Overview - VMC - Hydraulic Counterbalance


The counterbalance system uses a hydraulic cylinder and internal piston assembly to support the weight of the spindle head and relieve the load on the axis motor-drive system. The piston is pressurized continuously on one side [2], while the other side is open to the atmosphere. The pressurized side of the cylinder is filled with hydraulic oil from a tank [1] mounted on the column of the machine. The cylinder is fixed to the column casting next to the ballscrew. A bracket [3] attaches the cylinder rod to the spindle head casting .

The hydraulic oil is cycled from the tank [1] to the cylinder [2] when the spindle head moves up [B] and down [A]. As the spindle head is moved to the bottom of travel [A] , the tank pressure increases because the effective volume is decreased as it fills with oil. When the spindle head is moved to the top of travel [B], the tank pressure decreases because the effective volume is increased as it fills with gas.

Be aware: Many service and repair procedures should be done only by authorized personnel. The service technicians at your Haas Factory Outlet (HFO) have the training, experience, and are certified to do these tasks safely and correctly. You should not do machine repair or service procedures unless you are qualified and knowledgeable about the processes.

Danger: Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not completely understand. Contact your Haas Factory Outlet (HFO) and schedule a service technician visit if you have any doubts about doing a procedure.