NPI Team
Tooling Fabrication
Injection Molding
Value-added services



Injection Molding

Plastic injection molding is our expertise and core business activity. Over the past years, Shengguang has not only accumulated the knowledge of conventional molding, but also gas-assist molding, structure foam molding.

What is Structural Foam Molding

Structural foam molding is a modification of the injection molding process. Many large structural parts require thicker walls than standard injection molding can produce. Structural foam molding allows for the injection molding of thick wall parts through the addition of a foam agent. Any injection moldable thermoplastics can be foam molded. To produce the thicker wall part, a small amount of nitrogen or chemical blow agent is introduced into the plastic material. Under pressure inside the injection screw, the foaming agents do not expand. When the melted plastic enters the mold cavity, foaming occurs. As the foaming plastics fill the mold cavity, the wall of the part solidifies against the cold mold wall. A thin layer of plastic solidifies without foaming along the mold wall. This thin layer forms a skin structure over the foamed inter core. The thin solid wall is supported by the interior cellular foamed structure. A part produced this way results in a heavy cellular structure similar to wood products.
Common structural parts take advantage of the large size, thick walls (less than .500 inch) and dimensionally stable properties of a foamed-product. Typical products are large trash containers, freeway sand safety containers, and in-ground housing for water systems. Large instrument case housing has been successfully molded in thin walls of more than .250 inch using high impact and dimensionally stable polycarbonates. However, the post molding costs of filling and finishing the swirl surface and the corrosive problems of the blow agents has restricted the application of formed molding.

Molding Machines

ˇńRoutine Machine Calibration Program
ˇńPreventative Maintenance Program
ˇńComputerized Production and Process Monitoring System
ˇńTemperature Controlled +/- 2 Degrees
ˇńLighting Level of 100 F/C Through The Molding Area
ˇńCapability Analysis On Key Process Parameters



ˇńBasic Molding Industry Operator Training
ˇńJob Specific Operator Training
ˇńVisual Acuity Monitored With Annual Eye Exams
ˇńStatistical Process Control Charting Capabilities
ˇńProcess Control Engineers Available On All Shifts
ˇńTrainer Auditors Monitor Production Regularly




ˇńFull 24 Hour Operation, 7 Days Per Week
ˇńSecondary Operations Within Product Cycle
ˇńIn Process Inspection and Test Of Production
ˇńStatistical Process Controls On Key Dimensions
ˇńComputerized Order Entry and Scheduling System
ˇńResponsive and Preventative Mold Maintenance Program
ˇńFull 24 Hour In-House Mold Repair Capabilities


Material Integrity


ˇńLot Trace ability
ˇńSupplier Performance Audits
ˇńStandardized Mixing Ratios and Methods
ˇńMoisture Monitoring and Controls
ˇńMelt Flow Testing
ˇńShot/Barrel/Residence Time Analysis
ˇńRunnerless Molding For Specific Applications
ˇńPackaging For Product Integrity