Manufacturing Aids for Many Thermoplastic Processing Challenges
Thermoplastic processing operations involve the process of moving melted (viscous) materials with thermoplastic characteristics (soften when heated) into some form or mold and then cooling (solidifying) the materials for the purpose of making desired shapes. The first material, a celluloid based on nitrocellulose treated with a solvent, was invented by Alexander Parkes in 1855. This material was the birth of many of the modern aesthetic and utility uses of plastics. Further development of new synthetic polymers goes hand in hand with the development of new processes to transform thermoplastic materials into desired shapes. Thermoplastic materials are melted and then solidified at lower temperatures, often a cooled mold is used to transform the polymer melt into a desired shape. Chem-Trend, with its over 50 years of experience working with molding, forming and casting operations, is a world leader in the development of manufacturing aids for thermoplastic processing.
The number of processes which have been developed over the last 100 years to transform melted materials into desired shapes is continuously increasing and goes along with the development of new polymers. One of the major driving forces behind this trend is to replace metal or thermoset plastics with thermoplastic materials that can be reused and are lighter in weight. Although most forms of thermoplastic processing involve some type of extrusion, the processes go under a variety of names, have slightly different parameters, utilize different equipment and require different processing aids. Chem-Trend has vast experience, and a very different approach toward making its Lusin® range of products serve the needs of all kinds of thermoplastic processes. Our products help improve processing efficiency, and therefore, reduce the costs of the final part being manufactured. Many can also be found that are NSF registered.
Thermoplastic processes are constantly evolving, due to continuous innovation in materials. However, five major processes are most often employed. The common theme among all of the processes is the use of a thermoplastic polymer that’s transformed by heat into a different shape, which can then be reversed.
The five major thermoplastic processes used to form thermoplastic materials are;
- Injection Molding
- Blow Molding
- Extrusion (also includes the sub-process of Calendering)
- Rotational Molding
Injection molding can be used to economically produce formed parts in large quantities. A thermoplastic material is injected under pressure into a mold, with the cavity of the mold determining the shape and surface texture of the finished part. Parts of these types can be found as small as a few tenths of a gram to as large as the two-digit kilogram range. The injection molding process can be further divided into multiple subcategories, all of which have their own specific parameters and challenges for efficient production.
With injection molding, objects can be produced with high accuracy, such as those produced for use in precision engineering, and can be mass-produced in a short time. With this process the surface of the component can be selected to match the particular need. As well, the injection molding process is (almost exclusively) the best economic choice for production of large quantities; however the cost of the tool is often a significant investment, even for relatively simple tools. Therefore, it is very important to protect the tooling both during the processing of the parts, as well as during shipment and storage periods. For these reasons Chem-Trend has developed multiple manufacturing aids focussed on both making the injection molding process more efficient, such as mold release agents, as well as to protect molds and machinery such as our anti-corrosion and purge compound products.
Blow molding is a collective term for the production of hollow vessels made of thermoplastic materials. There are several distinct blow molding processes, such as;
- Extrusion (Continuous or Intermittent)
Each type of blow molding process presents its own particular challenges to efficiency and scrap rates. Chem-Trend’s years of experience in the field has driven our development of very specialized products to address the specific challenges of each process.
Extrusion is a broad category in which plastics are molded in one continuous process. Almost all processing of thermoplastics encompasses some type of extrusion, but the main extrusion process can be broken down into three main sub-categories;
- Pipe & Profile
Additionally, calendering is yet another, small sub-segment of thermoplastic extrusion. In the calendering process, melted plastic is passed through columns of these rollers to produce plastic films (PVC, PE, PS, etc.).
Chem-Trend’s line of mold maintenance, and related products for thermoplastics are uniquely formulated to support efficient production utilizing the extrusion process.
Compounding is a process of refining plastics by the addition of additives (fillers, etc.) for the targeted optimization of the characteristic profiles required for the parts being made. Compounding takes place predominantly in extruders and includes operations of: conveying, melting, dispersing, mixing, degassing and pressure buildup.
Our expertise in the development of products to promote efficiency and lower scrap within thermoplastic processing operations allows us a unique position within the industry to support thermoplastics compounders.
Rotational Molding is used to create thin-walled hollow forms by applying powdered thermoplastic layer by layer on the inner surfaces of a mold through biaxial rotation combined with heat. This method allows for relatively uniform, thin wall thickness. Rotomolding is a technique that suits products that need a good cosmetic outside appearance but do not require the inside surface to be as good looking.
The rotational molding process (rotomolding) enables relatively small volume part production for multitude applications, such as bulk fluid storage, children’s toys and automotive components. The release agent plays a critical part in the correct formation of rotomolded parts. It needs to perform several tasks, some of which appear to be conflicting. Rotational molding provides a very different set of challenges than those found in thermoplastic extrusion processes. Chem-Trend has developed a strong array of products specifically designed for meeting the challenges found in rotational molding. To learn more about those products read our main rotational molding page or contact us to speak with one of our rotomolding experts.
A Full Portfolio of Products for Thermoplastic Processing
The history of the Lusin® brand within the thermoplastic industry started well over five decades ago, and we utilize that experience every day as we work to solve production problems faced by our customers around the globe. Recognizing that the needs of thermoplastic processors were not at the forefront of the product development plans of many chemical suppliers, Chem-Trend embarked upon a program of continuous investment to further enhance the efficiency of our Lusin® products for the global marketplace. This is the philosophy behind the wide range of purging compounds (watch a video showing how purging compounds work), release agents, lubricants, cleaners and protective materials focused on the goal of increasing quality and productivity while minimizing any adverse impact on the environment, thus adding overall value to your bottom line.
- Purge Compounds, to clean and extend the useful life of screws, barrels, die sets and tooling. Learn answers to frequently asked questions and watch our overview video to see our purging compounds in action. The use of purge compounds also increases overall efficiency and reduces costs by reducing scrap and machine/personnel downtime between color and/or material changeovers. Of the five major thermoplastic forming processes, only Rotational Molding is not considered a form of extrusion and therefore only Rotational Molding does not suffer from the problem of the build-up of carbonization within the screw, barrel, die set and tooling system machinery. The problem of carbonization is a significant issue for the other four major thermoplastic processing operations, and causes processors to suffer loss of efficiency, high scrap rates, and long changeover times. For this reason the use of purge compounds is critical to modern plastics processors.
- Mold Maintenance products to improve efficiency, protect molding equipment and ultimately the investment in tooling. Our line of cleaners, lubricants and anti-corrosion agents have been developed from the intimate understanding of the challenges faced at thermoplastic operations around the world. Watch our videos on thermoplastic cleaners, lubricants and anti-corrosion agents, and learn more about mold maintenance products now.
- Mold Release Agents, to maximize process efficiency, reducing scrap and providing final part surface finish that meets end customer requirements. Watch a video and learn answers to frequently asked questions about our thermoplastic release agents to find out more.
To learn more about the portfolio of products that we have developed to support thermoplastic processing operations read our sections on purging compounds, mold maintenance products and release agents, or contact us directly to speak with one of our thermoplastic industry experts. If you don’t see your specific application or need mentioned, contact us and we can review your process together and determine a custom solution for you.