Motorcycle power from napkin sketch to aluminum prototypes

Like any good racing story, it starts in a bar on the back of a napkin.

In 2010, motorcycle drag racer Mitch Brown was having a drink with an engine builder friend. Sketching on the back of a napkin, the friend was saying, “If I could only get someone to make me a four-valve cylinder head that has valves at an angle like this and cam shafts that are this far apart, and. . .”

“I can do that,” Brown said.

Two and a half years later, he delivered a cylinder head manufactured from a solid billet of aluminum. The Monster Race Products prototype generated 305hp, power equal to the best OEM and third-party cast heads that have been on the market for more than two decades.

The engine builder, who had hit a performance wall with the older heads, believes there is a lot of upside for this new head design. He hopes his customers will be able pass 400hp after a number of racing seasons.

Not bad for a labor of love, done mostly after hours and on weekends.
 

Tapping into aerospace expertise

During the business day, Brown is co-owner of Black Rock Machinery, a CNC equipment dealer serving the thriving aerospace industry in Wichita, Kan. To make the new heads, he planned to take advantage of some of the deep talent he knew existed in many of the job shops he routinely visits.

Two shops agreed to participate in the head project when they weren’t preoccupied with aerospace work. Motocross racer and CNC programmer Niles Gibson began writing CNC manufacturing programs for prototypes based on models generated using Unigraphics NX software.

The work was painstaking and often delayed because the job shop had other priorities. After two years, Brown and Gibson had a preliminary model, but Gibson had moved to a new shop, severing ties to the location where Brown had expected to machine the part. Frustrated, Brown concluded that if he was going to connect motor sports customers with aerospace technology, he needed his own machinery.

Brown purchased a 5-axis mill and asked Gibson, who agreed to serve as programmer on nights and weekends, to survey the market for the CAM software. The goal was to make Monster Race Products a sophisticated manufacturing resource for motor-sports enthusiasts and the companies that support them. After studying the market and asking the opinions of users in aerospace job shops, Gibson recommended Mastercam from CNC Software.
 

Software for programming novices

Mastercam’s reputation for flexibility, its ability to cleanly import NX and other types of CAD files, its integration with Verisurf measurement software, and support via nearby Mastercam reseller QTE Manufacturing Solutions, all contributed to the selection.

Gibson installed Mastercam in 2012, a month before the CNC machine arrived, giving him time to become familiar with the software. Then, using Mastercam X6 and X7, Gibson created and ran the first programs for the mill. He said it took him about 40 to 60 hours to become reasonably proficient in the software while he was writing the program to manufacture a new production version of the head.

It was slow going at first because of Gibson’s limited availability. However, after several months and some help from QTE, Gibson was using Mastercam to generate programs for cutting complicated parts and creating workflows. This enabled Brown and a helper to safely set up and run parts on the machine, even though neither had programming experience.

To set up workflows, Gibson uses Mastercam’s simulation features to ascertain that there is no interference in the cutting paths that would damage the part or the tool. He then uses the software’s tool library to generate setup sheets that allow a variety of users to set up and run the machine consistently.

“It is rare when more than one of us is in the shop, so the set-up sheets allow the mill to keep producing for long stretches of time no matter who is here,” Gibson says.
 

Long, difficult cutting paths

To get a starting point for placement of all the heads’ features, Brown partnered with Suzuki drag racing engine builder George Bryce at Star Racing in Americus, Ga. Bryce provided a 2D drawing of the valve layout in the combustion chamber and a 2D side view drawing of valve geometry. Brown digitized existing features such as bolt pattern, bore spacing, and intake and exhaust manifold locations, incorporating them into the NX model.

The greatest manufacturing challenge was using long cutters to reach all areas where material had to be removed. This needed to be done efficiently to control costs, without putting lateral stresses on the tool that would result in chatter, wear out tools, and damage critical surfaces.

Gibson says Mastercam’s material-aware dynamic machining technology was critical because it runs tools at high feeds and speeds and full flute engagement with minimal stepovers. Dynamic machining automatically adjusts cutting parameters to avoid burying the tool in the material.

“On this head, we have a lot of reach issues,” Gibson notes. “I have a 3/4" diameter tool that is sticking out 4-1/2" to reach all the material I have to remove. Without those dynamic toolpaths, you would need to slow things way down to avoid worry about chatter or breaking tools.”

Gibson adds that he’s talked to colleagues in the CNC world, and they have a tough time believing that deep cuts at high speeds are possible. “With conventional roughing routines, you can only program as fast as whatever your worst cut is. Otherwise you are going to bang into those pockets and it will make a lot of noise. With the dynamic machining, you can listen to it cut and it sounds beautiful. And it sounds the same for the entire cut.”
 

Enthusiasts respond immediately

Word travels fast and far in the motor-sports world – most of it via the Internet. Photos of the new head design and posts about dyno results have attracted attention around the world. Within months of releasing the new head, Monster Race Products had delivered 20 heads to engine builders, racers, and racing teams in England, Hungary, New Zealand, Australia, and the United States.

As the word gets out, Brown believes his small, high-tech manufacturing team will easily fulfill double the number of orders in 2014. The advanced technology and manufacturing processes his team has assembled will easily integrate other systems used routinely in aerospace.

“The mission of our company is to use advanced manufacturing processes to help racers, engine builders, and OEMs fulfill their visions of improved racing performance,” Brown says. “Mastercam gives us the flexibility to integrate our manufacturing processes with advanced technology borrowed from the aerospace industry as our sales growth permits.”

CNC Software Inc.
www.mastercam.com
IMTS 2014 booth #E-3340

Monster Race Products
on.fb.me/1k42zIk