Research on Tightening Torque Control and Test of Screw Joint Bolts

The paper presents the results of a study on using mechatronics to enhance the performance and reliability of small electric powered screwdrivers (SEPS). A mechatronic solution to control the final tightening torque replacing the mechanical clutch of a purely electromechanical SEPS is presented. Torque estimation methods based on motor armature current measurements are integrated with an SEPS driven by a direct current motor. Strategies for controlling the final tightening torque of the screw fastening process are developed. The control strategies are tested in accordance with the ISO 5393 standard. It is shown that the mechatronic controller gives comparable performance to a SEPS with a mechanical clutch. The mechatronic solution has the advantage of reduced cost, size and complexity. The paper demonstrates the application of low-cost mechatronics in industrial power tools.

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Torque control of bolt tightening process through adaptive-gain second-order sliding mode

Measurement and Control ◽

10.1177/0020294020932354 ◽

2020 ◽

Vol 53 (7-8) ◽

pp. 1131-1143

Author(s):

Zhimin Wu ◽

Guigang Zhang ◽

Wenjuan Du ◽

Jian Wang ◽

Fengyang Han ◽

...

Keyword(s):

Closed Loop ◽

Control Method ◽

Sliding Mode ◽

Nonlinear Process ◽

Second Order ◽

Torque Control ◽

Sliding Mode Controller ◽

Tightening Torque ◽

Bolt Preload ◽

Second Order Sliding Mode

Bolts constitute a very important subset of mechanical fasteners. In order to tighten bolts, a degree of bolt preload scatter is to be expected. Since the torque control of tightening bolts is the most popular means of controlling the preload, an appropriate tightening torque becomes pivotal. This paper investigates the torque control problem of bolt tightening process. This process is not as simple as it looks because the inherently nonlinear process contains many uncertainties. To conquer the adverse effects of the uncertainties, this paper designs an adaptive-gain second-order sliding mode controller. Theoretically, such design can guarantee that the bolt tightening process has the closed-loop stability in the sense of Lyapunov. From the aspect of practice, the control method is carried out by a platform. Some comparisons illustrate the feasibility and effectiveness of the designed controller.

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Study of Two-Stage Tightening of Threaded Fasteners Using Various Tool Speed Combinations

Volume 2: Computer Applications/Technology and Bolted Joints ◽

10.1115/pvp2007-26719 ◽

2007 ◽

Author(s):

Saravanan Ganeshmurthy ◽

Sayed A. Nassar

Keyword(s):

Automotive Industry ◽

Mass Production ◽

Control Process ◽

High Volume ◽

Torque Control ◽

Bolted Joints ◽

Two Stage ◽

Tightening Torque ◽

Threaded Fasteners ◽

Bearing Friction

This paper investigates the effect of various tool speed combinations on the torque-tension relationship in a two-stage torque control process for the tightening of threaded fasteners. The tightening speed has a considerable affect on the thread and bearing friction coefficients. Hence, the amount of clamp load generated by a specified level of the tightening torque is significantly influenced by the tool speed combinations in many high volume applications. In two-stage processes, the fastener is first tightened to an intermediate torque level beyond which the tool speed is changed but the tightening is continued until the full target torque is reached. The effect of tightening speed combinations (for stages one and two) on the torque-tension relationship is investigated. Data on the coefficients of thread and bearing friction as well as the Nut Factor K is investigated. The findings of this study are helpful in predicting the clamp load generated in bolted joints, which enhance its reliability and safety. Additionally, the study provides helpful data that may be utilized for developing reliable assembly strategies in mass production applications such as the automotive industry.

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Influence of Prosthetic Screw Material on Joint Stability in Passive and Non-Passive Implant-Supported Dentures

The Open Dentistry Journal ◽

10.2174/1874210600903010245 ◽

2009 ◽

Vol 3 (1) ◽

pp. 245-249 ◽

Cited By ~ 11

Author(s):

Aloísio Oro Spazzin ◽

Guilherme Elias Pessanha Henriques ◽

Mauro Antônio de Arruda Nóbilo ◽

Rafael Leonardo Xediek Consani ◽

Lourenço Correr-Sobrinho ◽

...

Keyword(s):

Mechanical Behavior ◽

Significant Interaction ◽

Joint Stability ◽

Tightening Torque ◽

Screw Joint ◽

Passive Fit ◽

The One

Objectives: This study evaluated the influence of prosthetic screw material on joint stability in implantsupported dentures at two levels of fit. Methods: Ten mandibular implant-supported dentures were fabricated. Twenty cast models were fabricated using these dentures. Four groups (n=10) were tested, according to the vertical fit of the dentures [passive and non-passive] and prosthetic screw materials [titanium (Ti) or gold (Au) alloy]. The one-screw test was performed to quantify the vertical misfits using an optic microscope. The loosening torque for the prosthetic screws was measured 24 hours after the tightening torque (10 Ncm) using a digital torque meter. Data were analyzed by two-way ANOVA and Tukey’s test (α=0.05). Results: Overall, dentures with passive fit and Ti screws resulted in significantly higher loosening torque of the prosthetic screws (p<0.05). No significant interaction was found between fit level and screw material (p=0.199). The prosthetic screw material and fit of implant-supported dentures have an influence on screw joint stability. Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint.

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Impact of process engineering factors on stabilization of screw joint

Advanced Technologies in Mechanics ◽

10.17814/atim.2016.1(6).35 ◽

2017 ◽

Vol 3 (1(6)) ◽

pp. 12 ◽

Cited By ~ 1

Author(s):

Aleksander Nieoczym ◽

Zbigniew Krzysiak ◽

Sławomir Tarkowski ◽

Anna Skic ◽

Bartłomiej Rachwał ◽

...

Keyword(s):

Present Article ◽

Process Engineering ◽

Tightening Torque ◽

Screw Joint ◽

The Impact ◽

Protective Coat

The stabilization of screw joint and influence of factors protecting against loosening of the joint have been discussed in the present article. The results of experimental examinations associated with the impact of the type of protective coat on threaded section and lubrication on the value of tightening torque have been also presented.

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