The justification ratio

Feb. 12, 2009
When can a shop justify the purchase of a CNC multispindle machine? According to Olaf Tessarzyk, managing partner and president of ZPS America LLC, the answer depends on a ratio. If a shop is running one job on three or more ...

When can a shop justify the purchase of a CNC multispindle machine?

According to Olaf Tessarzyk, managing partner and president of ZPS America LLC, the answer depends on a ratio.

If a shop is running one job on three or more single-spindle machines with, say, subspindles and two or three turrets, the CNC multispindle the shop is considering should have the flexibility to produce three times the amount one of those single-spindle machines does for that job. This would be a 3:1 ratio, and, on average, good CNC multispindle justification ratios are 3, 3.5, or 4:1, said Tessarzyk.

He points out though that ratios increase depending on machine price. Some multispindles, because of price, may require a ratio as high as 5:1 to justify the purchase.

“A shop would be hard pressed to justify a CNC multispindle when comparing it to five single-spindle machines. It’s practically impossible. So if the ratio is beyond 4.5:1, a multispindle machine may not be the way to go,” Tessarzyk said.

He added that one CNC six-spindle multispindle machine does not necessarily replace six single-spindle machines. In the best case, it may replace five.

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