Revolutionizing Needle Production: Moldworx’s Automated Overmolding & Inspection Cell

When a medical OEM requested a single‑cavity injection mold to overmold a needle that had previously been glued by hand, Moldworx LLC of Gilbert, Ariz. turned the challenge into an opportunity to expand its expertise. Rather than delivering a single‑cavity solution, the team engineered a fully automated four‑cavity cell that operates on a horizontal press, maintaining the same 27‑second cycle time while quadrupling production output.

Before automation, the customer ran three shifts of personnel gluing needles into place. Moldworx’s design eliminated that labor entirely, delivering a more reliable and scalable process.

One of the key innovations was a custom “singulator” that feeds individual needles—each as small as 0.012 inch (0.305 mm)—from a bulk hopper into the assembly line. The singulator’s precision ensures that each needle is introduced one at a time, preventing jams and reducing waste.

Once a needle reaches the robot’s end‑of‑arm tool (EOAT) on a 3‑axis Yushin robot, the EOAT grips the needle and positions it in front of a high‑resolution inspection camera. The camera verifies that the needle is straight, the tip is intact, and the correct (sharp) end is facing upward. If the needle is misoriented, the system discards it after three attempts and triggers an alarm.

After inspection, the EOAT transfers the needle to the mold. The custom mold features a slide‑core pin with a 0.013‑inch diameter hole that locks the needle in place. A servo cylinder lifts the core pin to allow the needle to slide into the cavity, after which the EOAT releases it. A laser embedded in the mold confirms needle placement before the injection cycle begins.

When the mold opens, the robot removes the newly molded assembly and places a freshly inspected needle into the mold, ensuring each cycle starts with a perfect component. After molding, the EOAT brings the finished part to the off‑load station, where a mandrel supports it for the next inspection. Two cameras confirm the sharp end orientation and inspect for damage or bending. If the part passes, filtered, metered air is passed through the needle to check for occlusion before the cycle repeats.

This integrated system showcases Moldworx’s commitment to precision engineering, quality control, and manufacturing efficiency. By combining advanced robotics, real‑time inspection, and a streamlined overmolding process, the company delivers a solution that is faster, cleaner, and more reliable than manual assembly.