Non-naturally balanced feed system for an injection molding apparatus
A low constant pressure injection molding machine forms molded parts by injecting molten thermoplastic material into a mold cavity at low constant pressures of 6,000 psi and lower. As a result, the low constant pressure injection molding machine includes a mold formed of easily machineable material that is less costly and faster to manufacture than typical injection molds.
1. A non-naturally balanced feed system for an injection mold of an injection molding apparatus, the injection mold having a plurality of mold cavities, the plurality of mold cavities receiving molten plastic at a substantially constant viscosity, the non-naturally balanced feed system comprising:
wherein the feed system maintains a balance of 90% or greater;
a hot runner having a first feed channel that terminates at a first mold cavity in the plurality of mold cavities and a second feed channel that terminates at a second mold cavity in the plurality of mold cavities;
a gate for receiving molten plastic, the gate being in fluid communication with one of the first and second feed channels; and
wherein a temperature of molten plastic flowing through the first feed channel is different than a temperature of molten plastic flowing through the second feed channel.
2. The non-naturally balanced feed system of claim 1 , wherein a first cross-sectional shape of the first feed channel varies along a length of the first feed channel and a second cross-sectional shape of the second feed channel varies along a length of the second feed channel, wherein the first cross-sectional shape varies differently than the second cross-sectional shape.
3. The non-naturally balanced feed system of claim 1 , wherein a length of the first feed channel is different than a length of the second feed channel.
4. The non-naturally balanced feed system of claim 3 , further comprising a third feed channel terminating at a third mold cavity in the plurality of mold cavities, wherein a length of the third feed channel is different from a length of one of the first and second feed channels.
5. The non-naturally balanced feed system of claim 4 , wherein a length of the third feed channel is different from a length of the first feed channel and the length of the third feed channel is different from a length of the second feed channel.
6. The non-naturally balanced feed system of claim 1 , wherein at least two mold cavities in the plurality of mold cavities are oriented differently from one another in a common face of the injection mold.
7. The non-naturally balanced feed system of claim 6 , wherein the at least two mold cavities have different shapes from one another in the common face of the injection mold.
8. The non-naturally balanced feed system of claim 1 , wherein at least two mold cavities in the plurality of mold cavities have different shapes from one another in a common face of the injection mold.
9. The non-naturally balanced feed system of claim 1 , wherein at least one feed channel is formed from aluminum.
10. The non-naturally balanced feed system of claim 1 further comprising a heating element in thermal communication with the first feed channel.
11. The non-naturally balanced feed system of claim 10 , wherein a thermal conductivity of the heating element is substantially equal to a thermal conductivity of the material forming the mold.
12. The non-naturally balanced feed system of claim 10 , wherein the molten plastic has a melt pressure that is a substantially constant pressure that is less than 6000 psi.