Dear All,

Recently I have been told to additional Charge for ISO Activities.

Please guide/Inform
1. How do we calibrate SMT Machines? what Parameters to be considered?
Is it been calibrate In House or M/c Manufacture can Help to this?

Please inform how you Doing this Calibration?

Thanks

Shrikant Borkar

Assuming SMT stands for Solder Mount Technology oven, you can't calibrate the machine as it does not measure anything. You can calibrate the thermometer used to measure the temperature in the curing stations of the machine. is this your intent of the question?

Hi, kualititaj

Thanks For your Reply.

yes , Regarging Reflow Oven , I did necessary calibration arrangement.ie. Calibtation wrt. master Temp Meter.

But My Question is regading

SMT Mounting assembly machine. where 80 to 90% population of Parts been get mounted by machine.
this part may accomodate in Maintenance activities.
I just want to confirm whether this Part will come under ISO calibration?

Please comments

Thanks
Shrikant Borkar

In that case, in my experience we do not claibrate an SMT mounting machine as it is not a measuring instrument, but an assembly equipment. What would be more appropropriate is to do a PM on a regualr basis and show that the pick and place head is working within specifications.
Regards

In my experience with SMT equipment, there usually is no calibration for the screen printing, pick and place and reflow oven.
Verification or preventive maintenance activities are usually conducted as per the manufacturer's maintenance manual.

Assuming you are talking about Surface Mount Techonology machines,
Some points :

For Reflow and wave machine, there’s no request for verification, due to verify the machine performance every day though the profile testing.

Primary verfication, calibration ands preventive maintainence for mounting machine ( let's say all equipment ) also comes under ISO calibration.

Regards

We do practice mounter calibration on a bi-annual basis. The area of calibration covers the following areas:

- Z-axis calibration
- X&Y axis gantry calibration
- Theta calibration
- Recognition device calibration
- Feeder truck/cart x,y,z offset calibration.

All of this is followed by CpCpK measurement.

Sine it is a CNC type of a machine you could use a ballbar, or laser to calibrate it. You might contact the bigger companys such as reinshaw and see if they have any experience.

Sine it is a CNC type of a machine you could use a ballbar, or laser to calibrate it. You might contact the bigger companys such as reinshaw and see if they have any experience.


This company's name is Renishaw, Inc.

Stijloor.

Having worked as a Calibration Program Manager for a manufacturing company with several lines of SMT assy, I actually think I can input something useful! A first! :lol:

As was stated, the thermometer and other "measuring equipment" can be added to your list of equipment to be cal'd. If it can directly affect the realisation of the product, it SHOULD. However, the SMT assy machinery is not calibrated equipment because, again I am reitterating a previous post, it does not "measure". I fought this battle when I took over that job and FINALLY won.

A periodic Preventive Maintenance or Performance Verification *can* and SHOULD be done according to manufacturer specs at the minimum. THESE checks should be covered under your QMS or ISO 9001.

Assuming you have a final test of the assembled product, only a PM program would really be necessary. If the units are testing good after assy, then as long as the machinery is kept up (and documentation NEVER hurts) then Verification Checks are just an extra step you may or may not wish to embark on.

I have a screen printer, SMT assembly (pick and place) machine and a reflow oven. We have never calibrated or verified the screen printer as there are no instructions for doing so in the manual. Our SMT machine can be self-verified in two ways. Every time the machine turns on, it "homes" itself and then goes from home to a verifiable position on the other side of the machine and checks the encoder counts on the X & Y. It also checks Z axis using its built in laser measurement system. The laser measurement system can be verified against a block that came with the machine. Our reflow oven uses top and bottom heaters with PID controllers in each zone. Any out of tolerance condition would rapidly become obvious unless both controllers in one zone failed at the same time. Therefore, we have only verified that the temperature readings are correct using a traceable temperature meter.

We do perform the preventive maintenance as required by the manual for each piece of equipment and this is listed in our ISO preventive maintenance procedure. However, the SMT equipment is not listed in our calibration pool and I don't have a traceable calibration record for these items. Remember that there is a "where necessary to ensure valid results" in Section 7.6. If your SMT process is stable (i.e. you screen solder in the right place, put parts in the right places, and solder the parts properly) without extensive calibration and verification, then you don't need to add unnecessary burden.

7.6 "The organization shall determine the monitoring and measurement to be undertaken and the monitoring and measuring devices needed to provide evidence of conformity of product to determined requirements." Our customers do not require that we screen Q amount of solder at R coordinates, place part X at location Y and reflow solder at temperature Z. They require the finished assembly to meet their requirements. Consider.

My evidence of conformity is the 99.9% first pass yield of my surface mount assemblies at final test.

http://www.renishaw.com/en/7968.aspx

Can you get a pick and place SMT machine calibrated,,, I would say YES. Do you have to, I would say NO. Will it increase your placement success, maybe.

I would do a study on misplaced or misaligned parts, benchmark it before and after.

I have sat on SMT production lines and done touch up, I know the machines should be better, and it may allow you to cut touch up time.

Here we calibrate our CNC machines once a year or after a major crash with lasers. These are okuma vert lathes, they measure nothing, once error mapped and calibrated they can hold very tight tols. No one forces us to do this either, it is just good business. We prevent the problems before they occur. Imagine that......

However, the SMT assy machinery is not calibrated equipment because, again I am reitterating a previous post, it does not "measure". I fought this battle when I took over that job and FINALLY won.Be careful and be ready for this battle. My pick and place machine measures parts via laser and will reject them if they are out of tolerance (e.g. an 0603 instead of an 0805). It also measures pin coplanarity, alignment and pitch on QFPs to assure that everything will solder on a fine pitch placement. Your reflow oven is also measuring process parameters. If your temperature measurements are not correct, you may not be soldering properly. I am not suggesting that you should calibrate your SMT machines, but you do need to know exactly why you are not calibrating them.

I agree with the posts that calibration of SMT machines should be carried out when there is a drop in machine performance. But unfortunately in my case the monitoring is conducted live, through in-line SPI's and AOI's. Hence the pressure to do calibration at regular intervals to maintain high yield at the inspection machines. Add to this high-density (80 -90% populated) PCBA's with a minimum separation of 6mils, and line utilization not less than 85%.

But like what many pointed out, it all boils down to what customer wants. I guess my problem stems from a demanding 'internal' customer:)

Is there a thread on how to maintain high yield for pure SMT lines or some similar threads?