The dimension of a mold attached to the molding machine is determined by the
shape of the relevant part or the ejection method, whereas there is a restriction
by the tie bar distance or mold clamping stroke, which limits the mold dimension
within the range.
The tie bar distance is set in accordance with a molding machine; therefore,
vertical and horizontal dimensions of a mold are determined in consideration
of the tie bar distance.
For the example shown in the figure below, the vertical and horizontal dimensions
of the mold will be as follows.
- Vertical dimension of part should be less than vertical size of tie bar
and horizontal dimension of part should be less than horizontal size of
tie bar
- Vertical dimension of part should be less than vertical size of
cavity plate and core plate and
horizontal dimension of part should be less than horizontal size of tie
bar
- Vertical dimension of part should be less than vertical size of tie bar
and horizontal dimension of part should be less than horizontal size of
cavity plate and core plate
- Straight Hydraulic Type
Since mold clamping stroke is predetermined for each molding machine, the
minimum and maximum thickness of a mold is determined in consideration of
the stroke.
For straight hydraulic method, as daylight (mold clamping stroke + minimum
mold thickness) is kept constant, the mold thickness determines the mold clamping
stroke.
- Set the minimum thickness of a mold higher than the minimum mold thickness
that is written in the manual of the molding machine.
Daylight = maximum mold clamping stroke + minimum mold thickness
- Set the maximum thickness of a mold lower than the minimum mold thickness
+ mold thickness adjustment value.
Daylight = minimum mold clamping stroke + maximum mold thickness
- Toggle Type
Since mold clamping stroke is predetermined regardless of mold thickness,
the mold thickness is adjusted by a mold thickness adjusting device that is
installed into the mold clamping device.
For toggle type, the daylight is determined by the mold thickness.
There are two types of mold clamping
device: straight hydraulic type and toggle type.
As straight hydraulic type utilizes hydraulic cylinder, mold clamping is
available anywhere within the stroke range.
On the other hand, since toggle type utilizes a mechanical device, mold
clamping is only available at the maximum mold clamping stroke. Therefore,
the mold clamping device has a mold pressure adjustment device.
