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G 环球瞭望

LOBAL OUTLOOK

challenge: The company manufactures a lot of
different bearing series, amounting to thousands
of different component geometries, each of which
must be measured to extremely tight tolerances.
To better accommodate these needs, Timken
has added optical metrology to its suite of tactile
gaging technologies.
An Alternative to Comparative Gaging
and CMMs
Comparative-contact gaging, set up to part-
like masters, traditionally has been employed
to measure the outer diameters (ODs) of
axisymmetric components—components that
光学千分尺整个测量区域 ( 测量范围 VS 区域深度 ) 所测直径
的映射图。 are symmetrical along a given axis, like roller
bearings. Comparative gaging is direct, simple
尽。光学千分尺响应频率高，强制要求锥形或曲
to use and self-compensating for datums and
线形部件提供的感应面积小，并且相隔距离大。
temperature. However, precision masters are
由于没有任何接触，所以也不存在部件变形、偏
costly to manufacture and maintain. In addition,
移或因探头尖部留下印记的风险。 comparative gages tend to require series-specific
测量轴承组件直径时，光学千分尺在正规 tooling to fixture the parts for gaging.
测量系统分析测试中的能力已经得到证明。拉 As one alternative to comparative gaging,
里 · 凯勒先生说道 : “与 CMM 相比，光学千分 high-precision coordinate measuring machines
尺能够达到 1μm 的首项体积精度。” 此外，系统 (CMMs) have been used to measure these bearing
能够容忍工程内的油污、 灰尘、 温度和湿度变化。 components. As an absolute gage, CMMs do not
从费用开销和循环时间而言，其成本也比讨论的 require part-like masters and usually do not require
其他测量方式低 ( 比较式或绝对式 )。 series-specific tooling for measurement. However,
factors such as maintenance, recertification and
【英文如下】 sequence programming can cause the initial
The humble bearing may just be one of the capital cost and overall cost of ownership to trend
least-sung of unsung heroes. But bearings are high. Also, CMM measurement cycle times can be
important not only for manufacturers whose much longer than those of comparative gaging.
advanced equipment relies on them for smooth Not only that, but some parts are susceptible to
and reliable motion, but for too many machines deformation, deflection or marking from the CMM
(and their users) to number. probe tip contact force. These are unacceptable
Bearings are also paramount to The Timken conditions for Timken, which requires the utmost
Co., headquartered in North Canton, Ohio. The precision and fast cycle times to stay competitive.
company is a global leader in friction-management An alternative that addresses the
technologies and offers one of the most complete shortcomings of both comparative gaging and
lines of anti-friction bearings in the industry. CMMs is the optical micrometer. According to
This longstanding success has led to a gaging Larry Keller, metrology and gaging technologist

·84· 第08期 数控机床市场