Calculation of the Stripping Force
For most of the operations, stripping force range is from 10 to 20% of the cutting force. If the tool has more than one punch the stripping for that tool is the sum total of the stripping forces required for each punch.
Because the average thickness of plastic parts and the ratio of the diameter of its hole: t/D = 6/22 > 1/20, so here consider as thick-walled cylindrical plastic parts. According to the literature [43] equation 4-26: release force calculation formula is:
F = (2πrESL (f – tan φ) + 0.1A)/ ((1 + μ + K1) K2)
In the formula above: F - Release force (N);
E - The elastic modulus of plastic (MPa) (available in the literature [61],(2-12) r - Core size of the average radius;
S - The average shrinkage of plastic molding (%); t - The average wall thickness of plastic parts (mm);
L - Core length of package (mm); μ - Plastic Poisson's …show more content…
Ejector pins are mounted into the moving half in the ejector plate housing. At the end of the molding cycle when the mold opens, part will move with the moving half. Then the part is ejected by the ejector pins.
There are many ways to fix the push rod on a fixed plate, this design uses the most commonly used form, which is, press the shoulder of the push rod between the counter bore and push plate of the push rod holder and tighten with the screw shoulder height and the depth corresponding to the depth of the counter bore left margin, after assembly with the push rod fixed plate with the margin, to ensure a high degree of consistency, to avoid the back and forth in the height direction of movement.
The ejector pin contacts with the molded part of the moving half in the ejector plate, and the template with the corresponding holes in the gap should not exceed the plastic flash gap which is limit. Under these circumstances, H8 / f7 or H7 / f7 fit clearances with general requirements for fit
For most of the operations, stripping force range is from 10 to 20% of the cutting force. If the tool has more than one punch the stripping for that tool is the sum total of the stripping forces required for each punch.
Because the average thickness of plastic parts and the ratio of the diameter of its hole: t/D = 6/22 > 1/20, so here consider as thick-walled cylindrical plastic parts. According to the literature [43] equation 4-26: release force calculation formula is:
F = (2πrESL (f – tan φ) + 0.1A)/ ((1 + μ + K1) K2)
In the formula above: F - Release force (N);
E - The elastic modulus of plastic (MPa) (available in the literature [61],(2-12) r - Core size of the average radius;
S - The average shrinkage of plastic molding (%); t - The average wall thickness of plastic parts (mm);
L - Core length of package (mm); μ - Plastic Poisson's …show more content…
Ejector pins are mounted into the moving half in the ejector plate housing. At the end of the molding cycle when the mold opens, part will move with the moving half. Then the part is ejected by the ejector pins.
There are many ways to fix the push rod on a fixed plate, this design uses the most commonly used form, which is, press the shoulder of the push rod between the counter bore and push plate of the push rod holder and tighten with the screw shoulder height and the depth corresponding to the depth of the counter bore left margin, after assembly with the push rod fixed plate with the margin, to ensure a high degree of consistency, to avoid the back and forth in the height direction of movement.
The ejector pin contacts with the molded part of the moving half in the ejector plate, and the template with the corresponding holes in the gap should not exceed the plastic flash gap which is limit. Under these circumstances, H8 / f7 or H7 / f7 fit clearances with general requirements for fit