Approaches to creation of control plan

Hello,

I'd like to get some advices about control plan. The purpose is not to miss mandatory required content but get rid of unnecessary (not required) information.

1. Let's take e.g. process "Sealing of ultrasonic welded splices" - the splices are covered with tube using shrinking machine. We have a product characteristic "sealed splice" and related process characteristics "temperature and time". Is it enough to put in CP control of product characteristic and mention related process characteristics (attachment 1.1.) or I need to describe controls for both product and process characteristics separately (attachment 1.2.)

2. If description of controls of process characteristics required: besides routine daily monitoring of temperature and time mentioned in 1.2. we have additional monthly check to verify them (attachment 1.3.). Is it required to be in CP too?

3. New example: we produce the wire harnesses and have a continuity test at the end-of-line. To which process should it be related in CP:
- to "connectors assembly" as the product characteristic is created there
- or to "electrical testing" as it is controlled there (both options are in attachment 1.4.)

Thanks.

 

1.4. uploaded

 

Looking at 1.1 through 1.3 .... less is better. Let me say it again clearly LESS IS BETTER.

In the 1.3 document, you are listing your setting of your machine in the control plan, this is not the specifications of the part. And here is where it is going to cause you problems.... On the day you send me a bad one and I as your customer come in to your plant, I am going to audit your control plan against your settings. What if you change them from winter to summer? What if you rebuild your furnace and it has new insulation and you can lower your set points? It will not matter. You will be operating "different" from what your control plan says and we will spend a lot of time talking about:
a) How you are NOT running to your control plan and you are a very bad supplier
b) How you changed your process and you did not PPAP the change to me.

I am going to assume you run like most places and that each operation has a very detailed setup sheet of some sort that would most likely fall under your Level 3 work instructions. You mention t=230+/-10 deg C on 1.3. Do you have a detailed setup sheet for this machine with this on it (and a lot of other stuff?) If you do, then in the control plan, reference THAT document by controlled document number. In this way, you can change your settings as needed and avoid re-PPAPing every time you make a reasonable adjustment.

HOWEVER - if you truly do run using the control plan, and what I mean is, copies of it are on the floor and your setup/group leaders go to THAT controlled document to get the appropriate settings - then you need all of them in the control plan. I highly advise against it.

Here's my warning shots:
1) I'm not your SQE. Your real SQE may feel differently and insist you put them all in. But I would strongly recommend you go with less is more and let THEM tell you to add more. And again, less is not "see setup sheet". It needs to reference a controlled document number so your SQE gets the sense that you actually have controls in place.
2) Have the controls in place. Lord help you if you send me an 8D that says "We didn't use the setup sheets" as the reason for making the bad part.
3) If they do want more information, your next pass is JUST put the significant characteristic details in there. Again, less is more. It's like writing yourself into a corner in your ISO documentation. If you aren't going to do it each and every time, avoid SAYING you are going to do it each and every time.

People will fall into analysis paralysis and bludgeon you about paperwork problems instead of working together aligning your process to their needs. The former is just the waste of over processing, plain and simple.

But functionally - if your control plan has no specifics and is referencing Level 3 type setup sheets AND you have processes in place where there is some approval process needed to change them (other than "3rd shift guy marked it up on the fly") you are covered as far as PPAPing goes. You could win that argument (which is always better to avoid).

I have suppliers that give me control plans off the same processes (or damn near). I have 4 page control plans and I have 70 page control plans. The 70 pagers, while detailed, are much more of a pain because no matter what the change, it has to be PPAP'd because EVERYTHING is described on it. Sadly, the blue books are little help. And it makes sense, they have to be vague enough to cover EVERY process because they are overview documents. So they are not written in a way that paints the customer into a corner. You need to PPAP changes. But you are the subject matter expert. The best situation is when you are being honest about what changes in your process could affect my fit/form/function and when I (as the SQ) realize that there are also things you need to be able to tweak on the fly in order to run your business effectively and not get bogged down in the nitty-gritty. What should go on the control plan should reflect THAT.

Another way to look at it is this: If I can measure it on my end on an incoming inspection, then it is a good candidate for your control plan. But if it is a setting on your end that I cannot measure, keep it off of it.