Missing inserts in injection molding

S

sadhusong

hello all
we found one failure with plastic insert(should with metalic insert) and supplier give me the correct action is reduce the cushion tolerance, they explained if they reduce the cushion tolerance, when robot lose the metalic insert, cushion will be change, then control unit will find this.

but i am confused, when metalic insert missing, some other injection parameter such as injection time..also will change, why control unit did not find this?

any other commend from you?

thanks very much
 

harry

Trusted Information Resource
Re: inserts injection

hello all

We found one failure in a plastic part (without insert, it should be with metallic insert instead). The supplier said that the corrective action is to reduce the cushion tolerance. They explained that when the robot lost the metallic insert, cushion will change and if we reduce the cushion tolerance, then control unit will detect/find this.

I am confused. If metallic insert is missing, some other injection parameters such as injection time will also change, why the control unit did not detect/find this?

Any comments or ideas from you?

Hi,

I had edited your post so that others can understand your queries better and give their inputs. Kindly let me know if what was edited is what you are trying to communicate.
 
D

D.Scott

Re: inserts injection

hello all
we found one failure with plastic insert(should with metalic insert) and supplier give me the correct action is reduce the cushion tolerance, they explained if they reduce the cushion tolerance, when robot lose the metalic insert, cushion will be change, then control unit will find this.

but i am confused, when metalic insert missing, some other injection parameter such as injection time..also will change, why control unit did not find this?

any other commend from you?

thanks very much

I think the supplier is probably correct that reducing the cushion tolerance will probably detect the missing metal insert. My concern would then be the tolerance on the metal insert itself. The supplier may find that reducing the cushion tolerance might result in false rejects due to variance in the metal insert. The temptation to reduce false readings by increasing the cushion tolerance would bring the process right back to where you are now.

Whatever the supplier does as corrective action should be validated. You need to be sure there is no other problem caused by the C/A.

Dave
 

Wes Bucey

Prophet of Profit
I feel a little dense here. I know of several different ways to introduce metal inserts into a plastic molding process, each with its own peculiarities and potentials for error.

Perhaps if we had an idea of the robotic process used by the supplier to place the metallic inserts in the mold, we might be able to suggest mistake proofing methods to PREVENT the occurrence, rather than methods to DETECT missing metallic inserts. For instance, "HOW does the robot lose the insert?"

Much, of course, depends on the quantity and dollar volume of the order in order to "stimulate" the supplier to take mistake proofing action versus some type of "sorting" after production to reduce the number of nonconforming pieces reaching the customer.

Sometimes, suppliers do not possess the in-house expertise to perform a mistake proofing process. This is where big customers with knowledgeable Supplier Quality Assurance staff can be very helpful.

Depending on how crucial this product is to the [smaller] customer, it might be worthwhile to help the supplier find a consultant who can help provide the absent expertise.
 
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