A large automaker used Mapal's HFS toolholder to increase tool life for reaming connecting rods.
A new toolholder, which consists of only a head, holder, and differential screw, reportedly increases tool life, improves accuracy, and delivers higher speeds and feeds than conventional taper-flange-style toolholders. The Head Fitting System (HFS) uses the screw to draw in the taper to make face contact, providing exceptionally low runout.
According to manufacturer Mapal, Piscataway, N.Y., the toolholder helped a large automotive manufacturer extend tool life 5 in an application calling for the reaming of connecting rods made of C 70 carbon steel. The end user previously employed taper-flange-style toolholders that maintained the cutting load on just a few teeth, which caused excessive runout. The HFS holders, on the other hand, evened out wear over all of the reamer's teeth, increasing tool life from 2,000 to 10,000 bores.
In addition to extending tool life, the company also boosted concentricity and changeover accuracy to less than 3 µ and slashed machining time 15%. Reportedly, the new toolholding system is also much easier and faster to change.
The tapered-flange holders used before were often jammed together by cutting forces, making them difficult to remove. In many cases, the automaker had to take the holders off the machine and use a special fixture to change the reamer head. A defined release force in the HFS makes it easy to remove the tool. Users simply turn the tool-locking screw in the opposite direction. Now, the automaker changes the reamer head without removing it from the machine.
