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• CAD/CAM for Medical Machining

Hanan Fishman is president, PartMaker Inc. (Fort Washington, PA), a division of software developer Delcam plc (Birmingham, UK).

Manufacturing Engineering: How can CAD/CAM software help boost productivity for machining medical parts?

Hanan Fishman: Broadly speaking, CAD/CAM boosts productivity for machining medical components by speeding up CNC programming and reducing machine setup time. CAD/CAM speeds programming time by allowing the programmer to automatically generate an NC program from engineering design for a particular component. The more complex the part, or complex the machine on which it is being manufactured, or some combination of the two, the greater the time-savings provided by a CAM system. Perhaps the even more important productivity benefit of a CAM system for machining medical parts is its ability to reduce machine setup and prove-out time. With the appropriate CAM system matched to an application, users can visually prove out the machining process and catch any errors on a part before tying up valuable machine time. This is especially critical in medical manufacturing where lot sizes may be small, as in the field of medical machining, one size rarely fits all.

ME: Describe your 'divide-and-conquer' approach to machining.

Fishman: PartMaker's patented 'divide-and-conquer' approach allows the programmer to view the part the same way the multiaxis lathe on which it is being machined sees it. The software does so by breaking down a part into a series of machining tasks for different part faces programmed in 'Face Windows.' It lets the user see a multiaxis turn-mill for what it really is, which is to say, not just a mill and a lathe, but really a lathe with up to nine different types of milling capabilities, depending on the capabilities of the machine and the engineering requirements of the part at hand. Each Face Window in PartMaker serves a dual role in automating the programming of a part that will be made on a multiaxis turn-mill center or Swiss-type lathe. First, the Face Window automatically establishes a coordinate system for a specific task. For example, Part-Maker lets the user, through the selection of a given Face Window, choose whether a feature will be turned, will be milled on the face of the part, milled on the diameter of the part, or milled in some inclined plane. Second, the choice of Face Window automatically determines the type of machining that can be done in a given coordinate system. Each of these machining functions corresponds to a different mode of operation for a multiaxis lathe. Thus, this approach lets a user quickly program a part in the exact way his machine will cut the component.

ME: What types of medical components are made using your software?

Fishman: The range of medical components can be very broad, from the parts that go into the assembly of a hospital bed to the tiny bone screw used to hold pieces of the body together in surgery. The most common medical parts machined with PartMaker are of the second category, a group collectively known as implants, or components that end up inside the human body during and after a surgical procedure. Additionally, a number of the medical components made with PartMaker go into making medical devices, including surgical instrumentation.

ME: What does your software's new seamless solids programming capability offer users?

Fishman: PartMaker's recently improved solids programming allows a user to directly program onto a solid model and automatically detect the engineering data resident to that solid model. This further automates programming when a solid model is available. More and more, medical parts are designed in 3-D using solids modeling, so having the ability to automatically generate an NC program using the inherent properties of that model with minimal intervention can greatly speed up programming.

ME: How critical is simulation for machining medical parts?

Fishman: The importance of machining simulation for medical parts cannot be stated strongly enough. Generally, medical parts are very small. Often their critical features cannot even be seen with the naked eye. However, the machines and tooling used to make these parts are huge by comparison. With a computer-generated simulation of the machining process, the user can see in exacting detail what the part will look like after it's been programmed, no matter how small it is. In addition, with a full simulation of the machine tool itself, the user can see what, if any, machine collisions might occur during the manufacturing of a part.

ME: What factors, like quality and surface finish, are most crucial to medical applications?

Fishman: Clearly, the importance of quality and traceability is paramount in medical applications. Is it more important than in aerospace or automotive applications? That's clearly a debatable point. What is not debatable is the regulatory scrutiny that goes into the manufacture of medical components. We live in a litigious society, and one of the most common targets of very expensive litigation is the healthcare industry. If you're manufacturing medical parts, you have to be accountable for what you are doing, because if something goes wrong with a patient on the other end, it could well be the medical part that is scrutinized in court. As a result, maintaining the quality called for in the engineering specification of a part, whether it is surface finish or a tolerance, is vital.

ME: What other industries does PartMaker focus on?

Fishman: While a sizeable portion of the PartMaker software sold is used in medical applications, medical is certainly not the only sector in which PartMaker is used. PartMaker's patented technology was conceived to automate the programming of multiaxis turn-mill centers and Swiss-type lathes, typical tools of the trade in medical manufacturing. Due to the software's focus in these machining applications, we've had the great privilege to serve a number of the world's leading manufacturers of medical devices, be they OEMs or the contract manufacturers that work for them. As a result, over the years, we subsequently developed a lot of technology to help medical manufacturers do their jobs more efficiently. A number of our customers are involved in aerospace, telecommunications, fluid control, and automotive manufacturing. These fields all have extensive needs for creating complex components on multiaxis lathes. As a CAM software developer, we focus on developing our product around machining technology first and foremost. You'll tend to find our software will end up being used in the same industries in which the machines it was designed to support are applied.

ME: What's the outlook for medical manufacturing and other industries?

Fishman: The outlook for medical manufacturing is strong based on the demographics of society. We are all hopefully leading longer, more active lives. To put this in statistical terms, the medical manufacturing sector is valued at over $250 billion in sales worldwide, and expected to grow at a compound growth rate of 6.4% over the next two to three years. According to some recent studies, a man between the ages of 30.34 is expected to spend $1500 per year on healthcare, while a man 50.54 will spend about three times as much. Couple that with the fact that by the year 2020 it is forecast that there will be 55 million Americans aged 65 and over, and you can see where the growth is coming from.

10 July 2009