In robot development, many engineers encounter this dilemma: even though the hole diameters and dimensions of parts are within tolerance, assembly of joints or reducers results in jamming or abnormal noise. This is often due to the failure of positional tolerances (such as position, concentricity, and perpendicularity) of the parts.
How to maintain stable positional accuracy in the machining of small batches of complex, non-standard parts? Based on years of experience in robot parts machining, we break down the three core logics for ensuring tolerances.
I. Tooling and Fixtures: The Foundation of Positional Tolerances
“Tooling determines accuracy, machine tools guarantee dimensions.” For precision non-standard parts, fixtures are not only for fixing parts, but also for establishing a stable reference datum.
Eliminating Repeated Positioning Errors: Kzron prioritizes the design of dedicated flexible tooling for core robot components, using high-precision reference pins or V-shaped positioning to ensure positioning accuracy within 0.005mm during multiple reversal machining operations.
Stress-Balanced Clamping: For thin-walled shells, we use full-circumference enveloping soft jaws or vacuum adsorption to prevent uneven clamping forces from causing positional “rebound” after unloading.
II. Secondary Alignment Logic: Precise Alignment Through Online Probe
When parts need to be transferred between different machine tools or multiple clamping operations, “alignment” is the last line of defense to ensure positional accuracy.
Online Probe System: At Kzron’s precision production lines, we widely use Renishaw online probes. “Secondary alignment” of the datum surface is performed before finishing, automatically compensating the coordinate system.
Datum Unification Principle: Regardless of the number of features being machined, the same original datum surface is always used for alignment, completely avoiding dimensional chain errors caused by datum overlap.
III. Process Scheduling: The “Dimensional Reduction” of Five-Axis Linkage
The most effective way to control positional tolerances is to reduce the number of clamping operations.
Advantages of Five-Axis Linkage: Robot joint housings often have holes and slots at multiple angles. Kzron utilizes imported five-axis machining centers to complete the machining of multiple angle surfaces and holes in a single clamping operation.
Thermal Balance Control: We insist on performing precision machining in a temperature-controlled workshop to prevent positional deviations caused by machine tool spindle temperature rise and part thermal expansion, ensuring that the finished product tolerance is consistently controlled within ±0.005mm.
IV. Selection Reference: Comparison of Position Tolerance Control Solutions Ensuring positional tolerance is a systematic project involving fixture mechanics, detection logic, and machine tool kinematics. Kzron consistently adheres to stringent R&D requirements, deeply cultivating precision parts machining and solving the problem of “positional accuracy loss of control” through technological innovation. If you have high-precision small-batch/product prototyping needs, please contact us and experience our worry-free “one-time assembly success” service.
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