DESMA Sprue Waste Diagram

Implementing a DESMA Cold Runner Block (CRB) to the rubber and silicone molding process is a great way to improve product quality, molding efficiency and save on raw materials. Generally, 60% of elastomer molding cost is directly related to raw material pricing; the other 40% of the cost is energy, labor, and machines. Since material pricing can fluctuate and is a substantial portion of the overall cost incorporating a DESMA Cold Runner Block (CRB) into production can help reduce raw material costs.

For example, consider a DESMA machine producing rubber pipe seals in a 24 cavity hot runner mold. The molded articles, runner system, and flash extensions equate to 5 lbs. of rubber material. Modifying this existing mold to utilize a new 6-nozzle DESMA open tip Cold Runner Block (CRB) can quickly reduce the waste by roughly 1 lb. per cycle (20%!). DESMA can produce the new Cold Runner Block (CRB) and include cost effective mold plate modifications at the DESMA NAMC facility resulting in a much more efficient system.

Switching from traditional hot runner applications to DESMA Cold Runner Blocks (CRBs) typically provides an average waste savings of approximately 20%. Even factoring in moderate efficiency rates, production can easily realize several hundreds of dollars of saving per day. Payback for the Cold Runner Block (CRB), especially on high-volume production parts, can be a matter of months. A DESMA Cold Runner Block (CRB) is an investment that pays for itself in material saved – less material wasted is more material molded into sellable product and ultimately more profits.

DESMA USA designs & manufactures many different kinds of cold runners for various rubber & silicone molding applications. DESMA’s NAMC division offers cold runner solutions in both open nozzle and valve gate applications. Open nozzle cold runners are constructed from either a solid gun-drilled block design or a split block configuration, depending on the customer’s requests. The nozzle towers are constructed from stainless steel to combat corrosive coolants, and gun-drilled blocs utilize hardened steel diverters at each rubber transition. These diverters ensure material flow and facilitate purging of the Cold Runner Block (CRB) should the manifold become vulcanized. Our split block design uses CNC machined radiuses to facilitate balance and material transition.

Each Cold Runner Block (CRB) completes testing in our onsite Demonstration area before shipment regardless of its configuration. Our engineering team verifies there are no coolant leaks and that the hydraulic system is functioning correctly when applicable. Ideally, customers send in their material, and our engineering team balances the material flow from each nozzle tower. As a result, the customer receives a cold runner ready to be put into immediate production. DESMA Sales and Project Engineers can work with your team to analyze current applications & then recommend the proper cold runner solution to improve specific molding applications.

DESMA Cold Runner Block

Cold runner nozzle locations are flexible at the time of design, and in many cases, a single cold runner may be used in conjunction with multiple tools. As global supply chain issues with raw materials continue to be a day-to-day challenge, a cold runner system can help alleviate some of this pressure. Contact your DESMA Sales Engineer to discuss our cold runner offerings and how we can help you improve your molding application and quantify material savings.

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