机械制造技术英文PPT (26).ppt

Mechanical Manufacturing TechnologyProcessability Analysis of Machined PartsProcessability Analysis of Machined PartsFirst of all,there are two aspects of work:1).Familiar with the performance,use and working conditions of the product,clarify the mutual assembly position and role of each part,understand and study the basis for the formulation of various technical conditions,and find out its main technical requirements and key technical problems;2).Perform process review on assembly drawings and part drawings.nContents and steps of machining process specifications design1.Assembly drawings and parts drawings analysisMain review content:nWhether the technical conditions are reasonable;nWhether the technical structure of the parts are reasonable;nWhether the drawings lack the necessary dimensions,views or technical conditions;nAvoid too high precision,too high surface roughness and other technical conditions;nThe amount of labor for processing and assembly should be reduced as much as possible;nIf problems are found,discuss with relevant designers,and modify and supplement the drawings according to the prescribed procedures;nContents of part technical analysis1.Part drawing and assembly drawing analysis：It is important to make a detailed review of product parts drawings,perform technical analysis,and put forward revision opinions when formulating mechanical processing procedures.The completeness and correctness of the part drawing;the reasonableness of the technical requirements of the parts;whether the materials of the parts are appropriate.2.The technical analysis of the structure of the parts Reasonably determine the machining accuracy and surface quality of parts If the machining accuracy and surface quality of the part are too high,it will increase the manufacturing cost;if it is too low,it will affect the performance of the part.Therefore,on the premise of ensuring the performance of the parts,try to use lower processing accuracy and surface quality.1).Conducive to achieve the required processing qualityThe manufacturability of the part structure refers to the feasibility and economy of manufacturing the designed parts under the premise of meeting the requirements of use.Good structural manufacturability is conducive to ensuring high-quality,high-efficiency and low-consumption processing of parts.Possibility to guarantee position accuracyThe relevant surfaces with mutual position requirements are preferably machined in a single clamping.The structure shown in Figure 5-1(a)cannot guarantee the coaxiality of 60 and 80.After changing to the structure shown in Figure 5-1(b),the small outer circle on the left side of the clamping can realize the processing of 60 and 80 in one clamping,thus ensuring its coaxiality.Fig.5-1 Ensure position accuracyMinimize unnecessary processing areaNot only is it conducive to reducing the amount of labor in mechanical processing,it is also conducive to reducing the consumption of blank materials and tool wear,and it is conducive to reducing production costs and improving assembly quality.As shown in Figure 5-2(b),the bearing housing reduces the machining area of the bottom surface and reduces the amount of repair work.The structure shown in Figure 5-3(b)reduces the area of finishing,while also avoiding deep hole processing.Figure 5-2 Structure of bearing seatFigure 5-3 Structure of deep hole2).Conducive to reducing processing laborTry to avoid or simplify the processing of the inner surfaceFigure 5-4 Converting the inner surface to the outer surfaceThe manufacture and measurement of the outer surface are more convenient.Therefore,when designing the mechanism of the part,it should strive to avoid processing the inner surface of the part.As shown in Figure 5-4,in the structure shown in Figure 5-4(a),there are cases where the inner groove is processed.If the structure shown in Figure 5-4(b)is changed,the inner The processing of the groove is converted into the processing of the outer groove,which reduces the processing difficulty.As shown in Figure 5-5(a),the size of the undercut is inconsistent.It is necessary to use two tools for processing,and it is not conducive to assembly.The structure shown in Figure 5-5(b)should be adopted.The hole shown in Figure 5-6(b)can be processed with a standard tool,which facilitates the processing;the height of the boss shown in Figure 5-7(b)is the same height,which reduces the adjustment of the tool during the processing.3).Conducive to improving labor productivityThe relevant dimensions of the parts should be consistent and can be processed with standard tools,which is convenient for improving labor productivity and reducing production costs.Figure 5-5 The dimensions of the undercut should be consistentFigure 5-6 Easy to use standard drillFigure 5-7 The height of the boss should be consistent Reduce the times of parts installation.Figure 5-8 Consistent keyway orientationFigure 5-9 The drilling direction is the sameThe machining surfaces of the parts should be distributed in the same direction as far as possible,or on surfaces that are parallel or perpendicular to each other.The orientation of the keyway as shown in Figure 5-8(b)is consistent,which reduces the number of clamping of the parts;the machining surface of the hole It should be a round boss or counterbore so that when the hole is machined,all the boss or counterbore should be countersinked,as shown in Figure 5-9(b).The structure of the parts should be easy to process.As shown in Figures 5-10(b)and 5-11(b),there is a retreat and grooved sipe,which reduces the interference between the tool(grinding wheel)and the workpiece,as shown in Figure 5-12(b).There is enough distance between the hole and the side of the part,so that the drill can enter the tool.Figure 5-10 Overtravel groove should be leftFigure 5-11 There should be a thread undercut Figure 5-12 Should facilitate the introduction of drill bitsFig.5-13 Avoid drilling holes and single-edge cutting on the inclined planeAvoid drilling on inclined planes and single-edged cutting of drill bits.As shown in Figure 5-13(b),avoid drilling on the inclined plane,and also avoid single-edge drilling when the drill bit enters and exits the inclined plane.Thank You