Hydraulics

Excavator boom cylinders are among the largest hydraulic cylinders I work on. A cylinder for a 30-ton excavator might have a 160mm bore through 2.5 meters of barrel. The rod is typically 100mm diameter with a 40mm through-hole for weight reduction. These cylinders operate at 300-400 bar and see heavy shock loading. I have drilled cylinders for excavators ranging from 5-ton mini excavators up to 120-ton mining-class machines, and the scaling laws for drilling parameters are not linear. ...

The Unique Demands of Agricultural Hydraulic Cylinders Agricultural equipment uses large hydraulic cylinders for tractors, combines, and loaders. A typical cylinder might have a 150mm bore through 2 meters of barrel. BTA drilling is the standard method for these large diameters because single-lip gun drills cannot handle the material removal rate required for production efficiency. I have set up BTA drilling cells for three different agricultural equipment manufacturers, and each one had slightly different requirements based on their cylinder designs. ...

Agricultural and forestry equipment is a steady market for deep hole drilling. Tractors, harvesters, loaders, and loggers all use hydraulic cylinders for their working functions. Every cylinder needs a drilled bore, and every rod needs a drilled hole if it’s hollow for weight reduction. I’ve worked on components for several agricultural and forestry equipment manufacturers. The work is similar to construction equipment but with some differences in volume and pricing. ...

Construction and mining equipment is one of the biggest markets for deep hole drilling, even though most people do not think of it that way. Every hydraulic excavator, bulldozer, dump truck, and drill rig has cylinders that need deep drilled bores. The volumes are higher than aerospace, and the parts are bigger than automotive. I have worked on cylinders for excavators, loaders, and mining trucks. The work has its own character. ...

Seals in a deep hole drilling machine don’t get much attention — until they start leaking. Then they stop production and cost time and money to replace. I’ve dealt with seal failures on both gun drilling and BTA machines. The symptoms range from annoying drips to complete coolant system failure. Where Seals Are Used Deep hole drilling machines have seals at several points: Rotating coolant union. Where the coolant transfers from the stationary supply line to the rotating spindle. This is the most common seal failure point. Drill tube connection. Where the drill tube connects to the spindle. The seal here prevents high-pressure coolant from leaking around the connection. Pressure head. Where the coolant enters the bore at the workpiece entry. The pressure head seal contains the coolant and directs it into the bore. Cylinder seals. On machines with hydraulic feed systems, the cylinder seals keep the hydraulic fluid contained. Each of these seals operates under different conditions — pressure, speed, and temperature vary depending on the location. ...