Month: June 2020

Undesirable phenomenon:

1. Bubbles inside the product, NG for light guide (as shown below).

2. Deformation of the elastic reset buckle of the product (as shown below).

Reason: Due to the long packing pressure of 11×11×11 during molding, the PC material has poor fluidity. The design diameter of the main channel ∅4 affects the fluidity during molding. The size of the inlet: 0.8×1.2, which affects the inlet Unreasonable ejection design for speed and pressure. Only 4 ∅1.5 ejectors are ejected. Due to the large injection pressure required by the light guide, ejection is unbalanced and the product sticks to the mold.

Function: drive thermal induction roll paper thermal printing.

Undesirable phenomenon: flow marks on the surface of the product, runout degree 0.1mm, actual measurement: 0.22mm, judge NG.

Reason: The product uses POM material. The melting temperature of POM is close to the decomposition temperature, and the moldability is poor. When the material flows to the position of PL during molding, there are surface flow marks, resulting in a runout of 0.1mm. The actual measurement is 0.22, NG.

Material: PP + E / P-TD20.

Undesirable phenomenon: oil accumulates on the parting line after the product is sprayed, and the appearance is judged to be NG.

Reason: There is a mismatch in the parting position of the product, and the mismatch is 0.05mm. Due to the corresponding injection in the rear stage of the product, the appearance is NG. The mold price is controlled within the tolerance range of 0.03, which is the direct cause of the mismatch. The reason is the mold temperature difference between the cavity and core. (50 ℃ for the cavity and 25 ℃ for the core during injection).