What Makes a Better Presetter?
Start with a cast aluminum base, with the complete casting skin machined away. Then place the x-axis guides as far apart as possible, at least 220mm on the smallest machine, to guarantee rigidity. Build the vertical column with the same concepts, including wide spaced guides. Use three pre-stressed, lubricated recirculating ball bearings on each axis.
Inside the measuring column, Alfa Sys avoids springs for the z-axis counterweight, instead using a steel weight attached with a belt to allow for many years of maintenance-free operation.
To maximize accuracy, the measuring system bracket is machined from a single piece in a single clamping. In addition, the operating handle is removed from the measuring system, to avoid applying force directly to the camera mount. The operating handle itself also includes the unique split break – easily select to release only the X or Y axis (or both) to make it easier to quickly find position.
Each axis also has a manual fine adjustment, making it easy for the operator to perform fully manual measurement. This highly accurate manual measurement system is also used, along with an optional master mandrel, to perform machine calibration (which the user can do themselves in a few minutes, no service call required!).
The Alfa Sys Ball Bearing Sleeve
At the core of the system is the unique Alfa Sys ball bearing sleeve. It is crucial to have an effective interface between each tool holder and the taper pot. While other presetter makers opt for sometimes complex systems with vacuum clamping and full contact tapers, these systems have shortcomings.
The Alfa Sys answer is the ball bearing sleeve. The master seat in the presetter is vacuum hardened, aged stainless steel. Into this seat we place a sleeve holding 320 precision ball bearings, each machined to 0.00025mm accuracy. Contact between tool holder and the presetter is only on these balls, giving high precision while remaining forgiving of dirty or damaged tool holders. The sleeve can even be easily washed if it gets dirty, and can be replaced if damaged. The result is guaranteed runout accuracy ≤ 0.005 mm at 300mm above the gauge line. Typical control values are 0.001 to 0.003mm using a master mandrel.