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History and diversity fuel The Wakefield Corp
History and diversity fuel The Wakefield Corp The Wakefield Corp is a bit of an oddity among powder metallurgy (PM) parts makers - it targets non-automotive applications! Based in Wakefield, Massachusetts, USA, the company has an impressive pedigree of extending PM into niche applications.
ucked away in an industrial area not far from Boston, The Wakefield Corp is noticeably removed from the epicentre of the US powder metallurgy (PM) industry - both in its location and its product profile. The company’s long history of solid growth with a stable workforce, however, underlines the success of its approach. Tracing its history back 92 years, The Wakefield Corp attributes its success to the ability to change focus as the market changes. The company was established in 1904 as a manufacturer of oil-impregnated rock-maple bearings for the textile industry. In the 1930s the porous bronze bearing business started to develop in the US and Wakefield made the transition from wood to PM products. During the early 195Os, Wakefield began producing structural parts in addition to bearings. After serving in the US Army during World War II, Nathaniel D. Clapp joined, and subsequently purchased, The Wakefield Corp. His sons, David and Nathaniel B., joined the company in 1964 and 1974
T
FIGURE 1: To expand its product line, Wakefield
Ofrershi@’ te’riperature sig~~~~~~~‘in~a~~~~~~ engineering
properties
of
ferrous a//o,, PM.
32 MPR June 1996
0026-0657/96/US$15.00 All rights reserved.
respectively, and have been the principals since the death of their father in 1987. David and Nat Clapp guide The Wakefield Corp along a non-automotive path towards a diverse customer base serving such industries as equipment and machinery, hand tools, hardware and transportation. With sales between US$5-10 million, The Wakefield Corp is growing at an annual rate of approximately 15%. During the past year David Clapp made a commitment to his company’s compliance to IS0 9002. The registration target is early 1997. The company has enlisted the IS0 9000 Network Collaborative for training and support. Partial funding for this project is being provided through a grant from the Greater Boston Manufacturing Partnership. “We have taken this step to ensure that our customers receive the quality and service that they require and deserve,” explains Clapp. Also underlining the company’s commitment to staying in touch with the latest business developments is its presence on the Internet - The Wakefield Corp is one of the very few PM companies with a World Wide Web (WWW) site. The site, includes company information, case histories and technical information (its address is: http://www.wake.com)
Production
.
capability
The Wakefield Corp has 25 compacting presses ranging in size from five to 400 tonnes, with the bulk of the equipment in the 75-125 tonne range. The company also maintains a full metallurgical laboratory, headed by a graduate metallurgist, for both research and process control. The company has two electric belt sintering furnaces, but it is the high temperature electric sintering furnace that represents new opportunities for Wakefield. This process significantly increases engineering properties of ferrous-based PM components, broadening their application. High temperature sintering increases density by rounding pores and reducing their size. This action increases bonding between particles. As the degree of sintering increases, strength, hardness, ductility, thermal conductivity, electrical conductivity, magnetic permeability and corrosion resistance improve. Copyright
6
1996, Elsevier
Science
Ltd.
The benefits of high temperature sintering can be seen in a PM cam coupler handle the company produces. The 316L stainless steel part is normally sintered at 1120°C resulting in a density of 6.4 g/cm3. High temperature sintering at 1260°C raises density and substantially increases ductility. The increased ductility (Figure 1) enables the handle to resist severe twisting without breaking. At com,entional sintering temperatures the part exhibits almost no ductility
Diverse markets The Wakefield Corp serves a diverse range of markets, a business strategy that shelters it from sudden swmgs in the economy. The following parts are ,just a few successful applications from the company’s extensive product portfolio. CD plnyer r+p: In order for design engineers of the Rose ‘Lifestyle~t$~20’ home theatre system to incorporate an existing compact disc ((:D) player into their system, they needed to devise a fastening system. The fix was a simple clip holding the CD mechanism in place. After a review of available materials and processes, PM emerged as the natural choice. The process maintains the required angles of + 0.5’ and critical dimensional tolerance of kO.076 mm, as well the non-critical tolerance of f 0.127mm. The Wakefield Corp produced a net, sh.ape component incorpor-
f/GURE
2: This 3.8 gram.
14.73 mm x 12.7 mm x 3.511 4.34 mm PM clip is produced with an angle tolerance of kO.5 and kO.076 mm on the critical dimensional tolerance
ating a slotted hole, as+mmet,rical proiile and tight dimensional control. The range of materials is a benefit of PM. In this case, a nickel-steel alloy was chosen for its strength without additional heat treating after sintering. Secondary operations include plastic impregnation, hole drilling and tapping for a #4-40 socket head set screw, and zinc plating and clear chromate finish. The Wakefield Corp brings another advantage to its customers - the ability to economically produce net shape small parts. Although the clip is produced in lots of 10 000, the total weight is under 45 kg. Including tooling costs, PM provided the most cost, effective process for the produc tion of the CD mounting clip. Tap dir jaul: A jaw used in a hand held tapping die was ideally suited for PM through the combination of net shape forming and exact metallurgical require-
Gear enhances performance of winch line
S
uperwinch’s ‘X-Series’ has become a common sight on recreation and utility vehicles in North America during the last 25 years. This year it will be replaced by the completely redesigned ‘SSeries’ line. The project design engineer, Scott Lee, says the new series offers significant improvement in performance, including. load capacity, life and noise levels. The key element in the new design’s success lies in the gearing design. The X-Series winch uses a ring gear and housing design die cast in either 380 aluminum or ZA-27 alloy, depending on the winch’s load capacity. Working closely with the technical staff of The Wakefield Corp, Superwinch’s design team replaced the die cast ring gears with PM ones (Figure 7). By designing a package which incorporates steel ring gears in an aluminum housing, Superwinch achieved significant performance enhancement without a corresponding cost increase. The nickel-steel ring gears are double
replaced die cast aluminium ones in a popular winch for recreation and utility vehicles
the strength of the aluminum counterpart with a five-to-ten-fold increase in life
strength and wear characteristics, the PM gears run quieter. The PM gears are produced with an apparent hardness of Rb 78 and minimum tensile strength of 448 MPa. The stationary gear has a 134.6 mm OD while the rotating ring gear OD is 133.4 mm. Both ring gear diameters are produced with a tolerance of f 0.1 mm. Other critical design requirements include a maximum pitch diameter runout of 0.11 mm, a maximum concentricity on all diameters relative to the OD of 0.13 mm and a maximum radius on all gear teeth of
expectancy.
0.13 mm.
In addition
to
the
greater
n MPR June 1996
33
34
MPR June 1996
FIGURE 3: This PM tapping jaw is made out of 4600 Distalloy.
FIGURE 5: Wakefield Corp not only fabricates small parts, but also larger components such as this railroad nut.
menus. The jaw weighs 13 grams, measures 18.2 x 11.2 x 11.1 mm, and has a surface finish of 0.8 mm. The radius of the twin gripping teeth is held to within 0.5 mm of each other. The jaw is made out of ‘4800 Distalloy’, a high purity steel alloyed with nickel, molybdenum and copper. After sintering, the part has a density of 6.8 g/cm”, tensile strength of 689 MPa transverse rupture strength of 1309 MPa and a hardness of Rc 30-40. Microtome feed plate: The part of a biopsy machine that sections tissue for microscopic examination is called the microtome. The microtome is capable of slicing thin sections of tissue for continuous examination and updates. Wakefield produce a PM feed plate that delivers tissue to the microtome’s blade for slicing. PM was chosen to produce this part because of its low cost and precision. PM’s cost-per-piece eliminated investment casting as an option, while machining was also prohibitively expensive. ’
Railroad nut: Wakefield Corp has developed a washer nut for rail tie downs used in suburban train tracks. The washer nut secures a J-bolt which holds the rail to concrete ties. The single-piece fastener combines a 28.575 mm (l-1/8 in) square nut with a 76.2 mm diameter washer and weighs 283.5 grams. The washer nut is copper-infiltrated steel, %X2008-60’, with 413 MPa yield strength and 551.2 MPa tensile strength. The only secondary operation necessary is tapping. Machinery cam: The Wakefield Corp assisted a textile machinery builder by providing a PM cam net-shape and ready for final assembly. The cam, weighing approximately 28 grams and measuring 53.975 x 38.1 x 5.08 mm, is produced in lots of 5000, a prohibitively small quantity if produced by an alternative method such as fineblanking. The cam also requires an edge finish of 0.002 mm, easily obtainable through PM, but not feasible by blanking without secondary machining. The flexibility of PM means the part can
FIGURE 4: A PM feed plate delivers human tissue to a microtome, the part of a biopsy machine that slices the tissue for microscopic examination.
FIGURE 6: This PM cam is produced net-shape and ready for final assembly into textile machinery.
Wakefield’s part provides the parallel and squareness specification the part requires. Additionally, the process produces a diameter with kO.01 mm tolerance and 0.08 mm TIR. The feed plate is made from ‘Wakefield 23’ alloy, a bronze material specified for its corrosion resistance.
be produced yth the exact chemical and mechanical properties needed. The cam is specified as ‘FC-0206-40’, a copper-steel material with a tensile strength of 275.6 MPa. After sintering, the cam is surface ground to within 0.127 mm overall flatness and shipped ready for assembly. n
ucked away in an industrial area not far from Boston, The Wakefield Corp is noticeably removed from the epicentre of the US powder metallurgy (PM) industry - both in its location and its product profile. The company’s long history of solid growth with a stable workforce, however, underlines the success of its approach. Tracing its history back 92 years, The Wakefield Corp attributes its success to the ability to change focus as the market changes. The company was established in 1904 as a manufacturer of oil-impregnated rock-maple bearings for the textile industry. In the 1930s the porous bronze bearing business started to develop in the US and Wakefield made the transition from wood to PM products. During the early 195Os, Wakefield began producing structural parts in addition to bearings. After serving in the US Army during World War II, Nathaniel D. Clapp joined, and subsequently purchased, The Wakefield Corp. His sons, David and Nathaniel B., joined the company in 1964 and 1974
T
FIGURE 1: To expand its product line, Wakefield
Ofrershi@’ te’riperature sig~~~~~~~‘in~a~~~~~~ engineering
properties
of
ferrous a//o,, PM.
32 MPR June 1996
0026-0657/96/US$15.00 All rights reserved.
respectively, and have been the principals since the death of their father in 1987. David and Nat Clapp guide The Wakefield Corp along a non-automotive path towards a diverse customer base serving such industries as equipment and machinery, hand tools, hardware and transportation. With sales between US$5-10 million, The Wakefield Corp is growing at an annual rate of approximately 15%. During the past year David Clapp made a commitment to his company’s compliance to IS0 9002. The registration target is early 1997. The company has enlisted the IS0 9000 Network Collaborative for training and support. Partial funding for this project is being provided through a grant from the Greater Boston Manufacturing Partnership. “We have taken this step to ensure that our customers receive the quality and service that they require and deserve,” explains Clapp. Also underlining the company’s commitment to staying in touch with the latest business developments is its presence on the Internet - The Wakefield Corp is one of the very few PM companies with a World Wide Web (WWW) site. The site, includes company information, case histories and technical information (its address is: http://www.wake.com)
Production
.
capability
The Wakefield Corp has 25 compacting presses ranging in size from five to 400 tonnes, with the bulk of the equipment in the 75-125 tonne range. The company also maintains a full metallurgical laboratory, headed by a graduate metallurgist, for both research and process control. The company has two electric belt sintering furnaces, but it is the high temperature electric sintering furnace that represents new opportunities for Wakefield. This process significantly increases engineering properties of ferrous-based PM components, broadening their application. High temperature sintering increases density by rounding pores and reducing their size. This action increases bonding between particles. As the degree of sintering increases, strength, hardness, ductility, thermal conductivity, electrical conductivity, magnetic permeability and corrosion resistance improve. Copyright
6
1996, Elsevier
Science
Ltd.
The benefits of high temperature sintering can be seen in a PM cam coupler handle the company produces. The 316L stainless steel part is normally sintered at 1120°C resulting in a density of 6.4 g/cm3. High temperature sintering at 1260°C raises density and substantially increases ductility. The increased ductility (Figure 1) enables the handle to resist severe twisting without breaking. At com,entional sintering temperatures the part exhibits almost no ductility
Diverse markets The Wakefield Corp serves a diverse range of markets, a business strategy that shelters it from sudden swmgs in the economy. The following parts are ,just a few successful applications from the company’s extensive product portfolio. CD plnyer r+p: In order for design engineers of the Rose ‘Lifestyle~t$~20’ home theatre system to incorporate an existing compact disc ((:D) player into their system, they needed to devise a fastening system. The fix was a simple clip holding the CD mechanism in place. After a review of available materials and processes, PM emerged as the natural choice. The process maintains the required angles of + 0.5’ and critical dimensional tolerance of kO.076 mm, as well the non-critical tolerance of f 0.127mm. The Wakefield Corp produced a net, sh.ape component incorpor-
f/GURE
2: This 3.8 gram.
14.73 mm x 12.7 mm x 3.511 4.34 mm PM clip is produced with an angle tolerance of kO.5 and kO.076 mm on the critical dimensional tolerance
ating a slotted hole, as+mmet,rical proiile and tight dimensional control. The range of materials is a benefit of PM. In this case, a nickel-steel alloy was chosen for its strength without additional heat treating after sintering. Secondary operations include plastic impregnation, hole drilling and tapping for a #4-40 socket head set screw, and zinc plating and clear chromate finish. The Wakefield Corp brings another advantage to its customers - the ability to economically produce net shape small parts. Although the clip is produced in lots of 10 000, the total weight is under 45 kg. Including tooling costs, PM provided the most cost, effective process for the produc tion of the CD mounting clip. Tap dir jaul: A jaw used in a hand held tapping die was ideally suited for PM through the combination of net shape forming and exact metallurgical require-
Gear enhances performance of winch line
S
uperwinch’s ‘X-Series’ has become a common sight on recreation and utility vehicles in North America during the last 25 years. This year it will be replaced by the completely redesigned ‘SSeries’ line. The project design engineer, Scott Lee, says the new series offers significant improvement in performance, including. load capacity, life and noise levels. The key element in the new design’s success lies in the gearing design. The X-Series winch uses a ring gear and housing design die cast in either 380 aluminum or ZA-27 alloy, depending on the winch’s load capacity. Working closely with the technical staff of The Wakefield Corp, Superwinch’s design team replaced the die cast ring gears with PM ones (Figure 7). By designing a package which incorporates steel ring gears in an aluminum housing, Superwinch achieved significant performance enhancement without a corresponding cost increase. The nickel-steel ring gears are double
replaced die cast aluminium ones in a popular winch for recreation and utility vehicles
the strength of the aluminum counterpart with a five-to-ten-fold increase in life
strength and wear characteristics, the PM gears run quieter. The PM gears are produced with an apparent hardness of Rb 78 and minimum tensile strength of 448 MPa. The stationary gear has a 134.6 mm OD while the rotating ring gear OD is 133.4 mm. Both ring gear diameters are produced with a tolerance of f 0.1 mm. Other critical design requirements include a maximum pitch diameter runout of 0.11 mm, a maximum concentricity on all diameters relative to the OD of 0.13 mm and a maximum radius on all gear teeth of
expectancy.
0.13 mm.
In addition
to
the
greater
n MPR June 1996
33
34
MPR June 1996
FIGURE 3: This PM tapping jaw is made out of 4600 Distalloy.
FIGURE 5: Wakefield Corp not only fabricates small parts, but also larger components such as this railroad nut.
menus. The jaw weighs 13 grams, measures 18.2 x 11.2 x 11.1 mm, and has a surface finish of 0.8 mm. The radius of the twin gripping teeth is held to within 0.5 mm of each other. The jaw is made out of ‘4800 Distalloy’, a high purity steel alloyed with nickel, molybdenum and copper. After sintering, the part has a density of 6.8 g/cm”, tensile strength of 689 MPa transverse rupture strength of 1309 MPa and a hardness of Rc 30-40. Microtome feed plate: The part of a biopsy machine that sections tissue for microscopic examination is called the microtome. The microtome is capable of slicing thin sections of tissue for continuous examination and updates. Wakefield produce a PM feed plate that delivers tissue to the microtome’s blade for slicing. PM was chosen to produce this part because of its low cost and precision. PM’s cost-per-piece eliminated investment casting as an option, while machining was also prohibitively expensive. ’
Railroad nut: Wakefield Corp has developed a washer nut for rail tie downs used in suburban train tracks. The washer nut secures a J-bolt which holds the rail to concrete ties. The single-piece fastener combines a 28.575 mm (l-1/8 in) square nut with a 76.2 mm diameter washer and weighs 283.5 grams. The washer nut is copper-infiltrated steel, %X2008-60’, with 413 MPa yield strength and 551.2 MPa tensile strength. The only secondary operation necessary is tapping. Machinery cam: The Wakefield Corp assisted a textile machinery builder by providing a PM cam net-shape and ready for final assembly. The cam, weighing approximately 28 grams and measuring 53.975 x 38.1 x 5.08 mm, is produced in lots of 5000, a prohibitively small quantity if produced by an alternative method such as fineblanking. The cam also requires an edge finish of 0.002 mm, easily obtainable through PM, but not feasible by blanking without secondary machining. The flexibility of PM means the part can
FIGURE 4: A PM feed plate delivers human tissue to a microtome, the part of a biopsy machine that slices the tissue for microscopic examination.
FIGURE 6: This PM cam is produced net-shape and ready for final assembly into textile machinery.
Wakefield’s part provides the parallel and squareness specification the part requires. Additionally, the process produces a diameter with kO.01 mm tolerance and 0.08 mm TIR. The feed plate is made from ‘Wakefield 23’ alloy, a bronze material specified for its corrosion resistance.
be produced yth the exact chemical and mechanical properties needed. The cam is specified as ‘FC-0206-40’, a copper-steel material with a tensile strength of 275.6 MPa. After sintering, the cam is surface ground to within 0.127 mm overall flatness and shipped ready for assembly. n