1. The main cause of this issue is insufficient of heat acetate. It cause front and arms not fit the shape of a persons head. If insufficient of heat acetate, acetate eyewear, sunglasses will have some kinds of not good changes.
Acetate eyewear arms
–One change is that arms are too straight and do not have enough curve to fit the shape of a persons head.
Acetate eyewear front
–Other change that front too much curved inward and it makes arms very close to each other.
Too close between arms will causes the acetate eyewear very uncomfortable to wear for customer
–Another change is that front too straight and it makes arms very far away each other.
It causes the frame very uncomfortable to wear for customer
Aoker manufactory has detailed rules and addition steps for heating acetate.
The other manufactory doesn’t have time enough and addition steps for heating acetate compared with Aoker.
2. Maintain shape problem (it involves fix front, arms, arm opening size, screws tightness etc…)
Usually Maintain shape is processed by very skilled stuff. It is to make acetate eyewear in good shape and comfortable wear. But if insufficient of heat acetate, even if the stuff maintain shape perfectly, after a few time, the acetate eyewear must be loose shape quickly.
BTW, the acetate eyewear in folding condition in retail packing for a long time, it can cause right arm less curved than left arm. This is due to the gravity of acetate eyewear makes right arm less curved. So when maintain arms, right arm need curved a little bit more than left arms, in this way, the gravity of acetate eyewear will make the equal curve of arms. Aoker manufactory realized this issue.