Traditional Hammer Research Articles

Analysis and Structural Optimization Test on the Collision Mechanical Model of Blade Jun-Cao Grinding Hammer

Aiming at the problems found in grinding Jun-Cao, such as poor grinding effect and high grinding power of mill, this study proposes a blade Jun-Cao grinding hammer based on the traditional hammer mill. With dynamics model analysis, it had better performance than a traditional hammer. By simulating the operation process in the DEM, forces on Jun-Cao and their motions were analyzed. By optimizing the structural parameters of the hammer blade based on multiobjective optimization using the genetic algorithm, an optimal solution set was obtained as a reference for practical production. Meanwhile, a bench test was designed to compare the traditional rectangular hammer with the new blade hammer regarding the operation effect. The result proved the following: (1) cutting edge length, cutting edge thickness and hammer thickness had a significant influence on the grinding effect and grinding power; (2) a total of 22 optimal solution sets were obtained, based on which the blade hammer with a cutting edge length of 45 mm, a cutting edge thickness of 3 mm and a hammer thickness of 7 mm was finally selected in the bench test; (3) the bench test proved that the blade hammer was generally superior to the traditional rectangular hammer with the output per kilowatt-hour having been improved by 13.55% on average.

Investigation of Cutter–Woodchip Contact Pressure in a New Biomass Comminution System

A Crumbler® rotary shear system was recently developed to process fuel-grade woodchips into feedstocks having more uniform particle sizes for improved flowability and higher thermochemical output yield than a traditional hammer mill. It represents a significant innovation in the state of the art of biomass comminution equipment. However, the milling unit has experienced significant abrasive wear of the feeding teeth and cutters when processing hard and dusty feedstocks, such as logging residue and corn stover. Here, we present initial simulation results from a finite-element stress analysis of the rotary shear, which is used to investigate the dynamics of interaction between the cutters and woodchips. This is the first step for optimizing the cutter design to improve the system lifetime and processing efficiency, thus reducing downtime and improving overall productivity.

Effect of Hammer Shape and Impact Area on Hammer Mill Performance under Different Feed Rates

The research aims to compare the performance (PC) and specific energy consumption (Spc.) of the hammer mill when using the T-hammer against the (traditional) rectangular hammer. A homemade mill with four hammers was used in experiment. 36 treatments: 2 hammer shape x 3 impact area (840, 720 and 960 mm2) x 2 feeding rates (1500 and 3000 g min-1) x 3 replicates, with completely random design. The results showed that there was no significant effect of hammer shape on PC at the feed rate of 3000 g min-1, while there was an effect at the rate of 1500 g min-1. An effect was also found for the impact area on the PC at both feeding rates and on Spc., as an inverse relationship appeared between the impact area and mill productivity at the feed rate 1500 g min-1. The area of 720 mm2 surpassed the area 480 and 960 mm2 at the rate of feeding 3000 g min-1, as it recorded 1215.65 g min-1 compared to 950.65 and 882.65 g min-1, respectively. There is effect of feeding rate on PC and Spc. The traditional hammer is recommended for simplicity of design, manufacture and performance at high feed rates compared to the T-shaped hammer.

Experimental modal analysis for the plate structures with roving inertial shaker method approach

In this article, a new roving inertial shaker method approach, using an inertial shaker, is presented to obtain a steel plate’s modal parameters with bolt connections on four sides. It aimed to emphasize the superiority of the proposed roving shaker approach over the classical, traditional hammer method on the plate-like structures. The frequency response functions (FRF), obtained from both methods, are investigated using the stabilization diagram, and the superiority of the roving shaker method is presented based on high stabilization and detecting more modes. The accelerometer’s position effect on experimental modal analysis (EMA) is investigated in the roving shaker method, which is performed using accelerometers in two different places, and obtained modal parameters are compared with experimental modal analysis validation methods. Accordingly, the results for the two separate locations are very close to each other. Finally, the experimental and numerical results are investigated according to the TEST/FEA correlation for the traditional roving hammer method and the roving shaker method. As a result, the roving shaker approach gives a better result according to the TEST/FEA correlation success than the roving hammer test. In conclusion, the high stabilization, high TEST/FEA correlation rate, and the number of modes show the roving shaker approach’s superiority.

Investigation of the process of shredding coniferous sawdust in a crusher with a two-way material supply system

Russia is one of the main countries in the extraction and processing of forest resources. Waste from wood processing is still one of the cheapest energy sources. Therefore Russia is actively developing and introducing technologies for processing waste from the forest industry. The technology for producing fuel pellets and briquettes is widespread. One of the operations of this technology is the preliminary grinding of the feedstock. Nowadays, traditional hammer mills are used for this, which are used in the feed industry. As a result of the analysis of the designs of such crushers, it was revealed that when grinding materials with a low specific gravity, their potential is not fully utilized. A hypothesis has been put forward that an increase in the productivity of hammer crushers when grinding materials with a low specific gravity is possible due to a change in the conditions for introducing raw materials. To test this hypothesis, a crusher with two feed necks and a vortex chamber was developed. Research has been carried out to study the influence of the conditions for entering the shredded material into the crushing chamber. The performance of the crusher is determined with three ways of feeding the shredded material.

Experience of the Odesa-Based Artferrum Enterprise as One of the Ways of the Revival of Blacksmith Art in Ukraine

The author is still investigating the problem of the rebirth and development of blacksmithing and black-smith art in the southern region of Ukraine, not yet fully studied, for example, of the Odesa blacksmith enterprise "Artferrum". This is a powerful modern enterprise, founded in 1989 Oleksandr and Nina Humeniuk today is one of the largest factories producing forged products not only in Ukraine but also in Europe. The methods of this production are different - from the latest developments in the field of metal processing to the traditional grinder and a traditional hammer in the hands of a blacksmith, whose profession is eternal. The role of the artist at the Odesa factory of forged products is neither secondary nor the main thing. At the same time, there are several projects in the design bureau of artists. Unlike the smiths, where the artist is represented in one person, "Artferrum" is a typical representative of a modern European smith enterprise. And this means that cultural studies the study of art of this form of black-smithing – is obligatory.

Output-Only Modal Analysis of Micromilling Systems

An output-only modal analysis (OMA) approach is presented to obtain the direct frequency response function (FRF) at the tip of the tool in micromilling setups. White noise input is provided using acoustic excitation and the resulting vibrations are measured using a laser Doppler vibrometer (LDV). Autoregressive (AR) identification is used to extract the natural frequencies and damping ratios of the structural modes of the milling setup, and mass-sensitivity analysis is used to obtain modal stiffness values. The accuracy of the tool tip FRFs that are constructed using OMA is verified by comparing them against the FRFs that are measured using impulse hammer tests. The direct FRF at the tool tip is an essential component in predicting and avoiding excessive and unstable vibrations in milling operations, and the presented approach provides a practical method for the direct measurement of the tool tip FRF in micromilling where the application of traditional hammer tests is not possible.

Influence of Knives Wear Phenomena on Hammer Mill Productivity and Product Quality

This research aimed to determine the change of cutting knives decision depending on knife wear phenomena, anditseffect on hammer mill productivity and product quality. It can be done by tracing the knives wear stages and determine its safe time range to replace the knives. The experiments were done in El-Serw village Damietta Governorate from 2014 to 2016, by grinding both of corn ear and dough as popular agricultural productive using the traditional hammer mill. The studied variables also are four concaves hole diameters (2.5, 4.0, 8.0 and 12.0 mm), five operating hours of new knife, 150, 200, 250 and 300 h for corn ear. While, for dough, are used two concaves hole diameters (2.5 and 4.0 mm) and operating hours of new knife, 200, 400, 600 and 800 h. The measurement includes specifications of knives, product quality and hammer mill performance. The research recommended that the hammer mill knives must replacement after 220 operating hours to grind corn ear and 600 operating hours to grind dough which represents the safe limit time to keep product quantity and quality in accepted state.

An approach for measuring the FRF of machine tool structure without knowing any input force

Measuring the dynamics of a machine tool is important for improving its processing or design. In general, the dynamics of the machine tool structure is identified by the experimental modal analysis approaches that require the measurement of both the input loadings and the corresponding structural responses. However, the primary limitation for this method is that the input loadings are difficult or impossible to be measured when the machine tool is under operational conditions. In this paper, a method that is based on random decrement technology was used to identify the operational modal parameters of a machine tool without the knowledge of any of the inputs. To estimate the frequency response functions, FRFs, a structural change method was proposed. The approach is based on the sensitivity of the eigenproperties to structural modifications caused by the drive positions. The proposed method was verified experimentally by traditional hammer tests. Because no elaborate excitation equipment is used, the dynamics of the machine tool structure with arbitrarily feed rate or working position can be easily identified using the proposed active excitation modal analysis method.

A new electrical and mechanically detonatable shear wave source for near surface (0–30m) seismic acquisition

We present a new, impulsive, horizontal shear source capable of performing long shot profiles in a time-efficient and repeatable manner. The new shear source is ground-coupled by eight 1/2″ (1.27 cm) × 2″ (5.08 cm) steel spikes. Blank shotshells (12-gauge) used as energy sources can be either mechanically or electrically detonated. Electrical fuses have a start time repeatability of < 50 μs. This source can be operated by a single individual, and takes only ~ 10 s between shots as opposed to ~ 30 s for six stacked hammer blows. To ensure complete safety, the shotshell holder is surrounded by a protective 6″ (15.24 cm)-thick barrel, a push-and-twist-locked breach, and a safety pin. We conducted field tests at the 17th Street Canal levee breach site in New Orleans, Louisiana (30.017° N 90.121° W) and at an instrumented test borehole at Millsaps College in Jackson, Mississippi (32.325° N 93.182° W) to compare our new source and a traditional hammer impact source. The new shear source produces a broader-band of frequencies (30–100 Hz cf. 30–60 Hz). Signal generated by the new shear source has signal-to-noise ratios equivalent to ~ 3 stacked hammer blows to the hammer impact source. Ideal source signals must be broadband in frequency, have a high SNR, be consistent, and have precise start times; all traits of the new shear source.

Influence of a new crushing technique on the composition of the volatile compounds and related sensory quality of virgin olive oil

The influence of a new crusher i.e. blade crusher on the quality of virgin olive oil from two different italian cultivars (Coratina and Oliarola) was determined. In addition the quality of this oil was compared with that of olive oil extracted with the traditional hammer crusher. Tests were performed in an industrial oil mill using the two different crushing instruments. Results obtained showed that quality parameters i.e. free fatty acids, peroxide value, UV absorption and total phenols content as well as the phenolic composition of oils were not significantly affected by the two different crushers used. On the contrary, the use of the blade crusher influenced the composition of the volatile compounds. In particular, the oils obtained using the blade crusher showed significant increases of some aldehydes such as 1-hexanal and trans-2-hexenal, esters such as hexyl acetate and 3hexenyl acetate and a reduction of alcohols such as 1-hexanol. Moreover, the identified pigments of the oils produced using the blade crusher were found at concentrations slightly lower than those in oils obtained after using the hammer crusher. Finally, results of the sensory analysis showed an improved organoleptic quality for the oils obtained using the blade crusher due to an increase of the cut-grass and floral sensory notes.

The Modern Goldsmith

The basic tools of the modern goldsmith, differing little from the traditional hammer and file, are described. Making models in gold is particularly onerous as even the smallest gold nut and bolt has to be made by hand. Soldering of gold has been improved by the use of modern solders, the old ones giving rise to innumerable pinholes. Spinning gold to make round objects, for example a teapot, demands different tools and skills than smithing, and so does chasing, all being here discussed.

The Modern Goldsmith

The basic tools of the modern goldsmith, differing little from the traditional hammer and file, are described. Making models in gold is particularly onerous as even the smallest gold nut and bolt has to be made by hand. Soldering of gold has been improved by the use of modern solders, the old ones giving rise to innumerable pinholes. Spinning gold to make round objects, for example a teapot, demands different tools and skills than smithing, and so does chasing, all being here discussed.