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Air Poppets FAQs

Are there places in my mold where it is not recommended to place a DME Air Poppet?

Any place the face of the Air Poppet is expected to see increased injection pressure. Most notably, do not place the DME Air Poppet in a core or cavity with the flat face of the valve directly opposing the gate. Do not place the DME Air Poppet directly in front of a hot drop.

Can I machine a gate dimple into my DME Air Poppet?

No, do not machine the face of a DME Air Poppet. You should not require a dimple in a DME Air Poppet because a DME Air Poppet should not be placed in front of the cavity gate or in front of a hot drop. If you do place the DME Air Poppet in front of a cavity gate or hot drop, we cannot guarantee proper functioning of the DME Air Poppet. If you machine the front face of the DME Air Poppet (to add a dimple) this can interfere with proper actuation or functioning of the DME Air Poppet.

Can I order a special size DME Air Poppet?

At this time, only standard sizes are available.

Can I replace the spring in my DME Air Poppet?

No, do not attempt to disassemble the DME Air Poppet. The product is not designed to be disassembled.

Can I use a DME Air Poppet to remove trapped gas or air bubbles from my molded part, as part of the injection molding process?

Please note that DME Air Poppets are not designed to vent gas from a part cavity. DME Air Poppets apply a small amount of air in the part ejection cycle to assist in part ejection from the core or cavity. Therefore DME Air Poppets are not recommended for removing air bubbles found in a molded part, either mid-stream in a molded part or at the end of the flow front.

Can I use the DME Air Poppet as my sole means of part ejection?

No, the DME Air Poppet should never be used as the sole means of part ejection. Material shrinkage and other factors will not allow the DME Air Poppet to be used as an alternative to ejector pins or stripper plates.

I am molding Urethane, and I have trapped air bubbles mid-way in my molded part. Will Sintered Vents or Air Poppets assist me in removing those air bubbles?

With respect to Urethane molding, Urethane is very compressible and it is possible to trap air in the Urethane resin melt back in the injection machine barrel. Through we cannot guarantee that the following suggestions will solve your molding issue, but you might consider not using suck-back during Urethane molding as this can introduce air into the Urethane melt. Another option is to adjust the back pressure to try to push any encapsulated air back-up through the hopper as you auger the pellets. Again we repeat, we make no guarantee that the above suggestions will solve your molding issue.

Air that is encapsulated in the Urethane melt can be compressed by means of the high pressure used to inject the melt into the part cavity, effectively making the air bubbles almost disappear. Once the part begins to cool and the pressure is relieved, the air bubbles can re-appear. Sintered vents are used to eliminate gassing/burn marks as a result of trapped air at the flow front. This could occur at a weld line. However trapped air mid-stream in a Urethane melt would not be removed by the Sintered vent. If you are attempting to remove trapped gas at the end of the flow front, we recommend you consider machining a custom vent into your mold at that location.

Please note that DME Air Poppets are not designed to vent gas from a part cavity. DME Air Poppets apply a small amount of air in the part ejection cycle to assist in part ejection from the core or cavity. Therefore DME Air Poppets are not recommended for removing air bubbles found mid-stream in a molded part.

What is the purpose of an Air Poppet in a plastic injection mold?

An Air poppet is used to assist with molded part ejection. A small amount of gas is blown into the mold cavity (or off the core) at a desired location to assist with separating the molded part from the desired mold parting line feature. Examples using DME Air Poppets is with deep-draw parts (i.e., buckets) or thin-walled molded parts. Air flow is timed to coincide with the ejection cycle, and this air flow opens the valve to break the vacuum and facilitate part ejection.

Where can I find recommended installation instructions for my DME Air Poppet?

Installation instructions are provided with the packaged part. Installation hole sizes and tolerances are given in the DME Mold Components Catalog as well. Use a plastic or rubber hammer when installing the Air Poppet into the installation hole, do not use a metal hammer. Do not strike the front, flat face of the valve. Do not modify the front, flat face of the valve in any way, as this can affect the final operation of the Air Poppet valve. Maintain a close tolerance press fit as shown in the DME Mold Components Catalog. Too loose of a fit could allow the Air Poppet Valve to move out of position, while too tight of a press fit could interfere with the movement of the valve. Additional warnings and instructions are given in the DME Mold Components Catalog as well as with the instructions provided with the packaged product.

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