In order to ensure a good match between designed mold and injection machine, relevant data between the two must be checked, mold can be designed and injection machine model selected accordingly.
Aspects that require data verification include: injection volume, injection pressure, clamping force, installation size, mold opening stroke, ejection device.

 

Whether mold cavity can be filled with maximum injection volume allowed by injection machine is related. If there is a partial lack of glue in finished product, the most likely cause is insufficient injection volume. Therefore, when designing mold, it is necessary to ensure that the total amount of melt required by mold is within actual maximum injection volume of injection machine, which is equivalent to 80% of rated injection volume of injection machine.
Therefore: nm1+m2≦80%m
m1---weight or volume of a single finished product
m2---weight or volume of plastic required by pouring system
m ---Maximum injection volume allowed by injection machine (g or cm3)
n --- Number of cavities
Note: n is related to plasticizing rate of injection machine, maximum injection volume and clamping force, accuracy of finished product, and economics of production. Generally speaking, for every additional cavity, dimensional accuracy of finished product will be lower by 4%~8%, the higher mold cost will be. For example: Gears or blades can only be designed with 1*2 at most.

This is to verify whether maximum injection pressure of injection machine can meet needs of molding of plastic part. Injection pressure required for finished product is determined by factors such as injection machine type, nozzle form, plastic fluidity, flow resistance of pouring system and cavity, etc. Insufficient injection pressure will directly cause short shots.
Generally speaking, whether injection pressure is full for finished product can be controlled organically by adjuster. It should not be adjusted too high to prevent gate or insufficient strength of mold from being damaged by pressure or mold cannot be divided.

 

During injection molding, projected area of plastic part on mold parting surface is main factor that affects clamping force, and clamping force is proportional to projected surface. If clamping force provided by injection molding machine is insufficient, mold parting surface will not be closed tightly, contact and insertion will not be sufficient, which will directly cause burrs or flashing. Tonnage model of injection molding machine is determined by clamping force, formula for quickly calculating tonnage required for clamping force of injection molding machine is:
F1=(n A1+A2) P
A1---Maximum projected area of finished product, total length * total width unit: cm2
A2---Projected area of pouring system unit: cm2
P --- Pressure coefficient (high pressure: 0.75 tons/cm2, general pressure: 0.5 tons/cm2)
F1---Resin pressure unit: ton
F1≦80% F F---Clamping force of injection molding machine

In order to ensure that mold can be installed smoothly, it is very important to check installation size. In this link, designers often neglect problem due to excessive reliance on computer operations. As a result, mold cannot be tested on time.

Nozzle diameter dn and sprue bushing diameter dp, convex spherical radius of nozzle Rn and bushing surface radius Rp, must meet following relationships respectively.
dp=dn+1.0mm Among them, please refer to specific injection machine data for dn and Rn values.
Rp=Rn+1.0mm
Effective injection length of nozzle (length that can be extended into mold) and mold (especially hot runner system), sinking depth of sprue bushing should be well matched to prevent nozzle head from being unable to press against bushing.

Purpose of positioning ring is to ensure that center line of mold is overlapped with nozzle and center pin of injection machine after mold is installed, so that injection molding can proceed smoothly. A certain gap between locating ring dH and center hole dj of fixed pallet of injection machine is: dj=dh+(0~0.2mm). And locating ring has a thickness of 10mm in contact with center of pallet.

Mold thickness H (also known as closed height) must meet:
Hmin <H <Hmax
Hmin---Minimum distance between moving and fixed pallets
Hmax---Maximum mold thickness allowed by injection machine
Clamping thickness of injection machine is a range, and its value can be adjusted.

Mold is between uprights of injection machine on injection machine, the total width of all molds Wm and the total width of space between uprights
Safety relation of Wj deposit is: Wm≦Wj-50mm
If Wm value of mold is affected by Wj and there is no larger model injection machine to choose from, you can try to change "I" font to a straight mold for trial design
There are two common forms of mold fixing:
One is to directly fix with screws (used when pallet appears in the form of a screw hole in a fixed position);
The other is fixed with screws, pressure plate (or automatic pressure plate) (pallet appears in the form of a "T" groove). When fixing with a pressure plate, it is necessary to ensure that thickness difference between front and rear plates is less than 5mm, so that same type of pressure plate can be used.

 

Mold opening stroke refers to moving distance of movable mold fixed plate during mold opening and closing process. Its size directly affects height of finished product that mold can form. If it is too small, finished product cannot be taken out.
A simple method of weighing: When mold opening stroke of injection machine is less than twice the total height of finished product plus pouring system, finished product is difficult to take out. In actual calculation, mold opening stroke should contain a safety margin of 30-50mm for removal of finished product to suit action of manipulator, mold opening stroke has nothing to do with thickness of mold.

4.6.1 Verify position of KO hole opened on mold according to specific machine, and whether hole diameter matches it
4.6.2 Verify that ejection distance within reach of injection machine meets needs of ejection action of mold, especially in mold structure of second ejection, it is easy to produce insufficient ejection volume, or length of ejector rod is not long, and support columns must be added to the first two ejection plates.
4.6.3 In forced-return ejection mechanism, verify whether mold screw matches screw hole of ejector rod head of injection molding machine.