General Purpose Screws VS. Custom Designed



Plastic injection molding and extrusion companies are faced with many difficult challenges. Screw and non-return valve design is one such challenge that most processors have little or no experience.  Since the development of the Reciprocating Screw, most molders have purchased or have been provided with so called "General Purpose" screw designs, or designs with marginal improvements. The technology that general purpose screw designs incorporate was developed in the early 1950's. Many new resins have been developed to accommodate ever growing molded part requirements.


The rate of innovation in the parts being produced and the materials being developed is a clear indication that outdated components are bottle-necking the plastics industry. 


Many plastics manufacturers are satisfied with the performance of their screws and non-return valves simply because they have not tried anything else. The standard of what is good is not overall good but rather as good as it can be within the limitations of the designs. The issue is that as an industry, a majority of companies still use outdated general purpose technology, not knowing that it is costing them money. 


Custom R. Dray feedscrew and non-return valve designs will reduce material waste, cycle time, and excessive wear on equipment while increasing part quality - making your company more profitable.


General-purpose screws cost less to manufacture than modern screws. However, the molder is generally not aware of the hidden costs associated with a general-purpose screw design - costs that arise from its inability to properly process virtually any polymer.

Also, machinery manufacturers normally do not have the technical capability to provide modern screw designs, and their screw manufacturing is neither set up for, nor (in many cases) capable of machining modern designs. Therefore, injection molding machinery manufacturers and extruder manufacturers have little desire, or ability, to promote modern screw designs.

As compared to modern designs, general-purpose designs create longer cycle times, more rejects, higher resin cost, lower rate, higher melt temperatures, and the potential of part failure in use. These are all important, but part failure can be the most expensive. Furthermore, the cause of failure can be easily discovered if melt-flow analysis is used to check the physical properties of the failed part.

In the name of continual improvement, millions of dollars are spent on new state-of-the-art machinery, automation, software, facilities, training of new production philosophies, etc. all while ignoring the downfalls of some of the most commonly replaced parts. If you are purchasing general purpose screws and valves, you are bottle-necking your production line. 


Your company cannot depend on general purpose equipment when customers expect cheaper, higher quality, sophisticated parts.


The feedscrews, barrels, and non-return valves we manufacture are engineered for your production line.

  • We offer the most innovative solutions in the industry.
  • Our designs are tailored to best match your production goals and resin(s) processed in order to maximize efficiency.
  • The most cost effective way to boost your bottom line.
  • We have a customer portfolio with some of the largest molders and resin processors in the world. 
  • Efficiency is important in both High and Low volume facilities.
  • We back our designs with an Unconditional Guarantee. If you are not satisfied with the performance of our products, you may return them for full credit!



Increase your productivity today!


Our industry leading designs will increase your productivity.

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