One. The reason why the product produces a weld mark:
1-1 Since the first part of the molten material is cooled and solidified, no streaky weld marks are formed in the merged flow.
1-2 due to air and material volatiles are blocked
A release agent remains in the 1-3 cavity.
two. Associated knowledge:
2-1 Using a gate, there is generally no weld mark in the product that does not join the material from the two directions. In addition, if you want to avoid the weld mark, you can only change the position of the gate so that the weld mark occurs inconspicuous or Looks pleasing to the eye. (Figure A)
2-2 The pin on the mold (the hole in the product) usually has a weld mark. (Figure A)
2-3 There are many phenomena that cause the weld marks to be blocked by the air, so the air must be completely escaped.
2-4 is also useful in this way: the place where the weld mark is produced occurs on the excess sheet of the product, and then the sheet is cut (Figure C).
2-5 Excessive release agent causes the first part of the molten material to float into the cavity, and a weld mark will definitely occur.