Steps in Mould Design: Study of The Component Drawing
Steps in Mould Design: Study of The Component Drawing
Steps in Mould Design: Study of The Component Drawing
In designing a mould for manufacture and production, many aspects of the component, material
(both plastic and steel), construction of the mould, the moulding machine, machining facilities. . .
need to be considered. Suffice it to say that the design of the mould should be optimum.
Mould-related decisions
Number of cavities
Parting Line – flat, inclined, stepped (metal-matching draft of minimum 3⁰), profiled, 3D, . . .
Gate type and position – Sprue, Edge, Tunnel, Curved Tunnel, Pin-point, Diaphragm, Ring, . . .
To ensure that the Core and Cavity butt together (Parting Surfaces butting together}, create
a gap between their holder plates.
On each plate, provide two pairs of tapped holes on two opposite outside sides for lifting the
plates.
Mill Pry-bar slots on each plate at the 4 corners (or in the middle of each edge).
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Increase the Ejector Stroke by 8 to 10 mm, more than the minimum required by the
component.
Unsupported span in Ejector Grid to be minimum: make changes from the sizes given in the
catalogue.
Provide Ejector Guides, when there are Ejector Pins less than ø6. Ejector Guide Pillars of
ø16. Provide 2 Ejector Guides when Ejector Plate size is less than 300 x 300 mm and 4
Ejector Guides when it is bigger size.
When Ejector Plate width is narrow, check whether 2 Return Pins are enough.
Provide Eye Bolts with Carrier Bar on the top of the mould.
Provide Mould Feet (at bottom of the mould) towards the 4 corners of the mould.
Prefer direct clamping of the mould to the machine. Otherwise, Strap Clamps may be
used. Refer Machine Platen diagram.
Guide Pillars should engage in the Guide Bush before Cavity approaches the Core. Hence,
Guide Pillar lengths should consider this aspect.
For round Core Pins, procure the next larger sized diameter Ejector Pin from the catalogue.
Cut it to the length required and modify the tip.
Water lines should have a minimum gap of 5 mm with Ejector Pin hole / Core Pin hole /
Insert opening / tapped holes.
Change positions of Water line, Ejector Pins and tapped hole, as necessary.
Other details
Boss
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Ejector Adaptor
Runner
Tunnel Gate
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Gate Insert for Pin-point Gate
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Machine selection
Apart from Mould Bases and Ejector Pins, Latches, Springs, many other elements
and mechanisms are also available in the market. Providing these elements will
allow shorter mould manufacturing time and the mouldmaker can focus on the
manufacture of Core, Cavity and other important items.
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