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How is cycle time of SMT line (Chip shooter for ex) determined?

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#37894

How is cycle time of SMT line (Chip shooter for ex) determined? | 16 November, 2005

Once the gerber files and BOM list are generated by CAD packages for download on to SMT production line....How is the cycle time of that PCB operation determined?

Is their information with in Gerber files by which you can estimate, before actual production?

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bobpan

#37897

How is cycle time of SMT line (Chip shooter for ex) determined? | 16 November, 2005

If its newer equipment.....and newer software.....usually the software for the smt machine will tell you the estimated time once the board has been programmed. If its older equipment.....get the old stop watch out.

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aj

#37905

How is cycle time of SMT line (Chip shooter for ex) determined? | 16 November, 2005

The latest software packages and stopwatch will do the job but if your manager is anything like mine he wants to know straight away from the BOM.

If you split the bom down between placement machines i.e. caps and resistors etc on chipshooter and ICs etc on finepitch machine you should be able to estimate time taken from machine Tact time . e.g , lets say you know the tact time is 0.2sec per component and you have 200 components on this machine well including loading 5 sec this would give you an estimate of 45secs. You should be able to determine your tact time from cycle times of other products that you already run.

The more accurate your estimated tact time the better.

rgd's

aj...

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nkbkiran

#37908

How is cycle time of SMT line (Chip shooter for ex) determined? | 16 November, 2005

Bobpan ..Thanks for the 1st input

Let me ask in a little more detail

The controller on SMT machine will understand the X-Y positions to mount the chips/transistor based on a given centroid in gerber file---the software on machines like Fuji, Assembleon or Sanyo will give a cycle time - similar to CNC machines

Question is 1. What if the machine is on its way / remote site...and need to estimate (say 90-95%) probability ?

2. How do I decide/plan If I need 1 chip shooter or more machines to meet my production volume?

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nkbkiran

#37910

How is cycle time of SMT line (Chip shooter for ex) determined? | 16 November, 2005

AJ

Thanks for the reply --you answered my question

regards

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#37939

How is cycle time of SMT line (Chip shooter for ex) determined? | 17 November, 2005

And don't forget to implement the "Scotty" technique for estimating time.

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#37955

How is cycle time of SMT line (Chip shooter for ex) determined? | 17 November, 2005

If the machine is on it's way..... Question is 1. What if the machine is on its way / remote site...and need to estimate (say 90-95%) probability ?

A1. 1 x 8 hour shift 65% x 1 of software estimate or stop watch estimate run on same machine in a dry run.

2 x 8 hour shift 68% - 70 % x 2 of software estimate or stop watch estimate run on same machine in a dry run. Depending on the competency of shift one.

3 x 8 hour shift 55% - 60% x 3 of software estimate or stop watch estimate run on same machine in a dry run. Depending on the competency of shift one and two.

Question is 2. How do I decide/plan If I need 1 chip shooter or more machines to meet my production volume?

A2. Calculate on A1.

Feeders run out. Fids won't read. People gotta have lunch/dinner/breakfast/smokes. People gotta learn the machine. Lovers of machine go home. Stores go home. Management go home. Decisions go home.

Once you know the machinery and have top people running your line - 85% is sensational. 70% is usual. Anywhwere in between get out your wallet and pay 'em more.

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