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c. Machining of heat-treated dies (see Figs. 9–11).
Fig. 8. CAM role in manufacturing.
5.3. Attributes of HSC and EDM
Comparison of manufacturing technologies is shown in Table 1. From ecological point of view HSC technology is prevailing EDM for the following reasons:
- Low energy technology is friendlier to the environment.
- Permanent decrease of cutting lubricants and coolants leads to dry machining.
- There must be constant monitoring of EDM electrolyte during the process as later on for the waste treatment and disposal [6].
Fig. 9. Alloyed dies of 67 HRC.
Fig. 10. Hardened dies of 62 HRC.
The HSC introduction into tool-making drastically re- duces manufacturing times for die and mould forming, how- ever the EDM and HSC technologies are not competitive but they are adjective, since all different forming geometries can be achieved by EDM which is not the case for HSC [6].
6. CAD–CAM system
Today’s PC-based CAD–CAM software grows more so- phisticated. The prospective CAD–CAM users are presented with dozens of options through trade shows. It becomes dif- ficult for a shop to decide exactly what they need. Due to a rapid development of information technologies, CAD–CAM packages can perform NC programming tasks that would have been impossible a few years ago without an expensive workstation-based system. In general, mould shops should not purchase a system for their far future plans, because at that time the software will already have been out-of-date.
The current system should let them fulfil the capabilities they need now, and also offer additional functions that they can add as their needs change.
We gathered many years of experience in introducing CAD–CAM systems to the production, as we visited many companies, which confronted the problem of the implemen- tation of CAD–CAM system to the production. We would like to introduce our experiences from these visits and point out the problems companies were confronted with. Finally we will mostly consider the CAM part of the manufacturing process. Implementation of CAD–CAM systems in manu- facturing depicts Fig. 12.
Fig. 11. Heat-treated steel die hardened to 40 HRC.
6.1. CAM functionality
Modules like dynamic feed rate optimisation and high speed machining can shorten the NC program and reduce machining time. Dynamic feed rate optimisation module (Fig. 13) enables the feed decrease as the tool cuts more material, and increase as the tool cuts less material.
This helps keep a constant chip load on the cutter for longer tool life and more efficient cutting. Similar to federate opti-
Fig. 12. CAD–CAM System.
Fig. 13. Feed rate optimization.
misation is smart cornering (Fig. 14), which adjusts the feed rate around corners and small radii for smooth transition in tight areas, based on the part and machine tool characteris- tics. High speed machining is a powerful machining method that combines high feed rates with high spindle speeds, spe- cific tools and specific tool motion. HSM can deliver faster turnaround and a superior finish. CAM system should include a suite of HSM functions designed to help you make the most of this powerful technique such as: smooth tool motion on and off the part, contour paths with smooth, consistent ramp- ing motion, smooth circle milling, using 3D loops onto and off of Z-level cuts, specialized high-speed pocketing with “trochoidal” milling.