Energy-Efficiency

The coolant pump is the largest energy consumer on a deep hole drilling machine, typically using 60 to 70 percent of the total machine power. I have spent considerable effort optimizing pump energy consumption because the savings add up quickly on machines that run multiple shifts. The key is reducing energy use without affecting the coolant pressure and flow that the drilling process requires. Energy Consumption Baseline Before optimizing, I measure the baseline energy consumption of the coolant pump under different operating conditions. The baseline measurement identifies the largest opportunities for savings. ...

Deep hole drilling machines are not the most energy-intensive machines in a shop, but they use significant power. The main energy consumer is the coolant pump, which runs continuously during the drilling cycle. I’ve found several ways to reduce energy consumption without affecting cycle time or hole quality. I cut my own shop’s energy bill by 18% over two years by implementing the measures described below. Where the Energy Goes On a typical deep hole drilling machine, the energy breakdown looks like this: ...

Running coolant at higher pressure than necessary wastes energy without improving hole quality. I’ve learned to match the coolant pressure to the job requirements and save energy in the process. Pressure Requirements by Process Different deep hole drilling processes need different coolant pressures: Process Typical Pressure Pump Type Flow Rate Energy Consumption (kW) Gun drilling, small diameter (2-8 mm) 1500-3000 psi Positive displacement 2-8 GPM 5-15 kW Gun drilling, large diameter (8-30 mm) 800-1500 psi Positive displacement 8-30 GPM 10-30 kW BTA drilling 200-500 psi Centrifugal or PD 30-100 GPM 7-20 kW Ejector drilling 200-400 psi Centrifugal 20-60 GPM 5-10 kW The pressure requirement depends mainly on the drill diameter and the depth of the hole. Smaller-diameter drills need higher pressure because the coolant passage through the drill is smaller. The flow rate requirement depends more on the hole diameter — larger holes need more coolant volume to flush the chips. ...