Horizontal Boring Mill Installed Too High

[Zorndyke]

Hello Everyone,

How are you all today? Hopefully you’re not caught up in any winter storms.

I’ve used this site all through college to find solutions to problems but never had an issue serious enough to post for help. Now I’m an engineer at an Army depot and a problem has come up that is worthy of a post. I searched this section of the forum before posting so I’m pretty sure this question has not been asked before.

Here’s the rub: we have just installed a gigantic horizontal boring mill here from a company called World Machinery Works (model: BP150). The issue is that the spindle stops about 22 inches off the table when the machinists need closer to 6 inches(yes, somebody goofed). Ripping out the machine and busting up the monolithic pit foundation to lower the entire machine is a major problem and the production guys say stacking another table on the original one and bolting it down is not what they want (though this seems like the easiest fix). The other option is to prop all work pieces up on stand offs they call v-blocks. But doing this would have tall work pieces far in the air and chatter/vibration would hurt milling accuracy. There seems to be no easy fix for this issue as far as anyone could see.

I brainstormed and wondered if any 90 degree spindle transmission/gearbox attachments existed that could effectively lower the cutting head without changing the table or touching the pit. Obviously doing that would have some implications, primarily the moment generated on the original axis as the spindle bits into the work piece at the new lower axis. This was the only thing I could come up with and I know it’s a pretty silly idea.

Does anyone have any better ideas I’m just not seeing here?

Any help would be appreciated.

Thanks.

 

[MikeHalloran]

The 'errant' dimension suggests presence of a robust spindle drive. That's not a bad thing, in the larger picture. The machine is not a toy, so it may be inconvenient for hobby jobs or 'government work'.

To me, the extra vertical distance suggests that the machine was designed for palletized workpieces, where you set up the workpieces at separate simplified workstations that support the pallet but don't have a spindle, and just shuffle the pallets in and out while you load the appropriate CNC programs.

It's an opportunity to maximize the machine's uptime. Instead of wasting all kinds of time stacking shims under v-blocks to hold your workpieces with the machine not running, design a standard pallet (you can probably buy them, but it's an opportunity to have exactly what you want), and produce two to get started. That way, you can be machining one part, or several, if the pallet carries multiple workpieces, and setting up the next job while the machine is still running.

Then you just swap the pallets, and that's your only real downtime.
The Japanese can swap huge stamping dies in less than five minutes. Read up on how they do it.




Mike Halloran
Pembroke Pines, FL, USA

 

[racookpe1978]

Yes, I'd definitely go that route: Make sure the "pallets" are tough enough ("soft" carbon steel) but rigid as an assembly so they are cheap to build and weld up, but will not chatter while absorbing the movement from the machining thrusts and impacts from each tooth. the cover should have east-west and north-south T-slots compatible with the ones on the machine to let you bolt down the different parts to the table.

 

[BillPSU]

Your solution depends on what equipment is on the machine currently. I looked up other BP150 machines and it appears it is a traveling column machine with about 20 feet of X axis travel and 10 feet of Y axis travel.

The current table on the machine does it have indexing capabilities or is it a stationary table? If it is a stationary table the additional height would be used to mount an index/rotary table.

The next question is about the type of work you will be machining. Is there going to be a large amount of milling or are you typically using the machine to bore holes in welded structures. Large weldments require lots of experience of how not to distort the parts and position the parts with adequate material for machining.

If there is little experience of machining large components you will quickly learn what works and what doesn't. Shuttle tables has the possibility of increasing productivity but having the infra-structure to support the machine will also have to be reviewed.

Good Luck
Bill

 

[KENAT]

"chatter/vibration would hurt milling accuracy"

Some materials used for machine beds have some damping characteristics, maybe you can come up with some type of pallet as others suggest that essentially emulates or allows more robust mounting of the V blocks and helps manage the vibration.

Cast gray Iron and polymer concrete are 2 materials that spring to mind.

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[capnhook]

Off by 14 inches, eh? Not bad, for government work..!

Yer tax dollars, hard at work....

Proud Member of the Reality-Based Community..

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