Draft Angle of Rapid Tooling
By Nice Rapid | May 30 , 2020

The draft Angle is also known as the stripper Angle, which is designed on both sides of the bore for the convenience of the die. The orientation of de-molding Angle shall be determined according to the internal and external dimensions of the plastic parts. In order to make the molding products can be successfully ejecting from the mold, in the same direction as the mold opening and closing of the wall surface (including side core and reinforcing rib), it must be set to draw die slope to facilitate the release of the mold.


The size of plastic parts de-molding Angle, and the nature of plastic parts, shrinkage, friction factor, plastic wall thickness and geometric shape. The Angle of de-molding of hard plastic is larger than that of soft plastic. For plastic parts with more complex shapes or more forming holes, take a larger Angle of de-molding; The plastic part height is larger, the hole is deeper, then takes the smaller de-molding Angle; The wall thickness is increased, the force of the inner hole wrapping the core is large, and the Angle of de-molding should be larger. Sometimes the bevel is intentionally reduced or the bevel is enlarged in order to leave the molded part inside the die or on the core when the die is opened.


In addition, no matter convex, concave die and insert block or even sliding block have to have the slope, usually the minimum die drawing slope is 5., generally speaking, to 7. The above is good, and its direction is based on the machine's jacking rod or cylinder action direction. Especially when the concave die surface has etched, more attention should be paid to the issue of the draft Angle.


As the parts cool, they contract towards the core. The draft Angle helps the parts avoid the influence of the core. Even if there is an idea to cancel the drawing Angle, but also must not cancel the drawing Angle. If the drawing Angle is reduced, the locking force of the part will be increased and the force required to remove the part from the mold will be increased. Molding time has to be extended to allow the parts to cool enough to be removed from the mold. Because the parts have to be cooled to enough rigidity that they can eject without deformation. This cooldown can account for 50 to 80 percent of the overall molding time. On the contrary, the larger the drawing Angle is, the less force is needed to disassemble the part from the mold, and the shorter the time is for the part to be disassembled from the mold.

Please feel free to contact us at enquiry@nice-rapidtooling.com if you have any other questions about draft angle in rapid tooling. We looking forward to your enquiry. 

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