Draft angle
The draft angle of the molded part is a key parameter to facilitate the release of to the molded part from the mold cavity.
Using the wrong draft angle or surface finish of the mold cavity may prevent the mold from being opened, or cause the the molded product to crack during ejection, often resulting in defects such as galling.
Using the wrong draft angle or surface finish of the mold cavity may prevent the mold from being opened, or cause the the molded product to crack during ejection, often resulting in defects such as galling.
It is important to determine the value of the draft angle by considering the following :
- Material properties (molding shrinkage, stiffness and lubricity)
- Shape and structure of the molded product (height of the molded product in the mold opening direction, wall thickness of the molded product)
- Mold structure (extrusion direction)
- Mold accuracy (degree of finish of the mold cavity surface in the direction of molded product removal)
- Molding conditions (in-mold resin pressure)
A draft angle of 1 to 2 degrees is appropriate as a general rule. However, even if it is difficult to obtain a draft angle, a minimum of 0.5 degrees is a good guideline. Care must be taken to avoid overfilling for parts with small draft angles.
When graining the mold surface, increase the slope by 1º for every 10μ of grain.
Draft dimension quick reference table
(X : mm)
| Height (mm) | Slope | ||||||
|---|---|---|---|---|---|---|---|
| 1/4゜ | 1/2゜ | 2° | 3° | 4° | 4° | 5° | |
| twenty five | 0.11 | 0.22 | 0.44 | 0.87 | 1.31 | 1.74 | 2.19 |
| 50 | 0.22 | 0.44 | 0.88 | 1.75 | 2.62 | 3.50 | 4.37 |
| 75 | 0.33 | 0.65 | 1.31 | 2.62 | 3.93 | 5.24 | 6.56 |
| 100 | 0.44 | 0.87 | 1.75 | 3.49 | 5.24 | 7.00 | 8.75 |
| 125 | 0.55 | 1.09 | 2.19 | 4.36 | 6.55 | 8.74 | 10.94 |
| 150 | 0.66 | 1.31 | 2.63 | 5.24 | 7.86 | 10.49 | 13.12 |
| 175 | 0.77 | 1.52 | 3.06 | 6.11 | 9.17 | 12.23 | 15.31 |
| 200 | 0.88 | 1.74 | 3.50 | 6.98 | 10.48 | 13.98 | 17.50 |
| 225 | 0.99 | 1.96 | 3.94 | 7.85 | 11.79 | 15.73 | 19.68 |
| 250 | 1.10 | 2.18 | 4.38 | 8.73 | 13.10 | 17.48 | 21.87 |
| 275 | 1.21 | 2.39 | 4.81 | 9.60 | 14.41 | 19.22 | 24.06 |
| 300 | 1.32 | 2.61 | 5.25 | 10.47 | 15.72 | 20.97 | 26.24 |
Important Note:
We do not assure the quality or safety of products derived from our materials or suggestions. It is essential to determine the appropriateness for your product independently. Ensure adherence to laws, regulations and industrial property rights.
