Barcode pcbs for traceability

We haven't laser engraved PCBs but we have had 2D barcodes silk screened on. When I saw them I thought that they would not work because the white squares were blobs but they did work. With the Datamatrix format only the centre of each little square has to be light or dark.

Which 2D format are you using? Also talk to your equipment manufacturer. There is a huge range of quality for bar code scanners.

I just remembered that our AOI machine had to have very good bar codes to be able to read them. With new software it can read ok barcodes.

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Panasonic has a great training facility in Kentucky that could be of enormous benefit to you and your team.

Materials and Lasers range in capability. Generally speaking you need good contrast; which is not always guaranteed with bare PCBs.

As others have mentioned, common practice is to implement a silk screen area to improve barcode contrast.

Using an Ionizing Air Knife (like we use on our Laser Marking Systems) to remove lasered material can reduce external bar code scan failures by up to 35% as well.

Some laser software can also allow you to overwrite and/or reduce scan speed. Using a lower Laser Power Setting you can create a "lighter" mark but lengthing the marking process (slower scan speed) or create multiple passes (overwriting).

You can always reach out with our Laser Marking Team directly through our website at: http://www.promationusa.com

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I think you are going to struggle without a laser designed for PCBAs (Asys, XJ Link etc) as they are designed to just burn into the resist and give good defininition, then readback to know you have a good mark.

Key tips for our experience:

Datamatrix no smaller than 4x4, Decent scanner - there is a huge amount of difference, between a $100 scanner and a $500 scanner for repeatability of reading codes. Black resist is a nightmare - we had to go down to the copper for legibility, Personal recommendation is Asys.

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Laser the barcode on a label and place it on the board. Trying laser the substrate does not work well.

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We have used an area with silkscreen on the PCB to make the laser printing more readable. This works very well with a wide range of scanners without any issue.

This message was posted the Electronics Forum @ SMTA

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I have successfully used laser marked bar codes on PCBs. Use an area without any copper so that you are marking on the FR4 only

This message was posted the Electronics Forum @ SMTA

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