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MyData Missing Placements

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Hi folks, I've been bouncing off of MyData technical sup... - Jun 28, 2007 by SMT Frog  

Where's me steaks ? ... - Jul 09, 2007 by Sr.Tech  

#50898

MyData Missing Placements | 28 June, 2007

Hi folks, I've been bouncing off of MyData technical support for some time on an issue with a MyData machine. Seems that this My9 likes to skip an 0402 placement at a rate of ~ 1000/million.

Profile: MyData My9 Mechanical centering Midas only

Mechanical centering is being used. It seems that someone replaced the standard jaws with precision stainless replicas to reduce the frequency of replacement because the electrical verification is not used. They say that the stainless steel used is non magnetic.

The centering system is a little bit quirky, meaning that it would seem to have a floating 0 point. I say this because I've seen some really unrealistic dimensions being reported during out of tolerance errors. Reinitiating the motor controllers usually helps this, but the machine continues to "dodge" placements. Perhaps some of these missing components are ending up between the jaws during calibration, but I can't pin it down.

Additionally, the centering base level floats within a range of about 100 micron according to the centering base level test.

From what I understand, the Midas head being used uses a vacuum test with the C14 tool to ensure that components are placed. The centering jaws should also recognize a failure to pick a part, DIM=0. This system isn't catching these errors.

There is a setting for Z level test during place, but it has a tolerance of 1mm. Not much help for placing 0402s.

The centering level for the 0402 caps and resistors is set to -.025mm. Any higher and parts seem to surf up onto the jaws. Any lower and the tool head ends up getting chewed on.

Also, a custom plate is being used that provides complete support for the PCB. (No bouncing)

I'm losing my mind. I'll send somebody a frozen steak assortment (Continental U.S.) if they can provide information that will help me solve this issue permanently.

Thanks for enduring this long post.

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#50909

MyData Missing Placements | 2 July, 2007

Make sure that your C14 tool is black and that the tip is in good condition. Next, create a vision package for the 0402. I assume that your machine has a line scan camera.(Use it) 0402's do not mechanically center well unless your C14 and centering unit is in perfect condition.

It sounds like your centering unit is buggered up. I do know someone that fixes them if you are interested.

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#50962

MyData Missing Placements | 9 July, 2007

Where's me steaks ?

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#50963

MyData Missing Placements | 9 July, 2007

Hey Napoleon,

Give me some of your tots.

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#50972

MyData Missing Placements | 10 July, 2007

Hi SMT Frog

We are using an upgraded Mydata TP9-1 system to place 0402s. We do an electrical test plus mechanical centering and use the C14 tool. A few things we have observed/learned:

1) Is the machine not picking the part up out of the tape? Possible cause is the tool head tip is starting to get plugged up. We periodically take the tool out and look at the tip under a vision microscope. We have taken a fine tip exacto knife and cleaned out the blocked hole. This can lead to expanding the tip hole too big which gives problems also. Mydata makes replacement tips for each tool. I recommend replacing the tip every 6-12 months depending on how much use it gets.

2) The dimensions of a 0402 part are close to the dimensions of the C14 tool tip. You may not be getting the DIM=0 error when it fails to pick a part because the jaws are reading the dimensions of the tool tip which fall within the tollerance range for 0402 parts.

3) There is a setting for the force used by the centering jaws: low, medium, high. We are using medium force. If you are using high force, maybe the jaws are hitting the part so hard it knocks it off? We try to use the lowest force setting that still gives good results so that the jaws wear out slower.

4) With 0402 parts costing around $0.0025 each in large quantities, losing 1000/million is a minimal cost issue. As long as the machine goes back and places the part on the second try, I would not worry about it much. If, however, the machine thinks it has placed a part when it actually has not, this now becomes a yield issue that you want to fix.

5) A suggestion for testing any changes to settings or tip cleanings, etc. Take a pcb and put double sided tape on it. Then put it in the machine and load the board like normal. This alows you to verifiy the placement of all the components without applying paste and you are able to reuse the board for testing later.

6) There is a single step mode you can run the machine in. In this mode the machine does a single step (command) and then waits for the operator to press a button before doing the next step. This may be very helpful in identifying at what point the 0402 part may be getting lost in the pickup/centering/placement cycle. Contact Mydata tech help to find out how to do this.

7) Another suggestion is to slow down your Z axis, Theta (rotation) and possibly the X axis speeds. This can hep but also slows down your component per hour placement rates.

I hoppe one of these ideas fixes your problem.

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#50974

MyData Missing Placements | 10 July, 2007

Replace the stainless jaws with oem.

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#50975

MyData Missing Placements | 10 July, 2007

> Hi folks, I've been bouncing off of MyData > technical support for some time on an issue with > a MyData machine. Seems that this My9 likes to > skip an 0402 placement at a rate of ~ > 1000/million. > > Profile: MyData > My9 Mechanical centering Midas > only > > Mechanical centering is being used. It > seems that someone replaced the standard jaws > with precision stainless replicas to reduce the > frequency of replacement because the electrical > verification is not used. They say that the > stainless steel used is non magnetic. > > The > centering system is a little bit quirky, meaning > that it would seem to have a floating 0 point. I > say this because I've seen some really > unrealistic dimensions being reported during out > of tolerance errors. Reinitiating the motor > controllers usually helps this, but the machine > continues to "dodge" placements. Perhaps some of > these missing components are ending up between > the jaws during calibration, but I can't pin it > down. > > Additionally, the centering base level > floats within a range of about 100 micron > according to the centering base level > test. > > From what I understand, the Midas head > being used uses a vacuum test with the C14 tool > to ensure that components are placed. The > centering jaws should also recognize a failure to > pick a part, DIM=0. This system isn't catching > these errors. > > There is a setting for Z level > test during place, but it has a tolerance of 1mm. > Not much help for placing 0402s. > > The centering > level for the 0402 caps and resistors is set to > -.025mm. Any higher and parts seem to surf up > onto the jaws. Any lower and the tool head ends > up getting chewed on. > > Also, a custom plate is > being used that provides complete support for the > PCB. (No bouncing) > > I'm losing my mind. I'll > send somebody a frozen steak assortment > (Continental U.S.) if they can provide > information that will help me solve this issue > permanently. > > Thanks for enduring this long > post.

I know when my c unit starts acting funky it usually means one the the bands in it has snapped. Always is worse on the smaller parts too. Have you checked to see that the 3 bands in it are still good? There's a plate underneath the c unit that's held on with 2 screws. You can see the bands by removing the plate.

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

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FD

#50976

MyData Missing Placements | 10 July, 2007

Buy a new machine... That will permanently fix it.

Do I get some steaks, too?

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#50978

MyData Missing Placements | 11 July, 2007

I have read through the solutions the other techs have mentioned, however, I have a couple more thoughts to offer you when you have these kinds of problems.

1) If you are using a C14 tool it is a spring tool and thereby it utilizes the "Force Sensor" located inside the Midas head. The "Force Sensor" is a set of bulbous diodes, of which one transmits and the other receives (senses) light.

The base end of the spring tool will block the light from one diode to the next when placing a part, therefore it needs to be cleaned regularly as part of your daily or weekly maintenance.

If the glass bulb part is dirty which occurs due to the air transferred across the tops of the bulbs from the vacuum being drawn through the Midas, you will need to clean these with a Q-Tip moistened with Alcohol.

2) From the "Package Editor" press F8 and check to see where the part is being measured Position:(Upper, Lower, Middle, 1/4 from Bottom) Try the middle for an 0402 cap, or upper for 0402 resistor (thinner).

3)Ive heard folks telling you to make sure the tip is clean and all, but also try the real test which you can do easily. Wipe the grease off the mount flange of the tool and place between your lips and blow air through it until you are certain theres air flow through the tool. This ensures that the tube is clear of obstructions as well as the tip. I have seen parts dropped on the tops of tools which are in the tool bank and when the Midas retrieves that particular tool, the part sitting on the flange gets pushed inside the Midas and can block the vacuum line there, inhibit the complete insertion of tool into the Midas, restrict airflow of the tool or lastly block the light across the Force Sensor giving you a warning about the sensor being bad.

Just a few thoughts....Good luck with this problem!

Chris

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#50985

MyData Missing Placements | 11 July, 2007

Mr Tech, No steaks for you yet. I'm going to run some extensive tests on the centering system, but I have identified problems with the vacuum system as well.

Thanks!

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#50986

MyData Missing Placements | 11 July, 2007

I would really recommend that you use vision on the 0402's.

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#50987

MyData Missing Placements | 11 July, 2007

1) We have been using the replacement tips regularly. We, also, purchased a precision pin gauge that we are using to clear the C14 nozzle without risk of stripping it out.

2) Right. However I've pinned the 0402 centering level down at -25um. Stepper mode does not show the jaws contacting the tool.

3) Agreed. FYI: Unless the parameters have been changed the force settings for Medium and Low are identical for the latest revs of TP sys.

4) Agreed. I would fill a bean bag full of chip components without breaking the bank; however, the placement is never completed. The .1% rate is for genuinely missing components after the machine is finished creating defects post-reflow.

5) Correct! I have done this in the past for different tests. However, for a .1% occurrence rate we would need to place and inspect 1000s of placements to get any significant data. We would also need to use a diverse selection of components to simulate production. I intend to continue production while tracking the missing placements to achieve the same result.

6) Cntrl-S, know it, love it.

7) I haven't tried this. I've had success in doing this with larger components. I have to admit that it's on the back burner.

Awesome response!

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#50988

MyData Missing Placements | 11 July, 2007

We don't have a linescan. I wish we did. I can't afford to use the DVS for all the 0402s.

Thanks!

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#50989

MyData Missing Placements | 11 July, 2007

The steel belts are still suspect. I'm going to perform a thorough analysis of the centering system soon. Will let you know.

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#50990

MyData Missing Placements | 11 July, 2007

I'll send you a frozen cow if you buy the machine for us.

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#50991

MyData Missing Placements | 11 July, 2007

Check bands Check friction Ceck that the bearing spindles that ride on the little rods arent bent. The custom centering jaws would be suspect

Past that there is not a whole lota testing to do.

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#50992

MyData Missing Placements | 11 July, 2007

1) Swapped it out a few weeks ago to attempt to combat the problem ... Great minds eh?

2) I'll try changing the position setting to see if my yields improve.

3) Ahh yes, in fact, I have verified that our vacuum levels are low (range ~130). The pump pulls 180 when connected directly to the vacuum sensor, so, there is something wrong with the pneumatic network. I'm going to find the vacuum problem, shoot out its kneecaps, ask it some questions, and drag it beaten and bloody into the street. Now that's troubleshooting!

Awesome response!

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#50993

MyData Missing Placements | 11 July, 2007

I've suspected a floating home/zero/cal on the c-system. So, I intend to make it dance for a while in extended service and see if the numbers boogie dirty. I'll let you know what I find. I appreciate your efforts here.

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#50994

MyData Missing Placements | 11 July, 2007

130 is waaay more than enough to do 0402's

Dont get stuck on a tangent.

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#51002

MyData Missing Placements | 12 July, 2007

Hey Sr,

I agree that 130 is enough to pull a tiny little 0402, but I think that your forgetting response time. The machine has a small reservoir built in the system that keeps some moderate standing vacuum, however, when a part is picked, there is the Pick Wait Time. The system is designed to use 25ms by default, then the user may add more if necessary in the package itself.

With a lower vacuum level achieved during the manual vacuum test after 30 seconds of build up time, imagine how much vacuum is actually achieved when only using 25 milliseconds! Yes... 130 is enough to pick up the 0402, but I doubt highly that the machine ever fully reaches that 130 in a 25 millisecond time.

Just my two cents.

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#51003

MyData Missing Placements | 12 July, 2007

I agree avalancher. Your description is a valid point. But, I am still under the impression that the vac level is a separate issue.

His original problem was 0402's missing off the board ,and weird measurements showing up when parts get rejected. I would be more concerned at this point with the centering unit, the mount tool, and the Z.

It has been my experience that 0402's and mechanical centering can be difficult unless the above mentioned is perfect.

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#51004

MyData Missing Placements | 12 July, 2007

Sr Tech.....this is off topic, but check your email.

Chris

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#51005

MyData Missing Placements | 12 July, 2007

I checked it...nothing there...

???

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#51006

MyData Missing Placements | 12 July, 2007

I clicked on your name and it opened an email box. I proceeded to write you a message concerning spring tools.

Im leaving work now and will check back in when I get home

Thanks

Chris

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#51017

MyData Missing Placements | 12 July, 2007

SMT Frog,

If you want this issue taken care of promptly, please give phone number to contact you.

Regards, SG

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#51032

MyData Missing Placements | 13 July, 2007

I am not comfortable posting my phone number on a public forum.

It would appear that you created this account to post this message. If you are associated with MyData, rest assured that I am in touch with official technical representatives. I have always appreciated the customer service from MyData; however, complex issues have proven to be difficult to resolve without maintaining a contiguous communication (getting different techs -> explaining the problem in full each time -> miscommunication/misunderstanding and disagreement).

Additionally, I have not, until recently, admitted to tech support that we had modified our centering jaws. I have uncovered evidence that a slight magnetic field may have developed from the stainless steel jaws regardless of the low propensity of the alloy to develop magnetism. It wouldn't take much to pull an 0402 part off of a vacuum nozzle. Demagnetizing the jaws and keeping the C14 tip clean has reduced the missing part occurrence rate to .02-.03% (200-300PPM). However, this problem is reported to have occurred before the jaws were installed and the jaws were, in fact, installed to combat the same issue. Irony can be a jagged pill. I suspect that the original problem may have been caused by something else. I cannot be certain at this time.

The beryllium copper of the official My series c-jaws wears extremely quickly. I am certain that we are not the only company with a MyData machine that does not use the electrical verification system (we have to place parts with ratings as low as fractions of a picofarad). I would encourage MyData to develop hardened centering jaws for these customers.

I am not interested in soiling MyData's reputation. Let it be known that our My9 has proven to be a flexible and capable cornerstone of our small company.

I'm still working this whole thing out, I will keep everyone updated. We have not stopped production, so, the long duration of the fix is acceptable.

Even if you are not affiliated with MyData, I wanted to post this info to update everyone. I think that sharing opinions and ideas is, simply, good.

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#51035

MyData Missing Placements | 13 July, 2007

warning - not all stainless steels are non-magnetic! Quite a few alloys are magnetic, some as highly magnetic as ordinary steel. One quick test is to demagnetize the jaws. If you can find one of the old-style Weller soldering guns with the copper tip that bolts to two terminals on the front, these make excellent small-part demagnetizers. You squeeze the gun's trigger, put the part close to the tip (or pass between the two wires for even stronger field) and then pull the part away from the tip before releasing the trigger. I use this trick all the time to demagnetize tweezers, small screwdrivers, etc.

If this fixes the problem, even temporarily, then you know the jaws need to be remade from a guaranteed non-magnetic alloy. You could demagnetize daily until you can get new jaws made. My Philips (Yamaha made) has stainless steel jaws and nozzles. It never even ocurred to me they could get magnetized, but I'll bet they are non-magnetic alloy.

Jon

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#51047

MyData Missing Placements | 16 July, 2007

I am surprised you have a problem with the berilium copper. Properly heat treated it should be harder than any of the 300 series nonmagnetic stainlesses. Many of the heat treatable stainless can be harder and more wear resisting than the berilium copper but I do not know of any that are nonmagnetic. Tantung G is both, but I do not think it can be annealed to a condition that it could be machined. Try taking a file to your original Mydata tools and see if they are only cut with difficulty. Perhaps you got got a couple that escaped heat treating. Also I thought all the small chips were completely nonmagnetic and magnitism of nozzles are other handling tools would be irrelavent.

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#51058

MyData Missing Placements | 16 July, 2007

Interesting, thanks for the info. All that I know right now is that running the jaws through an "el-cheapo" demagnetizer was one of the actions taken that resulted in a reduction of missing components. It is possible that this is not a dominant factor.

As far as the beryllium copper. The standard jaws from MyData have worn fairly quickly. That is, much quicker than the 316 s-steel we used for the custom jaws.

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