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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


X outs

Bordiky

#20871

X outs | 25 July, 2002

I've been reading the forum here for a few weeks and found some helpful material from talented individuals. Now, I have a question(s). I'm looking into different alternatives for doing X outs. Right now I'm familiar w/ two of them:1. Bad Board Marks(a mark on each board of the array where the PEC camera would inspect and determine to skip the board out or not; considering using a small sticker to cover the mark which in turn would signify to the machine not to populate that particular board)OR 2. Punch outs(having a series of holes on the rail of the array representing the boards in the array; when a board in the array is not to be populated the corresponding hole would be punched out; a sensor would then detect the punched hole). Questions: 1. What is a good mark to use for method one? 2. How would you set-up a machine to do method two if an X out sensor is not installed? 3. What are other methods of doing X outs?

Thank you in advance for your replies.

reply »

#20872

X outs | 25 July, 2002

1: I use the fiducial mark as bad board mark. 2: First get the X sensor installed on the machine, then use method 1. 3: other methods: group boards according to which unit is X out. Then edit NC program to skip corresponding X out.

reply »

#20875

X outs | 25 July, 2002

You would have to tell us what machine brand you are using, as everyone has his own idea how to recognize X-outs. I find the auto-recognition very time consuming ( non-productive machine time ), unless the camera could recognize an image in one shot, like a bar-code. I would take the marked boards out of the stack and run them at the end of the batch. Your software should allow to skip just one pattern. If you add up all the seconds the machine looks for the marks on all unmarked boards, the manual program change appears to be the better choice.

reply »

#20879

X outs | 25 July, 2002

1.0 X-OUT POLICY 1.1 Each Panel not to contain in excess of X% X'd-Out boards. 1.2 Each X-Out board to be marked in a manner so that Pick & Place equipment will not attempt to insert those boards X'd-Out such as fiducial reference hole for panelization blocked. 1.3 Panels that include X-Outs shall be segregated from non X-Outs, if included with a normal shipment. 1.4 Panels with different X-Out schemes shall be sorted into groups, each group of different X-Out patterns to be identified.

reply »

#20888

X outs | 26 July, 2002

Using white labels on xouts works for us. I prefer to used the machine BBR ( Bad board recognition ) when building multiple arrays with no pattern on xouts. We always run xouts last, therefor, we enable the BBR only to finish the arrays with X on it.

Again, a white label works fine for us.

If we have arrays with xouts with a pattern, or located in the same board, I rather use the manual board bypass, no labels are required for this methode.

I'm not familiar with the "punch" methode you describe, but wouldn't you be taking time to punch holes on the board? Is that process automated?

If xouts are a big problem, you may want to start by demanding no xouts from your board house.

Good luck.

reply »

#20890

X outs | 26 July, 2002

I'm told that the Contact Systems machines we have will are set up so that if you put a sticker over the fiducial it will skip that board on the panel. I think the machine might prompt the operator that it can't find the fiducial and the operator tells it to skip that board.

reply »

Bordiky

#20891

X outs | 26 July, 2002

Thank you all for your input. Using Panaserts by the way.

reply »

Bob

#20962

X outs | 30 July, 2002

Be careful when using a sticker, if it is too thick it can affect the print, you may get leakage which can cause the underside of the stencil to get dirty.

Another option depending on the quantity is to segregate the boards so that you do not have to use bad board detection. i.e. process all panels with cct 1 missing and skip out the cct in the program. If time is important then this will save you a little as you dont have to read the block skip marks.

I always like to go for punched out holes, but you also have to make sure that the block skip marks are not near any appertures or you will again get paste being dumped in your machine.

Bob...

reply »

McDry Ultra-Low Humidity Storage Cabinets

ii-feed SMD Intelligent Feeder