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Cracking the Code on Efficiency

Sept. 29, 2011
Revising FAI software to include GD&T symbolic language reduces production time and cost on critical aerospace parts

STD Precision Gear & Instrument Inc. manufactures high-precision gears (AGMA Q14), splines, and related mechanical transmission components for critical applications —including NASA's International Space Station, the Hubble Telescope, commercial and military aircraft, and various defense products. Precision and accuracy are more than descriptors for the West Bridgewater, Mass., shop; they are defining features of the operation.

The company offers its customers a complete service, from prototype through production, with a full in-house manufacturing capabilities that include saw cutting, CNC turning and milling, Swiss screw machining, wire and RAM (die sink) EDM, surface grinding and internal/external cylindrical grinding, broaching, honing, CNC piece marking, heat treating, passivation, isotropic super finishing, and tool design and tool making.

“I’ve been in this business for 33 years and founded STD Precision Gear 26 years ago, and a constant drive to refine our processes and enhance efficiency has been an essential component to our growth,” said James Manning, the company’s president.

To maintain its attention to precision manufacturing while supplying a growing portfolio of customers STD chose DISCUS Software to supply its product-quality control platform, and very soon realized significant production time and labor-cost savings to complete first article inspections.

Paul Gomes is STD’s quality engineering manager, and he recognized that if the software could provide an automated process to insert Geometric Dimensioning and Tolerancing (GD&T) symbols he could cut significantly the time spent placing the symbols in drawings, a manual process. He presented his idea to DISCUS.

Gomes understands well both the problem for STD and the potential for the software. He is experienced as a draftsman and machinist with Texas Instruments, where he also taught seminars on using GD&T as a way to standardize communication from design to manufacturing to end product. “When I started working with STD, I saw the ability of this software to take customer drawings and make our markups using its built-in optical character recognition (OCR) feature,” he explained. “I recognized immediately how the software functionality fills the role of an entire drafting department. We use this software to run the whole shop. Nothing hits the shop floor without a DISCUS marked-up drawing.”

The improved FAI software from DISCUS presents inspectors with an extra panel that displays 15 GD&T symbols, which can combine with modifiers to create 30-40 unique marks to control characteristic types, orientation, location, run outs, part profiles, and other refinements to a product design drawing.
GD&T symbols installed in the program allow engineers to attach shop markups to customer drawings as built-in optical character recognition (OCR) features.

Since GD&T software capabilities are typically only an option in drafting-specific software packages, Gomes was unsure whether DISCUS would be responsive to his suggestion to integrate GD&T functionality into its software suite, which is designed to manage the whole Technical Data Package. But, he emphasized how the additional functionality would allow STD to create superior drawings, and thereby differentiate the company from it competitors.

DISCUS software products are used by OEMs and their supply-chain partners to reduce the time and labor for first article inspection, inspection planning, process planning, and producibility analysis. The company responded to Gomes, and worked with him to define the new capability according to his concerns and expectations. Eventually, the developer introduced GD&T capability in its next software update. Gomes was among the first to see the benefits.

Evolution of a language Although various evolutions of GD&T symbolic language have been around for more than 100 years, the engineering language spread more widely during World War II, when U.S. military sought a way to guarantee interchangeability of manufactured parts. Since then, manufacturers have adopted GD&T across numerous industries to describe geometric parts, completely and unambiguously.

Today, two major GD&T version standards have emerged: ASME Y14.5M and ISO/TC 213. Though not yet adopted by all quality engineers, proponents of GD&T see its benefits in locating holes and size dimensions precisely, and the language is expected to grow in use as it streamlines global industry communication. Among the reasons for this are:
• Dependability to explicitly describe tolerances;
• Emphasis on the intent of the design;
• Reliance on definition by math and numbers; and
• Easy translation into other languages.

Gomes knew what other quality engineers and design drafters who are skilled in GD&T understand: consistent and effective usage of the symbolic language can thrive when a method to automate the encoding and decoding process is in place. Working with the software development team, he was able to accomplish that for STD and its customers.

Manning estimated that DISCUS software now eliminates more than five hours of work in the shop each day. When he recognized how much time just one of his shop technicians was forced to spend writing out inspection reports, he sought a software product to manage the Technical Data Package. The decision to move forward with the software was obvious when he calculated the time spent by the number of STD employees, and the number of times each day that process was required. When Gomes joined STD, he was impressed with the efficiencies DISCUS allowed and took on the role of coordinating quality management for the company, implementing even more timesaving measures with the software’s functionality, including GD&T integration.

Now Gomes is responsible for guiding quality management throughout the life of a project at STD. When a part order comes in, a shop floor quality inspection plan drawing is created. Then at the end of the project, an FAI package is assembled to send out to the customer. Each drawing set requires STD to include precise dimensions and GD&T markups. Before STD implemented the software, both of these drawing sets were completed manually. Manning listed several downsides to this process including:
• Poor readability due to handwritten specifications;
• Greater potential for mistakes; and
• Difficulty to make changes.

An efficient solution
Now, Gomes uses the software tools as a one-stop shop to manage the intelligent Technical Data Package. “The software takes care of all of our needs as far as production documentation, instructions for the operators, inspection criteria and inspection documentation,” he said.

He separates the dimensions and balloon characteristics by job centers, according to the type of machine that requires those dimensions to make the part. Custom shop-floor drawings are distributed to every operator using balloons and token tags to create a customized set of characteristics that each operator needs to check. Throughout the manufacturing process, these drawings remain dynamic, and Gomes manages them easily.

After seeing the documentation advantages already available with the software, Gomes wanted to automate one more part of his process: GD&T integration. Depending on how many characteristics are present in a drawing, Gomes estimated that he previously spent 10-30 minutes drawing in GD&T symbols. When he conveyed his desire to see GD&T integration with DISCUS, the software developers were intrigued. Together, they shared screenshots and discussed how the symbolic language could be integrated into the software interface. “To say that DISCUS implemented a GD&T solution quickly is an understatement: They thoroughly understood what I wanted to see, and matched it excellently,” said Gomes.

Now an extra panel on one of the software pages opens a full selection of GD&T symbols. Fifteen main symbols can combine with modifiers to create 30-40 unique marks to control characteristic types, orientation, location, run outs, part profiles, and other refinements. To identify the location, portal polls and data points, Gomes can choose from the panel of options and insert the symbols with just a few mouse clicks. “I’m not used to a software company providing such valuable two-way communication,” said Gomes. “The result has been an added capability that provides a significant advantage for our business.”

Manning noted that those timesavings have not been the only benefit from this new functionality. “The high quality documentation we can deliver to our customers with clean ballooned drawings sets us apart from our competitors and gives us an edge in our industry,” he said.

Manning added that soon STD will begin using the DISCUS Planner and CMM modules to create in-process inspection plans and manufacturing process plans and to import results from CMM reports.

“The ways that we’ve been able to adjust DISCUS software for our own unique needs has reaped tremendous benefits,” said Manning. “What we’ve done here in terms of productivity allows us to save significant shop time, while delivering a 97% on-time delivery rate and excellent precision to our customers.”

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