CNC Feature
14-21 CNC 4/11/14 3:04 PM Page 14
What Can CNC Do For You? BY LARRY CARLEY, TECHNICAL EDITOR
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re you using Computer Numeric Controlled (CNC) equipment in your shop? According to our most recent Babcox Machine Shop Market Profile Survey, 12 percent of engine builders said they own a CNC machining center (a multipurpose machine that can do surfacing, boring, milling, drilling, etc.). The survey also asked what other types of equipment our readers own (boring & honing machines, surfacers, valve guide & seat machines, etc.), but we didn’t ask if the equipment was manual or CNC. Most shops (88 to 94 percent) own these types of machines, as one would expect since they make their living doing engine work. Had we asked for a breakdown between manual and CNC machines, the percentage of shops who are using some type of CNC equipment would likely be one out of four or maybe even one out of three. The point is the use of CNC equipment continues to grow -- and with good reason. Many of the CNC machines that are in use today are found in high-end performance shops, shops that work on a lot of late model engines, and shops that are doing specialized machining for both automotive and 14 April 2014 | EngineBuilder
non-automotive customers. The use of CNC shop equipment is growing because it offers so many advantages: • It reduces the need for skilled labor. An operator doesn’t have to stand in front of the machine all day manually controlling its motions and babysitting processes. The automatic controls run the equipment, freeing up the operator to work on something else. CNC machines also don’t punch a time clock, don’t call in sick, don’t take vacations and are not interrupted by phone calls, nature calls, coffee breaks, parts deliveries or shop chatter. Any of these things can interrupt the steady flow of work in a shop and create distractions that reduce productivity and sometimes lead to mistakes. Shop owners we’ve interviewed tell us that CNC allows them to do more work with the same number of employees, or in some cases to trim staff. One shop owner said, “We used to have seven people working in our shop. Now we do the same amount of work with just two people. It’s a huge cost savings in labor for us. Once a job has been setup, the automatic controls take over and do all of the machine
work. If it’s a long job, the machine doesn’t stop working at 5 o’clock and go home. We can let it run all night if necessary, and start the next job first thing in the morning.” • CNC offers a high level of accuracy and repeatability. A highly skilled operator who pays close attention to details can do the same thing, but everybody has a bad day now and then and makes mistakes. Late model engines have much closer tolerances than engines from a few decades ago, so you have to be right on when you bore, hone and machine critical components. There’s less room for slop, so once you have a process in place that delivers the accuracy you want, you don’t have to worry about mistakes messing up a job. Once you’ve setup the basic machining perimeters for a job, the programming can be stored and reused or easily modified the next time a similar job comes in. For example, say you want to blueprint a small block Chevy engine. Once you’ve established the basic dimensions for locating and centering the cylinder bores, lifter bores, crank and cam bores, deck surfaces, etc., you have a digital map that be used over and over