While some to many of you have not run into these problems, there are situations where putting all of the details into the control plan will not work. Experience has made me think standard control plans do not work well with highly complex parts and processes. High mix-low volume with a lot of automation is another situation where control plans may not work well.
When you are running 200 part numbers at any given time where many of the parts use various combinations of standard processes, referencing a master set of process documents makes process changes easy and reduces the chance of one part being missed.
Some parts went through over 250 processes stations, with a lot of circling back to the same process station. In some cases all the parameters would be the same and in other cases the process would be adjusted or a different program used. (Cleaning steps are an example of reusing the exact same process more than once.)
And is case you are wondering, we were AS9100 with lots of aerospace, technology, and industrial customers.
Information should not have circular references that lead nowhere and neglect to provide the information needed. But circular references can be a good thing if important document A references important document B and B references A at a high level, the focus of each document is kept clear and specific information is not duplicated. That way no matter which document someone starts with, they know the other document exists and they may need to check it.
Requirements that need photos to properly document can't be put into control plans without the photo being really small or the control plan really big. Reference samples also must be referenced in the control plan. Complex process flows and process requirements with many conditionals also work much better as a work instruction with a flow chart.
Some processes require more columns. One engineer at a previous job created his own version of a control plan. Management asked him to use the standard format but even after transition time we found his custom format worked better for the process and resulted in fewer errors by presenting information in a more clear format. He used columns for each category of process parameter and color coding that reduced errors. Based on what he did, I think when a process gets too complex, the standard control plan does not work well.
Also, in a high mix job shop, referencing part specific items on the control plan can become cost prohibitive. At a past job, the part traveler contained the critical part specific information, most of which was electronically transferred from the customer data to the shop floor system to the process machine. Putting part specific data on control plans would have required 2 to 4 people doing nothing but creating custom control plans for each part with no added value. Customer drawings were used when specific requirements needed to be verified against the traveler, machine setting, etc. Buying software would not work. The company had an internally developed and maintained shop floor control system that while using outdated technology and ugly looking had better automatic traveler creation than anything on the market. The company wasted several million dollars (plus the software company likely wasted more) trying to replace it only to find they could not. A part specific control plan with all the part specific specs was only created if the customer was willing to pay for it, and once they visited and saw how automated things were, none ever did pay for one. We lost a few potential customers, but those customers were likely a poor fit anyway.
When you have proprietary processes, you have to keep the details out of the control plan. At a past job we had a process where the supplier of the process chemicals and equipment limited disclosure to need to know. Only about 20 people out of 300 had a need to know. Customers were out of luck. Many customers grumbled, but found everyone offering the process was subject to the same rules. We later developed a different proprietary process There was a lot of R&D involved but the end result only required one common chemical and three process parameters. Too easy for someone to memorize. Again not disclosed internally except on need to know. Again customers grumbled, but the choice was accept no disclosure of any type or we would not use the process. Since nobody else in the industry could do this combination of requirements, we did not disclose.
When you are running 200 part numbers at any given time where many of the parts use various combinations of standard processes, referencing a master set of process documents makes process changes easy and reduces the chance of one part being missed.
Some parts went through over 250 processes stations, with a lot of circling back to the same process station. In some cases all the parameters would be the same and in other cases the process would be adjusted or a different program used. (Cleaning steps are an example of reusing the exact same process more than once.)
And is case you are wondering, we were AS9100 with lots of aerospace, technology, and industrial customers.
Information should not have circular references that lead nowhere and neglect to provide the information needed. But circular references can be a good thing if important document A references important document B and B references A at a high level, the focus of each document is kept clear and specific information is not duplicated. That way no matter which document someone starts with, they know the other document exists and they may need to check it.
Requirements that need photos to properly document can't be put into control plans without the photo being really small or the control plan really big. Reference samples also must be referenced in the control plan. Complex process flows and process requirements with many conditionals also work much better as a work instruction with a flow chart.
Some processes require more columns. One engineer at a previous job created his own version of a control plan. Management asked him to use the standard format but even after transition time we found his custom format worked better for the process and resulted in fewer errors by presenting information in a more clear format. He used columns for each category of process parameter and color coding that reduced errors. Based on what he did, I think when a process gets too complex, the standard control plan does not work well.
Also, in a high mix job shop, referencing part specific items on the control plan can become cost prohibitive. At a past job, the part traveler contained the critical part specific information, most of which was electronically transferred from the customer data to the shop floor system to the process machine. Putting part specific data on control plans would have required 2 to 4 people doing nothing but creating custom control plans for each part with no added value. Customer drawings were used when specific requirements needed to be verified against the traveler, machine setting, etc. Buying software would not work. The company had an internally developed and maintained shop floor control system that while using outdated technology and ugly looking had better automatic traveler creation than anything on the market. The company wasted several million dollars (plus the software company likely wasted more) trying to replace it only to find they could not. A part specific control plan with all the part specific specs was only created if the customer was willing to pay for it, and once they visited and saw how automated things were, none ever did pay for one. We lost a few potential customers, but those customers were likely a poor fit anyway.
When you have proprietary processes, you have to keep the details out of the control plan. At a past job we had a process where the supplier of the process chemicals and equipment limited disclosure to need to know. Only about 20 people out of 300 had a need to know. Customers were out of luck. Many customers grumbled, but found everyone offering the process was subject to the same rules. We later developed a different proprietary process There was a lot of R&D involved but the end result only required one common chemical and three process parameters. Too easy for someone to memorize. Again not disclosed internally except on need to know. Again customers grumbled, but the choice was accept no disclosure of any type or we would not use the process. Since nobody else in the industry could do this combination of requirements, we did not disclose.