1. Mold opening direction and parting line
Each injection product must first determine its mold opening direction and parting line at the beginning of the design to ensure that the core-pulling slider mechanism is minimized and the effect of the parting line on the appearance is eliminated.
1) After the mold opening direction is determined, the product’s ribs, buckles, protrusions and other structures should be designed to be consistent with the mold opening direction as much as possible to avoid core pulling to reduce seam lines and extend the life of the mold.
2) After the mold opening direction is determined, an appropriate parting line can be selected to avoid undercutting in the mold opening direction to improve the appearance and performance.
Second, the draft angle
1) Proper demolding angle can avoid product fuzzing (drawing). The demolding slope of the smooth surface should be ≥0.5 degrees, the fine dermatome (sand surface) surface is greater than 1 degree, and the coarse dermatome surface is greater than 1.5 degrees.
2) Proper demolding slope can avoid product top damage, such as top white, top deformation, and top break.
3) When designing deep cavity structure products, the outer surface slope should be greater than the inner surface slope as much as possible to ensure that the mold core is not deviated during injection molding, to obtain a uniform product wall thickness, and to ensure the material strength of the product opening.
3. Product wall thickness
1) All kinds of plastics have a certain wall thickness range, generally 0.5-4mm. When the wall thickness exceeds 4mm, it will cause excessive cooling time and shrink printing, so you should consider changing the product structure.
2) Uneven wall thickness will cause surface shrinkage.
3). Uneven wall thickness will cause pores and weld marks.
Four, stiffener
1) Reasonable application of reinforcing ribs can increase product rigidity and reduce deformation.
2) The thickness of the stiffener must be ≤(0.5～0.7)T product wall thickness, otherwise it will cause surface shrinkage.
3) The single-sided slope of the ribs should be greater than 1.5° to avoid top damage.
Five, fillet
1). Too small rounded corners may cause stress concentration in the product, leading to product cracking.
2) If the fillet is too small, it may cause stress concentration in the mold cavity and cause the cavity to crack.
3) Setting a reasonable fillet can also improve the processing technology of the mold. For example, the cavity can be directly milled with an R cutter to avoid low-efficiency electrical processing.
4). Different rounded corners may cause the parting line to move, so you should choose different rounded corners or clear corners based on the actual situation.
Post time: Nov-19-2021