Secondary Operations: Plastic Injection Molding Assembly and Finishing

Secondary operations are the processes of plastic injection molding assembly and finishing that occur after a part has been molded. These processes complete the production of plastic parts and add value to your products.


At Port Erie Plastics, we have extensive experience with assembly, including having the ability to tackle complex assemblies. This includes multiple molded parts being assembled using purchased components such as latches, springs, rods, aluminum extrusions, and more.

In-Line and Off-Line Assembly

In-line assembly occurs during the production process. Workers are assigned a specific task and complete it before sending the product further down the assembly line.  On the other hand, off-line assembly occurs after the production of the individual parts has been completed.

Off-line assembly does have constraints and can be difficult work.  At Port Erie, we combine engineering and automation in order to complete as many processes as possible at the injection molding machine—saving time by consolidating and streamlining the production process.


Pad Printing

This decorating technique transfers a 2D image onto a 3D plastic part using an etched plate. Pad printing allows for the printing of multiple colors on complex surfaces, such as concave or convex parts.

Heat Transfer

The process of heat transferring bonds high-quality digitally printed or screen-printed images to the plastic part or product using heat and pressure. Heat transfer allows for full-color printing and requires no cure time, so it is ready to ship right away.

Hot Stamping

Hot stamping combines heat and pressure to transfer pre-dried ink or foil to a plastic part. The process yields a reflective or high gloss color to raised areas. It is a durable printing process and can be paired with all thermoplastics.

In-Mold Decorating

In-mold decorating allows for the high-precision machining of plastic parts with specific colors and a high-quality appearance. During the process, a premade applique is placed into the mold before the injection molding process begins. The molding then takes place around the applique.

Port Erie Plastics can decorate both at the injection molding machine and in a dedicated, climate-controlled room depending on the process you select.



Using a 6-axis robot, we are able to drill holes in plastic products for inserts or other hardware. This careful process creates clean holes and slots in the plastic without causing damage such as cracking or warping.


We are able to join two plastic pieces or parts together using ultrasonic welding techniques. Ultrasonic welding works by sending a high-frequency vibration through the pieces until they are held together.


The process of fastening joins plastic parts together with fastening elements such as hinges, latches, screws, rivets, pins, and more. Fastening does not require any heat or welding in order to join pieces together.

Heat Staking

Combining heat and pressure, heat staking is used to join plastic parts together. Localized heating and cooling of the plastics all the material to be reformed and joined.

CNC Trimming

CNC trimming utilizes a pre-programmed route to remove excess material from a plastic part. This brings the piece to its desired shape and size so it is ready for use.

Trust Port Erie with Your Plastic Injection Molding Assembly and Finishing

When you partner with Port Erie Plastics, we can help you with your plastic projects from start to finish. Our engineers will assess your designs and make suggestions to improve manufacturing, saving you time and money. We have extensive experience in custom and automated injection molding, structural foam molding, and extrusion services.

Once your product has been manufactured, our secondary operations will ensure your products are ready to hit the shelves. From assembly to decorating, we have you covered. Port Erie also offers distribution and warehousing services to our clients so you don’t have to worry about finding storage space or a distributor. We provide a single point of contact to take your product from a fledgling idea to its finished state.

Contact us today to see what we can do for your next plastic project.

Comments are closed