And the rule about needing a long land for a small-diameter pin seems to me to be an incorrect conclusion as a result of an unsupported length
The longitudinal modulus, transversal modulus, shear modulus, Poisson's ratio of composite material, unsupported length
, inside radius, thickness and winding angles of inner and outer layers of composite long cylinders are taken as random input parameters, and the critical buckling pressure is taken as random output response.
To suppress grip noise and minimise slippage, aluminium end tabs were bonded to the specimens reducing the unsupported length
to 150 mm.
The longer the unsupported length
of the sliding element the greater the bending moment at the plate-sliding element junction.
An ejector pin's unsupported length
is a critical variable and a common cause of its bending, buckling and breaking.
In that same formula, the unsupported length
is also proportional to the third power.
La is the unsupported length
of the hot sprue at ambient temperature; Tp is the processing temperature of the molding material.
With ejector pins and lifters that have too much unsupported length
and cavity surface area, the plastic pressure can deflect the component.
Excessive ejector stroke adds cycle time, extra mechanical friction, and excessive unsupported length
of components, which can lead to wear and failures.
The lifters were on a 7[degrees] angle but had too much unsupported length
. The plastic pressure was deflecting the lifter shank and pushing the lifter down during the injection process.
The unsupported length
is just as much a concern as the angle.
Three of the issues we discussed fall under the topic I will be discussing here, unsupported length
of mold components.