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How to Choose the Right Mold Tool for Your Polymer Optics Project

Written by Apollo Optical Systems | September 24, 2025
The right mold tool is a strategic decision in a polymer optics project

In polymer optics manufacturing, the mold tool is the foundation of every component. It determines how quickly parts can be made, how complex the geometry can be, how consistent the quality will remain over time, and ultimately, how cost-effective the entire program becomes.

Choosing the right mold tool is a strategic decision that can influence the success of your product. In this article, we’ll explore the three main mold tool options — full-frame, MUD, and UMB — along with how to evaluate them for your specific needs. We’ll also compare them with an alternative fabrication method: single-point diamond turning (SPDT).


The Three Types of Mold Tools

 

Decision-Making Criteria

Volume Requirements

Ask: How many parts do I need — and over what time frame?

  • <1,000 parts: UMB or MUD.
  • 1,000–20,000 parts: MUD can bridge well.
  • 20,000+ parts: Full-frame is the most reliable.

Project Timeline

  • Immediate prototypes: UMB or MUD.
  • Commercial launch in 12–18 months: Consider MUD for the early stages, then full-frame.
  • Established product line: Full-frame is the industry standard.

Part Complexity

If the design requires intricate features — such as freeform optics, undercuts, or integrated assemblies — a full-frame mold may be the only viable option.

Budget Strategy

  • Lower initial investment: UMB or MUD.
  • Optimized cost-per-part at scale: Full-frame.

Comparing Mold Tools with Diamond Turning

Single-Point Diamond Turning (SPDT) is another way to create polymer optics, especially during prototyping.

Advantages of SPDT: Limitations of SPDT:
  • Extremely precise surfaces.
  • High per-part cost.
  • Rapid iteration without tooling.
 Not practical for scaling into thousands of units.
  • Useful for unique or one-off optics.
 Surface durability may not match molded parts.

In practice, many customers begin with diamond-turned optics to validate a design, then transition to injection molding with the appropriate tool once they’re ready for production.

A Decision Tree for Choosing Your Tool

Do you need fewer than 500 parts?

→ UMB.

Do you need prototypes now, but plan to scale within 12 months?

→ MUD, then migrate to full-frame.

Do you expect tens of thousands of parts over years?

→ Full-frame steel tool.

Do you need a single, highly precise prototype?

→ Consider SPDT.

 

 

When it comes to molding polymer optics, your tool choice shapes the success of the entire program.

Choosing the right mold tool is about balancing cost, speed, and scalability. Full-frame tools offer unmatched longevity, while MUD and UMB systems provide flexibility and lower entry costs. Diamond turning can fill unique needs at the earliest stages.

At Apollo Optical Systems, we don’t just build tools — we partner with you through the entire lifecycle, from design validation to full-scale production.

🎥 To see these tools in action, watch our video with Apollo Master Toolmaker Greg Schoen: YouTube Link.

 

About Dale Buralli

Dr. Dale Buralli has served as the Chief Scientist for Apollo Optical Systems since 2003. In this role, Dr. Buralli is responsible for the design and optical modeling of various optical systems. These systems include virtual or augmented reality, ophthalmic and other imaging or illumination systems. Additionally, he provides support for optical tooling of lens molds and prototypes, including the development of custom software for both production and metrology. Dr. Buralli got his Ph.D. in optics from the University of Rochester in 1991. Now he is an Adjunct Professor of Optics at the University of Rochester’s Institute of Optics.
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