Cranks Take a Beating, But Not Tools or Profit Margins
Crank Works of Tempe, Arizona has been using Mastercam’s high speed toolpaths on its conventional mills to improve productivity, along with reducing tool costs. These improvements have made a substantial positive impact on the company’s bottom line.
Founded in 1999 by Phil Schaefer, Crank Works specializes in building, rebuilding, servicing, and customizing 2- and 4-stroke crankshafts for power sports equipment, including ATVs, dirt bikes, jet skis, and snowmobiles. For the longest time Crank Works used conventional high-engagement, high-torque toolpaths for hogging out material from these machining intensive products. However, over the past several years, Mastercam has introduced a series of high-speed toolpaths. They use the full flute of the tool at very minimal depths of cut for very fast material removal, with very little strain on the tool or machine.
Crank Works began using one of these, Dynamic Mill, shortly after it was introduced and the impact on the company’s costs and productivity has been exceptional. Before implementing Dynamic Mill, Crank Works was using indexable tools with three to four inserts that cost $10 to $15. They were tearing up $30-$50 worth of tooling per crankshaft. “Now we do all our carving for a 3- or 4-piece crankshaft web with a single half-inch end mill that costs between $20 and $25. So we’ve cut our tool costs in half,” Schaefer said.
Tooling cost reduction was even more dramatic for connecting rods. Crank Works was going through $60-$70 worth of tooling for every few rods it made. Now the company can produce 20 to 30 rods before it has to replace the $25 half-inch end mill. Using the full flute of the mill, instead of just the tip as in conventional milling, is the primary reason the tool lasts so long.
Not only are tooling costs less, machine cycles are substantially shorter. When Crank Works started making rods, they used a conventional strategy that involved making a depth cut and then three high tool engagement cuts around the rod. These steps were repeated three times, requiring nine separate toolpaths and taking 45 minutes to complete a set of two rods. With the high speed machining strategy, a single toolpath guides the full flute of the half-inch end mill with a 0.035” around the rod at about 300 inches per minute to remove the same amount of material in about 20 minutes.
Shaefer said, “We don’t own any sophisticated high-speed mills. Even so, Mastercam’s high-speed toolpaths are allowing us to dramatically lower tooling costs and machine wear while we improve design, programming, and manufacturing productivity. As a result, we have seen dramatic improvements in our profit margins and this is allowing us to offer our own Crank Works branded shafts and rods in a price range that a greater number of power sports enthusiasts can afford. ”