a squaring station. We are doing it by hand here and the girls do not even use the magnifying lenses that I have bought for it. They just pick and place the component.. The machine will do better then them... 0.2 or 0.3mm should be enough and visual inspection and hand retouching of some solder joints will be necessary anyway if you do not use a big reflow oven. If the machine misses one in 500 components it is still much better than hand placement.

    We are on the same boat about speed. It is nice to have but not critical..

    Best regards,
    Alexandre Guimaraes

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