Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Tracking SMT Attrition (Load/Unload Loss)

#20751

Tracking SMT Attrition (Load/Unload Loss) | 18 July, 2002

Folks,

I'm working on setting up an automated process which captures data on SMT component dispensing during placement. Ultimately, I'm hoping to use it to account for component attrition (load/unload losses, vision/mechanical/electrical inspection rejects, and component drops) which will interface with our MRP system and facilitate automatic transactions.

The problem is our machine, a MyData MY15, only counts dispensed components. The part that's missing is the load/unload loss. Components dropped during magazine/feeder loading are not counted by the machine. Also the potential exists for skipped reel cavities which may throw off the actual number.

If I were building large production lots I'm sure it would be a negligiable figure. But since we are a low volume high mix operation I need to account for almost every part used.

Looking for anyone who has some experience with attrition measuring or allocation. Perhaps you've found a SIMPLE way around this? We are considering using a flat percentage estimator based on some experiments. But I'm a bit worried about over/under compensation.

As always any feedback is welcome.

Thanks, Gregster

reply »

Mark S.

#20753

Tracking SMT Attrition (Load/Unload Loss) | 18 July, 2002

>>But since we are a low volume high mix operation I need to account for almost every part used.99.5% (financial)

We then also report the machine reject information on an inventory adjustment sheet. This seems to cover all the bases.

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

reply »

Mark S.

#20754

Tracking SMT Attrition (Load/Unload Loss) | 18 July, 2002

>>But since we are a low volume high mix operation I need to account for almost every part used.

I'm in the same boat, and we do more changing of feeders than actual placements it seems.

What I have done which has improved things a lot is in our MRP system, for each part allocated there is a setting for a fixed amount and then a percentage of attrition.

So for a resistor, I set the allocation to 20 pieces and then 0.5% for the amount allocated. So if we have a job that only requires 100 peices, the WO will allocate 121 pieces...for 1000 peices it would allocate 1025.

This is then followed up with a cycle count program where I know the allocation is working as we are now adjusting our inventories POSITIVE on these parts...and the %accuracy is still >99.5% (financial)

We then also report the machine reject information on an inventory adjustment sheet. This seems to cover all the bases.

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

reply »

#20755

Tracking SMT Attrition (Load/Unload Loss) | 18 July, 2002

For component loss that cannot be accounted for by the placement machine's computer I would have the operators collect all loose components from the feeder setup area and in and around the placement machines after each product batch run. This is certainly not an "easy" method. I did it for a period of time to collect data on what the real loss was so that the material planning people could use an accurate "shrinkage" percentage. This method also showed the operators that they were loosing too many components and to tighten up on the handling. After doing this we were able to create an effective system. In our "checks & balances" we would do a physical count each quarter on SMT components to compare with what the MRP II system said we should have. After a few cycles of this it proved out that our system was accurate enough in accounting for shrinkage. Do you have the MYLABEL bar coding system? Mydata has the capabilty to account for component usage and can be tied into your MRP system via. the LAN hookup to the machine. MYLABEL can automate this process with the bar coding. Contact your Mydata rep. for details. The latest MYLABEL is version 2.0.

reply »

#20785

Tracking SMT Attrition (Load/Unload Loss) | 19 July, 2002

Pete,

We've been looking at that. Last I heard was August release for MYLabel 2.0. Do you already have it?

reply »

#20786

Tracking SMT Attrition (Load/Unload Loss) | 19 July, 2002

It has been release by Mydata. I haven't used it yet.

reply »

Manufacturing Software

Essemtec Spider SMT Fluid Dispenser