Nylon 66-structure standard test 2

[henks580]

Our products have been experiencing voids and jet stream flow lines on their nylon structure. Some of the factors contributing to this can be attributed to cleanliness, vents clogged, contaminated runners, etc... what I'd like to know is if there is any type of standard test that can be performed on these parts eg. hardness, or structural test....any studies to quantify qualitatively voids and correlate that to potential failures of the structure.

-henry

 

[ujeff]

hello
in my previous job we used to make glycol bath. The parts are stored in the hot (I do not remember the testing conditions)bath for a certain time. If there are air traps, burned material surface or flow lines the glycol corrodes the PA. If the part is molded correctly, the glycol won't correde it.
The tests were made with PA66 glass fiber reinforced. I do not know much more, since it was not my job, but maybe it is a hint for you ....
jeff

 

[mjh368]

why dont you just fix your mold. the factors you have attributed to you voids are the least of your concern except maybe the vents, but there are solutions for that too.

I would make good parts instead of measuring the "badness" of bad parts.

 

[patprimmer]

Just weigh the parts.

Bad mouldings will be light weight.

Also test material (especially regrind) for moisture before use.

Also as previously suggested, fix the mould and control the moulding parameters.

It sounds to me like the gate is to small, and probably in the wrong position.

It also sounds like wet material.

The effective hold up time might be to short.

The injection speed might be to high.

Simply wiping the vents with a rag every 1/2 hour or so can help.

Making vents with a short land with minimal gap to avoid flash, then a very large channel to atmosphere helps as they then self clean.

Regards

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