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The use or the recommendation of balls implies a thorough knowledge of precision criteria for all balls.

These criteria are chiefly :
– Diameter precision (tolerance)
– Sphericity or form defects
– Roughness or surface defects

These criteria are analysed in various standards.

These standards group the various criteria in ‘grades’. Each grade is followed by a number. The lower the value of the number the greater is the precision.
The standard ISO 3290 is the reference internationally. It is chiefly used in Europe.

Les normes sont parfois légèrement différentes selon les zones géographiques. En effet la norme AFBMA est plus présente aux États-Unis et l’ancienne norme DIN est encore utilisée en Allemagne.

However these standards are slightly different according to the geographical zone. The standard AFBMA is more commonly applied in the USA and the old standard DIN is still used in Germany.

The grades in question range from grade 3 to grade 2000. Each grade considers the variation in diameter, errors of sphericity and roughness in the ball and the batch of balls. These variations are imperceptible to the naked eye and only vary by a few microns. CIMAP carries out checks with highly sophisticated equipment in order to guarantee the quality provided.

These tolerances exist as well for plastics even if they are less complex. The grades used for plastic balls are grades 1 and 2. Please contact us if you want more information.

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    Selon NORME ISO 3290 – 2002

    GradeVariation de diamètre d'une bille µm Vdws *Erreur de sphéricité µm *RugositéVariation de diamètre d'un lot de billesIntervalle de classementDispersion des classes recommandéesIntrvalle de sous-classementDispersion des sous-classes
    µm Ra*µm Vdwlµm(sorties) µmµmµm
    * Note: les valeurs données dans ces colonnes ne tiennent pas compte des défauts de surface; en conséquence, les mesurages doivent être effectués en dehors de tels défauts.

    Selon NORME ANSI/AFBMA – 10.1989

    GradeVariation de diamètre d'une bille µm Vdws *Erreur de sphéricité µm *RugositéVariation de diamètre d'un lot de billesTolérance sur le diamètre nominalDispersion autorisée des sortiesIntervalle des sorties
    µm Ra*µm Vdwlµmµm - Δsµm
    30,080,080,0120,13*+/- 0,750,25
    1002,502,500,1255,00+/- 12,50**
    2005,005,000,20010,00+/- 25,00**
    50013,0013,00*25,00+/- 50,00**
    100025,0025,00*50,00+/- 125,00**
    * Ne s’applique pas