Pitney Bowes

A 60% reduction in tool-building time, possible with stereolithography, allowed Pitney Bowes to test plastic injection molded components before committing to final part design.

The Challenge
A new mailing machine under development by Pitney Bowes' technology team in Shelton, Connecticut, required design verification of a critical component before the company could commit to production tooling. To verify the design, Pitney Bowes engineers required ten parts molded from actual production material on which to perform cyclical, functional tests. Injection-molded test parts had to be delivered in 6 weeks or less, 60% ahead of the 18 weeks required to develop and build injection-molding tools using conventional methods.

The Results
A design team of engineers from Pitney Bowes, 3D Systems, CEMCOM Corporation and Santin Engineering opted to build injection-molding tooling by backing, with ceramic, a nickel shell formed by deposition on an stereolithography (SL) pattern.

The composite tooling successfully molded over 60 plastic parts. Ten parts that underwent product integrity testing successfully withstood different loading conditions for millions of cycles.

Pitney Bowes and its consultant, Santin Engineering, provided a 3-D solid CAD model of the part to SL design engineers at 3D Systems. By fine-tuning the SL building process, using 3D System® Zephyr® recoating system, they built a pattern having an accuracy of 0.005 inch.

The pattern was shipped to CEMCOM Corporation, where it received an electroformed 0.1 inch nickel layer. CEMCOM technicians mounted the nickel-coated pattern in a steel-mold pocketed frame and poured in a ceramic backing, which, after hardening, facilitated the removal of the pattern. Final tool assembly and installation of ejector pins were done at Acson Tooling. The test parts, injection-molded from 30% glass-filled modified polyphylene oxide structural-foam, withstood integrity testing. Pitney Bowes, now satisfied with its part design, built actual production tooling.

The SL technology, combined with the nickel-ceramic tooling methods, allowed Pitney Bowes to:

• Cut tool development and building time by 60%
• Reduce tool development costs over conventional methods
• Verify and optimize part design before building hard tooling
• Perform functionality testing on pre-production injection-molded parts

"Building a tool by electroforming a nickel shell over an SL pattern was probably the fastest method that would allow us to test parts before releasing the final part design."
                                                            - Vadan Nagarsheth
                                                            Business Unit Fellow
                                                            Pitney Bowes

The Process
Engineers from Pitney Bowes, Santin Engineering, 3D Systems and CEMCOM Corporation had six weeks to deliver injection-molded parts for product-integrity testing. The complex component, critical to the functionality of a new mailing machine, measured 15x6x4 inch and had complex geometry, ribbing and wall thickness ranging from 0.060 to 0.250 inch. The team opted for a composite molding tool built on an SL pattern and constructed of nickel shells backed with chemically bonded ceramic.

Designers from Pitney Bowes and Santin Engineering, West Peabody, Massachusetts, developed a 3-D solid CAD model of the part that was sent to the Research and Development department at 3D Systems, Valencia, California. 3D Systems technicians fine-tuned the pattern. The final SL pattern, with design accuracies of 0.005 in. on all dimensions, was then shipped to CEMCOM Corporation, Baltimore, Maryland.

CEMCOM applied its expertise in rapid-tool building by depositing an electroformed 0.1 inch thick nickel layer onto the pattern. The nickel-coated pattern was installed into a pocketed steel-mold frame, and the shell locked in place by pouring, then curing, a chemically bonded ceramic hacking. After removal of the SL pattern, the tool was shipped to Acson Tooling for installation of ejector pins and final tool assembly.

Company Profile
Pitney Bowes Inc., headquartered in Stamford, Connecticut, with operations in 110 countries, supplies mail-processing and office systems and business and financial services worldwide. The company is the technological leader in the multi-billiondollar metered-mail industry, helping businesses process mail more quickly, efficiently and economically. Pitney Bowes employs more than 30,000 people worldwide and had revenues of $3.9 billion in 1996.

CEMCOM Corporation, Baltimore, Maryland, is a research organization offering rapid-tooling services using its nickel-ceramic- composite technology. The company offers its expertise in CAD CAM, metallurgy and ceramic technology to the plastics injection-molding industry.

Santin Engineering, West Peabody, Massachusetts, is an engineering and manufacturing facility supporting the plastics part industry. It supplies design and analysis, prototypes, engineering models, and production-run services.