If it ain’t broke, fix it

END USER: SFI, (901) 363-1571, www.sfifab.com.
CHALLENGE: Reduce cycle time when slot milling an A-36 steel part.
SOLUTION: A 4-flute, solid-carbide endmill for roughing and finishing in one pass at full slot width and depth.
SOLUTION PROVIDER: Iscar Metals Inc., (877) BY-ISCAR, www.iscarmetals.com.

A shop’s standard, go-to cutting tool is subject to change when a better one comes along. SFI, Memphis, Tenn., realized this when cutting a 382 “-long × 0.25 “-wide × 0.253 “-deep slot in an A-36 steel oil pan. The company, which also has a facility in Conway, Ark., designs, develops, supplies and services medium- to heavy-gauge components for OEMs in the agricultural, construction, industrial, transportation and defense industries.

Courtesy of Iscar Metals

When slotting the first four prototypes of the oil pan, SFI was applying its then-standard ¼ “-dia., full-radius, 4-flute, solid-carbide endmill. Run on an SNK RB-4VM 5-axis gantry mill with a 6m × 2m table, the machining parameters were a 160-sfm cutting speed, 2,443-rpm spindle speed, 5.86-ipm feed rate, 0.0006-ipt feed per tooth, 0.25 ” WOC and 0.05 ” DOC. Average thickness for the fragment-type chips was 0.0006 “, the metal-removal rate was 0.07 in.3/min. and each cutter lasted one part, with flank wear being the predominant type of wear.

When run at the full slot depth on the oil pan job, the standard endmill snapped, causing rework, noted Matt Watts, machine shop supervisor. Using trial and error, SFI backed the tool off so it could get through the part, but the cycle time consumed about 6.5 hours. When extrapolated for the proposed 100-piece run for the family of oil pans, total cutting time would have consumed an unacceptable 651.6 hours, according to Watts.

Fortunately, Watts and Greg Archer, SFI programmer, attended a seminar presented by Iscar Metals Inc. at the toolmaker’s headquarters in Arlington, Texas. They asked Rex Luxmore, Iscar’s sales engineer for western Tennessee, if the FINISHRED solid-carbide endmill they saw demonstrated at the event was suitable for the oil pan application. “I said, ‘Hell yeah, that’s perfect for it,'” Luxmore recalled.

Courtesy of Iscar Metals

An Iscar ¼ ” solid-carbide FINISHRED endmill reduced cycle time from more than 6.5 hours to 8 minutes when slotting an A-36 steel oil pan at SFI.