Normal force reduction in electronic circuits

1991 ◽  
Vol 14 (1) ◽  
pp. 45-49 ◽  
Author(s):  
N.A. Stennett ◽  
T.P. Ireland ◽  
D.S. Campbell
Keyword(s):  
Normal Force ◽  
Electronic Circuits ◽  
Force Reduction

Roller Cutter Forces

1970 ◽  
Vol 10 (01) ◽  
pp. 57-65 ◽  
Author(s):  
C.R. Peterson
Keyword(s):  
Normal Force ◽  
Penetration Rate ◽  
Rolling Force ◽  
Skew Angle ◽  
Average Force ◽  
Straight Line ◽  
Bearing Load ◽  
Boring Machines ◽  
Force Reduction ◽  
Cutter Head

Abstract An experimental technique is described in which three component forces are measured while a typical toothed cutter is rolled in a straight line over a rock sample. The technique includes the attainment of a steady state in which volume-averaged penetration is correlated with average force during penetration is correlated with average force during the removal of several layers from the rock surface. Simple rolling and skewed rolling forces are measured. The cutter was artificially dulled for some of the measurements. Surprisingly little variation in force requirement is noted. A qualitative explanation is suggestedThe normal force requirement is substantially reduced when the cutter is skewed. A theoretical description of the force reduction is presented, showing reasonable agreement with the observed behavior in terms of cutter radius, tooth width, penetration and skew angle. penetration and skew angle Introduction Toothed roller cutters have long been in use on tricone bits, and they are in common use on boring machines. Yet the designer of boring machines is still faced with a dearth of good design information on the performance of such cutters. For example, what are the relationships between thrust, power, and penetration rate? How are these relationships influenced by rock properties and cutter configuration?While the data presented here provide answers to more specific questions than those mentioned above, these data are necessary for arriving at solutions to the broader questions. This work is restricted to one tooth type, typical of the wedge-shaped steel teeth used on medium rock. A limited range of rock types was tested; this coupled with the extreme variation of rock drillability, renders the data of limited value in predicting penetration rate. But the designer must predicting penetration rate. But the designer must answer questions even more important than the prediction of absolute penetration rate. For example, prediction of absolute penetration rate. For example, the cutter normal force is usually known in terms of the thrust to be applied to the cutter head. What is the torque or power required to rotate the cutter head? For an answer, one need know only the ratio of normal force to the tangential or rolling force. This ratio may be estimated from the present data. Variation of this ratio is reasonably small from one rock to another so that, lacking more specific information, these data can provide at least rough design estimates for other rocks. Tricone bits for soft to medium rock usually are constructed with skewed cutter elements that provide a "gouging and scraping action". Whatever the explanation, skewed cutters do provide increased drilling rate or, for a given drilling rate, a decreased thrust requirement. To my knowledge, skewed cutter elements have not been used on boring machines. If they were, bearing load could be reduced at a given penetration rate, or, conversely, an increased penetration rate could be obtained at the same penetration rate could be obtained at the same bearing load. Of course, a side load is introduced to the cutter bearing and this must be provided for. As for the rolling force, the designer really needs only the ratio of side-to-normal load. The present data indicate that this ratio is quite independent of rock type. The magnitude of the force reduction to be expected with skewed cutters is also of interest. The present data indicate that substantial reductions might be expected. A simple analytical model predicts the observed reduction reasonably well on the basis of the limited data available. EXPERIMENTAL APPARATUS AND TECHNIQUES Forces produced by a single cutter wheel rolling in a straight line over the rock specimen were measured. This simple geometry is experimentally convenient and is thought to be reasonably representative of cutter conditions on a large boring machine. Fig 1 illustrates the "linear apparatus" on which the measurements were made. The cutter wheel was rotatably mounted in a heavy yoke. SPEJ P. 57

Normal force reduction in electronic contacts

2002 ◽  
Author(s):  
N.A. Stennett ◽  
T.P. Ireland ◽  
D.S. Campbell
Keyword(s):  
Normal Force ◽  
Force Reduction

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

Rheological characterization of tack and viscoelasticity of compositions of crepe coating used in the Yankee dryer

TAPPI Journal ◽  
2019 ◽  
Vol 18 (11) ◽  
pp. 641-649
Author(s):  
JOSHUA OMAMBALA ◽  
CARL MCINTYRE
Keyword(s):  
Normal Force ◽  
Weight Ratio ◽  
Good Combination ◽  
Rheological Characterization ◽  
Nonlinear Viscoelastic ◽  
Coating Composition ◽  
Linear And Nonlinear ◽  
Work Done ◽  
Tissue Production

The vast majority of tissue production uses creping to achieve the required set of properties on the base sheet. The Yankee coating helps to develop the desired crepe that in turn determines properties such as bulk and softness. The adhesion of the sheet to the Yankee surface is a very important characteristic to consider in achieving the desired crepe. The coating mix usually consists of the adhesive, modifier, and release. A good combination of these components is essential to achieving the desired properties of the tissue or towel, which often are determined by trials on the machine that can be time consuming and lead to costly rejects. In this paper, five compositions of an industrial Yankee coating adhesive, modifier, and release were examined rheologically. The weight ratio of the adhesive was kept constant at 30% in all five compositions and the modifier and release ratios were varied. The normal force and work done by the different compositions have been shown at various temperatures simulating that of the Yankee surface, and the oscillatory test was carried out to explain the linear and nonlinear viscoelastic characteristic of the optimal coating composition.

Sign in / Sign up

Export Citation Format

Share Document