Application of the hottest proe wildfire version 2

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The application of pro/e wildfire version 2.0 in cam processing and improvement

a cam used in a certain equipment manufactured by a workshop of the China air to Air Missile Research Institute has been processed by the profiling method since the 1990s. At first, a relatively ideal model was obtained after many trial production, manual filing and machine installation tests. Later, rough machining was carried out by leaving a certain margin according to the drawing, and then the operator processed and filed the model according to the model, and finally polished the cam surface smoothly. The problem is that the processing is difficult and requires high technical level of operators. 4. In terms of cost performance, the processing cycle is long, the accuracy is low and the scrap rate is high. With the popularity of numerical control machine tools and wire cutting equipment, the necessity and advantages of using wire cutting or numerical control processing are becoming greater and greater

I. Analysis on the improvement of the original drawing requirements and processing methods of the cam

1 The original drawing data and technical requirements of the cam are shown in Figure 1. The drawing requirements are: 355 ° ~ 185 ° is the arc of R55, 185 ° ~ 235 ° is the transition section, 235 ° ~ 305 ° is the arc with radius of r37, and 305 ° ~ 355 ° is the transition section. Among them, the transition section is 5 ° equally divided, and the characteristic points are connected by spline curves

Figure 1 original cam pattern

2 Wire cutting trial production and problem analysis

the software used by our wire cutting machine tool is the CAXA electronic drawing board, which makes graphics according to the drawing requirements, in which the transition section is to make feature points first, and then make splines through each feature point to connect with two arcs, so that the trajectory curve of molybdenum wire is formed. Subsequently, the rough embryo was trial produced. After processing, it was found that the cam contour surface had edges and was not smooth. The reasons are analyzed as follows: firstly, the value of the characteristic points of the original cam transition curve is inappropriate, because the original drawing is drawn earlier and is a manually drawn spline curve, resulting in a large error in the value of the characteristic points on the curve; The second is that the arc is directly connected with the spline curve, so the tangency cannot be guaranteed, so the convex edges and concave edges at the joint are obvious. In addition, the shortage of WEDM is that it can not meet the coordination of surface roughness and machining efficiency

3. Analysis of machining cam with NC milling machine

if the NC milling machine equipped with NC dividing head is used to replace the original profiling processing method and wire cutting, it will not only greatly improve the processing efficiency, reduce the technical level requirements for operators, but also improve the processing accuracy and ensure the surface smoothness requirements

however, because the NC machining program of the cam is generally compiled manually, its disadvantage is that the NC milling machine software compilation adopts linear interpolation, and the feature points are connected in a straight line. Due to the limitations of the manual programming method, sufficient coordinate points cannot be obtained, which leads to a certain deviation of the processed cam contour, resulting in the appearance of joint edges on the cam surface. The original drawing is divided according to the interval of 5 °, and the interval is large, so the data cannot be used directly. If the programmer manually interpolates and refines the cam contour, the programming is complex, the workload is too large, and the data proofreading is difficult and prone to errors. If we can obtain the documents that can be recognized by the CNC milling machine through software, Hexcel, the world's advanced composite manufacturer, will greatly simplify the programming process

II. Use pro/engineer wildfire 2 when the safety protection device is damaged The perfect combination of all parts is 0

in view of the comprehensive comparison of traditional wire cutting and CNC milling machine processing methods, as well as the analysis of wire cutting trial samples, it is decided to make full use of pro/engineer wildfire 2.0 and Excel software to complete CAM data improvement, software simulation and automatic generation of data sheets that can be identified and used by CNC milling machines

1. Use pro/engineer to analyze and correct the original data

according to the trial production results of WEDM, we preliminarily conclude that the value of the original data is inappropriate. In order to verify this inference, we decided to conduct three-dimensional simulation in pro/engineer wildfire version 2.0 according to the cam pattern

after entering the software, click file, new, select new part, enter cam001 in the name, enter the drawing mode, and then click the stretching feature and enter the sketching environment. In the sketching environment, draw according to the design drawing, and make the inner hole first φ 55, R55 and r37, and then give a characteristic point of 5 ° in the transition section according to the figure, a total of 18. Then two spline curves are made through the endpoints and feature points of the large and small arcs, so that the sketch for stretching is generated, as shown in Figure 2. Click OK to stretch the solid, and enter the stretching thickness 10 to get the three-dimensional model, as shown in Figure 3

Fig. 2 cam sketch

Fig. 3 original cam three-dimensional drawing

it can be clearly seen from Fig. 3 that the cam surface is concave convex and unsmooth, especially at the junction of the transition section and the arc, there are obvious edges, which are very close to the cam contour processed by wire cutting

according to the simulation effect and the working timing requirements of the cam, it is now decided to use pro/engineer software to carry out numerical fine-tuning on the premise of ensuring the timing of large and small arc segments, so as to make the cam surface smoother. Adjust the values of obvious concave and convex parts, and add the connection points of spline curve and arc as tangent relationship. The modified pattern and three-dimensional model are shown in Figure 4 and figure 5

Figure 4 the pattern after modifying the feature points

Figure 5 the three-dimensional diagram of the cam after data correction

it can be clearly seen from Figure 5 that the three-dimensional effect of the modified cam has been very close to the ideal value, and the surface is relatively smooth. Next, how to convert the data into the text coordinate format that can be recognized by the NC milling machine and correct it. (end)

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