With our sound understanding of polymer science and high-tech production resources, PDI Molding produces close tolerance plastic injection molded parts for a broad scope of industries. For this high volume project, we worked closely with the customer in the fire protection industry to provide a value solution by integrating several assembly steps directly into the molding process.

This project involved using a polystyrene-based conductive thermoplastic compound that required tight temperature control as well as two molds built to perform reliably for a product lifecycle in excess of 10 million parts. The mold for the inner chamber featured four cavities with a hot manifold and 12 cams designed for rapid cycle times. We blended in a steel fiber during the fill process to hold the specific conductivity level required by the client. Mold two, which featured eight cavities and two hot drop manifolds to allow for closed loop recycling of the runners, was used to form the air deflector. Additional operations consisted of welding the air deflector and bug screen to the inner chamber.

This device featured dimensions of 3” in diameter x 1.5” in height. Conductivity testing validated it was in the 200 to 400 Ohm range, while dimensional inspection confirmed we met the tolerance requirements of +/- .004” on the inner chamber and ±.002” on the deflector.

If you are interested in learning more about this project, or how our extensive knowledge of injection molding technology can benefit your next project, contact us today.

PDI Molding provides plastic injection molding of components for a variety of industries such as Aerospace, Automotive, Entertainment, Fire Security & Protection, Medical, Military and Tele Communications. We work with or customers to add value not cost often by integrating some assembly of components straight off the molding presses. This is an Inner chamber we mold out of Poly Styrene Pre Elect we blend in a steel fiber during the fill process that allows us to hold a specific conductivity level required by our customer. Then in another press we mold a Noryl Air deflector. Then we sonic weld the Air deflector and a bug screen on top of the Inner Chamber.

Plastic Injection Molding and Assembly Project Highlights

Project Name & Description

Inner Chamber

Capabilities Applied/Processes

Designing molds
Developing processes
Sonic Welding
Plastic Injection Molding

  • Mold 1- 4 cavity mold with hot manifold and 12 cams designed with cycle time and longevity in mind this mold has produce over 10,437,000 parts
  • Mold 2 – 8 cavity mold with a two hot drop manifold to allow for closed loop recycling of the runners
Equipment Used to Manufacture Part

Mold 1 runs in a 110 Ton electric Niigata
Mold 2 runs in a 85 Ton Electric Niigata
Multi zone DME temperature controllers

to control manifold temperature on both molds
Branson Sonic welder

Overall Part Dimensions

3″ Diameter X 1.5″ High

Tightest Tolerances

Mold 1 – Conductivity 200 to 400 Ohms +/- .004”
Mold 2 – ±.002”

Material Used

Poly Styrene Pre Elect

Industry for Use

Construction Fire production

In Process Testing/Inspection Performed

Conductivity test and dimensional


1.7 million/yr

Delivery/Turnaround Time

POURS system/on demand direct to production line

Delivery Location

In house at customer’s plant

Standards Met

Customer Specifications