Aerospace shop flies through production

Accu-Tec Enterprises, an aerospace CNC machine shop in Oklahoma, has found that using Delcam’s PowerMILL CAM system to program its five-axis machining centre has allowed it to cut the cycle times on a family of four aircraft parts nearly in half while improving surface finishes.

David Steeber founded Accu-Tec with one customer back in 1988. As the aerospace industry has strengthened, so has Accu-Tec’s order intake, which last year saw a growth in turnover of more than 250%, mostly through referrals from its customer base.

To keep up with its customers’ demands for extremely complex air-frame parts, Accu-Tec has made shrewd investments in technology.  Despite the increase in work, the company added only three employees, bringing the total to 15.

Most of the machines in the shop are three-axis Okuma vertical machining centres.  Until recently at Accu-Tec, five-axis work was done by positioning and machining in three axes and then putting the parts on another fixture to align them in a new attitude. Now, the company is stepping up to true five-axis machining because the parts it is seeing have more complex surfaces and irregular shapes. They also require a high-quality surface finish but still need to be completed in shorter cycle times at less cost.

According to David Steeber, "After we realised the limitations of our existing software, the Delcam representative came in and actually helped us develop the code on our first part, proving to us that the software worked as promised.”

Five-axis machining has also simplified Accu-Tec’s fixturing requirements dramatically.  For the last major contracts it won, the company spent four months producing the fixtures.  They made good parts but, with five-axis equipment, less fixtures would have been required that would have taken only three weeks to make.

Also, according to Glen Cotton, Accu-Tec CNC programmer, "The finish Accu-Tec achieves is better, eliminating the need for secondary operations or handwork, and improving our quality further by avoiding the possibility of human error on the part.”

"The Delcam software also helps to keep the tool on the part,” added Mr. Steeber.  "This has helped us to reduce cycle times.”

PowerMILL’s integrated simulation is another advantage.  "Previously, I would not see an error until it got to the machining floor,” Cotton said. "Now, since the machinists know I’m using Delcam and can error-check before the part program goes to the floor, their confidence level in my programming has grown quite a bit.  We completely plan the process before we take it to the shop, so we can support the shop floor should any questions arise.”