feature TOCUS BY EUGENHOLZKNECHT, GENERAL MANAGER, ROSLER METAL FINISHING,BATTLE CREEK, MICH. Isotropic Superfinishing: A High-Powered Solution for Cornpiex Parts Finishing Advanced surface treatment process provides dramatic improvement in operation and longevity of critical parts. non-abrasiveceramic media and special,materia|-related compounds. ~ncreasing demands for higher product quality combined with pressure for cost reductions require new solutions, especially for suppli- ers of engine and transmission com- ponents, as well as companies active in the fields of propulsion technolo- gy and energy production. a is the world- EM Isotropic :hnology. REM and R6sler GmbH have this field for der developing .quipment and nishing media conjunction vith REM for the ISF process. By smoothing of the parts surface down to Ra of 0.02 /]m and Rz of 0.2 /am, the parts operat- ing character- ;tics with gard to friction, and operating atures are sig- L-proved, with a :rease of the Moreover, the IS'F technology allows implementa- tion of innovative product ideas that might not be realized due to constraints in the surface finish. Is there a relationship between the surface roughness of a gear and the life of the bearings in a transmis- sion? Scientific studies are under way to establish such a relationship. However, in many industries such as automotive, aerospace, bearing, medical, and textile equipment, as well as large gears and motor sports, it is considered as a proven fact that the surface smoothness of a part sig- nificantly influences the quality and life of such a part. The explanation for this phenomenon is that surface treatment methods such as milling, belt and wheel grinding, lapping, and honing frequently create a more or less rough surface with many "peaks." These peaks can interrupt the oil film, usually 0.2-0.5 pm thick, that is required for a reliable lubrica- tion of these high-performance parts. This can create gray staining and micro pitting on the critical parts sur- faces like, for example, on the teeth of a gear. In addition, the friction can break off the peaks and create debris particles. These particles then pass through the component as small chips and can cause damage to the component. ISF REMOVES THE PEAKS The ISF technology removes the "peaks" on many parts made from carbon steel, high-alloy steel, stain- less steel, and titanium. This process usually takes place in vibra- tory mass finishing systems special- ly designed by R6sler with dedicated high-density, non-abrasive ceramic media and special REM active chem- ical compounds. The REM active chemical compounds create a thin oxide film on the parts surface with a pH value of between 1.6-5.5. Due to the vibratory action in the work May 20081 metalfinishing 136 www.meta[finishing.com
Transcript
feature TOCUS
BY EUGEN HOLZKNECHT, GENERAL MANAGER, ROSLER METAL FINISHING, BATTLE CREEK, MICH.
Isotropic Superfinishing: A High-Powered Solution
for Cornpiex Parts Finishing Advanced surface treatment process provides dramatic
improvement in operation and longevity of critical parts.
non-abrasive ceramic media and special, materia|-related compounds.
~ncreasing demands for higher product quality combined with
pressure for cost reductions require new solutions, especially for suppli- ers of engine and transmission com- ponents, as well as companies active in the fields of propulsion technolo- gy and energy production.
a is the world- EM Isotropic :hnology. REM
and R6sler GmbH have
this field for der developing .quipment and nishing media
conjunction vith REM for
the ISF process. By s m o o t h i n g of the parts s u r f a c e down to Ra of 0.02 /]m and Rz of 0.2 /am, the parts operat-
ing character- ;tics with gard to friction, and operating
atures are sig- L-proved, with a :rease of the Moreover, the
IS'F technology allows implementa- tion of innovative product ideas
that might not be realized due to constraints in the surface finish.
Is there a relationship between the surface roughness of a gear and the life of the bearings in a transmis- sion? Scientific studies are under way to establish such a relationship. However, in many industries such as automotive, aerospace, bearing, medical, and textile equipment, as well as large gears and motor sports, it is considered as a proven fact that the surface smoothness of a part sig- nificantly influences the quality and life of such a part. The explanation for this phenomenon is that surface treatment methods such as milling, belt and wheel grinding, lapping, and honing frequently create a more or less rough surface with many "peaks." These peaks can interrupt the oil film, usually 0.2-0.5 pm thick, that is required for a reliable lubrica- tion of these high-performance parts. This can create gray staining and micro pitting on the critical parts sur- faces like, for example, on the teeth of a gear. In addition, the friction can break off the peaks and create debris particles. These particles then pass through the component as small chips and can cause damage to the component.
ISF REMOVES THE PEAKS The ISF technology removes the "peaks" on many parts made from carbon steel, high-alloy steel, stain- less steel, and titanium. This process usually takes place in vibra- tory mass finishing systems special- ly designed by R6sler with dedicated high-density, non-abrasive ceramic media and special REM active chem- ical compounds. The REM active chemical compounds create a thin oxide film on the parts surface with a pH value of between 1.6-5.5. Due to the vibratory action in the work
May 20081 metalfinishing 1 36 www.meta[finishing.com
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Figure 2: The ISF technology is applicable for surface finishing of high-performance parts made from carbon steel, high-alloy steel, stainless steel, titanium,, and zinc
Figure 3: Three-dimensional topographical plot of a standard bearing surface (left) versus the ISF bearing surface (right).
bowl, the ceramic media "wipes" off this oxide film. Over time this action removes the "peaks." The lower lying "valleys" remain intact and serve as a reservoir for the lubri- cant. The process continues-with the constant addition of fresh com- pound-unt i l the required surface finish of Ra 0.02 }am or Rz 0.2 }am is achieved. The actual ISF refinement process is followed by a rinsing/bur- nishing process in the same machine by dosing a burnishing compound with water into the machine. The rinse/burnish process removes the remaining oxide film from the parts and creates a matte or high-gloss finish.
The machine settings of the vibra- tory mass finishing machine ensure an optimum and gentle movement of the parts and media in the work bowl. The metal removal takes place very gently, thus preventing any
nicking of the parts. Vcqaereas the ISF process may produce a slight edge break, it does not produce an excessive radiusing (round edges) of the parts due to the nonabrasive nature of the media utilized. The ISF process takes place at room temper- ature and does not affect the materi- al properties of the metal compo- nent. Furthermore, long-term expe- rience has shown that there is no danger of hydrogen embrittlement. The required process time and com- pound usage for achieving a certain surface finish usually is determined by sample component processing trials. This allows exact planning of the ISF process within the overall parts manufacturing process. The result is usually a much better sur- face finish at a lower cost.
MONEY-SAVING ADVANTAGES After the ISF process, parts usually
have an extremely fine surface fin- ish. Depending on the initial sur- face roughness, this increases the contact area significantly, some- times up to 90-100% (measured at a depth of 0.4 }am). Performance and efficiency of the components are significantly improved, which allows the manufacture of smaller gear parts or the use of higher-input power motors at a significantly improved fatigue life. For example, the life of gears processed with the ISF technology could be increased four- to five-fold. Moreover, the ISF system creates an isotropic struc- ture on the parts surface, which sub- stantially improves lubrication, reduces friction and wear, reduces operating noise, and reduces operat- ing temperatures. This allows the operator to extend the time interval between preventive maintenance work. Of course, all these quality improvements also lead to energy savings. Last, but not least, as indi- cated earlier, the ISF technology also allows the design of parts that previously would not have been pos- sible. One example is the manufac- ture of a highly efficient turbine blade that would not have been pos- sible with conventional surface fin- ishing methods.
u n r o m l u m I~latlng By G.A. Lausmann. 1st edition 2007
with 360 pages. ~; 97,- plus postage. ISBN 3-87480-228-0
Table of contents: 1 History 2 The electrolytic deposition of chromium 3 Decorative chromium plating 4 The hard chromium plating 5 Stripping of chromium deposits 6 Troubleshooting 7 Equipment and auxiliary items 8 Waste water treatment and recycling 9 Analytical control 10 Tables
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i i i l l
Figure 4: The ISF process removes "peaks" from the parts surface, while the "valleys" remain intact. Surface readings of Ra 0.02 pm and Rz 0.2 IJm are possible.
THE RIGHT FINISHING EQUIPMENT The ISF process can be applied for parts as small as the head of a match, with a weight of less than one gram, for gears with a weight o f up to 5,000 kg. This requires special- ly engineered equipment to achieve cost-effective finishing results, for example, double-curved wall rotary vibrators. Such rotary vibrators induce an even parts/media rotation in the work bowl, allowing a 50%
higher fill rate of parts and media compared to straight wall vibrators. At the same time, double-curved wall vibrators produce a much better surface finish. The ISF technology produces a rela- tively small a mo u n t o f effluent, which can be treated with conven- tional waste-water t reatment sys- tems. Due to its low wear rate, the high-density ceramic media used for the ISF process can be used for an
extended period of time before it must be replaced.
BIO Eugen Holzknecht is general manager of P~sler Metal Finishin~ headquartered m Battle Creek, Mich. He has been working with customers to develop unique process- driven finishing solutions for more than 20 years.
RdJsler Obet~hentecbnik GmbH is a worldwide market leader in the field of mass finishing and shot blast equipment, paint and preservation lines, and consum- ables for mass finishing. P~sler offers com- prehensive technolo~es for surface finish- ing (deburring~ descalin~ sand removal, polishing~ grinding~ among others) of parts made from different metals or other mate- rials. Beyond Germany, the Riisler group maintains sales and manufacturing loca- tions in Great Britain, France, Italy, Benelux, Austria Switzerland, Spain, Romania, Brazil South Af~ca, China, and the U.S. ISF is a re~stered trademark of REM Chemicals, Inc.
The
ELECTRO-STEAM GENERATOR creates a total cleaning system for cleaning or cleanor/phosphatizing process. Metal surface
preparation for coatings to meet several Mil Specs
