Pressure Die casting and injection moulding are very common types of industry, they are different processes, one for the production of metals; such as aluminium, zinc and magnesium alloys; and the other for the production of plastics. today lets talk about more detail on that.
High Pressure die casting
Under extra force of die casting machine,press Molten Metal into pre-build molding or tooling, after cooling down and shaped; get the casting parts. here the Molten metal normally means Aluminum alloy, zinc alloy, magnesium alloy and Copper and so on.
Pressure die casting process
this process have mainly below steps.
1.Molten ingot, like aluminium,zinc and magnesium; different material with different molten temperature.
2. Loading the die casting mold on machine, and heat the mold temperature to 200 degree, avoid mold crack when molten material contact dies.
3. Mold Opening, Spray the release agent on mold surface. so that parts will not stick in mold.
4. Mold closing, Ladle pouring the molten metal into Nozzle; and machine force pressure the material into tooling.
5. Holding Pressure, Extra pressure keep on press bar. to keep material into cavity.
6. Cooling, Cast parts will be cooling down and shaped.
7. Mold Open, Ejection systems working and eject parts out. the whole cycle is finish. then mold close, repeat next cycle.
Pressure die casting pros and cons
| Advantage | Disadvantage |
| High precision, thin Wall products, Minium:0.5mm | A relatively large production volume is required to make the process cost-effective |
| Fast Production | High initial cost |
| High automation | Wall thickness not over 6MM |
| Wide range possible shape | Draft radiu and fillets required on the casting |
| High efficiency | Can not run Heat treatment |
| Reusable | Easy have porosity |
| Anodizing, Hardening | |
Injection Molding
The injection molding machine screw rotates the molten plastic or polymers; and pushes it into a pre-fabricated mold, where it is cooled down, and obtain the product.
Injection Mold Process
Normally the injection mold process is similar with die casting process. but there also some significant different; like they use different material. the injection mold process have below main steps.
A. Dry plastic or polymer material. debug the moisture of material.
B. Loading injection tooling on machine; and heat the mold to proper temperature, different material require different mold temperature.
C. Check Mold function, cleaning the barrel of injection machine. and Close mold.
D. Injection material into mold cavity. this process around 0.5 seconds. extreme high speed.
E. Holding Pressure and cooling down. avoid mold shrinkage happen.
F. Mold Opening, Ejection systems eject parts out of molds.
Injection Molding pros and cons
| Advantages | Disadvantages |
| High precision, thin wall | High investment. Mold is expensive. |
| High strength and long lifetime | Mold building complex |
| Short cycle time, around 8~40seconds. | Machine investment is high |
| Over million shots lifetime | Need experienced technician and engineer |
| Complex shape |
Pressure Die Casting vs injection Molding
| Pressure die casting | Injection molding | |
| Material | Metal ingot(Aluminum,Zinc,Magnesium and copper) | plastic pallets; ABS,PC,PP,PBT and so on |
| Mold material | 8407,8418,H13 | S136,NAK80,718,738 |
| Mold Temperature | over 180 degree | around 100 degree |
| Mold Structure | relative easy | Complex, Various mold type, hot runner mold, insert mold, stuck mold, double injection mold and so on. |
| Machine | hot chamber die casting machine, cold chamber die casting machine | plastic injection machine; 2k injection machine |
| Molten Metal Temperature | aluminum 650, zinc magnesium | around 200 degree |
| cycle time | 7seconds~2minutes | 30seconds |
| tooling life | noraml 50K shots | 1000K shots. |
| Tolerance | 0.2mm around | 0.03mm around |
| Post Process | CNC Machining | N/A |
| Surface finish | sand blasting, power coating, Anodizing; Painting | Painting, Coating,Texture,Printing |
Which Process is more better for your Project?
Till now you already understand die casting and injection mold process. how you choose the process for you next project? first is function, metal die casting parts more strong and more longer life time then injection molding products. that’s obviously reason to choose.
Conclusion
Diecastor Precision is Experienced die casting company; offer aluminum, zinc and magnesium die casting molds and high quality parts. experienced technician and engineer; fluent the whole process and surface treatment. want to sourcing supplier for you next project? please contact us.