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Machine Polishing vs. Hand Polishing: What You Need To Know

June 17, 2022, 8:36 p.m.

Polishing is a crucial step in installing or terminating fiber optic connectors. Some say it's more of an art than a science, and though that's not technically true, there are a many different techniques used in the polishing process that can make it seem that way. There are two types of polishing, machine polishing and hand polishing. We'll dive into the differences between those two methods and which one is best suited for you.


But first, let's cover the basics.

Why is polishing fiber optic connectors so important?

In order to increase optical performance, polishing the fiber/ ferrule endfaces of a fiber optic connector is a crucial step. Though it is highly susceptible to error, once you break it down, the polishing process is not nearly as difficult or mysterious as it might seem.

Polishing prepares the fiber to ensure that defects and non-uniformities in the fiber/ ferrule endfaces or geometry don't degrade the passage of light across the connector joint. It removes any excess epoxy or fiber stub leftover, shapes the ferrule, and removes scratches and fractures on the material. This creates an end finish that passes optical signals through the fibers with minimum loss.


All connectors have to be polished in order to work properly, whether installed in the field or in a factory. The choice between hand polishing versus machine polishing depends on a myriad of factors such as application requirements, connector volume, and connector types. Let's dive into the two different ways to polish...

The Hand Polishing Process

Here are some of the tools you will need to start the process: a polish puck, rubber durometer pad, a glass plate, and polish film.

When fiber was originally deployed in telecom and datacom networks, fiber optic connector performance was not as demanding and critical as with today’s high-speed systems. It was possible to achieve acceptable performance by polishing manually by hand.

Nowadays, that's not usually the case.

Hand polishing tends to be a less precise process. There are some technicians that have been doing this for a very long time and could get close to a perfect polish. But for the average technician, there are a combination of factors that can affect the outcome while hand polishing fiber optic connectors, many of which are out of their control.

Here are some important factors to consider in deciding if hand polishing fiber connectors is the best method for you.

Amount of pressure.

When hand polishing, understanding and then applying the correct amount of pressure is one of the hardest steps to learn. The amount of pressure used while doing your figure 8 on the polish paper can drastically affect the results.

Inconsistency.

Unlike machines, humans do not tend to be as precise, which in this scenario is not a good thing. It's impossible to control the same pressure application each time you polish. Though you may get a perfect polish on one fiber optic connector, you generally won't produce the same results on the next ones you do. For companies using multiple technicians in the the polishing process, you need to take into consideration variability of results between technicians.

A clean workspace.

Many technicians who chose to hand polish did it while out in the field. However, fiber optic connectors are very delicate, and even the smallest amount of dusty debris or dirt landing on the polish film can cause the connector to be compromised or even ruined. It is vital to create a clean workspace before polishing your fiber connector.

Costs.

Hand polishing can be less cost-effective than it seems. Though the upfront cost of the tools is likely to be lower, the long term costs tend to be in favor of automated polishers. Hand polishing is labor intensive and time consuming. Since there is inconsistency in the polishing results, there will be a higher amount of optical loss. Technicians also have to polish one fiber connector at a time.

The Age of Fiber Optic Polishing with Automated Polishers

In the early 1990's, the development of an automated fiber optic connector polishing machine modernized the process resulting in cost savings, efficiencies and ensuring repeatable results. Over the last few decades, automated polishers have advanced to be able to handle new applications that were never even considered with hand polishing. There are many different types of automated polishers, allowing technicians to use them in both labs and in the field.


The introduction of automated fiber optic connector polishers provided many benefits that hand polishing could never attain, such as...

Consistency through programming.

Automated polishers can be programmed for consistency, allowing them to repeatedly produce high yield polishing results. They also have flexible programming for controlling all types of polishing specifications, including pressure, polish speed, and cycle time.

Easier for technicians.

The use of automated polishers tends to be easier on technicians, which can help costs, consistency, and morale. Step-by-step prompts on machine usage help reduce errors and subjectivity from technician to technician.

Higher level of precision.

Automated polishers have new capabilities to help reach a higher level of precision. They allow for an optimal “random orbital” polishing motion which is superior to the standard “figure-8” technique used during hand polishing. High precision fixtures hold the connector at the proper angle to the polishing surface in order to reach Telcordia geometry specifications. It's also possible to trace a connector processing condition. This, coupled with the ability to lock in your specific programming, allows you to maintain high-quality results.

Wider application.

New fiber optic devices can now integrate bare fibers, waveguide and fiber arrays. These components have more stringent optical requirements than a traditional connector. Automated polishing systems have features such as micron-level positioning to prevent damage to these delicate components while providing the ability to monitor material removal for length control.

If you're interested in learning more about bare fiber polishers, we strongly recommend checking out one of these videos.

Analytics and inspection.

Businesses needs to be able to analyze and inspect their processing in order to gain maximum efficiencies and results. Automated fiber optic polishing can integrate a real-time vision system to monitor the polishing process and in-line inspection videoscopes for viewing fiber surface finish while the connector is loaded in the polishing fixture. All the original programming for the polishing variables can be reviewed and optimized.

Cost.

A polishing machine is a large investment. Automated equipment costs can range from $5,000 to over $25,000 depending upon the specific application. However, for large-scale production of cable assemblies, polishing multiple fiber optic cables or connectors at once, or any other high-volume application, a polishing machine is more economical. Most automated machines can batch-process 6 to 12 connectors at a time, making them more efficient than hand polishing.

So which should you chose?

The evidence is overwhelmingly in favor of automated fiber optic connector polishing machines. For someone who's only going to need to polish a fiber optic connector once or twice, then hand polishing is probably the choice for you. But it's also not a task that most people stumble upon as a fun side project. For companies, research and development labs, and engineers that require the precision of quality fiber optic polishing for their applications, investing in an automated polisher is the most cost-effective solution and will consistently yield high-quality, precise results.


For fiber optic polishing machines that provide the most accurate and precise results, KrellTech is known as the #1 automated fiber optic polishing and inspection system globally. If you have any questions or specific applications, let us know, and we’ll be glad to address them for you.

 

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