Tapping Machine Research Articles

The Theoretical Research on Technical Advance and Innovation Integration of Tapping Machinery

Mechanical tapping becomes an important issue to be resolved in urgent need at present, which is one hot problems of the technology research at present. This paper introduces the progress and frontier of tapping technology, and analyses and summarizes the research on semi-automatic tapping machinery and automatic tapping machinery. The development of mechanical tapping is still at the exploration stage, and the fundamental theory research is insufficient. The technology needs to move from prototype stage to more mainstream use for quite some time. The type 4GXJ-I of cordless brushless tapping knife designed by our team and automatic tapping machinery designed by Zhenkun Xu in China, have presented obvious advantage in the study of mechanical tapping machine. Application of mechanical tapping machines has a very important significance to sustainable development of natural rubber industrial economy.

Force to sound pressure frequency response measurements using a modified tapping machine on timber floor structures

In recent years, research has shown that the lower frequency portion of impact sound, down to 20 Hz, is of significant importance to residents’ perception in buildings that have lightweight timber floors. At low frequencies, the finite element method is a useful tool for predictive analysis. Impact sound frequency response functions, which are easily calculated using finite element software, are useful as they offer a common ground for studies of correlations between measurements and analyzes. On the measurement side, the tapping machine is well defined and has become the standard excitation device for building acoustics. When using a tapping machine, the excitation force spectrum generated – necessary to achieving experimental frequency force to sound response functions – is unknown. Different equipment may be used for excitation and force measurements and if a structure behaves linearly, the use of any excitation devices should result in the same frequency response functions. Here, an ISO tapping machine hammer is fitted with an accelerometer, enabling estimates of input force spectra. In combination with measurements of the sound in the receiver room, frequency response functions are then achieved using an ISO tapping machine. Various excitation devices have been used on a floor partition in a timber building and on a cross-laminated timber (CLT) lab. floor in order to compare the resulting frequency response functions. Structural nonlinearities are evident, implying that for accurate frequency response measurements in acoustically low frequencies, excitation magnitudes and characteristics that are similar to these which stem from human excitations, should preferably be used.

Influence of Perforated Ceiling on Floor Impact Sound Insulation in Reinforced Concrete Buildings

In this study, the influence of a perforated ceiling on the floor impact sound was investigated. The floor impact sound measurements were conducted both with and without suspended ceiling including the perforated and nonperforated panel, using heavy and light weight impact sources in a reinforced concrete test building. The results indicated that the perforated ceiling with and without absorption sheet greatly reduced the resonance of floor impact sound by the non-perforated ceiling. However, the perforated ceiling without an absorption sheet did not improve the single number quantity (SNQ, rubber ball: L′iA,Fmax,V.T and tapping machine: L′n,w) for the floor impact sound insulation. The perforated ceiling with attached absorption sheet produced SNQs of 2 dB lower and higher than that produced by the non-perforated ceiling for heavy and light weight impact sources, respectively. It was also found that the improvement in the floor impact sound insulation after the installation of the perforated ceiling was related to the mass-spring-mass system, rather than the absorption area of the receiving room.

Calibration of the ISO tapping machine for finite-element prediction tool on a wooden-base floor

One important challenge of the wooden constructions is to achieve a high quality of acoustic insulation, especially decreasing the impact noise in the low-frequency range. In order to avoid over-designed solutions and expensive experimental tests in the design phase, reliable prediction tools are called for. This article is an initial investigation of modeling the ISO standardized tapping machine on a cross-laminated timber floor, using finite element method. The wooden-based floor was first calibrated in terms of its dynamic properties. The influence of the material properties of the cross-laminated timber floor was discussed. The force generated by the tapping machine was then introduced in the established cross-laminated timber model. The model was finally validated by comparing the simulation results with the measured accelerations.

Measurement of in-room impact noise reduction

There are well-established measurement standards for the rating of impact noise reduction provided by floor coverings in relation to structurally transmitted impact noise, e.g. BS EN ISO 10140-3 and ASTM E492 are widely used in Europe and North America Respectively. Standardisation for “in-room” impact noise transmitted by an airborne path is however less well established. At the current time the standard used for rating the “in-room” impact sound reduction is BS EN 16205:2013 which focuses primarily on walking noise as a the impact source. This standard employs the same tapping machine used for impact improvement testing in BS EN ISO 10140-3 but has been found not to be ideal due to the mechanical noise it produces and because it is not fully representative of the walking loads that the standard primarily aims to address. There is currently no standard that deals with “in room” impact noise from falling objects which may be a greater concern than walking noise, for example in a healthcare or education setting. Thus, presented in the paper are the findings from a large measurement survey conducted to investigate the influence of impactor mass, hardness and velocity on measured “in room” impact noise reductions. Other measurands such as the reduction in impact force and floor acceleration are also considered. It is discussed in the paper how ‘In-room’ impact noise differs from transmitted impact noise and this is demonstrated by performing a transfer path analysis to separate out the impact noise contributions from a falling object and from the floor. The key finding of the study is that the whilst the impact noise reduction achieved by different floor coverings varies wildly for different impactor types the rank order of the floor coverings tested in terms of Impact noise reduction did not. Thus, the ideal test method may not be the one that simulates best the type of impacts a floor is likely to be subjected to, but rather, it ought to be the one that gives the biggest differences between similar floor coverings so as to highlight most clearly the differences between them.

An engineering method to measure the impact sound reduction due to soft coverings on heavyweight floors

In order to measure the improvement of impact sound insulation ΔL due to a floor covering in accordance with ISO 10140 standard, a specialised measurement facility is required. As a consequence, such measurements become fairly expensive and available only to those who have access to a specialised laboratory. Therefore, the authors propose an engineering method to measure the ΔL value in the case of soft coverings placed on heavyweight floors. This method enables the replacement of extensive test facilities with one room with a heavyweight floor and a mobile insulation case inside. The inside of the case acts as a source room; the tapping machine and the test sample are placed inside the case, which separates the airborne sounds from the structure borne sounds. The measurement procedure described in ISO 10140 standard is adopted – ΔL is determined by the difference between the sound level outside the case with and without the test sample. In this article, the proposed engineering method is thoroughly delineated and verified with theoretical and energy (SEA) analyses. Next, the results of experimental tests are presented – the reduction of impact sound on four different groups of samples measured in three different rooms. The obtained results are compared with the corresponding ΔL values measured according to ISO 10140 standard. This comparison shows a very strong convergence between the curves of impact sound reduction obtained by both methods. Based on all the above findings, it is stated that the presented engineering method enables accurate measurements of impact sound reduction of heavyweight floors due to soft coverings within the range of uncertainty and application. Due to the reduced measurement facilities in comparison with the ISO standard, the engineering method can be a useful tool in the process of designing and improving products such as soft floor coverings.

Low-frequency impact sound pressure level characteristics with three standard impact sources in Korean reinforced concrete structured apartment buildings

Floor impact sound is one of the major low frequency sound which are generated in residential buildings. In ISO standard, rubber ball standardized as heavy/soft impact source and modified tapping machine was proposed to simulate frequency characteristics of real impact sound. Rubber ball is 2.5 kg silicone rubber hollow ball and free drop from 1 m height. However, low frequency impact sound pressure level of tapping machine in a residential buildings with high floor impact isolation performance is relatively lower than real impact sound. It is need to be checked that measurement of floor impact sound isolation performance in residential buildings with resilient materials using tapping machine is suitable method. In this study, floor impact sound isolation performances of reinforced concrete structured residential buildings with resilient buildings were measured using tapping machine, bang machine and rubber ball. The low frequency measurement results were compared. It was found from measurement results that tapping machine impact sound pressure level below 100 Hz bands were lower than rubber ball and bang machine impact sound in Korean residential building where 20 mm thick resilient material was installed. Single number quantity of tapping machine impact sound pressure level in Korean residential building was 50 dB in L’n,W. From these results, it can be concluded that measurement of low frequency impact sound isolation performance using tapping machine in reinforced concrete structured residential buildings with resilient material is not suitable.

Performance Enhancement for Rigid Tapping by Iterative Learning Control

AbstractIn this study, an iterative learning control (ILC) algorithm is proposed to improve synchronous errors in rigid tapping. In rigid tapping, the displacements of the z‐axis and spindle must be kept synchronous to prevent damage. Using learning control provides better commands for both the z‐axis and spindle dynamics, improving the synchronicity of the output responses of the z‐axis and spindle. The proposed ILC makes use of synchronous errors in the previous cycle of tapping to modify the current position commands of both the z‐axis and spindle. A systematic algorithm is proposed for the computation of learning gains that guarantee the monotonic convergence of synchronous errors. A systematic procedure of applying ILC to rigid tapping is also proposed, where the ideas of effective learning gains and stop learning criteria are discussed. Experimental results on a tapping machine verify the effectiveness of the proposed ILC algorithm.

Review of acoustic comfort evaluation in dwellings: part II—impact sound data associated with subjective responses in laboratory tests

The concept of acoustic comfort is hardly defined and used to refer to conditions of low noise levels or annoyance based on standardized descriptors. Airborne and impact sound measurements are used to rate acoustic comfort in dwellings, but they often do not express human perception of noise or comfort. If the descriptors are statistically associated with self-reported responses, they can be used as prediction models and considered sufficient for acoustic comfort assessment. This review article presents studies that approach acoustic comfort in dwellings via the association of acoustic data and subjective responses in laboratory tests. Specifically, we investigate the cases of impact sound, since it is usually reported as the most disturbing noise source in dwellings. We also evaluated the reviewed studies with the Bradford Hill’s criteria. The reviewed studies indicate that self-reported annoyance to impact sound is an important issue and it can be predicted well in overall. Various standardized descriptors are studied and associate sufficiently with subjective responses. Inclusion of low frequencies down to 50 Hz in measurements improves the association of impact sound descriptors to subjective responses. Some impact noise stimuli associate only with some descriptors but not all. From the standardized impact sources, the tapping machine is the most efficient to predict overall annoyance and the impact ball for human walking or typical impact sounds in dwellings.

Kinematic Analysis of Tapping Machine and Simulation with Simmechanics

In this study, the design, kinematic analysis and simulation of a 4-degree-of-freedom tapping machine were performed. Solidworks software was used. The design was transferred to the Simmechanics module and transformed into MATLAB blocks. The results of kinematic analysis were introduced to the system with Mfunctions, and the movement of the system was controlled depending on the position input. The tapping machine design is computer controlled and is a suitable solution for tapping on automation supported assembly lines.

Field testing of in-room impact noise

The sound generated by footfall within the source space, sometimes called in-room impact noise, affects the noise level due to movement within a room and also the occupants’ perception of quality. Initial studies are based on the standard tapping machine as the source. While no ASTM standard yet exists for measuring the source room sound level, source room measurements with the tapping machine have been performed on several recent laboratory testing programs. The authors have measured source room power levels in the field using the same flooring products that were measured in the laboratory. The data are analyzed to evaluate the correlation between the laboratory data and the resultant noise level realized in the field. The usefulness and applicability of future laboratory and field in-room impact noise standards is discussed.

Non-standard uses of the mechanical tapping machine in field measurements

The mechanical tapping machine creates a continuous series of floor impacts which generate a steady-state sound field when measured indoors. Because each individual hammer has the same weight and free-falls from the same distance, the machine creates a calibrated and steady impulsive force into the floor structure. This presentation will illustrate potential future test methods for assessing sound transmission in buildings with examples to evaluate structure-borne sound transmission into structurally isolated anechoic and reverberation rooms.

Experimental study of the impact noise through concrete floor with resilient layers

In this paper, we present an experimental approach to evaluate the sound transmission through floors and building structures. This method is developed in our laboratory at the National Center of Studies and Integrated Research of Building Engineering, CNERIB, Algeria. The method is based on measurement of sound due to impact vibration generated by a standard tapping machine placed on the upper surface of a small concrete floor. This floor has dimensions of 1.2(m)×0.8(m)×0.2(m) and simply supported on four elastic supports with 2 cm of rubber layer. The natural frequency of the floor is measured with an ambient vibration apparatus, and the obtained value is f = 19 Hz. The measurement consists of recording vibration levels in the upper and lower surfaces of the floor, in 1/3 octave frequency bands between 16 Hz and 16 KHz using piezoelectric accelerometer Brüel and Kjær 4508. The sound level meter Brüel and Kjær 2270 has been used to analyze the vibration signal for different cases. The weighted sound reduction index of the floor has 4 dB without any cover. Some samples of cover floor are tested using this procedure. The results show that the weighted sound reduction index of resilient layer can reach 18 dB, 11.6 dB and 6.6 dB for the rubber, Bitumen and PVC material, respectively. The important results obtained in this paper can be used as a platform to correct the impact sound insulation in multi-storey residential building and renovation plans using recycled resilient materials.

The responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact sound: a pilot study

BackgroundRecently, noise coming from the neighborhood via floor wall has become a great social problem. The noise between the floors can be a cause of physical and psychological problems, and the different types of floor impact sound (FIS) may have the different effects on the human’s body and mind. The purpose of this study is to assess the responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact.MethodsTen men and 5 women were enrolled in our study, and the English listening test was performed under the twelve different types of FIS, which were made by the combinations of bang machine (B), tapping machine (T), impact ball (I) and sound-proof mattress (M). The 15 subjects were exposed to each FIS for about 3 min, and the subjective annoyance, performance ability (English listening test), cortisol level of urine/saliva and heart rate variability (HRV) were examined. The sound pressure level (SPL) and frequency of FIS were analyzed. Repeated-measures ANOVA, paired t-test, Wilcoxon signed rank test were performed for data analysis.ResultsThe SPL of tapping machine (T) was reduced with the soundproof mattress (M) by 3.9–7.3 dBA. Impact ball (I) was higher than other FIS in low frequency (31.5–125 Hz) by 10 dBA, and tapping machine (T) was higher than other FIS in high frequency (2–4 k Hz) by 10 dBA. The subjective annoyance is highest in the combination of bang machine and tapping machine (BT), and next in the tapping machine (T). The English listening score was also lowest in the BT, and next in T. The difference of salivary cortisol levels between various types of FIS was significant (p = 0.003). The change of HRV parameters by the change of FIS types was significant in some parameters, which were total power (TP) (p = 0.004), low frequency (LF) (p = 0.002) and high frequency (HF) (p = 0.011).ConclusionsThese results suggest that the human’s subjective and objective responses were different according to FIS types and those combinations.

Development of an automated system for American society for testing and materials test method E1007

The use of a tapping machine in four specific configurations is required in the determination of the field impact insulation class rating of a floor-ceiling assembly as prescribed in the American Society for Testing and Materials Test Method E1007. When performed with presently available equipment, the procedure requires either two acousticians be present—one taking measurements in the room below while the other moves the machine into the four required positions in the room above or one acoustician who must repeatedly return to the machine to change its position after taking each measurement. Either case results in a waste of man-hours, which could be more effectively utilized. The objective of this work is to design a proportional-integral-derivative-controlled automated testing system using National Instruments MyRIO robotics components to be retrofitted to an existing tapping machine. This allows for the wireless remote control of the position of the tapping machine from the floor below, allowing a single acoustician to perform the test more quickly and accurately.

Four-bar linkage-based automatic tool changer: Dynamic modeling and torque optimization

An Automatic tool changer (ATC) is a device used in a tapping machine to reduce process time. This paper presents the optimization of a Peak torque reduction mechanism (PTRM) for an ATC. It is necessary to reduce the fatigue load and energy consumed, which is related to the peak torque. The PTRM uses a torsion spring to reduce the peak torque and was applied to a novel ATC mechanism, which was modeled using inverse dynamics. Optimization of the PTRM is required to minimize the peak torque. The design parameters are the initial angle and stiffness of the torsion spring, and the objective function is the peak torque of the input link. The torque was simulated, and the peak torque was decreased by 10 %. The energy consumed was reduced by the optimization.

Variations in impact sound level as a function of tapping machine position

Impact insulation class testing per ASTM E 492 requires measurement of the sound field at exactly four tapping machine positions. Previous research by the authors [J. Acoust. Soc. Am. 121, 3113 (2007), J. Acoust. Soc. Am. 122, 2955 (2007)] indicated that for field tests, the variation between tapping machine positions was small. To our knowledge, a systematic investigation has not been performed for tapping machine positions in the laboratory, and some recent results indicate that the variation may be larger than expected. Large variation in sound level may be inherent to the method, or may point to problems in construction or installation of flooring materials. The variations with tapping machine position are analyzed for a set of laboratory tests, and the previous field test studies are updated with additional data. The authors investigate possible changes to the standards to mandate a maximum allowable variation between tapping machine positions, and to require additional positions as necessary.

Intelligent Computer-aided Process Planning of Multi-axis CNC Tapping Machine

The increasing complexity of the manufacturing industry demands computer numerical control (CNC) machining, a massively used process that is equipped with an intelligent feature. Not only does its control function revitalize competition in a sustainable manufacturing ecosystem but also advances the Industry 4.0 readiness. This paper develops an intelligent computer-aided process planning (i-CAPP) based on two widely accepted performance measures: manufacturability and efficiency. Machine tapping is a very popular CNC machining process making threaded holes, from which there is an investigation of two manufacturability scenarios. The first scenario deals with all holes with the same size that undergo the same operation (OP). The second one handles the groups of holes with different sizes machined by various OPs. Meanwhile, the study of efficiency focuses on point-to-point drilling, tapping, and chamfering. This research work verifies such indicators by proposing hybrid-two-stage optimization algorithms: 1) traveling salesman problem and 2) innovative Tabu Search. The i-CAPP verification of both indicators was confirmed in an application with a five-axis CNC tapping machine to realize the Industry 4.0 readiness. Extensions of the research in the pursuit of higher intelligent manufacturing platforms are discussed.

Effects of Perforation on Rigid PU Foam Plates: Acoustic and Mechanical Properties.

Factories today are equipped with diverse mechanical equipment in response to rapid technological and industrial developments. Industrial areas located near residential neighborhoods cause massive environmental problems. In particular, noise pollution results in physical and psychological discomfort, and is a seen as invisible and inevitable problem. Thus, noise reduction is a critical and urgent matter. In this study, rigid polyurethane (PU) foam plates undergo perforation using a tapping machine. The mechanical and acoustic properties of these perforated plates as related to perforation rate and perforation depth are evaluated in terms of compression strength, drop-weight impact strength, and sound absorption coefficient. Experimental results indicate that applying the perforation process endows the rigid PU foaming plates with greater load absorption and better sound absorption at medium and high frequencies.

Impact noise insulation performance of commonly used materials when excited by different impact noise sources

This study aimed to verify the performance of different materials used as impact noise insulation when excited by different impact sources. The method applied consisted of several acoustic measurements, following the standards' instructions and using different impact sources, such as the tapping machine and an impact tire. When using the tapping machine results indicate rather big differences in noise insulation performance for the different materials, showing a range from 50 to 76 dB for the Weighted Standardized Impact Sound Pressure Level while measurements with the tire showed a range of 72 to 82 dB for the Average Maximum Impact Pressure Level, meaning very similar noise insulation for all materials.