The cutting spindle rotates...
The cutting spindle rotates at up to 12,000 rpm. It moves up and down along the Y-axis, and inward and outward along the Z-axis. Combined with the A-, B-, and X-axes, they can cut virtually any shape imaginable.
Everywhere you look in the aftermarket and racing industry, you'll find a SAM graduate. Racing powerhouses like Hendrick Motorsports and John Force Racing rely on them every day. As the premiere vocational school in the performance automotive industry, the School of Automotive Machinists' curriculum has proven quite successful for several decades, however, founders Judson and Linda Massingill felt it was necessary to expand upon the school's existing courses in short-block machining and cylinder head design to keep pace with the changing times.
With the growing popularity of CNC machining in the industry, the school invested nearly $1 million to add a Haas five-axis mill, cutting-edge digitizers, 3-D modeling software, and several qualified instructors to its Houston-based facility. "CNC machines are going to be everywhere very soon because they're becoming so much more affordable. Teaching our graduates how to program and operate CNC machines is going to give them a leg up on the competition, which is why we felt the need to add CNC courses to our curriculum," Judson says. "A five-axis machine like ours used to cost $1 million not that long ago, but now you can get them for $100,000 to $200,000. Even basic machine work, like machining lifter and cam bores, are now being done on CNC machines. Manually doing operations like that on a Bridgeport take five times as long. Our goal is to give our graduates the skills they need succeed in a rapidly changing industry that is increasingly dependent on technology." -Stephen Kim
Different types of cylinder...
Different types of cylinder heads require different fixtures to hold them in place on the CNC table, so SAM makes its own. The fixture has dowel pins to help locate the heads, and they are then bolted down through the head boltholes. The entire assembly then bolts to the A-stands on the CNC table.
Before SAM turns its students loose on the CNC machine, they get lots of practice on Haas simulators, which feature the exact same functions as the actual five-axis mill. Although it's easy enough to manually write a program for things like flanges and spacers, the G-code for one port has over 30,000 lines of command. A typical combustion chamber requires 10,000 lines of code. "Even with 30 years of experience, it would be nearly impossible to manually write the G-code for a five-axis machine to cut out a port. A digitizer is a must," Jonathan Waitt says. "It's unlikely that our graduates will have to do much manual programming in the real world, but it's important to learn it anyway to understand how the CNC machine works. Knowing G-code enables you to look at a CNC machine and understand exactly what it's doing at any given time. Plus, not all shops use the same software to program their CNC machines, but G-code is universal." -Stephen Kim
The five-axis mill can be...
The five-axis mill can be fitted with a variety of cutting tools depending on how much and how quickly material needs to be removed. Larger tools remove more material in a shorter duration of time. The big tool (far left) is used to cut objects like the deck plate fixtures upon which the cylinder heads are attached. The medium-sized tools (top) are used to cut ports and combustion chambers. The tiny tool (far right) is used for engraving valve covers, while the gold-tipped tool features a serrated edge and cuts much like an end mill.
A steady stream of pressurized...
A steady stream of pressurized coolant is sprayed on the cutting surface to keep both the tool and cylinder head cool. The coolant also acts as a lubricant and helps remove metal chips. An augur at the bottom of the CNC machine expels metal chips out from the machining chamber and into an external collection bin.
After the prototype ports...
After the prototype ports are completed, they need to be digitized. The FARO arm is a space-age device that creates a virtual computer model of the cylinder head. By simply running a probe across the surface of the ports and chambers, the FARO arm exports data points into a PC using Verisurf software. SAM students digitized a factory LS6 head during our visit for illustration purposes, but the process is the same regardless of the style of heads.