Gas-Assist Injection Molding from AdvancTEK
Advanced Gas-Assist Solutions for Complex Injection Molding Challenges
AdvancTEK delivers specialized gas-assisted injection molding services that solve complex manufacturing challenges while reducing costs and improving part quality. Our advanced nitrogen gas injection processes enable the production of parts that would be impractical or impossible with conventional injection molding.
How Gas-Assisted Injection Molding Works
Nitrogen is introduced to the part after the first stage injection has completed. With the aid of the nitrogen gas pressure, the part can be packed without having to use injection pressure to pack in more material to achieve the same aesthetic results.
This innovative process transforms how manufacturers approach complex part geometries, offering solutions that traditional injection molding simply cannot match.
Internal vs. External Gas-Assist: Understanding Your Options
Internal gas-assist is introduced directly into the melt stream, allowing the part to be packed from within the wall thickness.
External gas is introduced to the “B” side of the part, allowing the part to be packed from the “B” side surface, packing the material to the “A” surface.
Internal Gas-Assist Benefits
- The gas is contained within/internal to the part
- Can be used with or without an overflow depending on the specific use of the process
- Great for hollow handle applications
- Lower clamp tonnage required for packing
- Increased design flexibility
- Can reduce molded-in stress by reducing pack pressures
- Can create a functional channel for both sink reduction and strength
- Good surface finish
- There can be additional tooling costs for gas pins and gas channels
- Can be used simultaneously with EGM
External Gas-Assist Advantages
- Reduced press size requirements – in many cases reducing clamp requirements by over 50%
- Increased design flexibility, but some custom design elements are required to facilitate the EGM process
- Gas external to melt on B side – pressing material to A cosmetic side
- In some cases, it can slightly extend cycle due to reduction of material contact to the B side steel
- Good cosmetic surface on the cavity side only – all sink is located to the non-cosmetic B side
- Can have significantly thicker rib- or boss-to-wall ratio without sink marks
- Reduced molded-in stress reducing/eliminating part warpage or twist
- Does not help with mold filling as internal gas does, but can be used simultaneously with internal gas
- There is some increased tooling costs for sealing of the mold and ejector system
- Some decrease in part weight due to reduction/elimination of second stage pack
Gas Counterpressure: Additional Surface Quality Enhancement
Another process using nitrogen gas is called gas counterpressure. In this process, the cavity is pressurized with nitrogen gas prior to injection of the resin, and the pressure can improve both surface cosmetics and part strength. The process is most commonly used to improve surface/part skin quality by reducing flow and swirl inherent to structural foamed components.
Complex Manufacturing Problems We Solve
Gas-assist can help create geometries that otherwise would be impractical in conventional injection molding, such as the thick wall section of a grab handle. Gas-assist can also decrease the amount of tonnage required to fill out a part, reducing energy and cost associated with having to run it with a larger press.
This process can allow large parts to be molded in a lower tonnage press, which can provide an opportunity to reduce the manufacturing cost.
Key Problem Solutions
- Thick-walled sections without sink marks
- Large parts requiring reduced tonnage
- Complex geometries impossible with conventional molding
- Cost reduction through energy efficiency
- Enhanced part strength and quality
Industry Expertise and Technical Know-How
A gas-assist process that injects nitrogen directly into the wall stock requires a specialized component (gas-pin), whereas external gas can be introduced through a core pin or pins, located on the core side of the part. Gas can be introduced to the parts in a number of strategic locations depending on the part design requirements.
Our engineering team understands the nuances of gas injection placement, timing, and pressure optimization. This technical expertise ensures your parts meet key specifications while maximizing the cost and quality benefits of gas-assist technology.
Why AdvancTEK Is Your Source for Gas-Assisted Injection Molding
AdvancTEK’s engineering team has extensive experience with both tooling and processing for internal and external gas-assist technologies, as well as the unique capability to combine both processes within the same mold. This expertise opens up design possibilities that other manufacturers simply cannot offer, giving you a partner who has truly mastered these advanced manufacturing techniques.
An Example of a Successful EGM Part
Below, we have supplied two External Gas-Assist (EGM) samples. On the left side is with the gas turned off, and on right side is with the gas activated. These examples were shown at trade shows by the inventor of the EGM process, James W. Hendry.
“The relationship is extremely positive. Basically, without AdvancTEK support, we would not have been able to solve our emergency situation and, for me, I see the relationship as a true partnership vs. a customer/supplier relationship. I look forward to developing the relationship for years to come.”
Material Compatibility and Capabilities
Our gas-assist services work with a wide range of materials, ensuring flexibility for your specific application requirements. Both the Concord and Saltillo facilities have gas-assist capabilities.
Frequently Asked Questions About Gas-Assisted Injection Molding
Can gas-assist parts achieve the same level of quality as a painted part?
In most cases, gas-assisted production parts can meet the normal cosmetic results that would be achieved from a straight injection part. It will not, however, completely eliminate knit or flow lines.
Does “gas-assist” increase piece price over conventional IM?
This is a part-specific result. The weight reduction from reduced packing pressure in the molding pressures can offset the additional cost of the gas process.
Which types of plastics are more suited for gas-assist?
Both amorphous and semi-crystalline materials are suitable for gas assist. Long glass-filled resin products can present processing challenges.
Get Gas-Assisted Injection Molded Products
Contact us today for more information on our abilities in gas-assist injection molding! We’re standing by to help.