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Optimal Speed for Universal Chip Shooters


Optimal Speed for Universal Chip Shooters | 11 June, 2003

I am running A Universal Chip shooter 4792 HSP machine. I would like to know the optimum speeds this machines can be run at. I am currently running the machine at a tact time of 18S-14S depending on the types of components and the complexity of the board. However if I try to run the machine at a tact time lower than 14S I began to see placement defects.

Please advise if these defects are due to the component not being defined correctly or due to machine limitations

I would like to know what tact times are used by the Universal chip shooter users for certain basic components such as

0402 0603 0805 1206 and large Tant caps

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Optimal Speed for Universal Chip Shooters | 11 June, 2003

We rarely use the tack-time on our machines, even if we run products that are populated with large components. ( ICS, Tant caps etc.)

There is a default tacktime for each component on the component library, is called Speed Data. For the components that you mentioned, the tacktime is .10 sec (pick up, Head Rotation and placement) that we rarely modify it, since it's a default.

Now, there is an " Overall tack time reduction" that reduces the speed of the whole program, I am not sure which one is the one that you are referring to. If it is the " Overall tacktime reduction" we almost never use it, because it will reduce the speed of the small chips as well as the large ones.

Here is a checklist that may help:

*Make sure that your feeder setup is optimized, small components firs 0402.0603,0805,1206, tanta caps, ICS etc.

* Make sure that your placement pattern is optimized as well, pick up from feeder #1,2,3,4,5,6 etc.

* Make sure that you insert a slow down step in the program, so the machine places all the small components first, and the large ones last using a slower speed.

* For large components, increase the tack time on your component library, not the Overall tack time reduction.

* You should be able to run all the small components at full speed and the large ones at a slower speed without slowing down the whole program.


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Optimal Speed for Universal Chip Shooters | 11 June, 2003

I have the speed data set at 0.12S for the small caps and in addition to that I am using an overall tact time reduction of 14 to 16 seconds. If I use the default overall tact time then I have placement defects such as components being placed:

1. Twisted 2. At an offset from the pad 3. Inverted This may be a component definition problem. What particular part of the component definition should I concentrate on?

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Optimal Speed for Universal Chip Shooters | 11 June, 2003

There are many variables that could cause components to be misplaced. Using the overall tack time reduction is in reality putting a band-aid on a larger problem.

Are your small components shifted as well? ( 0402,0805 tec)

Components "twisted or offset from the pad":

* Check your board thickness. * Check your component thickness. * Make sure that you have the right nozzle * Component placement level, we have it at +.0118. ( default)

If your component thickness is less than what the component actually measures, the nozzle will drop it before it reaches the surface of the board. Causing it to shift or not place it at all. This is very critical. The thickness and vertical data must be accurate.

Please let me know if any of this helped.


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Optimal Speed for Universal Chip Shooters | 11 June, 2003

I've never worked on that machine but I won't let that little detail stop me from commenting. Are your nozzles clean, and have you checked your vaccuum levels? On every machine I do have experience on, management doesn't allow time for proper maintainance and placement reliability goes down. Then the machine part data gets slowed down to get the placements perfect again.

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Optimal Speed for Universal Chip Shooters | 11 June, 2003

You have received some great feedback so far. I would like to summarize and add a few points regarding maintenance. You should start (as recommended already) by verifying your component library data. Using the default values from the master library is definitely best). Beyond that, Id suggest reviewing the items listed below. This list is specifically for a 4796 HSP, but most of it is still related. If you are a registered customer of Universal, you can sign up for our Knowledge Bases on our website . I've cut and pasted the list below from one of the debug entries on this site. If all else fails, it wouldn't hurt to get a qualified UIC FE in to verify everything and to get this resolved quickly. Alot of this could be based on the age, cycle counts, and the care that this machine has been given. The 4790/91/92 series HSP's have several more "wearable" parts than the new generation. We suggest a PMP (preventive maintenance program) evaluation after 200million cycles to prevent potential failures from occuring and to avoid any decreases in performance from creaping up. Please also feel free to contact our HSP Technical Specialists at 1-800-842-9732 to discuss.

Best regards, Todd Vick, Universal Instruments HSP Product Marketing Specialist

4796 checklist:

1. Nozzles tips worn--replace with new nozzles 2. Nozzle Type- Verify correct "Nozzle Type" is used for size or type of component used. 3. Nozzle Tip Dirty- Perform nozzle maintenance and necessary calibrations afterwards 4. Nozzle Position- Nozzle not installed correctly check vacuum port hole is facing outward. This is the upper portion of the nozzle. 5. Nozzle Vacuum Holes Clogged - check for grease in vacuum hole, also ensure nozzles do not have solder paste or glue inside of them. After cleaning perform necessary lighting and nozzle offset calibrations. 6. Nozzle Movement Sluggish- Clean nozzle and ensure nozzles slide up/down with free movement, replace nozzle if needed. 7. Vacuum Filters- Replace dirty filters, check that two filters are installed correctly (Qty 1 filter for Vacuum and Qty 1 filter for Airkiss). Reference maintenance manual for the to types of Filter Retainers. Ensure that the type on your machine is installed as prescribed in section 1.4 page 1-42 8. Vacuum Filter retainer- Check position of retainer to vacuum ports , make sure they are aligned correctly 9. Vacuum Valve- Check valve replace if suspected. 10. Vacuum Level- Check vacuum level at nozzle ensures vacuum level is within spec. Verify vacuum at pump. 11. Vacuum Line Contaminated- Check for oil in vacuum line 12. Vacuum Low- Silicon Hose maybe damaged due to wear replace hose if needed. Or placement head o-rings defective replace o-rings. 13. Solder Paste- Verify paste alignment to pad locations, verify correct amount, verify paste tackiness (Extended process time between PCB's) 14. Adhesive- Verify glue location to pad locations, verify correct amount. Check glue viscosity, 15. Reflow- Process issue or profile parameters causing components to tombstone or to break free from pads. 16. Component Surface- Check for oil or contamination on component surface, determine source and correct cause. 17. Component ID- Verify component parameters for correct dimensions and placement offset, tact time speed reduction. See UIC specifications to ensure you are not masking a problem by reducing tact time. 18. Component lifted off placement location- Check vacuum valve replace valve, if suspected slow in activation speed, Air-Kiss pressure may be set to low to evacuate vacuum chamber to positive pressure at the correct time. 19. PCB Vibration- Parts may vibrate off board during population or transfer of board. 20. PCB Warpage- Verify board is within warpage spec. 21. PCB Support- Verify correct support pins are used in accordance to board thickness. 22. PCB Height Setting- Verify placement program operation data for correct PCB thickness and placement offset 23. PCB Width- Verify PCB width to rail width setting, Verify board is not trapezoid. Verify board is held securely in X/Y table rails 24. Programs- Wrong version program or component skipped in placement program. 25. Air-Kiss- Air flow setting maybe either to high or to low 26. Air-Kiss- Blow pipe alignment and gap set incorrectly to slide assembly 27. Solenoid assembly, verify smooth action, This can be done by putting a reduced tact time in. If problem disappears- this could be the cause. Replace and reset new solenoid set-ups. 28. Placement Head Loose- Verify head/s is/are secured to slide/s 29. Placement Heads Rotor free play- Check for excessive free play in head rotor - replace head if defective. 30. Placement Head Seals- vacuum lost can occur if seals are defective, replace seals 31. Placement Head Hooks- If hook springs are worn or defective a nozzle may drop from the upper position to the lower position allowing a nozzle to 32. Top Block Assembly- Verify constraint load is set correctly, 33. Top Block Lever- Verify movement of lever, 34. Top block Cam Follower- Check cam follower condition, replace as needed. 35. Head Up/Down Linear Guide- Verify free movement, check for excessive free play, or stiffness in its movement. - Replace as needed. 36. Moveable Shelf- Shelf position may need to be adjust to allow smooth transition of head from fixed rail to movable rail. 37. MZ axis- MZ axis may have a vibration causing part to vibrate on the nozzle. Check servo set-up, change servo driver if vibration is still present after complete evaluation of mechanical parts are found in good working condition.

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Optimal Speed for Universal Chip Shooters | 12 June, 2003

I really appreciate the Information JB, T, Vick, and Stepheno provided me with my problem. I will work on preventive maintenance and will also check the component database. Please provide me with any additional pointers that will help me optimize my machine

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M. Cruise


Optimal Speed for Universal Chip Shooters | 27 August, 2003

Todd covered it all. And you will have a hell of a time verifying all that. BUT he is perfectly correct. I have worked on such problems and boy are they difficult to trouble shoot. But one time the problem was found to be "the height of the machine". This contributes to PCB vibration as mentioned by Todd. So check that it is not at the end of its leveling legs and then start with Todds list. Like I said it got one of our HSP machines up to full speed.

Regards M.

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Optimal Speed for Universal Chip Shooters | 28 August, 2003

Tod, I am a user of 4797 and we too have this problem. A question regarding nozzles. How could I check whether they are worn-out? Only in vision check? We have worked for about 2 years without changing them, but worked just one shift.

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Optimal Speed for Universal Chip Shooters | 10 September, 2003

Yukim, First off..sorry I haven't responded to this already. I hadn't noticed any responses in a while.

I would be very surprised if you have worn nozzles in a two year period, but it is possible. For instance, if you have been running with an extra Z-offset at pick or place, this will accelerate wear. The best defense is to track the machines performance via the management data. If you notice that a particular nozzle is having more issues than others, it could be an indicator. As long as the nozzles are sealing properly you should be OK. Also...It wouldn't hurt to calibrate nozzle heights from time to time. This is an automated "teaching" that you can find in your machine documentation. regards, Todd

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Optimal Speed for Universal Chip Shooters | 16 September, 2003

Murtuza You have recieved loads of good info mainly all the preventive maintenance to be done. But can I ask was all of components placed twisted or just some when machine was run at full tact time 0.12s, I ask this as I run a 4791 and if its only some components I would check vacuum pipes to each head,as I have had this same problem and found that a couple of split vacuum pipes may pass vacuum test to the head but when machine is running the pipes loose vacuum at the critical placement point. Also a big issue with this machine is the springs in the top blocks of each head as they are suspect to crack, check that each spring is ok and that each head is held down onto the cam. Regards G

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