I wanted to write a post on Traceability firstly to remark its importance in the companies and secondly in order to share with you all my experience in the industry visiting suppliers, specially automotive, where Traceability is a must and must be controlled continuously.
If you are about to install a Traceability system in your process, first you need a leader, that would be the quality department. My recommendation is first do it in the shopfloor and afterwards make a procedure, never implement Traceability in your process from the office. Once you have a clear process in the shopfloor, do a procedure (or adapt the one you have) and perform regular audits.
I am not going to explain all the rules of Traceability and marking of products, but you need to track any operation in your shopfloor and make sure working parameters are recorded and specially manufacturing lots. So the best thing is to make sure operators note it. If you have an automated system do it directly in the computer system (german companies tend to this compared to many spanish that use the old paperwork way).If not possible, please make sure the registers keep record of the lot used and the day produced. Registers in paper do it better than IT in Traceability, believe me!
If you record parameters or lots in your MRP/ERP system, make sure you can easily list them in queries for information, I have seen many examples of perfect Traceability systems that take hours to compile information. Also do consider the option of one unique query to easily get information altogether of Traceability along all your manufacturing workflow. Your logistics will thank you, they do check this information more often than you think.
One thing I like a lot is a one and only manufacturing order paper that records all operations, named to say 10, 20,30… and the lots or Work-in-progress lot numbers used. This usually goes along all the manufacturing process with the parts. This is the perfect Traceability for me if it is backed up by a proper IT system.
Be careful with mixing lots in continuous processes like painting, surface treatments, shot blastings, washing, etc.. You have two clear options here. One is to establish a method that supports a label substitute compatible to the one used in the process (i.e. A piece of metal with a correlative number for painting) (be inventive in these situations) or set up a physical separation between lots and put the original label at the end of the process (this solution I do not recommend). But continuous process do not justify never, ever the end of Traceability.
Be ready to have a space in the paper to the re-work operations. Be aware that in all these operations most quality problems occur. So at this stage the important point is never mix lots in reworks. It is almost mandatory to have an operation instruction on reworking adjusted to your Traceability system.
Frequently make your own audits, remember the more you audit, the better process you have. Also invite customers to do it, sometimes someone from the outside has a better vision. It is true.
Finally a very important point is the discipline from all departments affected, you can always design a Traceability process perfect but if operators do not follow it you can have a big issue in the worst case scenario. Worst case scenarios always come when you less expect them!