The two-cylinder drive is one of many commonly used mechanical drive forms. Its synchronous control accuracy determines the movement accuracy of the working machinery. The paper established the ...mathematical model for the two-cylinder electro-hydraulic servo synchronous drive system, and revealed that the two-cylinder horizontal electro-hydraulic synchronous drive system has the cascade form of the linear system with the nonlinear system. Taking the band sawing machine and the broaching machine as the application object, the paper analyzed their compositions and synchronization CNC systems. Aiming at the dual-cylinder drive form for the broaching machine, the IPSO-PID synchronous controller of the two-cylinder system was designed. Through the digital simulation and actual testing, the results show that the IPSO-PID synchronous controller is faster in the tracking response speed and better in the synchronization performance than the conventional PID synchronization controller.
With the development and application of expensive, difficult to cut metals and metal alloys, the minimization of waste material for final operations has, together with the quality of the band sawing ...process, become more and more important. As the onset of chatter can have a very detrimental effect on the quality of the cut, on the quality of the resulting surface, and on process performance in general, the prompt detection of chatter is of high importance. In the paper a multisensory approach is investigated for chatter detection in the band sawing process. In the experiments steel workpieces of geometrically different profiles were used. Based on an analysis of the acquired signals of the cutting forces, machine vibrations and emitted sound, a method involving a set of features for the detection of chatter in a cutting regime has been defined. The proposed method is not affected by the workpiece geometry or the process parameters. Analysis of the individual features extracted from the various process signals has been performed for chatter and chatter-free band sawing regime classification. The paper presents the results obtained using a cross-validation approach, and summarizes the most informative extracted features with respect to the various process signals.
This article takes the large band sawing machine GB42500H as the research object, and establishes the dynamics models of its various parts. Respectively, the relative research is done from the ...theoretical modal analysis and the dynamic performance testing. According to the analysis results, the structure or geometry improvement scheme of the parts is proposed. This article also studies preliminarily the dynamic characteristics of the large band sawing machine GB42500H. During the analysis, the models of the parts and the whole are established using the finite element method to optimize the structures of the parts and the whole. That has undoubtedly a very important significance for improving the dynamic performance for the new machine tool's structure, increasing the processing accuracy, and shortening the development cycle and costs.
In order to investigate sawing dynamics on band sawing machine, a general dynamic model is proposed to represent the actual system with the dynamics of strain of band saw, mechanism of hydraulic ...motor with proportional valve and load of sawing. Firstly, an element strain model of band saw along the arc coordinate is established with the elastic deformation theory of closed band saw, momentum theorem of band sawing element and sawing load. Then, the relationship between control input, sawing load and band saw tension is addressed with the dynamics of hydraulic motor with proportional valve. The results of dynamic simulations and experiments show the proposed model can effectively describe dynamics of band sawing process. This model provides a useful way to improve dynamics of band sawing.
In order to establish a mechanistic model of cutting force, specific cutting pressure was first obtained through cutting experiments. The band sawing process is similar to milling in that it involves ...multi-point cutting, so it is not an easy matter to evaluate specific cutting pressure. This was achieved by making the thickness of workpiece smaller than one pitch of the saw tooth, analogous to fly cutting in the face milling process. Then the cutting force was predicted by analysing the geometric shape of a saw tooth. The tooth shape used was the raker set style that is generally used in band sawing. A set of teeth comprises three teeth, ranked as left, straight, and right. The mechanistic model developed in the research considered the shape of each tooth in a set. The predicted cutting forces coincided well with those measured in the validation experiment. Therefore, the predicted cutting forces in band sawing can be used for the adaptive control of saw-engaging feed rate in band sawing.
In this paper, the performances of several kinds of extreme-pressure anti-wear additives were evaluated. The produced machine oil-cutting fluid for band saw had been applied to the industry and its ...toxicity was tested. The results showed that the admixture of the compounds containing element sulfur and the compounds containing element phosphorous had better anti-wear performance. This kind of cutting fluid had good using performance and could be used more safely.
A possibility was investigated to calculate the surface roughness of woods by band sawing by using the acoustic emission count rate, the cutting force and the specific gravity of woods. Five ...different softwoods, four different ring-porous woods and eight different radial- and diffuse-porous woods were used as workpieces. Ripsawing was carried out. The acoustic emission count rate was measured by the ring down method using a measuring system with a microphone. The cutting force in the cutting direction was measured using a load cell attached to the feed table. The surface roughness of a wood measured by a contact instrument with a stylus of 0.25mm curvature was described by ten point height of irregularities. The results obtained in this study are summarized as follows: The surface roughness of softwoods and ring-porous woods can be calculated by the multiple regression of the specific gravity of woods, and the AE count-rate or the cutting force. The multiple regression using the AE count-rate is more precise than using cutting force for the calculation of softwoods and ring-porous woods. The surface roughness of radial- and diffuse-porous woods can be calculated by the linear regression of the AE count-rate when they are classed by the similar characteristics of their structures. Moreover, it can be calculated by the multiple regression of the specific gravity of woods and the cutting force.
Tool damage due to chatter poses harmful economic impact in modern machining production therefore it is important to avoid or suppress chatter during the production process. In order to establish ...automated chatter-free cutting conditions, the methods for online recognition of chatter and chatter-free cutting should be developed. It this paper a band sawing cut-off process is considered where a combination of selected workpiece properties and cutting parameters result in chatter. A method for online chatter detection based on processing of acoustic signals is proposed. The method consists of pre-processing sound signals with Short-Time Fourier Transform (STFT), extracting frequency invariant features, and finally applying Quadratic Discriminant Analysis (QDA) for classification. The proposed method, tested with two-fold cross validation on experimental data, yields high recognition rate (over 96%).
CNC CARBIDE CUTOFF SAW SAVES SPACE Anon
Modern Machine Shop,
04/2015, Letnik:
87, Številka:
11
Magazine Article, Trade Publication Article
Nishijimax cutoffsaws, avai l a b le f rom Pat Mooney, are said to be capable of completing the work of four to five tradi t ional band saw machines, saving space and improving efficiency.
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