Agilent Microplates Blog

Designing an Injection Mold for Microplates

Posted by Steve Fillers on Mar 22, 2016 4:15:05 PM

Perspective of a Microplates Design Engineer

Design-Engineer-500pxl.jpgInjection molds create the unique characteristics of standard and custom microplates. Quite simply, a mold is a huge hunk of metal cut in half and milled out to flow molten polymers into the physical shape details of a microplate. The design phase directs the cutting of the steel to optimize the specifications of the final microplate product. But, as you might imagine, it’s not that simple. We had a discussion with a Seahorse Microplates design engineer, Paul McGarr (pictured here), who designs molds for microplates. He answers some questions that help explain some of the basics and nuances of what goes into creating microplates. 

How do you design microplates—where do you start?

It all starts with gathering information about the microplate’s requirements. Once we have a thorough understanding of the requirements, we determine a direction for an appropriate mold design. Injection molds can be quite costly, so building a mold properly tailored to a project’s requirements is critical to the success of the project. For example, building an aluminum mold and expecting one million cycles is likely to result in premature mold failure, delays, and repair costs. Conversely, building a mold suitable for millions of parts, when only thousands of parts are needed, results in excessively high mold costs— sometimes even unnecessarily deeming a project unfeasible. This balance is absolutely critical.

What are the critical parameters?

Microplate geometry, dimensions, and tolerances have the greatest impact on the mold design. Needlessly tight tolerances on the microplate design can result in mold costs double or even triple what is actually necessary. Gate type (the flow port that directs the hot polymer into the mold) and location is critical to the ability to uniformly fill the cavity with plastic, and also affects microplate flatness and overall precision. Volume plays a large role as well. High-volume capability requires provisions to be made to decrease cycle time. This can be costly upfront, but ROI is generally quick. These provisions are commonly higher cavitation, direct gating, and more efficient cooling.

What skill sets are necessary? Helpful? How many hats do you wear?

A complete understanding of plastic part design and injection molding technologies is clearly a requirement. Flow simulation (FEA) skills help with choosing the most effective gating strategy, ultimately resulting in improved quality of part. Sometimes this can be the difference between success and failure. An understanding of mold-making technologies results in designs that are easier to manufacture, and therefore lower cost. The more skills the designer possesses, the more likely the molded product will be of the lowest possible cost, while still meeting quality specifications.

Where is the fun?

Every project has unique challenges. Accommodating these challenges keeps it interesting. The real fun is in learning new ways to achieve things that were previously thought to not be achievable.

Is a full-scale mold always necessary?

No. For a high-volume, multi-well cell culture plate with high optical and flatness requirements, a full scale mold is typically required. But, for a less demanding or low volume part, such as a reservoir or lid, a modular mold system (MUD) and/or soft steel/aluminum inserts for an existing mold can drastically reduce mold cost without sacrificing quality. Knowing which direction to choose comes with experience. Of course, it is wise to err on the side of caution when it comes to these decisions.

Can you offer advice on how to minimize design time?

A thorough product design and specification is critical to the mold design project. The more we know about the product and how it will be used, the better the choices we make with the mold design. The more information supplied up front (the lower the number of Q&A cycles), the shorter the time before the metal is cut.

These are some of the necessary considerations when we design microplates. Consider Seahorse Microplate for your microplate needs. Download our Product Brochure to learn more about how we can make your innovative ideas a reality.

Seahorse Microplates Product Brochure Download

 

Topics: Microplates