Injection Mold 100% Visual Inspection - Short Shots and Debris not being found

[Avogel]

I have been in the automotive industry for 12 years now. I always seem to run into the same issues. My new employer (non union) is having an issue with short shots and debris not being found in-process and turning up at the customer.
The process is 100% visual inspection and in alot of cases, because of internal and external containment requirements, it is 200% sometimes 300% visual.
In my experience I would look at this as a systemic issue and would want to ensure that the operators and inspectors are given proper training, tools, lighting, and time to do their visual job. I would look at the process itself and implement 5s Lean, and quality alerts.
Ultimatly the I weed out the bad performers based on evaluations.
After that I always seem to scratch my head. I know that it could be a reflection of the culture, or executive commitment, but how do I report that to the Operations Manager and Owner?
I posted this to hopfully start a thread of ideas and brain storming.
Thanks,

 

[Proud Liberal]

From one injection molding quality mgr to another, I think you're looking in the wrong place. The problem isn't the detection rate, it's the occurrence rate. There is something wrong with your process. Talk to your molding technicians.

I've been down your path. The problem is there isn't a big enough stick to beat the operators with. Quality is not an inspection process, it's a design process. There's something in the design of your molding process not up to the task. Check your cushion.

 

[Big Jim]

Its the same old story. You don't inspect quality into a part.

That said, I feel you do indeed have something wrong with the operators or inspectors. Can't you track back to the offenders from lot of batch code information? You should be able to pin down the shift, operators, and even machine. If you can't, you need some effort given to set up a more responsive traceability program.

 

[Claes Gefvenberg]

The process is 100% visual inspection and in alot of cases, because of internal and external containment requirements, it is 200% sometimes 300% visual.

In the light of previous 100% inspection discussions you may want to have a look at the summary in the old thread How effective is 100% inspection?

/Claes

 

[bobdoering]

The process is 100% visual inspection and in alot of cases, because of internal and external containment requirements, it is 200% sometimes 300% visual.

You have pretty much proven your current system is ineffective, so continuing to use it is not going to resolve the issue. It's like having a gas tank with a leak, and you add more gas gages on the dash to fix it. You still need to deal with the process issues that are the root cause of the problem. Sounds like that line item of the FMEA needs some serious review.

Beyond that, you may want to consider other systems for inspecting the parts. Are these issues capable of being detected by weight or other physical attribute? Can they be seen by cameras? Have you tried to get any help from people in the vision system field?

 

[somashekar]

From one injection molding quality mgr to another, I think you're looking in the wrong place. The problem isn't the detection rate, it's the occurrence rate. There is something wrong with your process. Talk to your molding technicians.

I've been down your path. The problem is there isn't a big enough stick to beat the operators with. Quality is not an inspection process, it's a design process. There's something in the design of your molding process not up to the task. Check your cushion.

Process setting and then uninterrupted cycles are the key things to look for. We had flaps that could be set to divert first few shots into RED bin and the inspector would clear parts in the run when the flap then diverts parts to GREEN bin, and a confirmation inspection is made. Any stop for any reason, and then when start, the flap is set to RED bin again for inspection. 100% inspection is such a waste of time, let alone 200% or 300%. You need to build it into your moulding process based on your tool complexity and tool condition.

 

[tbsiva]

In terms of injection moulding process, if the melt cushion of the machine is consistent, the most probable reason for shortfill could be the interruptions in moulding cycle... Better to look into your start/stop procedures of moulding machine and also the effeciency of detection controls available in the moulding shop whenever there are interruptions

 

[Phil Fields]

I have been in the automotive industry for 12 years now. I always seem to run into the same issues. My new employer (non union) is having an issue with short shots and debris not being found in-process and turning up at the customer.
The process is 100% visual inspection and in alot of cases, because of internal and external containment requirements, it is 200% sometimes 300% visual.
In my experience I would look at this as a systemic issue and would want to ensure that the operators and inspectors are given proper training, tools, lighting, and time to do their visual job. I would look at the process itself and implement 5s Lean, and quality alerts.
Ultimatly the I weed out the bad performers based on evaluations.
After that I always seem to scratch my head. I know that it could be a reflection of the culture, or executive commitment, but how do I report that to the Operations Manager and Owner?
I posted this to hopfully start a thread of ideas and brain storming.
Thanks,

Can you convert your findings into $$$$? What is the cost of 100, 200,300% inspection? Cost of possible loss of work due to poor quality?
What is the opportunity cost for improving the process (install cavity pressure transducer), 5s, and training?

Phil

 

[trainerbob]

I would be checking the consistency of your injection cylinder strokes. The issue sounds like it is in the equipment, not in the money wasting inspection processes. You are not pushing enough or you are pushing too much material into the mold. Inspection cannot fix that. Machinery PM, setup, etc. That is where I would be looking.

 

[shantelwhite]

You can not inspect quality into a part. Look at the process to see if there is anything that can be done to fix the issues.