Query on Poly Carbonate (PC) - Durability of the Product

[vivkrish]

Hello All..!

This is Vivkrish,

I have faced one problem on our product which was produced on Polycorbonate (Unfilled) clear color material.

During Durability of the product (After 40,000 Kms running of the vehicle) the product gets dull in visual, Not in whole area of the product (Some area only).

Why it gets dull in visual? any idea..! Pls share.


Regards,
Vivkrish.

 

[howste]

Since we don't know what your part's shape and function is and what kind of durability testing was done, I don't think we can answer your question without more information. Is it being subjected to some kind of bending force?

I assume you're talking about polycarbonate.

 

[NikkiQSM]

More information pertaining to the type of testing you are conducting could help to answer.

But from what you have provided, it sounds as though the PC part is developing stress fractures at the point when you are apply pressure.

While PC is strong, it can stress, break and shatter if not properly processed. PC requires drying before being processed / molded. If it is wet during this process, you will surely lose physical properties and the part can become brittle.

Was the material properly dried before being molded? If so, what was the moisture level?

 

[vivkrish]

Since we don't know what your part's shape and function is and what kind of durability testing was done, I don't think we can answer your question without more information. Is it being subjected to some kind of bending force?

I assume you're talking about polycarbonate.

Hello Howste,

I will answer your question. My product is head light of the passenger car. After it sale to the end customer it was happened with 40000 kms runs the vehicle. Rather than atmospheric force no other force applied on it.

As per you statement it was right we are talking about Poly carbonate material which was used to produce Outer surface (Lens) of the product.

Thanks,
Vivkrish.

 

[vivkrish]

More information pertaining to the type of testing you are conducting could help to answer.

But from what you have provided, it sounds as though the PC part is developing stress fractures at the point when you are apply pressure.

While PC is strong, it can stress, break and shatter if not properly processed. PC requires drying before being processed / molded. If it is wet during this process, you will surely lose physical properties and the part can become brittle.

Was the material properly dried before being molded? If so, what was the moisture level?

Hello NikkiQSM,

As my statement above we are not applying any external stress on the product, rather than atmospheric pressure. We were doing pre-drying before molding. The moisture level of the material before molding is 0.01% which we accept because, as per our raw material manufacturer comments. They fixed the maximum moisture level before molding should be 0.02%.

I have mentioned durability is nothing but after the car sale we fixed some time duration as a durability period. We have faced the problem within this period.


Thanks,
Vivkrish.

 

[Miner]

My product is head light of the passenger car. After it sale to the end customer it was happened with 40000 kms runs the vehicle. Rather than atmospheric force no other force applied on it.

As per you statement it was right we are talking about Poly carbonate material which was used to produce Outer surface (Lens) of the product.

You are limiting your thinking to mechanical forces, which go beyond wind. You could also have abrasion from airborne particulates and gas pump window cleaning squeegees, vibration transmitted through the chassis, gravity causing creep, etc.

There are other forces that affect reliability such as thermal (internal heat from lamp/external ambient heat), electrical, radiation (e.g., UV light from sun) and chemical (e.g., car wash cleaners, gas pump window cleaners, road salt, bug guts).

 

[vivkrish]

You are limiting your thinking to mechanical forces, which go beyond wind. You could also have abrasion from airborne particulates and gas pump window cleaning squeegees, vibration transmitted through the chassis, gravity causing creep, etc.

There are other forces that affect reliability such as thermal (internal heat from lamp/external ambient heat), electrical, radiation (e.g., UV light from sun) and chemical (e.g., car wash cleaners, gas pump window cleaners, road salt, bug guts).

Hello Minor,

I agree with you. If I suspect your points is main root cause for the failure means, i need to get the dull shade in whole area.But Its not like that. I have the problem in small area only. That why I can't conclude. Any other factors please.


Thanks,
Vivkrish.

 

[Miner]

I have the problem in small area only. That why I can't conclude. Any other factors please.

Is the small area immediately in front of the headlamp? If so, heat may be a cause, or an accelerating factor.

 

[vivkrish]

Is the small area immediately in front of the headlamp? If so, heat may be a cause, or an accelerating factor.

Hello Miner,

Yes, Small area only affected.

I have dismantled the product and verified. It looks like smoke formation inside the lamp.
While wiping by hand it sticking on the hand. But not in black color. It was in light grey.

Can we suspect with the electrical devices(Bulbs, Leveling device) inside the lamp.

Thanks,
Vivkrish.

 

[kuyakut]

Hi,

Your molded part may have mold in stress wherein if it is subjected to thermal stress such as heat for bulb and heat form the sun it becomes blurry on some areas.
We always do annealing at Tg temperature of the plastic if we found out our parts have extreme mold in stress.