|
Gas Assist Molding FAQ's
What is the NitroJection Gas Assist Molding Process?
NitroJection is a revolutionary low pressure gas assist molding
process. During the gas assist process a calculated short shot of resin is
introduced into the mold. Flow runners or ribs direct material to the desired
areas of the part. Inert nitrogen gas is injected into the molten resin. The
nitrogen forces the material outward along the flow runners and packs the part
out under extremely low pressures. The NitroJection process is an extension of
the traditional injection molding process.
It can be added to any model injection molding machine. The
NitroJection process is capable of injecting nitrogen into the sprue or
directly into the part or runner system.
Why should I use Gas Assist Molding?
The challenges of today’s highly competitive and global market
place have dramatically increased the demands on the plastics manufacturer.
Today’s market requires improved quality, increased part complexity, reduced
time to market and lower product costs.
The process limitations of conventional molding systems are
inherently restricted in meeting these demands. NitroJection process expands
the capabilities of injection and structural foam molders. The Nitro process
improves part quality, increases design freedom and reduces cost.
Gas assisted molding is the fastest growing segment in the
plastics market. In many cases conversion from yesterday’s problem process to
today’s revolutionary solution is being done with current tooling. The list of
end users designing products utilizing gas assist is growing dramatically.
These are your customers today, if you don’t take the chance they maybe someone
else’s tomorrow.
What are the Gas Assist Process Advantages vs. Conventional
Molding?
NitroJection provides real solutions in overcoming the process
restrictions of conventional injection and structural foam molding.
| Injection Molding Restrictions |
Structural Foam Molding Restrictions |
-
Inability to mix thick & thin sections
-
Molded-in stress & warp
-
Dimensional instability as part cools
-
Surface imperfections (i.e.) sink
|
-
Swirled surface finish
-
Out-gassing of chemical blowing agents
-
Surface porosity
-
Cosmetic applications require painting
|
What are the other major advantages of the gas assist molding
process?
The low pressure gas assist process produces parts with thick
sections which are internally cored out. Properly designed flow runners
increase material flow and transfer packing pressure uniformly along the part.
This evolution in injection molding gives you the:
Gas Assist Advantages
-
Elimination of sink marks and molded in stress
-
Increased surface quality, dimensional stability, stiffness to weight ratio and
design freedoms
-
Reduced cycle times, material cost, clamp tonnage, tooling cost and total
product cost
What molded products are Gas Assist Applications?
Gas Assist technology has opened the door for a vast new array of
molded plastic products and also significantly improves production of
traditional plastic components. There are two basic part designs that can
benefit from gas assist molding:
1. Thick walled-tubular components or fully round product
designs
-
Thick walled components such as handles, hangers, arm supports, spoilers etc.
can benefit from material savings up to 50% and phenomenal cycle time
reductions. This is achieved with very little impact to part integrity and
function. In fact hollow tubular designs are inherently stronger.
2. Thin wall products or flat panels
-
Large flat parts such as auto door panels, grilles and business machine
enclosures benefit from substantial reductions in press tonnage, faster cycle
times, and elimination of molded in stress. These types of parts can be molded
warp-free with improved surface finished. Molds for large panels can be
constructed with a single center sprue gate eliminating costly hot manifolds or
valve gating. The gas assist process allows molders to run large components on
smaller presses using less costly tooling.
What products are currently using gas assist molding?
The gas assist molding benefits, increased design flexibility,
improved quality and lower part costs have met the challenges of parts in all
major industries. Shown below are the major industries and parts which gas
assist technology has commercialized.
| Industry |
Parts |
| Business Equipment |
Copier panels, doors, paper path components, side covers, cash
register/terminal components, printer housings |
| Medical |
Diagnostic machine covers, wheel chair hand rim |
| Furniture |
Office chair arm rests, seat backs and pedestal bases |
| House Wares |
Handles, towel rings, shovel handles |
| Automotive |
Interior & exterior grab handles, door panels, headlamp bezels, front
grilles, inner door panels, rear spoilers, body side moldings |
| Appliances |
Refrigerator handles, oven handles, ice maker components, washing machine
agitators and augers |
| Television |
Front bezels 27" and larger |
What equipment is required?
The gas assist NitroJection process can be easily adapted to any
existing injection molding or structural foam machines. This is done by adding
the stand alone, portable Processing Unit and a specialized nozzle which
injects and decompresses the nitrogen gas during the molding cycle.
 Return to prevoius page
|