Wiring Diagram System for Large Scale Manufacturing - Page 1
Forum section: electronics / general

author: MikeW
author_rank: Regular Contributor
timestamp: January 29, 2016, 09:46:40 pm
content: Mods, please move this to whichever sub-forum you feel appropriate. Manufacturing sub-forum seems to be pcb specific and there weren't too many other obvious options.Anyway, my question is....How would you go about setting up a wiring diagram system for a company with about 40,000 (technically) different products and counting, being wired by a couple hundred people of varying (mostly very low) electronic skills/knowledge? Bearing in mind they should in theory be disciplined if they do not follow the diagram specified on the BOM for that product, but also that the product could be wired in such a way as to seem to work just fine, but not actually be correct for the customers requirement.Not all of the products require different wiring as it's not always electronic but cosmetic components that change, but still on the order of thousands. The same product is offered in a multitude of possible variants, requiring changes spanning from nearly every electrical component to just a couple of labels. So it's not a simple product-diagram relationship.Many products are essentially wired the same, but because you are using components from different manufacturers to achieve different power outcomes versus cost, the terminal labelling on internal components might be slightly different, making it difficult to draw a diagram 'anyone' can follow.Many products might be pretty much exactly the same but with one or two small wiring/terminal changes that must be labelled correctly. Many products might use the same components but the position of the earth connection to the main terminal might change as the body materials change.These are mains connected appliances and correct labelling/wire colour/earthing is safety critical and the CE mark depends upon it.The same component could be wired in a number of different ways dependent upon the requirements.Changing components to achieve the same outcome (schematically but not physically) due to supplier and cost requirements can happen on an extremely regular basis.How do you futureproof the system against entirely new components being introduced for new products and old components being changed for slightly different models?How do I create a system that minimalises information being repeated whilst still exactly defining the requirements for each product if read correctly, whilst not overloading a low skill operative with too many decisions to make when they look at a diagram?I know this is a big (and kinda vague) question but it's a big headache for me and even vague answers could be really helpful in sorting this big problem out (I'm not going to even attempt to introduce the problem of special one-off requests from big customers confusing things).EDIT: Did I mention that ideally this system should be maintained by one guy? As part of other duties too.

author: Seekonk
author_rank: Super Contributor
timestamp: January 29, 2016, 10:48:58 pm
content: Forgive me, but I had to chuckle reading your post. You are about to experience thingsyou never thought possible. I worked at a place that worked from models. I was always tooclever for my own good. The model board I gave production was the same one I used fordevelopment, Thought I could save the company some money. I happened to cut one of thetraces to see if a mod gave a little better performance. I soldered a wire over the cutto get it back to the standard board. When I got the first production run every boardhad that cut with a wire soldered over it. No one in production thought that was a bitunusual.One product had a transistor that became obsolete. A suitable replacement was found. Foryears half the prouction run failed testing and had to be repaired. Test procedure had aresistor to be changed if it failed test. As long as they had a procedure It never botheredanyone that half the production failed initial test. I only discovered this by accidentwhen I walked by and saw a stack of boards in repair. A slight value change and we wereback to 99.99% acceptance.I was actually a ISO 9001 auditor and I could never get one thing changed in the company.Production did not need an engineering sign off to go into first time production. I wouldbe working on the prototype at my desk and production would come in with a big box of unitsand say none of these work. That ment they had to come up with a label, silkscreen for thecase, a model to build from ,and a test procedure to test it with. None of these existedyet the creative people in production were able to do it. Sometimes it was even shipped tothe customer. The creativity of people can never be underestimated. There was also aculture of never acknowledging a problem.Components.....I was an artist at getting the maximum number of variants in a single ULapproval. If you don't state them the first time you pay, pay, pay, pay.