Screws and Screwing

1951 ◽  
Vol 164 (1) ◽  
pp. 52-67
Author(s):  
C. Eatough
Keyword(s):  
Simple Formula ◽  
Mathematical Treatment ◽  
Screw Thread ◽  
Thread Profile ◽  
Tool Profile ◽  
Wide Range ◽  
Screw Threads

The paper describes the various commercial methods of producing screw threads by cutting, rolling, grinding, and milling. The operating principles on which the several processes depend are dealt with and their advantages and limitations are discussed. A workshop method of determining the torque required for tapping and for threading is described, and a chart based on the results gives figures suitable for determining the power of machines to undertake the tapping or screwing of a wide range of work. A mathematical treatment of the clearance between the flanks of a tool and a screw thread is given. This permits the investigation of clearances at any point on the tool profile or flank, and enables relief and tilt angles to be chosen to suit various conditions of lead, thread profile, and diameter for both internal and external threads. For design purposes, a simple formula is available which gives clearance angles in relation to the portions of the tools most subject to interference.

Comparison of Commercially Available Thread Forming Profiles on Flow Drill Joining of 6061-T6 Aluminum to Thermoset Carbon Fiber Reinforced Composite

2019 ◽  
Author(s):  
Brandt J. Ruszkiewicz ◽  
Gene Simpson ◽  
Eric Breidenbaugh
Keyword(s):  
Shear Strength ◽  
Carbon Fiber ◽  
Sheet Material ◽  
Peak Torque ◽  
Process Time ◽  
Screw Thread ◽  
Fiber Reinforced ◽  
Lap Shear ◽  
Thread Profile ◽  
Carbon Fiber Reinforced

Abstract Flow Drill Screws are self-piercing, self-tapping screws used for single sided joining of light metals, such as aluminum. This technology has been adopted by many automotive OEMs for use in metals. Thread forming profiles exist for material stackups that are made of entirely metals and entirely polymers/composites. This research evaluated the effectiveness of these thread profiles in dissimilar metal-on-composite stackups. Thread profiles designed for use in polymers/composites and aluminum were compared with a traditional machine screw thread profile for flow drill joining of 1mm and 2mm thick 6061-T6 aluminum to 3mm thick thermoset carbon fiber reinforced polymer. The three thread profiles were manufactured as M5x25mm flow drill screws in their commercially available configurations and materials. Two parameter sets from the FDS equipment manufacturer were evaluated, the first designed for use with the polymer thread forming profile, the second designed for use with the aluminum thread forming profile. The thread profiles were evaluated based on outputs of process time, peak torque, and lap shear strength. The polymer thread profile had shorter process times than the other 2 profiles but caused more damage to itself and its mating material. All 3 thread profiles exhibited greater shear strength when aluminum was used as the lower sheet material.

Effects of Nut Thinning due to Corrosion on the Strength Characteristics and the Sealing Performance of Bolted Flange Joints Under Internal Pressure

2011 ◽  
Author(s):  
Tsutomu Kikuchi ◽  
Yuya Omiya ◽  
Toshiyuki Sawa
Keyword(s):  
Internal Pressure ◽  
Yield Stress ◽  
Strength Characteristic ◽  
Small Scale ◽  
Screw Thread ◽  
Flange Joint ◽  
Bearing Surface ◽  
Sealing Performance ◽  
Bolted Flange ◽  
Screw Threads

The effects of nut thinning due to corrosion on the strength characteristic and the sealing performance in 3B bolted flange joints under internal pressure are examined from both FEM calculations and experiments. The following results are obtained. When bolts and nuts in a bolted flange joint are tightened with 50% of yield stress, no yield region at the engaged screw thread occurs, however, when they arc tightened with 90% of the yield stress, a small scale yield region occurs at the roots of the engaged three screw threads from the bearing surface of the nut. While verifying this phenomenon using FEM, it was newly discovered that when the height of the nut was reduced to 1/3 (equivalent to approximately two threads) of the original dimensions according to the standards, the sealing performance could no longer be assured.

scholarly journals Examination of a Low-Profile Spinal Implant

2017 ◽  
Vol 11 (6) ◽  
pp. 895-901
Author(s):  
Takuto Iwade ◽  
Noriyuki Hisamori ◽  
Junichi Fujita ◽  
Kenji Yamaya ◽  
◽  
...  
Keyword(s):  
Contact Area ◽  
Cyclic Load ◽  
Load Test ◽  
Screw Thread ◽  
Static Load Test ◽  
Spinal Implant ◽  
Thread Surface ◽  
Low Profile ◽  
Screw Threads

Most spine implant devices are fabricated outside Japan, and therefore do not always fit the bodies of Japanese people. This causes a quality-of-life (QOL) problem in which patients feel the embedded implant devices on their back. The aim of this study was to develop more compact and lower-profile spine implant devices. Three types of devices with different heights and different screw threads were created, and the removal torque (fitting force) of the devices was measured after a static load test and cyclic load test. In addition, the screw thread surface was observed in detail after the tests. The results indicated that the mechanism of the reduction in the fitting force was related to partial contact due to abrasion or plastic deformation of the screw thread surface and decrease in the contact area between the screw threads caused by the increased diameter of the upper opening of the implant device after tightening. Therefore, we concluded that lowering the height of the implant device, securing the number of the screw threads, and securing the contact area of the threads are important in developing a low-profile spine implant.

scholarly journals Conceptional cutting tool design for internal thread turning

2020 ◽  
Vol 10 (2) ◽  
pp. 41-48
Author(s):  
Dániel Kiss ◽  
Gergő Mihályi
Keyword(s):  
Cutting Tool ◽  
Tool Design ◽  
Internal Thread ◽  
Grinding Process ◽  
High Pitch ◽  
Tool Holder ◽  
Thread Profile ◽  
Tool Profile ◽  
Conceptual Designs ◽  
Cutting Tool Design

This article describes the different machining methods of the ball nut thread. One of the disadvantages of machining high pitch ball nuts by grinding process is to produce a modified tool profile to avoid collisions between the tool holder and the workpiece. However, by using profiled lathe inserts, it is possible to produce the thread profile of the ball nut using turning technology. The applicability of the technology is verified by tooling and experimental machining based on conceptual designs, the results of which are described at the end of the article.

3-D FEM Stress Analysis of Screw Threads in Bolted Joints Under Static Tensile Loadings

2014 ◽  
Author(s):  
Shunichiro Sawa ◽  
Mitsutoshi Ishimura ◽  
Yuya Omiya ◽  
Toshiyuki Sawa
Keyword(s):  
Plastic Deformation ◽  
Bolted Joints ◽  
Experimental Result ◽  
Screw Thread ◽  
Numerical Result ◽  
Static Tensile ◽  
Hollow Cylinders ◽  
Stress States ◽  
Plastic Deformation Region ◽  
Screw Threads

The stress concentration factor (SCF) for the roots of screw threads in bolted joints under static loadings is analyzed using 3-D elastic FEM taking account the spiral of screw threads. At first, the stress states at the roots of screw threads in initial clamping state in a bolted joint where two hollow cylinders were clamped with a bolt and a nut were analyzed in initial clamping. The elastic FEM result of SCF for the first root was obtained as SCF=3.2. When the bolt was clamped in initial clamping (preload) at the 60 % of bolt yield stress, the plastic deformations were found at the first and the second roots, and non-engaged screw threads. It was found that as the external tensile loads increased, the development in plastic deformation region increased from the first root to the other roots as well as the non-engaged screw threads. It was found that the rupture occurred from the non-engaged screw threaded part while the plastic deformation increased at each root of screw threads. The numerical result was coincided with the experimental result. In the experiments, it was observed that the rupture occurred from the non-engaged screw thread and not from the first root of screw thread. Also, the bolt fatigue was predicted from FEM and it was shown that a fatigue fracture occurred from the first root.

Stability of Flow Between Arbitrarily Spaced Concentric Cylindrical Surfaces Including the Effect of a Radial Temperature Gradient

1964 ◽  
Vol 31 (4) ◽  
pp. 585-593 ◽  
Author(s):  
J. Walowit ◽  
S. Tsao ◽  
R. C. DiPrima
Keyword(s):  
Temperature Gradient ◽  
Couette Flow ◽  
Simple Formula ◽  
Negative Temperature ◽  
Radial Temperature Gradient ◽  
Radial Temperature ◽  
Simple Set ◽  
Wide Range ◽  
The Stability ◽  
The Galerkin Method

The stability of Couette flow and flow due to an azimuthal pressure gradient between arbitrarily spaced concentric cylindrical surfaces is investigated. The stability problems are solved by using the Galerkin method in conjunction with a simple set of polynomial expansion functions. Results are given for a wide range of spacings. For Couette flow, in the case that the cylinders rotate in the same direction, a simple formula for predicting the critical speed is derived. The effect of a radial temperature gradient on the stability of Couette flow is also considered. It is found that positive and negative temperature gradients are destabilizing and stabilizing, respectively.

Optimal Design of Triangle Fastening Screw Thread's Turn Number

2011 ◽  
Vol 314-316 ◽  
pp. 657-660
Author(s):  
Jian Min Chen ◽  
Meng Zhang ◽  
Jia Deng
Keyword(s):  
Optimal Design ◽  
Research Method ◽  
Equivalent Stress ◽  
Coupled Model ◽  
The Other ◽  
Screw Thread ◽  
Ansys Software ◽  
Axial Pressure ◽  
Maximum Equivalent Stress ◽  
Screw Threads

The paper firstly numerically simulates the coupled model of triangle fastening screw threads in the application of ANSYS software. Calculate stress intensity of the screw thread on the axial pressure of 200MPa. The fittest coupled turn number of the screw nut is designed to make sure the strength of coupled teeth and make every turn of the screw thread go on very well and also save material. The maximum equivalent stress of the screw thread changes linearly with the axial pressure. The stress of the thread's root is greater than that of the thread's top so that the root is easily damaged. The paper's research method can apply to the optimal design of the other patterns of screw thread's turn number.

Stress Analysis of Stainless Steel Elbow and Tee Fittings Subjected to Internal Pressure and External Loads

1999 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Tetsuya Furuya ◽  
Tadahiro Murakami ◽  
Yasuyuki Kagaya
Keyword(s):  
Internal Pressure ◽  
Wall Thickness ◽  
Bending Moment ◽  
Maximum Pressure ◽  
Screw Thread ◽  
The Finite Element Method ◽  
Internal Working ◽  
Stress States ◽  
Screw Threads ◽  
External Loads

Abstract In this paper, mechanical behaviors of the Elbow and Tee fittings connected to pipes by screw threads under internal pressure, external tensile loads and bending moment are analyzed using the Finite Element Method (FEM). FEM code employed is MARC. The maximum Mises stress of the Elbow and Tee fittings are obtained when the wall thickness is changed while the internal working maximum pressure is held constant at 20bar. The elasto-plastic stress states of screw threads the fittings and the pipes are obtained under internal pressure and external loads. Under the assumptions that nodal points are released when the strain of the elements reaches the rupture strain of the fitting’s material, the load when the rupture occurs at the screw thread is analyzed. The safety factor for the wall thickness of the Elbow and Tee fittings used in the experiment is found to be about 5. The results indicate deduced that the dimensions of Elbow and Tee fittings can be reduced. The strength of the fittings under internal pressure and external loads is obtained. It is found that the stress concentrates at the first root of male thread and expected that a fracture initiates at the first root. The strain of the Elbow and Tee fittings subjected to internal pressure were measured by using strain gauges. The numerical results are in a fairly good agreement with the experimental results.

Study on High-Frequency Quenching of Steel Tube Screw Thread Lined Glass Used for Petroleum Pipe Line

2012 ◽  
Vol 155-156 ◽  
pp. 668-673
Author(s):  
Li Chen ◽  
Xi Ming Liu
Keyword(s):  
Heat Treatment ◽  
High Frequency ◽  
Steel Tube ◽  
Screw Thread ◽  
Pipe Line ◽  
Power Frequency ◽  
Joining Strength ◽  
Screw Threads ◽  
High Degree ◽  
Quenching And Tempering

The easy-to-wear and easy-to-deform of screw threads resulting in screw thread damage often form to the steel tube lined glass used for petroleum pipe because of their low joining strength. The reason resulting above problem was found through experiments. Moreover, it was found that the high-frequency quenching and tempering heat treatment process could effectively improve strength of screw threads with optimized process parameters. The optimized parameters are output power, frequency, and thickness of steel tube wall, high degree of screw threads, induction coil current, relative speed, and medium jet pressure, respectively. The high-frequency quenching and tempering heat treatment processes are a new approach to improve the hardening of strength for the steel tube lined glass.

Optical Simulation of Omnidirectional Inspection System for Screw Threads

2014 ◽  
Vol 625 ◽  
pp. 706-711
Author(s):  
Keun Park ◽  
Chang Hun Lee ◽  
Seung Woo Ra
Keyword(s):  
Surface Defects ◽  
Optical Measurement ◽  
Optical Simulation ◽  
Inspection System ◽  
Light Illumination ◽  
Screw Thread ◽  
Simulation Based ◽  
Screw Threads ◽  
Optical Paths

Machine vision systems have been used in the automatic inspection of screw threads using backlight illumination for the inspection of the screw thread profiles. In this study, an alternative inspection system based on front light illumination is developed to directly obtain thread images so that surface defects can be measured. To realize such an inspection system, an omnidirectional optical measurement device is proposed to obtain 360oimages of screws for inspection of whole thread regions. Optical simulation based on ray tracing is then performed to analyze optical paths and to optimize the image quality of the designed optical system.

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