Backbone of Scrap-Free Aerospace Manufacturing

Jacob Grey, Inc. (Columbia, SC) is scrap averse. “Our attitude,” said owner Jake Brackett, ‘”is that we don’t want any scrap. We machine 10-15,000 titanium parts a year and a lot are complicated. They cost $5-15,000 each. Our scrap rate is very low. I think we’ve had two bad parts since January out of about 7,000. We check 100% of our parts. Even if it’s 200 pieces we check each of them completely.”

He indicated that the Mastercam is the backbone of his 5-year-old company’s scrap-free CNC manufacturing strategies. It is the digital environment where 95% of the work is accomplished before the workpiece is set up on the machine. To keep all the digital work in a single environment relies on a set of advanced tools that are part of the Mastercam software or that have been purchased from third party suppliers and integrated seamlessly within the CAM software via Mastercam’s C-hook technology.

Lead programmer Jesse Simmons explained that this integration is vitally important because the two programmers are expected to begin programming within a few hours of the part arriving in their queue. He said, “The faster I can get the part programmed, the faster I can machine it. The part will come in, we analyze it, program it and start machining the same day.” These parts, which have been modeled in SOLIDWORKS are imported directly into Mastercam. A Mold-Plus software module is of use to all of the MDB (Model Based Definition) data associated with the part. This saves a substantial amount of time because it eliminates the need to work back and forth between Mastercam and CATIA to access MDB.
Verisurf, another module integrated within Mastercam, is used to visually analyze MDB data and determine how to machine difficult part dimensions and meet difficult dimensional requirements. Simmons said that Verisurf is particularly useful for aligning hole axes and analyzing the thickness of walls coming in at odd angles. Critical process variables identified with Verisurf trigger in-process gaging sessions on the shop floor using the machine’s spindle probes.

The programmers also make extensive use of the X-Plus module within Mastercam. This allows them to design standalone set-up sheets for the operator. The operator can use the same sheet to send comments back to the program where Simmons can take advantage of shop-floor experience to further improve the CNC program.

Simmons also cited many features within Mastercam to improve workflow so that parts move from model to machine faster. These include model prep features that help him analyze the part and build workholding solutions faster; simulation to verify the accuracy of toolpaths; machine simulation to detect interferences within 5-axis toolpaths, and 5-axis toolpaths themselves, which Simmons believes have “come a long way” in terms of collision detection and tool control.

In just five years the company has grown from 3 to 10 employees and production output has grown more than 10-fold with two CAM programmers, so far, keeping up with a steadily increasing flow of work largely from the aerospace industry.