Baldwin Piano & Organ Co. has artistry, craftsmanship and science in abundance. Its pioneering work in sound physics has helped create much of the scientific basis of modern harmonic acoustic theory in stringed musical instruments. But until recently, engineering lagged available technology. Now this is changing rapidly, part of a company-wide revitalization to propel Baldwin into the new century.

Knowing what its experts had achieved in the science of harmonics and the application of acoustics to piano design, Baldwin was confident that the bedrock of modern engineering 3D computer aided design (CAD) posed no insurmountable barriers. Managers soon discovered, however, that they were short of the kind of data CAD requires. The coordinate data CAD systems use to precisely locate points in 3D space cannot be generated from the metal templates and frequently under-dimensioned drawings on which Baldwin relied.

Baldwin quickly realized that the lack of sufficient reliable data would be a major stumbling block to CAD implementation as well as related diagnostic and analysis tools. Although templates, forms, and patterns work beautifully for manufacturing, the data must still be captured in a numeric form that can then be applied to CAD data.

The engineering group quickly recognized the need to tackle a huge reverse engineering job: that meant purchasing a coordinate measuring machine capable of acquiring the data necessary to complete fully detailed models and drawings required for manufacturing. Among Baldwin’s biggest measurement challenges were awkwardly shaped large parts that are difficult to measure with other types of measuring tools normally available in manufacturing. Measuring those parts, and the presses on which some are made, dictated portability and flexibility in the CMM equipment. Because of these requirements, Baldwin bought a portable CMM from ROMER CimCore.

“The ROMER is enormously valuable to us in bringing precision to the engineering process,” said Randy Marks, Baldwin executive vice president for piano operations. “We are eliminating process variables so that each instrument is as good as we can possibly make it. The portable CMM technology is a terrific adjunct to us as we go into the most massive, top to bottom modernization project ever undertaken by Baldwin in its 136-year history.”

Baldwin has been building pianos since the Civil War, and the company is justifiably proud of that legacy. In engineering, however, the term legacy has a second meaning: data and systems which lag behind the information that is currently available. Legacy information and systems are hard to use, costly to maintain, and often poorly documented. Many manufacturing experts characterize the ability to work with legacy data as “tribal knowledge.”

At Baldwin, craftsmanship played a much more critical role than engineering. Managers and workers knew very well what they were doing; process changes occurred at a slow, steady pace. New techniques and new designs were introduced slowly. What was lacking was the application of science to all the repetitive processes of manufacturing.

This lack can show up in surprising ways. As engineers are taught early in their education, lack of good data allows processes to drift out of tolerances. This means either that quality is sacrificed or rework climbs. Lack of good data also means that process variability increases. Variability and rework can lead to unpredictability in costs and delivery. Good information well applied is also essential in dealing with suppliers. Tribal knowledge and legacy data are not much help in disputes with outside vendors (or on the manufacturing floor).

SOLUTION

Focus of this work is in Baldwin’s production engineering operations in Trumann, Arkansas. The Trumann plant assembles all Baldwin uprights and some of its grand pianos, produces cabinetry for the grands, and manufactures wool felt used throughout the piano.

“Over time,” said Lisa Schmitt, CAD and systems administrator for Baldwin, “the connection between the templates and existing drawings had drifted apart. This connection is being restored now through evaluation of the templates, parts, and drawings. The ROMER is proving to be a valuable tool in re-establishing this connection.”

“Baldwin began to address engineering shortcomings with dimensional measurement and CAD because of perceived quality issues here,” explained Don Reynolds, process engineer at Trumann. “We also needed to be able to make design and styling changes more rapidly. We needed more reliable data to allow us to reduce some rework, and reduce hand work by cutting and shaping pieces closer to final dimensions.”

The ways that Baldwin used portable CMM technology to implement 3D CAD are as complex as the harmonics of a piano. This is probably best understood in terms of the major tasks tackled with the ROMER.

First and foremost is collecting dimensional data in terms of coordinate points for key components and subassemblies. This effort captured the dimensional relationships (and gaps) between Baldwin’s drawings and templates and the parts they defined. Fundamentally this effort is aimed at restoring the associability between tools and parts that had been lost over the years.

One of the biggest and most critical components in a piano is its rim, the gracefully curved sidewall enclosing all the workings. Rims are laminated from seven to twelve plies of carefully selected hardwood. They are formed on horizontal presses, some of which were designed decades ago. Although the designs are not new, the presses have been rebuilt and maintained regularly to keep them as close as possible to the original design.

“We use the ROMER to do comparison and verification between the rims, presses, and the templates which define the desired shape,” Reynolds said.

After dimensional verification of the components and tools, re-engineering is the ROMER’s second big role at Baldwin. Primary focus is the wing-shaped cast-iron plates on which the piano’s 200-plus strings are mounted. Baldwin has 11 different plates, all sand cast in high-tensile strength iron. The plate for an upright or spinet piano weighs about 150 pounds. Plates in concert grand pianos can weigh up to 450 pounds. Plate widths vary from 54 to 56 inches. Lengths range from 40 to 90 inches.

Piano strings -- each under up to 200 pounds of tension -- are mounted in two parallel planes. The 42 longest and heaviest single and double bass strings are set diagonally over the others. This can add up to a total stress in excess of 20 tons of pull.

To manage the resulting unequal stresses, each plate is cast with three bracing struts, a cross brace behind the lower two-thirds of the keyboard, and a big X-brace beneath the bass strings at the longest part of the plate. Dozens of holes and bosses or elevations are cast into the plate and all must be precisely located. Plate drawings can require several pages in order to display all the required detail and cross-sectional views necessary to build the plate correctly.

Unfortunately, plate documentation had not kept adequate track of changes to the plates. Reynolds noted that, “Many of the plate drawings were done by hand years ago. Much of the information needed for our CAD system, Pro/Engineer, such as surface dimensions and curvatures, arcs and radii, is not in the existing drawings, despite their complexity. Without defining every one of those dimensions, the data cannot be entered into Pro/E.

“However, just because the parts are all correct doesn't mean the tonal quality that we must have is there,” Reynolds cautioned. “We cannot assume that. But we can and do use the ROMER to eliminate variability, so that at least we know the parts themselves are not causing any problems. There is, of course, no direct relationship between ROMER’s dimensioning and tonal qualities, at least not yet,” he added. “There is still a lot of artistry involved at that level.”

The cost of reverse-engineering the plates was Baldwin’s original justification for buying the ROMER. “Before buying the portable CMM, Baldwin also evaluated outsourcing the entire effort. The cost would be prohibitive,” said Schmitt. “The ROMER was a much better investment of our financial resources.”

Shan Abbott, industrial engineer and lead ROMER operator, noted that “Without the ROMER we never would have been able to get the dimensions we need as accurately as we need them. Existing plate drawings needed to be verified to prove the accuracy of the castings.”

Checking and verifying Baldwin’s old drawings is the ROMER’s third big role. “In some cases drawings did not match parts, some parts did not have drawings, and some subassemblies did not have drawings,” said Schmitt. “Data needed to be gathered in order to verify existing drawings and to recreate drawings that were missing from the files.”

Among the major benefits of having accurate drawings for every part:

• Reducing rework due to manufacturing errors. Accurate factory floor work instructions will eliminate guesswork, a major source of errors. Complete with drawings, they will eventually be available for every piano built, not just for each different model. “We are just starting to release the first of these drawings to the factory floor now,” Schmitt noted.

• Eliminating rework because vendors will finally be held to complete and unambiguous specifications.

• Eliminating undocumented changes in manufacturing. Part of the process of making the CAD model the master repository of part information is tracking down the root causes for many small changes made in production.

• Supporting automation, in particular, new computer numerical control (CNC) routers and computer-aided manufacturing (CAM) software to generate programs for them. Several faster, more automated machines are already in place in the Juarez plant. More are being added to the U.S. operations as well. “The routers are expected to go a long way to meeting the primary revitalization goals of uniformity, consistency, and timeliness,” Reynolds said. “While Romer operation won’t help shorten the time to build pianos directly, indirectly it has been a big help.”

• Reducing the amount of costly, time-consuming hand work required by Baldwin’s large variety of pianos.

In summary, CAD and the ROMER’s dimensional data are helping Baldwin combine acoustics and artistry with engineering.