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On autopilot: machining in the dark

On autopilot: machining in the dark

Florida shop rakes in profit with the lights out.

Chasco Machine & Manufacturing supplies parts to Boeing and other customers.

Part accumulator table at Chasco.

Chasco Machine & Manufacturing Inc. ( in Port Richey, Fla., is a picture of a traditional job shop. Its eight employees run seven primary production machines and five secondary machines to support $1.8 million in annual sales to the aerospace industry. But the way Chasco operates is anything but traditional.

After the sun goes down — and on weekends and holidays — the shop keeps buzzing. Chasco does some of its best — and most profitable — work when no one is around. Chasco has been operating at least one lathe each day on a 24/7 schedule, machining barstock supplied by a barfeeder with the lights out and no operator attending the machine.

The six-year-old shop has been profitable each year it has been in business, cranking out parts for the aerospace industry (75 percent of sales) and for the oil patch and other industries. It easily gives its aerospace customers an annual 3 percent reduction in prices, and cranks out 100 jobs a month, with production lots that range from 50 to 1,000 parts. Owner Jeff Roth has a two-word philosophy posted on the wall in his company's lobby. It says " Limit-less Creativity," and he expects everyone in the shop — including his father, a retired machinist who still comes in to help out on occasion — to live by it as he does himself.

The shop operates a Lynx 200 LC turning center, a Puma MSB four-axis turning/milling center, and an LSY-GL five-axis turn-mill center with a gantry loader, all from Daewoo; two EuroTech turn-mill centers — a 420 SLLY, eight-axis machine, and an E42 SLY five-axis machine; and two Kitamura vertical machining centers. Chasco also has a Hyd-Mech H-10A dual-post horizontal saw, a Bridgeport mill, an Acra 1440 engine lathe, a two-axis, Twister LT-2A speed lathe, and an Acra KB vertical bandsaw. It also uses a Branson 8510 ultrasonic cleaner and a coordinate measuring machine.

Four of Chasco's lathes are equipped with barfeeders, and Roth said his philosophy of pushing the creative window led him to keep one of the Daewoo machines running unattended overnight in 2001. The machine was producing a part for an aerospace customer Roth said he set it up and supplied it with enough barstock fed by an SMW barfeeder for unattended overnight operation.

"I pictured that machine like a slot machine in Vegas. When I walked in the next morning and saw all of those parts that we had done, it was like hitting the jackpot," he says.

Chasco has had as many as three turning machines operating for as long as 18 hours in an unattended, lights out mode. In fact, the shop typically runs its turning centers unattended from 5 p.m. each day to 6 a.m. the next day, and several machines operate over each weekend and most holidays. For weekends and holidays, Roth or one of his operators visit the shop to ensure that the parts are being discharged from the machine properly, that coolant levels are adequate and that chips are being removed from the work area. Otherwise, the machines are on their own. "I made $30,000 over the Christmas and New Year's holidays," Roth said, running machines that may have stood idle in other shops. Parts are removed from machines onto slowly rotating part accumulator tables that, in some instances are designed to keep aluminum parts from damaging each other by bumping into one another.

Running parts on an unattended machine requires well thought-out scheduling, Roth says. The first thing he considers is the material. Parts that are made from brass, for example, typically machine faster than parts made from stainless steel, and the raw material would be consumed faster. For the same reason, the next thing Roth considers is the intricacy of the part. Simple parts are machined more quickly and bar stock is rapidly consumed. However, when he has a complex aerospace part made from stainless steel or aluminum, the lights go out in Roth's head.

"We had a job to make a part out of 304 stainless steel. It had a tolerance of ±0.001 in., and it took three minutes to run. With a barfeeder supplying barstock to the lathe, we could run that part for eight-and-three-quarter hours and get 175 pieces without anyone attending the machine," Roth says. So he schedules jobs that can take that amount of time or more overnight or over weekends.

"Sometimes we have to schedule our jobs out a week or two in advance. We schedule spindle time to run parts that take longer over the weekend, and sometimes we are running our spindles better than 90 percent of the time," Roth says.

Chasco organizes the parts its makes in groups according to the type of machine they would run on along with the tooling and the setups required for the job, Roth says. Those groupings have increased its productivity. "If we take eight hours to do a setup or to do multiple setups, that's nothing when we are able to run a job for 24 hours each day for several days," he says. Additionally, grouping jobs led to the realization that several jobs had identical tooling requirements but called for different stock sizes. So a single tooling setup was done to run several jobs in sequence with different feedstock.

Careful scheduling let Chasco cut its per-part cost 71 percent — from $69 to $20 — for an item for one of its aerospace customers, Roth says. The shop had an order for 50 parts at $69 each, with the promise that as many as 1,000 parts would eventually be purchased. Roth said he worked with the customer to increase the order immediately, giving his shop the option to run it overnight and over the weekend in one setup.

Roth cited another part that Chasco was to run in early March:

"We have a 700 piece job that has bore diameters of 0.188 in., and other part features with tolerances of ±0.005 in., and the job includes hex bores. Each part takes 7.2 minutes to machine, and we will run for three-and-a-half days straight. We have a similar job scheduled to run on Wednesday, so we are going to minimize our setup time," he says. The 700 parts were scheduled to start running at about 6 p.m., Thursday. They would run for about 84 hours, and be finished by Monday morning at 6 a.m. when Roth's first machine operator comes in for the week. The only operator time devoted to the job from Thursday through Monday morning would be about two hours spread over the three-day period needed to check that the coolant reservoirs were topped off, that cut chips were removed and that the parts were ejected from the machine properly. Roth said those particular parts required some off-the-machine work, such as deburring and anodizing, and another 0.006-in.-diameter hole had to be drilled, but the shop was being paid profitably at $11.25 each. Roth says there are some parts with demanding dimensions — such as a 0.025-in. tolerance on one made from 2024 aluminum — that he would not run on an unattended machine overnight, but the number of parts that he does not run in that mode are diminishing.

And, Roth says he is not worried about the prospect of one of his machines failing overnight — which has not happened yet. In the event of a machine failing, Roth said he could lose several hundreds of dollars in raw material or tooling costs, but since it has not happened yet, he would still be ahead in profit for all the work that has been done with lights out.

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