Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Tooling

[Bjourne]

Hi guys,

I work for a small sub-contract semiconductor manufacturing firm and I would like to ask for help from you about starting a Control Plan for specific toolings that we have in the production shop. This is a first as we do not have one. What we have as Control Plan is Control Plan for production process.

What needs to be considered on a specific tool like a mold tool? (not necessarily a semiconductor mold tool, any tooling like punch and die or stamping tool would do as long as it is critical to your process)

If you guys have a sample of such a Control Plan for Mold Tooling, well not necessarily mold tooling, maybe just a sample pertaining to a specific tool (critical tool is preferred) so I can base that on our manufacturing toolings.

Here is what our blank control plan sheet looks like but this one is tailored made for a specific customer's manufacturing process.

This is not my normal work as I am a technician but now the team is involving me in this endeavor. I would like to contribute as much as possible and learn how to make one.

Among the existing controls for tooling parts for punch/die sets are the tool life data spc which is derived from:

a. number of hits (SPC trend chart)
b. surface(side) measurement of punch / die tooling to determine wear (SPC trend chart)

For mold toolings we have:

a. number of shots
b. plunger pot diameter (SPC trend chart)
c. plunger tip diameter (SPC trend chart)

Plunget pot data

Number of shots (Mold)

Plunger tip data

Now for mold there are other parts of the mold tool like the mold chases (top/bottom) which do not have control at the moment. I just know that they are refurbished when damaged which is about yearly.

I know the data I provide is insuffucient at this time but I'd like to ask for help how you preventive maintenance/equipment guys do it and if possible share some samples from which I can help derive a better control plan.

Any inputs and sample share will be a great help for me

Thanks

 

[Stijloor]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

A Quick Bump!

Can someone help?

Thank you very much!!

 

[Bjourne]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

I know my question on this post is overwhelming or may generate mixed reactions but please do bear with me on this...

I may also have erred there because the plunger tip/pot is not part of the mold tool but that of the mold press. So currently the only control we have for the mold tool(chases etc) is the PM procedure which is of a general detail only.

I think this topic is related to a generation of a Machinery FMEA first and then doing the Control Plan based on the FMEA? If so may you guys help me on this one? Since I see in this forum that the majority of the molding process discussed is "injection molding", probably we can start there so a Machinery FMEA can be derived from it...?

I have not done a full FMEA on my own (process FMEA exposure only) I just help out when I can.

Thank again

 

[Bjourne]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

Anyone pleasseeeeee........

 

[Bjourne]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

Anyone...maybe just a reference guide so I can start on the right track...thanks

 

[Marc]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Tooling

<snip> What needs to be considered on a specific tool like a mold tool? (not necessarily a semiconductor mold tool, any tooling like punch and die or stamping tool would do as long as it is critical to your process)

If you guys have a sample of such a Control Plan for Mold Tooling, well not necessarily mold tooling, maybe just a sample pertaining to a specific tool (critical tool is preferred) so I can base that on our manufacturing toolings.

Among the existing controls for tooling parts for punch/die sets are the tool life data spc which is derived from:

a. number of hits (SPC trend chart)
b. surface(side) measurement of punch / die tooling to determine wear (SPC trend chart)

For mold toolings we have:

a. number of shots
b. plunger pot diameter (SPC trend chart)
c. plunger tip diameter (SPC trend chart)

Now for mold there are other parts of the mold tool like the mold chases (top/bottom) which do not have control at the moment. I just know that they are refurbished when damaged which is about yearly.

I know the data I provide is insuffucient at this time but I'd like to ask for help how you preventive maintenance/equipment guys do it and if possible share some samples from which I can help derive a better control plan.

Any inputs and sample share will be a great help for me

Thanks

I'm not familiar with control plans specifically for tooling. I am very familiar with production control plans. Are you asking what to put on a production control plan for tooling aspects?

 

[Chennaiite]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

Hi Bjourne,

Keep it simple. A good process FMEA and Production Control plan will take care of all controls required for the tools such as what needs to be monitored, in what frequency, how to measure, etc. Why do you have to do a different FMEA/Control plan when tooling is very much part of the process. You already seem to have identified some check parameters for monitoring in a different tool perhaps. By what methodology you arrived at those?

Another way is to go back to the table and analyze your past problems. Just understand how many of them were caused by the tools and by monitoring what parameters these problems can be prevented from recurrence. Nothing teaches us better than what past problems do.

 

[Bjourne]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

@Chennaiite,

Thanks for the reply.

Keep it simple. A good process FMEA and Production Control plan will take care of all controls required for the tools such as what needs to be monitored, in what frequency, how to measure, etc. Why do you have to do a different FMEA/Control plan when tooling is very much part of the process. You already seem to have identified some check parameters for monitoring in a different tool perhaps. By what methodology you arrived at those?

Another way is to go back to the table and analyze your past problems. Just understand how many of them were caused by the tools and by monitoring what parameters these problems can be prevented from recurrence. Nothing teaches us better than what past problems do.

We have actually the process FMEA for the mold process itself. The Control plan is also in place. One of our customers is requiring us that we must have a machinery FMEA for our machine and critical toolings and a separate control plan for them. The data above are all existing monitoring (SPC trend charts). I wanted to help in the generation of the required Machinery FMEA and Tooling Control Plan but I have no experience with it. This is a first for me so I am trying to understand it still also the reason why I asked if someone has some reference I can look at so I can base the data that we have here.

As of the moment we are backtracking data where we have encountered some defects attributed to some toolings but it's a slow pace and some still need to be proven / validated.

On the machinery FMEA, I have downloaded one here from Ford (from Ford Machinery FMEA) but it would really be a great help if there's something similar (how ever small it maybe to molding and toolings) I can base my data.


@Marc,

Thanks for the reply.

I'm not familiar with control plans specifically for tooling. I am very familiar with production control plans. Are you asking what to put on a production control plan for tooling aspects?

-- For the molding process and the related process before / after mold, we have the control plan in place(including the process FMEA). This is a new requirement actually from one of our customers to have a "specific" Control Plan and FMEA for existing machinery / toolings that are connected with their products. All the data that we have for toolings are only based on (mostly) the tool life (based on wear) like that of the punch die sets and of the plunger pot/tip. The rest like that of the parts I have mentioned, say, top/bottom mold chases and their parts do not have monitoring on it.

As mentioned above in my reply to Chennaiite, I have downloaded the sample machinery FMEA that was from Ford here but the sample is not related to molding / toolings. It would be very helpful for me/us to understand the data generation better if it were a bit similar (even if it's vaguely similar) to the process and toolings used. We have some data jotted down from the past weeks but it's still on a slow roll..like ice fishing I might say

I also sent some email to some of our machine manufacturer's (existing or still operating manufacturer's) and even some that refurbish / repair toolings for semiconductor equipment/toolings but sad to say not one has replied. I believe it is they who know more about the critical parts of toolings because they are the ones that are refurbishing/repairing it. Definitely we will require all machine makers of new machine/toolings and parts to furnish us the needed data prior qualification but that's a step away from this problem that we have now.

That is the dilemma we are now facing here...

 

[Marc]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

First - This is a stamping mold, correct?

I don't have much direct experience in mold tooling. Over the years when I was involved in mold tooling I was always "up stream" - There were always tooling engineers whom I interfaced with and they handled that aspect. I don't remember ever having seen an FMEA for a mold, and I have never done an FMEA for a mold (or mold tooling for that matter) so there's not much I can add with regard to specifics. Chennaiite cited some of the basics. And you identified:

Among the existing controls for tooling parts for punch/die sets are the tool life data spc which is derived from:

a. number of hits (SPC trend chart)
b. surface(side) measurement of punch / die tooling to determine wear (SPC trend chart)

For mold toolings we have:

a. number of shots
b. plunger pot diameter (SPC trend chart)
c. plunger tip diameter (SPC trend chart)

What is really needed here, if any are lurking about, is feedback from a mold engineer.

My experience with molds was basically what you mentioned: Tool Wear as a maintenance function. Feedback from production is an input to maintenance just as many pieces of machinery have hour meters and failure indicators. If the maintenance system is working, they will get process feedback either as something like number of hours, number of cycles, or a failure whether somewhat gradual (our plunger pressure is falling and we can't adjust it upward any further with the regulator) or "catastrophic" (as in it just stopped working). These are just a few things to think about. Again, I'm not a tooling engineer so thinking back to what I do know about molds and mold tooling my knowledge is limited.

I wish I could help you more personally, but without an engineer to talk with I can't add to what has been said.

That said.... The level of detail is typically decided upon when a *team* does an FMEA. You mentioned, for example, the mold chases. I would look to the past and decide whether that is even a critical aspect if, as you say, they only see refurbishment after what sounds to me like a catastrophic event such as a press crash of some sort.

Now for mold there are other parts of the mold tool like the mold chases (top/bottom) which do not have control at the moment. I just know that they are refurbished when damaged which is about yearly.

I don't know whether you have investigated why/how they are damaged.

Maybe there is a mold/mold tooling engineering lurking that help in this.

 

[Bjourne]

Re: Need help with a Control Plan for Encapsulation Mold / Trimming / Forming Toolin

Thanks for the reply.

First - This is a stamping mold, correct?

I don't have much direct experience in mold tooling. Over the years when I was involved in mold tooling I was always "up stream" - There were always tooling engineers whom I interfaced with and they handled that aspect. I don't remember ever having seen an FMEA for a mold, and I have never done an FMEA for a mold (or mold tooling for that matter) so there's not much I can add with regard to specifics. Chennaiite cited some of the basics.

This is a transfer encapsulation mold tool much like an injection mold. Smaller/lighter in size, say, 4.9 to 7 tons.

One of our resin suppliers with a GIF animation of how to encapsulate leadframe semiconductor devices
http://www.hitachi-chem.co.jp/english/products/srm/011.html

Plastic encapsulation molding process used in semiconductors.
http://www.ami.ac.uk/courses/topics/0269_pem/

As mentioned this is a first for us also. The tooling engineers that have started here have gone to some greener pastures and have left almost all to newbie engineers who I am sad to say have not been exposed to the semiconductor industry long. For some of them this is their first job and mostly rely on technicians to guide them through.

That said.... The level of detail is typically decided upon when a *team* does an FMEA. You mentioned, for example, the mold chases. I would look to the past and decide whether that is even a critical aspect if, as you say, they only see refurbishment after what sounds to me like a catastrophic event such as a press crash of some sort.....

I don't know whether you have investigated why/how they are damaged.

Maybe there is a mold/mold tooling engineering lurking that help in this.

There are some data (validated) that we have obtained like,

1. stained / dirty cavity (bottom mold chase parts) that have been caused by prolonged use of the mold without cleaning beyond the time it was intended. It was so because the company was in a cost-cutting scheme and cut the cleaning materials in half. That act caused the mold to stain. Now the stain is imprinted onto the molded plastic IC which was rejected as per customer spec. The cavity bars was sent out for refurbishment. Production delay due to the refurbishment was experienced.

2. dirty cavity which caused cracked parts after the mold cycle. Ejection(after molding cycle) was not smooth because the molded parts stuck to the dirty mold cavity. Again the cause was the same as of above.

3. cracked center block which was caused by a bottom spring plate accidentally detached from the resin-pellet loader. The bottom spring plate was left on the bottom mold chase and then got clamped damaging the top/bottom mold chases. This was negligence of the mold operator not checking the top/bottom mold before clamping/mold cycle. The bottom spring plate was found to be loosening but was not checked properly prior production use. Again negligence of the individual. Downtime was 2 hours replacement including mold prep. Parts where sent out for refurbishment.

The other data we are still validating for true root causes. The downtime / end result we have as when we have damaged tooling (re: damaged tooling > stop production> replace > prep mold again > re-qualify > resume production)

Really hoping there are some mold engineers lurking around as I see that there are some injection molding related topics posted here...