SEMCO Plastics

SEMCO Plastics

5301 Old Baumgartner Rd.
St. Louis, Missouri 63129
Phone: 314-487-4557
About the Company


We are located in St. Louis in a 400,000 sq. ft. facility that provides centrally
located shipping. Design, Development, Tooling, Production, Decoration,
Pack Out & Shipping all under one roof.

SEMCO is not reliant upon any one type of customer for its success. SEMCO
is a stable custom blow molding & large tonnage injection molding company
and we supply a wide spectrum of industry types & company sizes. Still family
owned by the 4th generation, SEMCO has made the commitment to provide
state-of-the-art new presses to quality control testing equipment to Wireless
Real Time Production Monitoring.

SEMCO offers Just In Time shipping, Vendor Management Inventory, EDI,
Full In-house PPAP Process, Robotic Automation Cost Reduction Programs
all managed by a state-of-the-art IQMS Software System.

Clean Room Molding

SEMCO's Custom Clean Room Molding utilizes state of the art HEPA air filter system with positive air flow to ensure ISO Class 8 Class 100,000 Clean Room Standards. Our custom tailored programs include automation, assembly, drilling, testing, packaging and continuous quality inspections provide the high quality standards you demand. SEMCO can offer part design, prototyping, Operational & Process Qualification, and production all under one roof.

Blow Molded parts provide an advantage when molding larger irregular shaped hollow parts. The Accumulator Head Blow Molding Method begins as an accumulator gathers melted polymer plastic. When the mold has cooled and enough plastic has accumulated, a rod pushes the melted plastic and forms the parison. The parison is a tube-like piece of hot thermo plastic with a hole in one end in which compressed air can pass through. The parison is then clamped into a mold and air is pumped into it. The air pressure then pushes the plastic out similar to a balloon to match the mold. Once the plastic has cooled and hardened, the mold opens up and the part is ejected trimmed of flash (excess plastic) and allowed to cool.

17 accumulator head blow molding machines

Single and Dual head presses

1/2 pound up to 35 pound shot size

Insert molding with robotic placement

High density polyethylene and engineered materials

SEMCO Plastics is equipped with large volume silos and rail capacity to buy resins at the best market price available to handle large tonnage parts.

Large Tonnage Injected Molding can be done easily here at SEMCO Plastics with the emphasis on transforming metal components through our design engineering department. These parts have a cost advantage when comparing to assembled metal components, painting or finishing.

SEMCO brings to the table Full Turnkey Operations including:
3, 4, and 6 Axis CNC routers and robotic automation
VA/VE Programs (value added/value engineering)
Design Engineering EDI (Electronic Data Interface)
Silk Screen Printing
Ultrasonic Welding
In Mold Decorating
Custom Foam Filling
Hot Stamping
Pad Printing
Pressure Foam Filling
Gel Insertion Filling
Custom Assembly, Press Fitting, Riveting and Drilling
Low pressure containment vessel, leak testing
Custom Labeling
Custom Packaging
Retail Packaging and Pack-Out
JIT (Just in time)
Real time monitoring of production
ERP State of the art IQMS. System to manage the everyday operations
Research and Development