Ejector Pins and Draft
Ejector Pin Marks
Optimum greatest depth of cored holes as related to diameter is shown in the table. The values shown for hole depths are subject to the draft requirements.
Location of Ejector Pins
Ejector pin locations shall be at the option of the die caster subject to the customer’s agreement where required.
Acceptable Ejector Pin Marks
Ejector pin marks on most die castings may be raised 0.38mm maximum or may be depressed 0.38mm maximum. Ejector pin marks are surrounded by a flash of metal. If end use permits, ejector pin mark flash will not be removed. Where this is not suitable, such ejector pin mark flash may be crushed or flattened.
Note – Complete removal of ejector pin marks and flash by machining or hand scraping operations should be specified only when requirements justify the expense involved in the extra operation or operations necessary.
All walls on die castings normally vertical to the parting plane of the die casting die require draft or taper. This draft is not constant. It will vary with alloy used and with the depth of the wall as indicated. Draft required on outside walls is half of that required on inside walls.
It is a good policy to specify a large draft angle wherever practical but angles of one degree or less are tolerable.