GF AgieCharmilles FORM 20

The FORM P 350 is GF AgieCharmilles' precision-oriented sinker EDM with higher accuracy, better surface finish capability, more advanced orbiting, and a larger work envelope than the FORM 20. The FORM P 350 achieves VDI 0–4 finish versus VDI 6 on the FORM 20, positions to ±0.002 mm versus ±0.005 mm, and accommodates larger electrodes and workpieces. The FORM P 350 is approximately $80,000–$120,000 more expensive. The FORM 20 is the right choice for standard toolroom sinking where the FORM P 350's precision is not required and the budget is a primary constraint.

For most standard toolroom applications on the FORM 20, copper and fine-grain graphite are the primary electrode materials. Copper provides excellent finish quality and is preferred for final polish passes in P20 and H13 cavities. Fine-grain graphite (grain size 8–15 µm) offers faster rough cutting speeds with moderate electrode wear. For very detailed work with sharp corner definitions, copper offers superior feature fidelity. GF AgieCharmilles' technology tables on the AC FORM HMI provide parameter sets for both electrode types across common workpiece materials, simplifying setup for less experienced operators.

The FORM 20 supports 2D orbital and circular orbiting motions for cavity finishing, which covers the majority of standard mold cavity finishing requirements. Full 3D orbital motion — where the electrode follows a spherical or complex 3D path — is available on the higher-specification FORM P and FORM S machines. For standard round, square, and rectangular cavity profiles, the FORM 20's 2D orbital capability is sufficient to achieve the specified VDI 6–12 surface finish range.

Key maintenance items include regular dielectric oil analysis and filtration — oil quality directly affects cutting stability and surface finish. Filter elements require periodic replacement depending on use intensity. Ball screw lubrication and periodic backlash verification are important mechanical maintenance items. Wire guides (if applicable to the machine configuration), power contacts, and flushing nozzle condition should be inspected routinely. GF AgieCharmilles recommends annual preventive maintenance visits for calibration verification and generator inspection.

Yes. The FORM 20's IPG generator includes technology table settings for cemented tungsten carbide. Carbide sinking requires lower discharge energy, more careful dielectric management, and slower material removal rates than tool steel, but is a standard application for compact sinker EDMs in toolroom environments. Carbide punches, inserts, and gauging components are typical FORM 20 carbide applications. The ball-screw positioning accuracy at ±0.005 mm is adequate for most carbide tooling sinking requirements.