Delivering Consistent Fabrication, Every Time

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By Jason Kimmel
Jason Kimmel

When looking at the finished products fabricated in your facility, can you tell one technician's work from another's? Do you see a quality difference from device to device? Do you often see a lot of waste or rework on certain steps in the fabrication process? If you see high variability in fabrication, you are delivering inconsistent devices, and this variability is a weakness.

Consistent fabrication is the ability to produce and deliver a quality product each and every time, regardless of the size of your facility, the number of technicians who work there, or the financial, time, and material constraints.

Before you reject consistent fabrication as impractical or unattainable, let me assure you that every fabrication facility is capable of achieving this and that the journey is rewarding. The beauty of consistent fabrication is that it instantly shrinks variability and sparks continuous improvement. Once you commit to consistency, you'll enjoy a cascade of benefits: less rework, less waste, faster turnaround, higher satisfaction among practitioners and patients, and increased profit.

Standardizing Custom Fabrication

We tend to hear the same questions repeatedly when we talk about setting standards for O&P fabrication: How can you set a standard for custom-fabricated devices? Each device is for a specific individual, so how can you possibly standardize that?

There is no need for confusion. It's not the fit, form, shape, or function of the device that we standardize; it's the steps that the device undergoes during the fabrication process.

Consider a sheet of plastic. The manufacturer has a recommendation for the heating temperature and the length of time needed in the oven, based on the thickness of the plastic. Obviously, if the oven is not set at the correct temperature or the plastic does not heat in the oven for the correct amount of time, you will experience problems. The finished thermoplastic product will either be too thin or have an uneven thickness. If it involves a drape pull, the plastic may not seam properly.

So the recommended temperature and length of time for the plastic to be heated in the oven can be considered a standard with a measurable tolerance: heating the plastic for the thermoforming process.

The Road to Consistency

As you might expect, implementing a better process is itself a process. Follow these five steps to achieve consistent fabrication:

1. Define your processes

Consistent fabrication starts with defining the processes that a device goes through. Let's use a laminated prosthetic socket with a flexible liner as an example. The major processes are plaster fill, thermoforming, lamination, and finishing. These processes cannot be standardized unless each is first broken down into steps. For example, thermoforming breaks down into these steps:

  • Mold preparation
  • Plastic and oven preparation
  • Pulling the plastic over the mold
  • Finishing the product

Then break down the other processes into a series of steps. Do the same with other devices fabricated in the facility. Some processes, like plaster fill and alignment transfer, are repeated in the fabrication of many different devices. Some devices involve one or more unique processes, such as fabricating a laminated flexible brim.

Defining processes ultimately helps you recognize the complexity, similarities, and differences for each type of device.

circles graphic
circles graphic

2. Set the standard for each step

This refers to setting a standard for each step of each process. For example, if you have three people in a facility all laying up the same mold to be laminated, and each has a different way of applying the fabric, laminating, and finishing the socket, you will end up with three different finished products. If your goal is to deliver consistent fabrication, you need everyone fabricating the same way.

How do you do that? Technicians use the techniques that they feel work best, and no one likes change. To solve this challenge, involve the group to come to a consensus about the best fabrication method for each step. Make your decision based on what will produce the most consistent outcome. Document the agreed-upon method, and the standard is then set for that specific step.

In the thermoforming process previously mentioned, mold preparation is the first step. Standardize the mold preparation based on the type of plastic used. For example, one part of the process is to always create an air channel when pulling over a valve dummy, or to always pull a nylon over the mold when using a particular type of plastic. A standard for the third step, pulling the plastic over the mold, could be to always put the seam on the lateral side when draping the plastic, unless instructed otherwise by the work order.

Standardizing each step in the thermoforming process-as well as each step of the other processes-ensures similar quality every time regardless of which technician executes those processes.

3. Set tolerances for each standard

Measurable tolerances are based on your expectations and quality preferences. They determine the quality of your finished product. As an example, for the final step in thermoforming, a tolerance could be that the finished product must be within 1/16 inch of the requested thickness. If the finished product does not fall within the given tolerances, it must be refabricated.

4. Track nonconformities

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Document and evaluate mistakes that occur during fabrication. It soon becomes apparent where devices repeatedly fail to comply with tolerances. Once you detect a problem, evaluate the variables that may have contributed to the situation. For instance, if the thermoforming process produces a finished plastic product that is consistently too thin, what could be causing that? The skill of the technician, the temperature of the oven, a problem with the vacuum system? Getting to the root of the problem allows you to make adjustments to avoid the same mistake in the future.

5. Pursue continuous improvement

Now you're in a position to take action to streamline processes and make other improvements. Ask yourself, "How can I consistently repeat this step with the least amount of error?" For example, if your evaluation of nonconformities with thermoplastic products reveals that the technician excessively stretches the plastic over the mold, causing the finished product to thin out, then provide retraining to correct the problem. Once corrected, fewer jobs will require rework, which reduces waste and shortens the average cycle time, which reduces overhead, which means more profit is made on those devices.

With a questioning mindset, you're likely to see potential for greater efficiency in many steps. Don't be surprised if technicians who change to a new standard discover innovative ways to execute the step even better.

Delivering consistent fabrication is an ongoing process that involves input from everyone involved. It starts with step-by-step standards and may transform your facility into a collaborative team that works together to prevent mistakes, elevate quality, eradicate inefficiency, and delight practitioners and patients.

Jason Kimmel is a founding partner of Motion Unlimited, Minneapolis. He has specialized in prosthetic and orthotic fabrication since 1999. He can be reached at .