State-of-the-art low-pressure plastic structural foam multi-nozzle molding machines allow us to mold very large plastic parts or run multiple molds on a single machine at the same time. This capability is driven by low-pressure injection molding multi-nozzle technology.
What is Plastic Structural Foam Multi-Nozzle Molding?
Multi-nozzle molding, also called sequential injection molding, is used for more complex designs and parts that can’t be filled from a single nozzle. The large press platens contain hundreds of inlet holes where multiple injection nozzles can be precisely located so the plastic will fill the hard-to-reach extremes of the tool. Multi-nozzle plastic injection offers a key advantage when producing very large or complex parts. The technique is used because it can greatly improve the cosmetic finish of a part.
Multi-nozzles eliminates the need for a hot runner system which saves on costs. Multiple tools with multiple cavities can be run at the same time using multi-nozzles and the large platen presses. This can be done on the same machine that would be used to mold a single large plastic part. Multiple materials or colors can be molded simultaneously.
Much like traditional high-pressure injection molding, structural foam multi-nozzle injection molding machines use a reciprocating screw and barrel to inject heated plastic into a tool. This however is where the similarities end. The most obvious difference is the size of the machines themselves. Structural foam multi-nozzle machines are large, so are the parts, and the design opportunities they provide to mechanical engineers. Unlike injection molding, plastic structural foam molding uses low pressure, gas-assist, and other unique methods to mold components or full assemblies up to 400 lbs. in one machine cycle.
With multi-nozzle molding the optimum number of injection nozzles can be located throughout the platen surface. Each is independently controlled producing the perfect fill and better finished product.
Shot size, sequence, open & close time, gas-assist and more is digitally controlled at each individual nozzle. This saves material and time and produces a higher quality product.
Multi-Nozzles Mean Multi-Options
Instead of a single nozzle, multi-nozzle structural foam presses have multiple injection locations. Using sequential injection molding, we have complete control over shot size, sequence, open & close time, gas-assist, and more through each individual nozzle.
One tool and cavity
A single large-sized part may be molded using four or the optimum number of injection nozzles. Each nozzle is individually controlled.
Multiple tools and cavities
The same press used to produce a single large part can also be run with numerous tools and cavities using many nozzles.
Structural foam molding and multi-nozzle produce a perfect fill for large parts or multi-part runs. Molds can be switch out or changed for future productions to give ever more flexibility.
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See a more in-depth guide to how multi-nozzle technology works!
Multi-Nozzles Give Complete Control
Instead of a single nozzle, a structural foam molding press has multiple injection locations, eliminating the requirement for a hot runner manifold system
Shot size, sequence, open & close time, gas-assist, and more are digitally controlled at each individual nozzle via sequential injection molding technology. This saves material and time and produces a higher quality product.
The nozzle inlet holes are spaced 6 inches apart. This allows precise positioning of every nozzle that is being used.
When to build a multi-cavity tool instead of multiple tools for a multi-component assembly.
Assume your program is an outdoor garden bin. Your product has 2 sides, a front, back, base & lid for a total of 6 parts. Once molded, the cabinet will be placed in a single package for shipping for the end-user to assemble.
This program could use 5 separate tools: 1 tool for the sides, 1 tool for the front, 1 for the back, 1 tool for the base, and another for the lid. Each tool would need to be running on a separate machine and would require a separate cell for final assembly and/or packaging. Since each piece will be running on a different machine, the color could have some variation between the 6 separate pieces.
This tooling strategy could be used in a multi-nozzle process; however, a larger machine would be needed to make up for the size in multiple tools. Unless the tool for the sides was a 2 cavity mold, it would also require more tool cycles to make a complete unit since the production ratio would be off. The material color would be uniform and the product could be packaged after molding.
Using the multi-nozzle process, you can fit each one of these parts in a single tool with 6 cavities. Or 6 separate tools all running at the same time in the same machine with the same mold cycle. The material color would also be uniform across all parts.