First Articles Review

Mar 25,2019

After the mold manufacturing done, it is the most exciting moment to test the mold and get the first articles.

For Injection mold review and first sample confirmation, Lyter Engineering Team will check below items.

1. Exterior:
Is the surface texture correct?
Are there impurities in the material?
Are there any bumps or scratches on the surface of the product?

2. Parting Line:
Is there a front in the parting position?
Is it a die? (Note that the hole position is also easy to produce a die and cause the hole to deform)

3. Gate:
Infer the location of the weld line according to the gate distribution, and check the weld line.
How to repair the excess material at the gate?
Can the local location far away from the gate be full?
If glass fiber is added to the raw material, the gate is prone to flashing, and the surface of the product is prone to floating fiber.

3. Deformation:

Plastic products usually produce internal shrinkage and deformation, which cannot be fundamentally avoided.

Therefore, the design should consider adding necessary ribs or reasonable structure to avoid deformation.

4. Shrink:

Shrinkage usually occurs on the back of thick glue and ribs

5. Stress marks:
Stress marks usually occur at the position of the thin glue and the back of the thimble or tube.

6. Thimble:
Is the distribution of thimble uniform and reasonable?
In order to avoid assembly interference, the thimble is usually recessed into the product by 0.05~0.1 mm.
When the product is ejected, is the back of the thimble white?
Does the thread clamping burr of the thimble exceed the design requirements?
In order to avoid sticking to the front mold, an undercut structure will be added to the top of the thimble, which will be reflected on the product after demolding, and it needs to be repaired in a subsequent process.

7. Slide block, Inclined top:
There will be traces around the slider, the insert and the inclined top. Is it within the design allowable range?
When demolding, the inclined top position is prone to shoveling glue.

8. Insert:
Insert injection molding (such as sheet metal parts, nuts, etc.)
After the product is molded, the nut must be hot-melted. At this time, it is necessary to determine the torque, the pulling force and whether the glue overflows.

9. Key dimension measurement:
Measure and verify key dimensions.

Three ways to deal with unqualified dimensions:

①Supplier improvement;

②Accept (given the allowable range value);

③Modify the drawing tolerance.