Are 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 multi-purpose 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 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 again for every engine you do.
• CNC provides a higher level of quality control through automation. Assuming the job is set up correctly the first time, the CNC machine can do the same job over and over with the same degree of accuracy each time. This takes the human operator our of the equation and delivers consistent results no matter who pushes the buttons on the machine.
• If you are currently sending out parts for CNC machining, you can keep those jobs in-house by installing your own CNC machine. This can give you greater control over your work and reduces the time it takes to complete a job by eliminating shipping and delivery delays.
Can’t find a performance head for the engine you want to build? Having a custom-made CNC billet aluminum head is always an option.
• One of the most popular applications for CNC machining is for porting high-performance cylinder heads. This type of work usually requires a 5-axis machine that can reach all areas of the intake and exhaust ports for a seamless transition. But a CNC machining center can do more than heads. It can bore cylinders, line bore blocks and OHC heads, machine lifter bores, surface decks, lighten blocks and even fabricate custom billet parts from a solid chunk of metal.
• With a CNC machining center and some CAD/CAM design software, you can even make your own parts. A growing number of shops with 4-axis and 5-axis CNC machines are finding new markets where they can offer custom machining services. This includes copying parts, making custom automotive and motorcycle parts and even fabricating custom non-automotive components for a variety of industrial and agricultural customers.
A digital probe on a CNC machining center can be used to map parts, giving you a blueprint of all the key dimensions and surfaces on that part. If you then want to replicate a part out of solid billet aluminum (like a cylinder head, engine block, connecting rod, or crankshaft), you have the three-dimensional map for making it.
“If you can dream it, you can machine it,” said one CNC equipment supplier. With the proper software, you can digitally map and copy or modify parts, and you can design new parts from scratch. It opens up a whole new world of possibilities for expanding and growing your business.
CNC Fear Factor
In spite of all the advantages CNC offers, some shop owners are reluctant to embrace new technology — especially anything that involves computers. Old school machinists are used to pulling handles and turning knobs on their equipment, and watching the machine as it does its work. They enjoy the hands-on control over what’s happening and are reluctant to turn the controls over to a computer. What happens if the computer locks up or crashes? Can they still operate the machine manually or do they have to wait for a service technician to come fix it? These are legitimate concerns for anyone who is considering a major new equipment purchase.
“Those who don’t see a need for CNC equipment are living in the past,” said one shop owner. “As time goes on they’ll find their old school ways of doing things are no longer competitive with shops who have gone to CNC. It’s survival of the fittest.”
The resistance to computers is a generational thing, with younger shop owners and machinists being much more open and receptive to automation. Almost everybody has some type of smart phone these days, or own a tablet, laptop or desktop PC. Cars are packed with numerous control modules and even simple appliances now have computer chips inside them. So it’s not like its totally alien technology that’s being added onto shop equipment to make the equipment easier to operate, more productive and efficient.
