TECH Manufacturing Co. (St. Louis) supplies complex aircraft component parts for companies such as McDonnell Douglas (Boeing) and Lear Jet (Bombardier). Founded in 1956 by William C. Stinson, CEO, TECH Mfg. employs 35 people and currently makes parts ranging in size from smaller than a wristwatch battery to upwards of 120 inches in length. Recently, the company was asked to make a part that spanned close to 19 feet in length - the largest part they had ever produced - under an extremely tight deadline. "We knew we could do it," said William Stinson, CAD/CAM Manager for TECH. "But we also knew we would have to upgrade our method of verifying cutting motion to today’s industry standard. We decided to utilize what is considered by most to be the best CAD/CAM verification and simulation software package on the market."

 

In early 1997, TECH Mfg. decided it was overdue to invest in a solids-based verification module to be used by the CNC Programming Dept. We had previously used our current CAM package to view cutting motion sequences in a wireframe environment, which sometimes could allow for a visual error by the programmer. Our program try-outs were run on machinable foam blocks before any real chips were ever cut," said Stinson. The foam verification was sufficient to detect obvious mistakes, but left much to be desired for most inspection purposes. Additionally, machinists could not easily clamp the part the fixture without damaging it, and machining the foam part took costly machine time away from real production work. After looking into the available verification tools on the market and speaking to other experienced users, TECH Mfg. purchased CGTech’s VERICUT software program.

 

Shortly thereafter, TECH Mfg. was awarded a contract for a newly redesigned longeron that replaced multiple smaller parts in the cargo ramp door section of the C-17 Globemaster. The door sub-assembly is done in St. Louis and later shipped to Long Beach, CA for final assembly. The part is one of the last to be added to the sub-assembly and mates with numerous other bulkheads. No one had manufactured this part before - the final blueprint on this part was not released until the end of March 1997 and no CAD model had ever been developed.

 

Using NCCS’s NCL502 CAD/CAM software, TECH Mfg. constructed 3D models of the part, the required mill fixtures, and additional tooling . "We utilized VERICUT to verify the CNC programs for cutting the tooling before they were sent to the machine control," said Stinson. Our net result was the completion of three individual mill fixtures (each consisting of several details) without any rework whatsoever."

 

As soon as the tooling was complete and part programs were verified through VERICUT, they began cutting chips from the 230+ inch aluminum plate (which was received later than expected). By the time the part would be finished, approximately 90 percent (850 lb.) of the stock material would be removed - a hefty amount of cutting to say the least. In order to have access to all areas of the part, machinists had to locate the part in several orientations, each at different angles. With its versatile toolpath orientation setup, VERICUT gave us an easy solution to check for any mismatch (or lack of) between the various operations without having toburn up valuable machine time," noted Stinson. VERICUT’s "in-process" saving feature made jumping directly into any program at any tool sequence a snap. With the ability to do ‘ First Article Inspection’ right inside of VERICUT, even the close-tolerance contoured surfaces running the full length of the part were inspected and compared to the customer’s quality specifications prior to cutting any chips.

 

Although progress was moving well with the production of the new part, minor technical delays had given rise to some concern. As the delivery date for the first shipment drew closer, the team at TECH Mfg. began to realize that any miss-cut on the part would not only put them behind on the delivery schedule, but could possibly hold up the C-17 assembly line. "Not the ideal way of being noticed by a major contractor," reflected Stinson. "I can only guess at what a plane worth over $110 million would cost daily if delivery is postponed."

 

The tentative delivery of the first left and right-hand part was crucial to the assembly schedule in St. Louis, as well as Long Beach. TECH Mfg. had this part on top priority status and worked on the project around-the-clock. Customer representatives were briefed daily on the progress of the first part and sent a team to TECH Mfg. each week to get a first-hand look at the status of the critical project. They were concerned not only if TECH Mfg. could fulfill its commitment to deliver on time, but also whether the company could produce a finished part at all. But with the time they saved by proving all part programs with VERICUT, Stinson and his crew were confident they could pull it off.

 

Just as St. Louis sub-assembly reached the point where that part was to be fastened, TECH Mfg. was finishing the final processing. They had made the delivery date, but now would the part - a part they had designed and manufactured without a single dry run or prove-out - a part bigger then they had ever machined before - fit correctly with its mating parts on the assembly line?

 

When the part arrived at the receiving dock it was immediately unpacked and prepared for installation. The following morning it was mated with the rest of the assembly while an unusually large group of executives and engineers watched closely. This was no time for an overlooked discrepancy to rear its ugly head," remembers Stinson. But, to everyone’s delight it fit like a glove, mating uniformly to multiple other parts already fastened in place. The sub-assembly was then shipped to Long Beach and fitted to the C-17 as planned.

 

Our success on this project was a combination of talented people, like our top-notch CNC machinist, Doug Randell, and the right tools. VERICUT played an essential role. Needless to say, VERICUT has quickly become an integral part of our plan for continuous improvement in the quality of our production."

 

TECH Mfg. has recently acquired close to five acres and is currently building a new 40,000 sq.ft. plant approximately 50 miles west of St. Louis in a newly developed industrial center. With successful results such as this, our company’s growth has gone from a future plan to a plan of "action," said Stinson With the strong showing that VERICUT has made at TECH Mfg. thus far, there’s no question as to whether or not it is a worthwhile investment. In fact, after the first delivery our plant manager, Jerry Jones, came to me and said, You know, I really think that VERICUT has already paid for itself on this part alone.’ Now that’s not the kind of thing programmers are used to hearing from a plant manager!" TECH has just been notified that the contract for this part will be extended to almost triple the current quantity. That is what a job well done is really all about.