We are the screw designers.


The Pioneers of Screw Design in the Plastics Industry


We specialize in helping molders and plastics processors increase output and overall quality while decreasing cycle time. Since patenting the first and most widely used basic barrier screw design in the United States in 1972, we have been the leaders of industry advancing patent technology. 

Our capacity to machine screws from 3/4" to 20" in diameter to 40' in length is unmatched in the industry today. Our in house engineering team can custom design screws to maximize the performance of your machine-to-material relationship, or we can manufacture according to your design specifications. We offer the best emergency screw rebuilding and repair service in the industry which will save your company time and money. R. Dray Mfg. is the only manufacturer to Unconditionally Guarantee feed screw performance. If you are not satisfied with the performance of our product, you may return it for full credit.

We were the first to guarantee performance in the Plastics Industry. Other companies may claim to be the performance leader in design technology, we go a step further - we guarantee that our designs will out perform all others - and have guaranteed this for over forty years. Screws purchased from R. Dray Mfg. are designed and manufactured by R. Dray Mfg., therefore we can provide the service and reliability of a single source supplier.

We are the leaders in primary technology in all types of screw designs and processes. R. Dray Mfg. Inc. of Texas is a progressive screw design company that incorporates time proven technology with industry advancing ideas to provide a successful solution for our customers. We have led the industry with new patent technology since our inception and are one of the few companies that have extensive knowledge in all types of extrusion and injection molding processes.

Let us increase your production efficiency!

Barrier Type Screw Designs

Barrier type screw designs are the most widely used screw designs in the plastics industry. The first barrier screw design was by Maillefer (Swiss patent # 82,535/59, filed 12/3/1959). The second and currently the most widely used barrier design is by R.F.Dray (Patent # 3,650,652, filed 5/5/1970). There are many different names for versions of this design by virtually all manufacturers and designers, although the basic part of the patent is common in all of these versions. In figure one you will note that the primary channel width is maintained allowing the barrier flight and auxiliary channel to be formed with the remaining width. Although these various versions incorporate the original technology, they do not include new innovations by the original inventor. These new innovations allow R. Dray Mfg. to maintain its competitive advantage.

The advantages derived from properly designed barrier screws are improved rate, lower melt temperature, and improved melt quality. To fully enjoy these benefits, barrier screw designs normally incorporate a downstream mixing device. R. Dray Mfg. offers both distributive and dispersive mixer types.

R. Dray Mfg. advanced mixing technology.

Let us take your production to the next level!

We are the screw designers.