Accutek Balancing Methodology

Accutek's high quality and high precision tool clamping products conform to the latest ISO/DIN balancing specifications. In this section, you will find a copy of an actual balance specification sheet supplied with each Accutek rotating product to show exact balancing dynamics of the product purchased. Before we dive into the specifics of our holder balancing certificate, let's cover some theoretical and practical factors that govern the balancing framework that we follow.

Proven Theory of ISO/DIN 1940-1 and ISO/DIN 1940-2 Balancing specifications

The balance of a rotating tool clamping product is critical to machine spindle wear and cutting tool performance, but how perfect does the balancing need to be? To answer that, we must first look at what imbalance is and how it impacts a holder.

Imbalance – an unbalanced tool holder (one which has its center of mass away from its rotational axis) produces a centrifugal force at the rotation spindle, impeding efficient operation of a cutting tool. Imbalance also has a negative effect on machine spindle bearings lifespan and cutting tool performance. As in the figure above, corrective action of material removal (compensation hole) rebalances the holder and brings the center of mass back in alignment with the rotational axis.

At Accutek, we balance our general purpose holders to a realistic G6.3 @20,000 RPM specification designated by ISO/DIN 1940-2. For most tool holders, any higher degree of balancing is impractical and misleading since the percentage of error increases and the practical application requires re-balancing of every tool assembly to maintain the higher standard. For example, an ER Collet holder balanced to G2.5 will not remain balanced once a retention knob, collet, and cutting tool have been installed. Multiple studies have proven that G2.5 balance levels cannot be maintained on steep taper and HSK taper CNC holders (End mill, Shell mill, ER collet chucks, etc.). The following variances create a high degree of imbalance that makes G2.5 a false rating and misrepresentation of actual repetitive tool assembly balance:

Higher balance rating on AccuGrip Shrink Fit holders and AccuClamp Hydraulic Holders of G2.5 @25,000 RPM is achievable and maintained because there are limited mechanically moving parts to cause variances other than the retention knob. To mitigate any impact of the retention knob installation, all of our holders come with a ground pilot ID for the retention knob pilot location accuracy. Accutek balancing methodology ensures performance balance of G6.3 @ 20,000 RPM on all CNC holders and G2.5 @ 25,000 RPM on all AccuGrip shrink fit and AccuClamp Hydraulic holders. All Accutek rotation products are balanced with certified test gauge pins and collets to maintain a consistent accuracy reading. All rotating products are balanced in an “assembly” mode – meaning gauge pin and lock screw or gauge pin and ER collet with specific torque ratings to provide accurate and consistent measurements in accordance with ISO/DIN 1940-2 specifications.