You can automate more than you think: this shop expedites 3D milling work by reducing its dependence on employees for oil of the information-related tasks that occur before the machining center can start to cut

Modern Machine Shop, Oct, 2003 by Peter Zelinski

With a CNC machining center you can just hit Cycle Start and stand back. Imagine if the whole machine shop worked that way. Imagine if the arrival of a customer's geometry set in motion a series of unattended or lightly attended steps that resulted in the finished part being shipped out the door just a few hours later.

Now meet Richard Sweat. Mr. Sweat is the owner of a nine-employee machine shop that runs and ships 50 to 75 separate jobs per day. Every piece the shop machines is as unique as a snowflake, with a distinct 3D geometry unlike that of any other part the shop will ever machine. And every one of these pieces is delivered to the customer within 48 hours of when the geometry file arrives--within 24 hours if the file arrives before 5:00 p.m.

The shop is Southeastern Radiation Products of Sanford, Florida. The shop makes "'tissue compensators" used in cancer treatment. These parts work like filters--lenses--for radiation therapy machines. They give hospitals a level of control over radiation therapy machines far better than what they used to be able to achieve.

Mr. Sweat worked in radiation therapy physics for 8 years. He became a machine shop owner because he saw an opportunity in the improved scanning and modeling technology that started to become available to hospitals. Measurement technology today makes it possible to determine precise 3D coordinates for a cancerous tumor along with precise locations and densities for the healthy bone and tissue surrounding it. These data make it possible to design a metal fitting for the radiation head that uses variations in the thickness of the metal to vary the intensity of radiation, producing a radiation field conforming to the topography of the patient. Mr. Sweat even invented a brand name for this custom-machined part, calling it "Digitally Enhanced Compensation/ Intensity Modulation with Aluminum" That is, "'Decimal.'"

It would be difficult to imagine a more sensitive component. Patients in need of this kind of therapy need it now, so every order is an emergency order. And there is little room for error, because a machining discrepancy or a mistake in labeling two different orders would have severe consequences for the patient. These requirements threatened to limit the size of the business because the larger size necessary to take on more work would have introduced too much potential for error or delay. In short, the business wasn't scalable. Or more accurately, it wasn't scalable so long as the shop continued to operate the way a contract machine shop usually operates.

For the company to increase its volume, it needed to win more value from existing employees' time. It needed an automated process that could deliver work to the shop floor with much less employee intervention. Automating machining was not the challenge--effective CNC machining centers took care of that. The challenge instead was to streamline the information-related tasks that have to be performed before a machining center can do its work.

Today that streamlined process has largely been put in place. Orders e-mailed to the shop are logged automatically, causing travelers to be automatically printed. Modeling and programming functions are so automated that CAD/CAM work takes 5 to 10 minutes per job. E mail confirmations and shipment tracking numbers are sent to customers as soon as the job ships, without anyone in the company having to think about closing this loop. The system is close to hands-off--and for an independent shop, maybe about as close to hands-off as possible

This success at streamlining deserves examining for at least two different reasons. One is that it offers a model for other shops that may wish to automate their own information-related tasks.

But more fundamentally, SRP's example suggests how broadly automation can be applied. This shop managed to automate various innocuous and "fuzzy" tasks that wouldn't seem to be automation candidates. The implication, in other words, is that you can automate more than you think.

Today the reduced human intervention makes the process not only scalable, but also reproducible. Mr. Sweat can now imagine copying this shop in some distant location. In fact, he has begun to contemplate exactly this. For a business dependent on fast delivery, a facility in a separate time zone could be an important benefit.

File Translation

The streamlined process didn't come all at once. It was developed in phases, and the phases unfolded over the course of years. The first phase--file translation--didn't directly relate to automation at all. It was necessary just for the shop to be able to program any job.

The data files that describe a tissue compensator's geometry don't arrive in a format that a typical shop would recognize. There's no IGES here. Instead the data come in about five different flavors for different makes of radiation machines, with coordinate measurements often given in centimeters, and point locations often defined using some non-Cartesian scheme such as a spherical coordinates.