UPV SERIES WIRE EDMS BUILT WITH OIL-BASED DIELECTRIC SYSTEMS IMPROVE SURFACE FINISHES
The Makino (Auburn Hills, MI) UPV-3 and UPV-5 Ultra-high Precision WEDMs are designed with an oil-based dielectric fluid system for high-accuracy machining of hardened materials and mirror-like surface finishing capabilities.
“The oil-based dielectric fluid system design of the UPV series is completely different from our other EDM machinery, offering multiple unique benefits,” says Jeff Kiszonas, Makino’s EDM product manager. “We’ve integrated a thermal control system that maintains constant dielectric and casting temperatures, Makino’s latest SPG II circuit for improved finishing operations, and our proven high-performance PICO guide system. Together these features create a rigid, reliable, high-accuracy machining platform capable of producing surface finishes to 0.08 ?m Rz.”
Makino’s UPV machines feature a fixed table design in which axis movements are controlled by machining heads. Sizes of the UPV-3 and UPV-5 are 101.57 in x 126.97 in (2580 x 3225 mm) and 113.58 in x 131.30 in (2885 x 3335 mm) with X, Y, and Z axis travels of 14.57 in, 10.63 in, 8.66 in (370, 270, 220 mm) and 21.65 in, 14.57 in, 8.66 in (550, 370, 220 mm) respectively.
INCREASED SPARK CONTROL FOR IMPROVED SURFACE FINISHES
Included in the UPV design are ceramic insulators placed between the worktable and machine casting to reduce stray electric capacitance and enable the SPG II machining circuit to stabilize micro electrical discharges. Utilizing these capabilities under standard machining conditions for a 20 mm (0.79 in) thick work piece measuring up to 100 x 100 mm (3.93 in x 3.93 in) users can achieve 0.2 ?m Rz surface finishes.
The table’s electrically conductive machining area can also be limited for jobs requiring a surface finish better than 0.2 ?m Rz. This further reduces stray electric capacitance for surface finishes down to 0.08 ?m Rz (actual measured value).
In similar performance tests using carbide, the UPV machines performed up to 22 percent faster than water based machines, and up to 78 percent faster than prior oil based technology with good sealed flushing.
ADVANTAGES OF OIL-BASED DIELECTRIC FLUID
The machines’ oil-based dielectric fluid systems create a smaller spark gap between the electrode and work piece than standard water-based fluid systems. This facilitates precision machining of narrower slot widths and smaller corner radii in a variety of materials, including hardened metals and polycrystalline diamond (PCD).
Using oil-based dielectric fluid also eliminates the soft layer that can result from the EDM process and surface corrosion caused by electrolytic action. In long run applications where machined parts remain submerged for extended periods, this can be critical in controlling corrosion or oxidation layers susceptible to these effects.
The UPV’s bed tank system provides enhanced thermal control by circulating temperature controlled dielectric fluid through the machine’s lower castings. Simultaneously, Makino’s machine-temperature control functions adjust air temperatures to that of the dielectric fluid and direct airflow through the machines’ upper castings. Controlling the machines’ cast-iron parts to the same temperature in this way minimizes changes in machine attitude.
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About the Author: John Dymale
