The Knock Sensor is located on the engine block, cylinder head or intake manifold. This is because its function is to sense vibrations caused by engine knock or detonation. The PCM uses this signal to alter the ignition timing and prevent detonation. It will compare this information with its preset tables to identify a valid knock or ping. If a ping is sensed, it will retard the ignition timing to protect the engine from this damaging pre-ignition.
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Reverse engineering originated in the 1990s and was developed mainly with modern measurement, computer, modern manufacturing and other related technologies. Without the development of related technologies, reverse engineering has not made such great progress. The reverse engineering technology referred to here mainly includes three aspects: rapid profiling technology, rapid geometric modeling, and rapid processing technology. The main difference between reverse engineering and forward engineering is that forward engineering is a high-level abstract conceptual design to a concrete object. There is a clear process from conceptual design to CAC model. Reverse engineering is based on the available physical models, pictures, and software to construct its design model. By adjusting and modifying the characteristic parameters of the reconstructed model, the approximation of the prototype of the object can be achieved to meet various requirements. Digitizing a point to a CAD model is a process of backward reasoning.
1 three coordinate measurement and data processing 1.1 data measurement transmission rear body as shown. The Z002 type CNC coordinate measuring machine produced by Qingdao Sentinel Yingkefa Measuring Equipment Co., Ltd. is composed of three parts: main machine, three-dimensional measuring head and electrical control system. These three parts are connected by communication cable and communicate with each other. Shown. The measurement software ZZ-DMS is used to complete the measurement coordinate system establishment, data measurement, data processing and data export. The probe has little contact with the measurement surface during measurement. Because the mass of the rear body blank of the transmission is very large, it is fixed by the self-weight and the friction of the workbench, so that the shell blank does not sway when it comes into contact with the workbench. Because the blank is more complicated, a series of points are manually shot, and the system automatically finds Out of the center of the heart. Add a "Begincurve* statement at the beginning of each curve and replace all commas in the data with spaces to generate an IBL format that Pro/E can recognize. The modified IBL data is as follows: L2 data format conversion L3 data processing in reverse In the project, a large number of scattered three-dimensional data points are obtained on the surface of the object with the relevant equipment, and they are called "Pointaoud" visually. In the point cloud, there will inevitably be mixed with some unreasonable sound points, which will directly affect the quality of subsequent modeling, so it is necessary to filter out these sound points. The process of removing the sound point is the smoothing process of the curved surface.
The so-called smoothness, as the name suggests, is that the curve is smooth and smooth, and its smoothness judgment criteria mainly include the following four: second-order geometric continuity (refer to position, tangential direction and curvature vector continuous, that is, G2 continuous); there are no singular points and redundant inflection points; The change in curvature is small; the strain energy is small. In general, the over-pole spline has better smoothness because it uses the measured data point as the apex of the control polygon, and the fitted curve does not strictly pass the measured value point, so its smoothness is improved. It is guaranteed by offset measurement points.
The 3D data measured by the coordinate measuring machine is a file with the extension DAT output in the QTECH format, as shown below: the output data is the measured curves, and the obtained data is converted into an IBL format that can be recognized by Pro/E. Add the "CpenarclengthBeginsectiori* statement at the beginning of the file to introduce the available IBL format data obtained from the 3D modeling of the 2 parts and the mold. The data is processed as the reference curve. Click Insertadatumcurve, pop up the Crvoptions menu, select FromFile. Done pops up the GatcoordS menu to select the system default system to create the solid base of the size end. The curve creates an intermediate connecting curve, which gives the surface a solid thickness to form a solid feature. Then the process of adding and subtracting materials is used to form the basic frame of the rear body of the transmission. Finally, auxiliary features such as holes, ribs, chamfers, drafts, etc. are added to form the rear body of the transmission as shown.
To avoid recurring problems, Pro/E checks for geometric errors. When needed, the system automatically activates the Info, Trim Model menu, and the Geometry Check option in Model Player* (if open).
2*2 mold three-dimensional modeling 221 convex, concave mold three-dimensional modeling The three-dimensional parts after modeling are connected to the cavity and core by Pro/EH. This process mainly includes the construction of the blank, the construction of the parting surface, and the extraction of the mold volume.
Enter the shaped 3D parts and select a reasonable positioning method to locate in the coordinate system. The blank is generated by manual stretching according to the designed size, and the blank should be symmetrical on the main parting surface. The sketching plane selects the main parting surface, and the stretching method adopts the symmetric stretching method. After inputting the thickness, Pro/E will automatically stretch symmetrically with the parting surface.
In the process of constructing the parting surface, the main problem encountered is the repairing problem by the broken hole. The problems to be noted are: the parting surface must intersect the workpiece or the mold volume, and multiple surfaces can be combined.
Any surface can be used as a parting surface as long as it meets the first two criteria.
The parting surface features are created at the component level.
The parting surface is created by the surface of the part itself. In this design, two methods of filling by the emptying are combined. Taking the construction of the parting surface of the bottom core as an example, first copy the surface from the part with the surface option as shown. Then click on the fill ring option, because this quilt only contains simple holes, so the option will be filled by the holes. First click on the option, then click on the surface containing the hole. You can observe the filling by clicking the ship button as shown.
If there is no problem with the filling, click on the construction of the first part of the surface of the bottom parting surface, as shown.
The surface created during the styling process is copied as part of the parting surface, which is roughly the same as constructing the parting surface from the surface of the part copying the solid. The main reason for this process is that the solid surface is different from the constructed surface type, so it cannot be selected at the same time in the process of copy selection. So you need to do two constructions and then merge the two quilts you get. When merging between quilts, Pro/E will automatically use the first quilt obtained as the main quilt, but when the face combination is combined, the system will automatically combine the main quilt as the first element of the face combination. Of course, users can choose if necessary. If there are multiple boundaries, you can select the boundary to be extended by the menu below. The extension distance can be determined by extending to the plane, and the plane can be generated or selected from existing features. The generally extended terminating edge is the boundary of the blank as shown.
Select the component to be opened, and determine the Pro/E requirements to determine the mold opening direction and mold opening distance. To determine the mold opening direction, you can click the corresponding line in the vertical direction of the plane or in the direction of the line, and then input the mold opening distance. This process is to simulate the mold opening process on the die casting machine, so the mold opening step is the same as the die casting machine. After setting, you can view the mold opening process one by one through the functions in the mold opening tool. The final mold opening result is as shown.
The other parts of the ZZ2 mold assembly mold are three-dimensionally solid by stretching, punching, chamfering, cutting, etc. in Pro/E. There are two ways to assemble the mold when it is assembled: one is a fixed assembly, and the other is a motion relationship assembly. The design is intended to be assembled in a motion relationship. The mold has six parts: the fixed part, the movable part, the push-out mechanism, the top core, the side core and the bottom core. Considering the flexibility of the mold assembly, the method of partial assembly is selected for assembly, first assembling several large parts and then assembling several large parts. The assembly result is shown as 0.
3 mold NC machining designed by the mold does not use Pro/E's own processing module, but uses a special CNC machining software PowerMil. PowerMil is an independent processing package, which can be based on the input model. Quickly create tool paths without overcutting. The model can be generated by other software packages, IGES files, STL files, triangle files, CLE models, or models (solid or curved) from PowerSHAPE.
The process of producing NC machining: loading the model - view the model as shown in Figure 1.