Another Recent Application - And more ON TOPIC metalworking content

So I promised to post some of our challenges here...

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?

Reply to
Joe AutoDrill
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As a quick side note, you guys have inspired me to post some of these on the web site... If you enjoy them, I presume site surfers will as well!

This one got stuck here:

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Reply to
Joe AutoDrill

It sounds like a good way to use the available thrust and horsepower, but I'd like to know where the guide rods are -- what it is they guide.

Reply to
Ed Huntress

The guide rods will likely be outboard of the head's standard housing. They will simply solidify the set-up a bit. Because the customer is using drill bushings, we don't need four and can get away with using only two. They are mostly there as cheap insurance and to offer a way to mount balancing springs if desired / needed.

The pneumatic stroking machine itself has two guide rods already so as I said, it's just cheap, removable insurance.

In a situation like this, I'll likely anchor them to the head with set screws for easy removal. They will then extend back and away from the part to guide rod blocks on the customer's dedicated fixture.

Here is a four spindle set-up (for tapping - slightly different) that uses the same basic idea:

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In that photo, the springs are actually installed incorrectly by a shop guy. I told him I wanted a photo for the files and he assembled it quickly just for the photo. I snapped this just before it was corrected, set-up to look a bit more "pretty" and properly photographed, etc.

Here is a photo of a rather large ER32 style head that went on a huge drill press at a foundry. The guide rods in this case where larger diameter, anchored elsewhere and in a pattern the customer specified.

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The way I look at these types of options is this... You are spending lots of time and money on a dedicated fixture, industrial electrician and EPanel, etc. My stuff is relatively affordable and an option like this is extremely affordable in the big picture. If it adds a few more percentage points to the "likelihood of total and joyful success" rate, then I'll offer it.

The worst possible thing I could ever do to someone is tell them to wait

4-5 weeks for a custom machine that is needed in 5-6 weeks - and then deliver a non-working machine. That would put me out of business overnight.

I tell folks, "I would like to visit your town on vacation, not to fix my drill. If I sell this, it will work."

Reply to
Joe AutoDrill

Aha. I gather that, in regard to the present job, the idea is just to assure the bits will enter the bushings without clanging against the top openings.

Is the customer planning to use a conventional drill jig?

Reply to
Ed Huntress

Sort of... The platform that drives the heads is stable enough to keep that from happening normally. Without drill bushings, it's to help control vibration and hole location a bit - with "a bit" being the operative words but no pun intended.

With rigid tooling, making a hole in a round pipe is still a challenge. Drill bushings are the #1 solution. Very short tooling and as much stabilization of the driver is #2...

You know, I wish I could answer that. We hear so very little from customers post-implementation that I'm not sure how he is setting that up - or has set it up in the past for that matter...

I presume that because it is a fixed, dedicated set-up that the drill bushing plate will have renewable inserts and be anchored to the work surface somehow. ...He may not ever retract the tooling 100% out of the bushing for all I know...

Reply to
Joe AutoDrill

Or..he could do it like they did it in the old days. Put the part on a spndle mounted on a solid base..put a drill press in line to drill the holes, where it rotates to the next and the next..and on t he other side..a tapping head comes down and taps the part.

Use a double unit and spin the part under them. Now you are only drilling/tapping 2 holes at a time, but very rapidly.

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013

Reply to
Gunner Asch

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Just out of curiosity -- is he going to be using split-point drills? He should, as they should reduce the thrust needed significantly.

Enjoy, DoN.

Reply to
DoN. Nichols

Indeed they will!

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013

Reply to
Gunner Asch

On larger diameter tooling, I always suggest a split point tool - or even single step tooling at times. At this point, I'm not sure what he has chosen though.

Reply to
Joe AutoDrill

With ductile iron, machineability depends heavily on hardness (this sounds like a soft casting, though) and the level of free, dispersed carbides. Trying to get too delicate with drill bits is not likely to give good results. Something like a Racon point may be the trick, but I'm sure there is experience-based data on drilling the stuff, which is a lot better than guessing.

Reply to
Ed Huntress

The guy is making thru holes which will then be manually cut into slots in a future operation. I doubt "good results" for this particular customer actually has much more meaning than "a hole in roughly the right place" but I still need the stability for the machine as we build for thrust, but side load.

Reply to
Joe AutoDrill

Hmm. It sounds like an interesting workpiece. Do you know what it's for?

I don't know if you caught this, but I'm now chief editor of Fab Shop Magazine Direct. Any fabrication jobs you encounter could be interesting to me -- and with possible promotion value for you.

Reply to
Ed Huntress

In this case, I'm quoting the company that casts the part and then does quick prep work for the end user.

I can guess at the end user by data on the drawing, but I don't have definite info on what - or really who might be ultimately using it at the end of the story. I can tell it gets epoxy coated and that the name of the next user looks to be water-oriented... But that's about it.

I didn't catch that. Now I have to be nice to you!

I hope you are enjoying it.

I would always need to clear any really detailed release of data with the customer, but we are working with a few folks that might be interesting to you and your readers. ...Especially a certain electric car company that really turns heads. I'll reach out and see if they might want to share stuff (we signed an NDA) for some possible publicity.

Of course you can shoot me a message here or privately if something pops up that looks like it might fit a desire / need you have.

...This could be fun.

Reply to
Joe AutoDrill

I've read all the responses so far and I'm surprised that nobody mentioned using core drills to reduce HP HP and pressure requirements. Of course, I don't know the ups and downs of it, I just came to mind.

I'll have to send you a pic of a "multi-drilling machine" we put together to drill two screw pilot holes in a block. I took a small B&D hobby drill press and bolted a Harbor Freight 3/8" $20 hand drill on the side. Truly inspired!

Reply to
Tom Gardner

How does one determine clearance for drill bushings?

Reply to
Tom Gardner

Fantastic point! Annular cutters or core drills are great! I could perform the entire process with less stroke, etc. The only problem is the "plug" of material that sometimes remains in the center of the tooling regardless of how fancy of an ejection spring or system is used.

With a core drill, the customer would also have to stop the motor after each "stroke" to check for the plugs. With standard tooling, they can turn the motor on at 8 AM and off at lunch, then repeat at 1 PM until closing time, etc.

The start-up loads sometimes cause companies to pay extra so many prefer to simply run the machines constantly during a shift if it's a production job.

Hey... If it worked for the job, then it's perfect, right?

I have a customer who has 12 Dewalt hand drills tie strapped to a bar of some sort. They stroke it *manually* down into their wood part to create a line of holes. He replaces at least one drill a week.

I could sell him a device to do it, but he doesn't have the volume to justify a larger, bigger ticket purchase for that specific application.

It's not like a 12 spindle fixed pattern head with 7" spacing could be re-used for much else...

Reply to
Joe AutoDrill

Depends on the application.

If the device is a single drill, then the bushings can be tighter tolerances.

If the device is 36" long, has an expected growth pattern of a few thousandths+ due to thermal expansion during use, then it's a whole new ball game.

...then you have to worry about whether the head is aluminum or steel, whether the bushing plate is the same material or different, whether you can sufficiently cool the device to control growth or manage it in another manner, etc.

Reply to
Joe AutoDrill

LOL, reminds me of some of the things we did at my previous employer. Was always fun rejecting offers of extended warranties (never mind that retail warranties often exclude industrial use...) by explaining just how I was going to modify what ever tool I was buying that day.

Reply to
William Bagwell

Nah. Just get me a good story that will interest our readers, and you can swear at me all you want. d8-)

Very much. I've been freelancing for a few years and I didn't realize how much I missed being in charge of the editorial. I closed my first issue yesterday; it will appear Sept. 6th or 7th. Here are some old ones:

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The search box is at the bottom of the page. I'd like to move that to the top. The issues are pretty much independent entitities but the search engine spans all of them.

Ok. You can see what we cover from the link above. It's laser, plasma, waterjet and punch-press cutting; welding and other assembly; sawing, fabrication-related drilling; bending; shearing; stamping; related software; and so on. Anything you'd find in a fab shop. I imagine some of your customers are drilling parts for fabrication-shop assembly.

Also, I wrote a roundup for them last year on multi-function chip-making machines, and we're finding that fab shops are interested in those machines for a variety of value-added jobs.

You can bet on it.

It is. It beats the heck out of work. d8-)

Reply to
Ed Huntress

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