De ce nu este suficienta precizia pe o singura axa

Precizia de pozitionare pe o singura axa este adesea primul indicator citat in specificatiile tehnice. Insa in realitatea productiei de precizie, ceea ce conteaza cu adevarat este precizia volumetrica — comportamentul geometriei masinii in intregul spatiu de prelucrare.

Cele 21 de componente de eroare

Orice masina CNC cu 3 axe liniare contine 21 de grade de libertate de eroare:

  • Pe fiecare axa liniara: eroare de pozitionare, 2 erori de rectitudine, eroare de tangaj (pitch), eroare de deviatie laterala (yaw), eroare de ruliu (roll) — 6 componente × 3 axe = 18
  • Erori de perpendicularitate intre axe: XY, XZ, YZ — 3 componente

Rezultate masurate dupa compensare

Eroare diagonala (spatiu 1 metru)

Eroarea diagonala pe un spatiu de 1 metru a fost redusa de la 0,044 mm la 0,010 mm — imbunatatire de 77%.

Circularitate DBB (Double Ball Bar)

In planul XY, cu lungimea sculei de 150 mm:

  • Circularitate: de la 7,3 µm la 4,1 µm (imbunatatire 43%)
  • Eroare de perpendicularitate: de la −6,0 µm la 0,4 µm (imbunatatire 93%)

Precizie la alezare

Eroarea diagonala intre punctele D1 si D3 a fost redusa de la 2,828 µm la 1,626 µm — imbunatatire de 42%.

Aplicatii vizate

  • Prelucrarea camerelor de vid pentru semiconductori
  • Fabricarea matritelor si stantelor
  • Componente aerospatiale de precizie
  • Asamblari mecanice de inalta precizie

Concluzie

Conceptul Micro-Stability Hartford abordeaza precizia CNC la nivel de sistem, compensand simultan toate cele 21 de componente de eroare pentru o geometrie stabila si repetabila in intregul volum de prelucrare.

Why Single-Axis Accuracy Is Not Enough

Single-axis positioning accuracy is often the first indicator cited in machining center specifications. However, in precision production reality, what truly matters is volumetric accuracy — the geometric behavior of the machine throughout the entire machining space.

The 21 Error Components

Any 3-axis CNC machine contains 21 degrees of freedom errors:

  • On each linear axis: positioning error, 2 straightness errors, pitch, yaw, roll — 6 components × 3 axes = 18
  • Squareness errors between axes: XY, XZ, YZ — 3 components

Measured Results After Compensation

Diagonal Error (1-meter space)

Diagonal error over a 1-meter space was reduced from 0.044 mm to 0.010 mm — a 77% improvement.

DBB (Double Ball Bar) Circularity

In the XY plane with 150 mm tool length:

  • Circularity: from 7.3 µm to 4.1 µm (43% improvement)
  • Perpendicularity error: from −6.0 µm to 0.4 µm (93% improvement)

Boring Accuracy

Diagonal dimensional error between D1 and D3 reduced from 2.828 µm to 1.626 µm — 42% improvement.

Target Applications

  • Semiconductor vacuum chamber machining
  • Die and mold manufacturing
  • Precision aerospace components
  • High-precision mechanical assemblies

Conclusion

Hartford's Micro-Stability concept addresses CNC accuracy at system level, simultaneously compensating all 21 error components for stable, repeatable geometry throughout the entire machining volume.