Our Process

At Sle-Co Manufacturing we specialize in injection, insert, and over molding of a wide range of plastics. Our advanced capabilities and in-depth industry knowledge allows us to work as a single source solution for your manufacturing needs. From prototypes to high volume production, our state of the art equipment and facility gives us the flexibility to deliver precision molded products with rapid turnaround times.

For over 25 years we’ve provided our customers with quality products and value added services, we’ve grown up in the industry applying a hands on approach to precision injection molding. We offer complete project management services that leverage our years of experience manufacturing products for a wide array of applications. This vast knowledge base allows us to make materials selection, facilitate parts sourcing, as well as complete product development, engineering, and mold making.

From 1 part to 1 million parts, we possess the production capabilities and services that will meet your product’s needs. The Sle-Co production facility operates on a 24-hour schedule. We offer expedited services and lights out manufacturing; we provide logistical support such as JIT deliveries, Kanbans, and stocking programs.

With over 30 injection Molding Machines from 44 ton to 1450 ton we have the ability to meet your needs.


In addition to our full molding capabilities Sle-Co also performs full assembly work. Sle-Co has the knowledge and the technology whether it’s installing a single clip, adding anti-squeak tape or assembling a full child seat safety system with over a hundred components. Sle-Co has developed several assembly processes for multiple customers.

Through the use of latest technology in laser alignment system, camera part detection and full bar code scanning, we can collect all the data through the process. This data is then saved to a dedicated server that is matched by serial number to the product assembled. This data can include assembly screw torque data, installed part detection, and time and dates for each and every station through the assembly process.

Secondary Operations

Sle-Co Plastics Inc. offers multiple secondary services to enhance the value of our customers’ parts.

Sonic Welding

Sonic Welding

Ultrasonic welding is an industrial technique using high-frequency ultrasonic acoustic vibrations that are locally applied to the parts being held together under pressure to create a solid-state weld. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together.

Solvent Welding

Solvent Welding

Solvent welding is when a solvent is applied which can temporarily dissolve the polymer at room temperature. When this occurs, the polymer chains are free to move in the liquid and can mingle with other similarly dissolved chains in the other component. Given sufficient time, the solvent will permeate through the polymer and out into the environment, so that the chains lose their mobility. This leaves a solid mass of entangled polymer chains which constitutes a solvent weld.


Heat Staking

Heat staking uses heat to deform the plastic boss, instead of cold forming. A plastic stud protruding from one component fits into a hole in the second component. The stud is then deformed through the softening of the plastic to form a head which mechanically locks the two components together. It is a versatile technique benefiting from being quick, economical and consistent.


Pad Printing

 Almost acting like an iron-on, the ink from the label is transferred directly onto the part creating a very clean, high-end decoration on the part.


Hot Stamping 

In the hot stamping process, a heated die applies pressure to a hot stamping foil that is pressed against the plastic part. The heat and pressure from the die transfers the pigment from the hot stamping foil onto the plastic part.