Cycle-Time

I have spent the better part of my career watching shops try to force job-shop workflows into production environments, and it almost never ends well. High-volume deep hole drilling is not just job-shop work done faster. The entire process architecture changes. When you are running thousands of parts a month instead of a handful of prototypes, every minute of downtime, every inconsistent tool change, every coolant fluctuation multiplies into real cost. Over the last decade, I have designed, tuned, and occasionally had to rescue production cells across automotive, hydraulic component, and aerospace fastener lines. Here is what I have learned about making deep hole drilling work at volume. ...

Cycle time reduction in deep hole drilling is a balancing act between speed and reliability. I have reduced cycle times by 30-40% on some jobs without degrading hole quality, but pushing too hard causes tool breakage and scrap. The key is knowing which parameters to change and in what order. Problem Description Deep hole drilling is inherently slow compared to conventional drilling. The depth-to-diameter ratio limits the feed rate, the peck cycle adds retract time, and the need for chip evacuation constrains the speed. The challenge is reducing the time per hole without causing chip blockages, tool breakage, or surface finish defects. ...

Estimating cycle time for deep hole drilling is straightforward if you break it into parts. I have been quoting jobs for over a decade, and the formula below has served me well across gun drilling, BTA, and ejector drilling. The total cycle time determines whether a job is profitable. Miss it by 20% and you either lose the quote or lose money on every part. Here is how I calculate it. ...

The Basic Calculation Penetration rate is the speed at which the drill advances into the material, expressed in mm per minute. The formula is straightforward and I use it on every job: Penetration rate (mm/min) = Feed rate (mm/rev) x Spindle speed (RPM) For a 10mm gun drill running at 2500 RPM with a feed of 0.04 mm/rev: 0.04 x 2500 = 100 mm/min To estimate the drilling time for a 500mm deep hole: 500mm / 100 mm/min = 5 minutes of actual cutting time ...