The Application of Five-axis Machining Center in the Wooden Moulds Production

Customers produce more than 100,000 tons of V-shaped castings each year, all casting molds are wooden molds, and about 60 new products are developed every year. The products are mainly counterweight and the mold size is large. We introduced the Master546 five-axis machining center produced by Paolino Bacci, Italy. In the mold making process, the mold design is completed by Solidworks, Cimatron E and other software, and Cimatron E software is used for programming. The use of machining centers for mold processing saves a lot of labor costs, reduces labor intensity, and makes mold production more accurate and efficient.

Main parameters of five-axis machining center

The gantry structure of the machining center, the size of the worktable is 1600×1600mm, the X×Y×Z stroke is 3000×2600×950mm, the inclination angle of A axis is ±135°, and the rotation angle of C axis is ±200°. The disc turret type tool magazine can accommodate 16 tools, all of which are automatically replaced. The host adopts the FANUC servo control system.

Traditional wooden mold production process

The traditional wooden mold manufacturing method is based on the part casting process drawing, determining the model classification, modular construction, hand drawing of the lofting drawing, and block creation and assembly. Among them, loft is the standard for module production, which reflects the size of the 2D drawing of the part. At the same time, it is also an important process in model design and manufacturing, which requires high skills for mold manufacturers. For some complex parts, in the mold manufacturing process, due to the incomplete size of the two-dimensional drawing, the mold manufacturer does not fully understand the drawing, and the manufactured mold is inevitably inaccurate and affected by the size. Most of these problems can only be verified step by step during the model manufacturing process, and some can only be discovered after the casting is manufactured. This not only increases the workload of mold development, but also delays the development of new products. There are also problems such as low mold accuracy.

Five-axis machining center application process

Three-dimensional design of casting mold

At this stage, V-balance heavy-duty product design is usually carried out using 3D CAD software. In the mold design process, you import the customer’s product 3D map into the Solidworks software. According to the product casting process drawing, set the mold shrinkage rate, draft angle and other parameters, and draw the upper and lower mold 3D diagrams, as shown in Figure 1.

Processing and post-processing

We use Cimatron E8.5 programming software. Cimatron E8.5 is a product of Israel’s Cimatron company. Cimatron E’s CNC machining technology has always been in a leading position in the world, and is recognized as one of the best CNC programming software. Cimatron E8.5 supports 2.5 to 5 axis programming.

The processing procedure is usually divided into the following steps.

• 1) Due to the characteristics of casting molds and the preliminary development of processing technology.
• 2) Program according to the different surfaces of the mold and select the appropriate processing program. Select the appropriate tool, spindle speed, feed rate, tool path and other processing parameters to generate the tool path.
• 3) Post-processing to generate NC program

The post-processing program is the compilation software between the tool path source file generated by the general CNC programming software and the ISO format CNC program that can be recognized by the special CNC machining center.

Simulation check of 5-axis machining program

Italy Paolino Bacci developed Pitagora, an intelligent 3D physical machine simulation software. Perform accurate and realistic dynamic simulation of the movement process of 5-axis CNC machining center, and you can directly read in the ISO code generated by Cimatron E post-processing. You can perform dynamic scaling and rotation, over-travel processing, interference and collision checking, tool head high-speed trajectory adjustment, and processing time calculation. Pitagora guarantees the accuracy and safety of the program programmed by Cimatron E, which is very practical.

Five-axis production of mold blanks

The casting process drawing shows that mold blanks with correct edges can be manufactured without considering the detailed dimensions, reducing the workload of the mold maker.

Model processing

The model blank is fixed on the worktable of the machining center by a special punch, and the relationship between the workpiece coordinate system and the machining coordinate system is realized by setting.

Input the numerical control program into the machining center to realize the conversion of the encoder, realize the coordination of each tool axis of the machining center, and complete the model processing. The mold cannot be easily formed, so it must be made as a live block, and the model can be processed directly

In Conclusion

The application of five-axis linkage machining center saves labor costs and shortens the V method development cycle. In addition, you can create high-precision surfaces to create high-precision models and high-precision castings. Due to the increase in labor costs and the improvement of the accuracy of wooden molds, the use of five-axis machining centers to manufacture V-shaped wooden molds will become the development trend of the casting mold industry.