Image source: Röders GmbH
(CNC-)Precision machining
CNC multi-axis precision machining aims for highly automated and efficient manufacturing of components with dimensional and geometric accuracies of less than 1 micron. The pressure to achieve high surface finishes in the production of optical components is steadily increasing. With Levicron’s spindle solutions, a significant step has been successfully taken toward merging ultraprecision and CNC machining.
Levicron’s Mission
“To make CNC Machine Tools more ultra-precise”
Requirements on the CNC machining centers:
Requirements on precision components with enhanced optical properties:
Ultra-precision qualities in CNC machining with spindle solutions from Levicron
Milling is a machining process that uses one or more defined, rotating cutting edges – typically made of coated tungsten carbide or CBN *). It can be performed as a single-point process (fly-cutting) or with multiple cutting edges. The machine’s path control shapes the workpiece through the rotating tool, removing material.
Grinding is a machining process that uses an undefined cutting edge (grain). The grinding materials are typically made of alumina or CBN *), bound within a ceramic, plastic, or metal matrix.
Grinding tools can eiher be dressable or non-dressable. For non-dressable grinding tools, low tool run-outs and synchronous spindle errors are crucial. In the case of dressable grinding tools, also the asynchronous spindle errors affect shape and surface quality of the machined part.
The most precise process with the longest machining time is polish-grinding.
Turning is a material removal process that uses a defined, stationary cutting edge, typically made from tungsten carbide, CBN *), or diamond.
With synchronized multi-axis movement, non-rotationally symmetric parts can also be produced, where the tool tip is moved along a path (usually continuously). A process where both the tool and the workpiece rotate is referred to as turning-milling.
Other processes: EDM (Electric Discharge Machining) and Laser ablation
*) CBN= Cubic boron nitride
Our recommendations for CNC machining of parts with enhanced optical properties
U/ASD-H25(A)
The reference for the machining of molds for optical components with HSK-E 25 interface
Our U/ASD-H25(A) was designed for extremely low spindle errors in any direction, high stiffness values and exceptional dynamic and thermal stability. It provides you with all the features of a modern tool spindle for CNC machining.
Thanks to our new hybrid bearing technology (porous+jet aerostatic), it gives an outstanding overload and crash safety and can be used with tools of 4 mm in diameter. With speeds of up to 90,000 rpm, dynamic run-out values of less than 1 µm and our springless HSK-E 25 clamping system (SLH25), it is also ideal for micro-machining with very small tools.
U/ASD-H20A
Semiconductor and opto-electronics components machining with speeds of up to 150,000 rpm and automatic HSK-E 20 clamping
Thermal and dynamic stability was the goal. With a dynamic tool run-out of less than 2 micron, a thermal shaft growth of less than 1 micron and a soak-time of only 3 minutes over its entire speed range, we seem to have reached it.
Designed for the semiconductor industry, electronic packaging in particular, our U/ASD-H20A also is very successfully used in applications such as mold machining for bipolar plate molds
(fuel cells), where fine structures in hardened steel are required. It offers increased productivity and reduced tool wear at high speeds.
Selected references
