Moldworx explains its unique single cavity injection mould

Moldworx a Gilbert, Arizona-based company which specialises in plastic injection moulding presents a unique, improved manufacturing solution for the production of medical devices.

Moldworx who focus on designing solutions for medical device original equipment manufacturers (OEMs), were asked by a medical OEM to develop a single cavity injection mould to overmould a needle that is currently being glued in place. The overmoulding process will automate the production of hypodermic needles, and as a result aim to reduce costs and improve productivity.

In order to inject medical grade plastic around stainless steel needles as small as 0.012 in (0.305 mm), Moldworx managed to perfect the design and building of the moulds, as well as the automation for this project.

The first stage involved designing and developing an A-Series, single cavity injection mould with slides, with the needle being hand-loaded into the mould by an operator and then moulded to a finished assembly to test the design.

Commenting on the new process, Moldworx president Jim Taylor said, “this allowed us to overmould the needle eliminating a step in the current manufacturing process and reduce overall production time and cost.”

The next stage was designing a production mould and automation that would robotically feed the needles into the mould cavity and eliminate the need for the operator.

Taylor explained, “we designed the mould to integrate with the automation and the automation to work in unison with the mould. In an effort to accelerate the timeline, the entire automation cell was built in parallel with the mould.”

In order to separate thousands of bulk-packed delicate needles Moldworx designed a singulator. The singulator was developed with a hopper which enabled each needle to be introduced one at a time to the assembly line cell.

A robot affixed to the injection moulding machine then picks up each needle and indexes it in front of the high resolution cameras. This process ensures the needle tip will not be rejected due to damage.

Once the needle is placed in to the mould, the mould then closes for the injection cycle.

When the mould opens the robot removes the moulded assembly and places a newly inspected needle into the mould.

Every stage of this process requires inspection and verification. To ensure process precision, the highest quality motors and controls are used in the automated cells.

Following the success of the single-cavity mould, Moldworx have gone on to build a multi-cavity mould. This multi-cavity mould is able to quadruple the automated cell production, helping to increase the levels of production in order to meet high demands.

“This is a prime example of the benefits of working with Moldworx,” claimed Taylor. “We partner with our clients to deliver innovative, automated plastic injection moulding manufacturing solutions.”