Whenever we engage with our casting supplier to reduce defects, they usually come up with corrective actions like "add chill", "add material", "change gating", etc.
I have noticed that defects at a particular location in casting varies with the pour date. This points to the direction that their process in not in control, and that there is process variation present.
So the next time our supplier suggested another pattern change, I asked them to rather try controlling their process first. For example, amount of metal in ladle, control of total time required to fill the mold, etc.

However, our supplier is adamant not to even try any such process control measures.

I am not a casting guy. So I am wondering if I asked something which is beyond foundry practices?!

So I need confirmation if it really is absurd (my choice of word) to ask a foundry to try some process control. Can anyone help?

Thanks.

Whenever we engage with our casting supplier to reduce defects, they usually come up with corrective actions like "add chill", "add material", "change gating", etc.
I have noticed that defects at a particular location in casting varies with the pour date. This points to the direction that their process in not in control, and that there is process variation present.
So the next time our supplier suggested another pattern change, I asked them to rather try controlling their process first. For example, amount of metal in ladle, control of total time required to fill the mold, etc.

However, our supplier is adamant not to even try any such process control measures.

I am not a casting guy. So I am wondering if I asked something which is beyond foundry practices?!

So I need confirmation if it really is absurd (my choice of word) to ask a foundry to try some process control. Can anyone help?

Thanks.

My father was a salesman for a foundry in the 80's which sold castings to Ford. Even the sales staff was required to take courses in control charting. He got sent to a Deming 4 day seminar.

The general impression I get from him was that they only went through the motions to keep Ford happy, but there is at least some precedent for SPC in foundries. No reason a foundry couldn't implement process controls, and if the customer pushed a little harder than Ford did in order to see that the charts were actually used, you would be far ahead of the game.

I am not a casting guy. So I am wondering if I asked something which is beyond foundry practices?! So I need confirmation if it really is absurd (my choice of word) to ask a foundry to try some process control. Can anyone help?Thanks.

You are correct. A world class foundry will have robust process controls in place. These process parameters will have come from computer based solidification and fluid flow simulations.

Twenty years ago, foundry work stopped being an "art" with the availability of relatively inexpensive simulation software. Your foundry should be able to demonstrate "for sure" that the new chill location or gating change will work based on model results, otherwise they are falling back on the black arts (essentially guessing).

That said, you won't find world class process control in a foundry selling at the world's lowest price. Good luck.

I have personally worked as a caster and been over casting in a Quality role.

It is possible to control there processes. We had a variance of +/- 5% for all of our process parameters. If the process could not be run in that level than it was shut down.

We also tested all of our melting parameters and were required to stay with-in them. If they were out, (Quality audited them 3 times a day) then the Metallurgist had to make a call if he would ok the product. Quality always put the material on hold until he SIGNED off on the product.

Along with process control they should really have summer/winter parameters. With the drastic change in temperatures, (if you are in the norther states) the process acted much different in the summer vs winter. We changed our degas times to get more impurities out of the metal during the summer because there was more water in the air.

Whenever we engage with our casting supplier to reduce defects, they usually come up with corrective actions like "add chill", "add material", "change gating", etc.
I have noticed that defects at a particular location in casting varies with the pour date. This points to the direction that their process in not in control, and that there is process variation present.
So the next time our supplier suggested another pattern change, I asked them to rather try controlling their process first. For example, amount of metal in ladle, control of total time required to fill the mold, etc.

However, our supplier is adamant not to even try any such process control measures.

I am not a casting guy. So I am wondering if I asked something which is beyond foundry practices?!

So I need confirmation if it really is absurd (my choice of word) to ask a foundry to try some process control. Can anyone help?

Thanks.

May I share a real world audit story? A few years ago, I audited a company that bought castings and machined them. Their incoming defect rate was 10%, plus even more that were discovered after they began to machine them. I suggested that 10% was very high, and they said it was normal for castings.

They also said it wasn't a problem, the supplier reimbursed them. I pointed out that there were a lot of additional costs they weren't considering, and those were not reimbursed. But, it was their money, and their choice. I justed wanted to point it out and wrote an OFI.

Upon finishing that audit, my next stop was to do an assumption audit at a casting house, as luck would have it. That caster was running at virtually 0 external ppm! They agreed to let me tell my previous client.

First my client did not believe me, then they took action. Six months later, their incoming defects were at 4%, and 12 months, they were at 2%.

When I asked what they had done, they said first and foremost, they simply told their current suppliers that they had found a supplier with 0ppm, and that 10% was no longer acceptable. A few other things too, but that was the main catalyst. It's amazing what can change when we have the right motivation.

A few other things too, but that was the main catalyst. It's amazing what can change when we have the right motivation.

There must be various things the casting supplier might have tried. Do you know if they needed to have improved process controls?



That said, you won't find world class process control in a foundry selling at the world's lowest price. Good luck.

That is the sad part. Their casting is not cheap.
The only advantage they have is their quick (emergency) development time. A good foundry will take time to develop a product using FEA etc. Product thus developed experiences far less defects.
On the other hand our supplier can send new product samples in half a time. It is another thing that only when production starts does our manufacturing finds about myriad of problems. And then corrective actions start...

Once a part is in production, it is very difficult to change a supplier of as basic a component as casting. We are thus stuck with them for the life of product.

There must be various things the casting supplier might have tried. Do you know if they needed to have improved process controls?

I'm sure the casters did many changes, but I was not privy to what was done. I would point out that for the performance to improve that dramatically and so quickly, some of it had to simply be they started to pay more attention.

It is not your job to tell them what to do. But, you can collaborate with them if they are willing.

Visual Surfaces - appearance criterias.

1. Die casting
We are having some suppliers that die cast products that are visible. It is also machined to get rid of the parting lines etc but then pores are revealed. After painting (at another company) it is even more prominent. Moment 22.

Have any of you any likewise experience with appearance and die casted product?

Is it a good idea to have a die casted product in applications with "high" surface demands? (Visible area, interior parts for automotive industry)

Someone who has a surface class standard for visible die casted products (ASTM ??? only defines pores inside the material, correct)?

And for you who has experience with die casted products: what is the process capable to do regarding to appearance criterias?

2. Extruded Alu profiles
Is anyone familar with a surface class standard for anodized extruded aluminium profiles?
Anyone with experience who has some good recommondation how to handle visual surfaces?

(Two different suppliers having two different standards, not really coherent. We have not found any OEM customer that have standards for this, so it would be very welcomed if there was a common way to assess the appearance.)

Any experiences told, suggestions and advices are highly appreciated!

BR

I agree that your supplier isn't really 'trying' to do the right thing. I've worked with a very excellent casting supplier. From my knowledge of their process, the FMEA showed that it wasn't often the position of runners, risers, gates amount of metal etc., but many other parameters that affected the casting integrity.

Has your supplier ever done an FMEA on the process?

No, Andy. They have not done FEA.
It's not surprising that they claim that they don't make money on this product. How can any industry make profit when fallout rate is upto 10%?

Lately they have refused to continue business with us, which is trouble for us in short run, but will be worth headache in the long run.

This new supplier is a well established multi-national foundry. So we hope to have good relationship with them.
Icing on the cake is that they are significantly cheaper as well.

Visual Surfaces - appearance criterias.

1. Die casting
We are having some suppliers that die cast products that are visible. It is also machined to get rid of the parting lines etc but then pores are revealed. After painting (at another company) it is even more prominent. Moment 22.

Have any of you any likewise experience with appearance and die casted product?

Is it a good idea to have a die casted product in applications with "high" surface demands? (Visible area, interior parts for automotive industry)

Someone who has a surface class standard for visible die casted products (ASTM ??? only defines pores inside the material, correct)?

And for you who has experience with die casted products: what is the process capable to do regarding to appearance criterias?

2. Extruded Alu profiles
Is anyone familar with a surface class standard for anodized extruded aluminium profiles?
Anyone with experience who has some good recommondation how to handle visual surfaces?

(Two different suppliers having two different standards, not really coherent. We have not found any OEM customer that have standards for this, so it would be very welcomed if there was a common way to assess the appearance.)

Any experiences told, suggestions and advices are highly appreciated!

BR

I am a caster that has to meet very subjective visual characteristics. We supply engine components for Motorcycles. Unfortunately, there are no real standards for visuals. It is truly subjective. The only saving grace is a good APQP process. Collect a lot of samples and retain those samples for each possible defect. I know this is not the answer you are looking for but it is truly a challenge. I feel your pain.

We are not a die caster. We are perm mold (gravity pour) and low pressure molding. Our visuals are more influenced by the operator than in Die casting.

Whenever we engage with our casting supplier to reduce defects, they usually come up with corrective actions like "add chill", "add material", "change gating", etc.
I have noticed that defects at a particular location in casting varies with the pour date. This points to the direction that their process in not in control, and that there is process variation present.
So the next time our supplier suggested another pattern change, I asked them to rather try controlling their process first. For example, amount of metal in ladle, control of total time required to fill the mold, etc.

However, our supplier is adamant not to even try any such process control measures.

I am not a casting guy. So I am wondering if I asked something which is beyond foundry practices?!

So I need confirmation if it really is absurd (my choice of word) to ask a foundry to try some process control. Can anyone help?

Thanks.


I have worked in casting for some time. I have worked in Die Casting and perm mold and sand casting. Each type of casting has different level of process control. If you are manually ladeling metal you will have different potentials than in an automated die casting ladel. Die casting can do signifcant process control. In my experience, a good RAW die casting PPM is 8,000 or less. If you are in perm mold (gravity pour) it will be significantly higher.

The best way to maintain good process controls in a foundry is metal temp at time of injection or pour and specific gravity of the metal. The die coating affects a great deal but unless it is automated in its application, there is no good way to control it.

In short, it is possible to have good process controls but there are only truly a handful of parameters that will give a consistent part.

My 2 cents........:D

I appreciate your comments. Thanks!

Thanks alot for the inputs from foundry guys. Can anyone share a control plan for sand casting moulding and melting processes.

New to the industry, trying to bring some ideas learnt in semiconductor. Do describe any application of process control charts if any.

Thanks alot for all yor assistance.

IQBAL:agree::applause:

Thanks alot for the inputs from foundry guys. Can anyone share a control plan for sand casting moulding and melting processes. New to the industry, trying to bring some ideas learnt in semiconductor. Do describe any application of process control charts if any. Thanks alot for all yor assistance.
IQBAL

You will most likely only see "generic" control plans that say things like "see set up sheet". Very little of any value will be shared.

Foundry suppliers to the "old" big three have seen their CP given to competitors, basically giving away all the hard won tricks to their competitors.

I suggest looking at the AFS bookstore for what you are after.