A quick write-up from one of our application engineers:
We do simple drilling in most cases. No CNC, no feed calculations, just an air stroked automatic drilling machine with a supplemental hydraulic feed control that is manually adjustable. You look at the chips and determine whether you need to go faster or slower, etc. RPM rates are usually conservative but slightly adjustable. It’s a purpose built machine for most people.
So… I’ve got a return customer who loves our product. We were initially nervous about selling to this guy because of the difficulty of this projects, but it turns out he implemented drill bushings and all other types of stabilization that made it a huge success. …And we were transparent with him about our concerns from day #1 but he admitted that after many calls, we were the people who would actually work with him and provide a custom solution for an affordable cost.
Anyhow… He calls me a few days ago with a new challenge. He needs to drill six holes in one stroke. 7/8″ diameter in ductile cast iron. Nothing fancy, just needs thru holes for mounting a flange-type part.
Problem is, the largest machine I have is a 3 HP unit (sometimes 5 HP on special jobs). It can only create 1000 lbs. of thrust at 100 psi shop air and we really don’t like pushing it with more air because the components inside have not been tested under heaver loads in a production atmosphere. We’ve run as high as 1600 lbs. of thrust for a number of tests, but tests are different than real life, day in and day out use…
So, after the standard “Well, you know we need to really think this through because it’s once again a uniquely challenging application.” statements, we dig into it.
His cycle time isn’t critical but being able to press a button and walk away is.
We came up with a staggered length head design that we believe will work for him. In essence, the machine will only see the load of two holes at a time as the “bits” will pass thru the part before the next two engage, etc.
We are likely quoting a 6″ stroke machine with a full 6″ of hydraulic feed control. Air stroked at 120 PSI shop air. Drill bushings. Guide rods to further stabilize the heavy multispindle drill head (maybe spring loaded to decrease some of the weight load too). ER40 style spindles and collets – maybe ASA. 3 HP with a gear reduction system running around 375 RPM (conservative). Pneumatic stroke controller (FRL, start button, tubes, fittings, starter bottle of oil – Press the button and the drill will stroke forward to a limit switch and then retract and wait for the button to be pressed again.) 3 phase motor – panel and additional controls by the customer.
If he needed a faster cycle time, we would have face mounted the multiple spindle head onto a motor and gear reducer combination and suggested he have someone build him a hydraulic slide mechanism… We’ve done that many times successfully but prefer to avoid making the slides themselves. Those big slide jobs excite me as I really enjoy the larger drilling devices. …But they are rare these days.
…Still working on the details with this customer, but it is just another example of what gets placed in front of us on a daily basis. Cost is still reasonable since there isn’t much customization going on here, just some creativity…
Any random comments, questions or critiques? Give us a call or shoot us an e-mail!