Nathan Barker, mill department manager for
Sicom Industries, hated scrapping an aluminum casting worth thousands of dollars
because a chip lodged in the back of his
traditional back spotfacing tool gouged the
casting’s intricate interior.
Sicom Industries, a contract toolroom and
machine shop with locations in Vancouver
and Houston, Texas, works in the oil and gas,
aerospace, and mining sectors, but aluminum
castings for the defence industry are its bread
and butter. According to Barker, these castings are expensive and complex, with up to 40
internal cavities that make it hard to manually load the head of the conventional-style
back spotface tool.
For years Barker and his team spotfaced
using traditional methods. The operators fed a
shaft through a bore, then manually attached
a cutting head. Once the head was attached,
the operator followed an extensive routine:
Start the program, start the spindle, run the
tool, stop the tool, take off the cutting head,
retract the post, and repeat the whole process
on the next cavity.
With 40 cavities this was a time-consum-
ing process, and one which was not always
successful. The enclosed cavities make it
difficult for the operator to manually attach
the cutting head to the body, creating further
production downtime and increased frustra-
tion from the operator.
Barker began researching alternative back
spotfacing methods and tools. Some automated tools project the cutting blade when the
spindle is reversed, but Barker found that this
tool also had problems. On one occasion when
he was testing out this style of back spotface
tool, material built up around the blade after
cutting 0.656-in. holes with 1.410-in. counterbores. The built-up material prevented
the blade from retracting back into the shaft,
damaging the casting. The high-value cast
aluminum had to be scrapped, and Barker
knew that this style of spotface tool was not
the right one for the application.
Producing off-spec parts can damage a
shop’s reputation, as well as waste production
time and labour. Barker needed automated
back spotfacing to speed production time, free
manual labour for different machines in the
shop, and most important operate with the
precision Sicom’s clients demanded.
“We don’t have our own products; we’re
at the mercy of whoever’s giving us work,”
Through online research and metalworking
catalogues, Barker found Heule Tool’s BSF
(Back Spot Facer), an automatic back spotfacing tool that retracts the boring blade by coolant pressure. Designed for CNC machining,
this tool functions without an antirotation
device, change of spindle direction, or contact
mechanism. The blade expands using centrifugal force when the spindle is activated.
Coolant pressure moves a piston, pushing a
Automatic back spotfacing frees manpower at
Vancouver machine shop
Back spotfacing counterbores backwards allows the
machining of large spot faces without turning over the
workpiece. Photo courtesy of Heule Tool.