Pre-Launch vs Safe Launch

[optomist1]

FULL DISCLOSURE IHAVE NOT READ ALL THE REPLIE…First, nice Elsmar Name - "Leftoverture", I like it...if you are in the automotive field, err noiw called mobility field, your OEM/Prime should have a very specific process set up, with terminology and concise definitions...

My two cents as someone who has purchased and had suppliers under my control providing injection molded parts those that are of various classifications in terms of “surfaces”, We as a customer both in supplier quality and engineering were always anxious to get a look at “first off parts” to get an idea of the Rainey issues or the tools needed to be modified or reworked etc., mainly appearance issues… I hope this input is some value to you cheers Optomist 1

 

[Johnny Quality]

leftoverture,

Your organization sounds like a carbon copy of ours and what @John C. Abnet says is what we do.

Don't overthink it. The "pre-launch" control plan can simply be the intended mass production control plan "plus". The resultant mass production control plan may turn out to be the pre-launch control plan, "minus".

We ramp up inspection on the first few pre-production runs so we have lots of data on process variation. Once we can use the data to predict the tool performance and process variation, we remove a vast majority and reduce the frequency unless there is justification for keeping it.

 

[leftoverture]

leftoverture,

Your organization sounds like a carbon copy of ours and what
We ramp up inspection on the first few pre-production runs so we have lots of data on process variation. Once we can use the data to predict the tool performance and process variation, we remove a vast majority and reduce the frequency unless there is justification for keeping it.

Thank you so much for the reply. That is helpful! May I ask, what size is your molding facility? How many presses and how many QC on each shift?

 

[Johnny Quality]

30 presses.

Single shift, visual QC one shot every hour by an inspector. Dimensional QC one shot at start of shift. If we are pre-production it's dimensional QC every hour until we know what the tool is like, then we reduce variation with processing and/or tool modifications and reduce dimensional inspection.

 

[leftoverture]

30 presses.

Single shift, visual QC one shot every hour by an inspector. Dimensional QC one shot at start of shift. If we are pre-production it's dimensional QC every hour until we know what the tool is like, then we reduce variation with processing and/or tool modifications and reduce dimensional inspection.

Thank you so much. This is very helpful. You are correct, we are very similar. We have 26 presses, but we run 3 shifts. We run 2 inspectors per shift. How many do you have? Are you doing any SPC?

 

[Johnny Quality]

One inspector can cover all 30 machines but that is pretty much all they do. Another inspector manages first off/last off and general QC administration.

Apparently we used to do SPC for customers who requested it, but for our processes I've found it far more valuable to ensure standard setting conditions, mould heaters regularly services and set correctly, raw material conditioned correctly, mould tool serviced regularly. Most of the variation and issues I've found are from those factors, as well as suitable tool design. Our biggest problem parts are from tools with 20g shot weight, 18g of which is sprue. Customer is responsible for tool design. Drives me mad.

Someone has a paper here on SPC and injection moulding and how they've found it doesn't really work, the variation is too small if your processes are setup correctly. If I can find it again I'll link it here.