Molding is a type of manufacturing process in which liquid material — typically rubber, plastic, or other polymers — is added to a mold to create a product. The raw material is normally heated, after which it is added to the mold cavity. As the material cools, it hardens while taking the shape of the mold cavity.

Not all molding processes are the same, compression molding and injection molding, for example, involve contrasting processes.

What is the difference between compression molding and injection molding?

Compression molding is a molding process that is defined by its use of pressure and heat. In compression molding, the polymer raw material is placed in the mold cavity where it is heated. Next, plugs are inserted into the top of the mold cavity. The plugs seal the mold cavity and are designed to pressurize it. With the polymer material exposed to both heat and pressure, it begins to cure inside the mold, resulting in the formation of a new product or component.

Injection molding, on the other hand, is the molding process that is defined by its use of injection technology. This process involves the injection of polymer raw material into a mold cavity. During injection molding, a screw pulls the material into a hopper. As the material is heated, its injected into the mold cavity. Injection molding is very similar to compression molding, with both processes involving the use of heat and pressure. The difference is that injection molding moves the material through a screw and a hopper, while compression molding does not.

How can Patriot help with the maintenance and repair of your mold machines?

Aftermarket Seal kits

Patriot Fluid Power offers a wide range of hydraulic/pneumatic seal kits and products for industrial molding applications. The seals and seal kits are directly interchangeable with those of original equipment manufacturers (OEM) and continually meet or exceed the needs and expectations of our customers. Original equipment manufacturers names and OEM part numbers are used for reference purposes only. Here is a list of some of the popular brands of compression and injection molding that we have aftermarket seal kits for: REP, Cincinnati Milacron, Desma, Panstone, and more…

Patriot offers solutions for hard-to-find seals and kits. We can identify and recommend a substitute for a different seal or component with the same form, fit and function for your application, or machine a custom seal to fit your needs.

Let us service you with our superior commitment to the customer service expertise we are known by. Patriot Fluid Power will help in any way you need to find and get you the right parts in the right time.

Injection Molding Machine - Patriot Fluid Power

Oil Cleaning Filtration

Our CJC® Oil Cleaning Fine Filters are offline depth filters for removal of the most common types of contamination sources: Particle, Water, Varnish & Acid.

Built for all sizes of oil systems from ½ gallon to above 53,000 Gallons. CJC filters are installed offline, meaning system shutdown is not necessary when changing filter inserts.

GO GREEN! All CJC Filter inserts have a 3-micron absolute filtration ratio. They are produced of 100% natural cellulose fibers from sustainable resources – no metal, no plastic, no chemicals! We can assist with your company’s Green initiatives!

CC Jensen Filter - Patriot Fluid Power

Remember, in-line filtration alone is insufficient! In-line filtration protects your oil system against larger particles, but CJC offline filters maintain your oil continuously clean and dry, free of small and harmful particles using a constant pressure and flow. This is the best way to extend the lifetime of components and oil, minimizing breakdowns.


Maintenance is the largest single controllable expense in all compression and injection molding manufacturing plants. With as many as 80% of all machine failures related to contamination in the oil, pro-active methods are saving industries considerable costs every year. Below are some true benefits of Oil Maintenance:

  • Up to 70% less machine stoppages and 60% savings in maintenance costs
  • Increases machine availability = higher productivity
  • Setup costs are quickly recouped (short ROI)
  • Increases lifetime of the hydraulic components
  • Continuous maintenance of the tank (no cleaning necessary)
  • Lower pressure loss and longer lifetime of in-line pressure filters
  • Reduces malfunction and rejects due to higher control accuracy (no varnish layer)
  • Increased lifetime of hydraulic oil
  • Minimizes oil purchase and used oil disposal costs
Let Patriot help with all your machinery maintenance needs!


CC JENSEN UNIT ON SITE - Patriot Fluid Power Oil Sample - Patriot Fluid Power