Re: [Emc-users] Metallurgical Advice?

[andy pugh]

On Thu, 29 Jul 2021 at 03:02, Gregg Eshelman via Emc-users
 wrote:
>
> Use Devcon Titanium Putty to bond the crack edges together

I think that it would be best not to put anything in the crack, as
doing so almost guarantees that the edges can't close together to
where they were.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Metallurgical Advice?

[Gregg Eshelman via Emc-users]

How about once the rest of the mill is fixed, drill and tap some holes in edges 
of the table to install a pair of plates to hold the pieces together. Then use 
the router to mill a recess bridging the crack, and an exact fitting splice 
plate, with matching holes for rows of socket head cap screws with their heads 
recessed. Use Devcon Titanium Putty to bond the crack edges together and bed 
the splice plate, and fill the bolt head recesses. Finish off with a full skim 
cut of the table to level it.


   On Wednesday, July 28, 2021, 7:03:29 PM MDT, andy pugh  
wrote:  
 
 On Wed, 28 Jul 2021 at 19:25, Milosz K.  wrote:

> Lock-N-Stitch pins are also another option. Advantage is it's a cold
> process, but it's rather slow.

I forgot to say, this does seem like an avenue worth exploring.
Especially as the part is already conveniently mounted under a router
spindle. The slow, tedious part is suddenly trivial.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912  
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Re: [Emc-users] Metallurgical Advice?

[andy pugh]

On Wed, 28 Jul 2021 at 19:25, Milosz K.  wrote:

> Lock-N-Stitch pins are also another option. Advantage is it's a cold
> process, but it's rather slow.

I forgot to say, this does seem like an avenue worth exploring.
Especially as the part is already conveniently mounted under a router
spindle. The slow, tedious part is suddenly trivial.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Metallurgical Advice?

[Gregg Eshelman via Emc-users]

The table can't be made worse. It needs replaced anyway, but if you can find a 
person who can weld it without warping the alignment of the guides, it would 
save a bunch of money. Some cast aluminum alloys just don't take well to being 
welded. They either resist having the weld metal stick, melt too easily, or 
after bring welded will shrink.
What might work is Muggyweld. There are many videos on youtube showing various 
repairs with it.


   On Wednesday, July 28, 2021, 11:28:00 AM MDT, Todd Zuercher 
 wrote:  
But the biggest problem is that the 5ft by 10ft 1.5inch thick cast aluminum 
table cracked!  It cracked about 2ft in from the front left corner and runs 
about half way across the table in the 5ft direction.  The table is supported 
from below by 10 linear guide blocks on two rails. The crack runs across 
between the 1st and 2nd set of blocks, about 4inches from the 2nd block.

Is there any hope of repairing the table?  Are we going to have to replace the 
whole table?  Could the crack be welded, or is that a bad idea?  My main fear 
is that warpage issues will cause the linear guides to bind.  (The table 
surface can always be re-milled flat.)  The crack isn't gaping or misaligned, 
and the table doesn't "look" warped now that It's cool  
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Re: [Emc-users] Metallurgical Advice?

[Bari]

I'd pull the plate off the machine and weld it. Then mill it flat. It's 
a router, not a mill.


The problem might be finding a local welder and mill that can handle a 
piece that size.  Handling costs can get pricey if you don't have your 
own truck.


On 7/28/21 12:37 PM, andy pugh wrote:

On Wed, 28 Jul 2021 at 18:28, Todd Zuercher  wrote:


Is there any hope of repairing the table?  Are we going to have to replace the 
whole table?  Could the crack be welded, or is that a bad idea?

It's probably a bad idea, but I would think that it is worth at least
a try. You don't have a lot to lose.




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Re: [Emc-users] Metallurgical Advice?

[Gene Heskett]

On Wednesday 28 July 2021 13:57:20 Todd Zuercher wrote:

> Well, we could lose the 20ft long Bosch Rexroth linear rails and
> bearings.  (Which I'm guessing aren't particularly cheap either.)
>
Agreed. So I think I would dismount the table from the bearings and see 
if it could be heli-arc'd, and be prepared to do some shimming as its 
remounted to the bearings. Then once the spindle is back among the 
living, see about machining any warpage back out.

> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street 
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
>
> -Original Message-
> From: andy pugh 
> Sent: Wednesday, July 28, 2021 1:38 PM
> To: Enhanced Machine Controller (EMC)
>  Subject: Re: [Emc-users]
> Metallurgical Advice?
>
> [EXTERNAL EMAIL] Be sure links are safe.
>
> On Wed, 28 Jul 2021 at 18:28, Todd Zuercher  
wrote:
> > Is there any hope of repairing the table?  Are we going to have to
> > replace the whole table?  Could the crack be welded, or is that a
> > bad idea?
>
> It's probably a bad idea, but I would think that it is worth at least
> a try. You don't have a lot to lose.
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912
>
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>


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Re: [Emc-users] Metallurgical Advice?

[andy pugh]

On Wed, 28 Jul 2021 at 19:25, Milosz K.  wrote:
>
> Brazing with Aluminum Bronze would be the preferable alternative to welding.

That's good on cast iron. I don't know that it works on aluminium?

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Metallurgical Advice?

[Milosz K.]

Brazing with Aluminum Bronze would be the preferable alternative to welding.

Lock-N-Stitch pins are also another option. Advantage is it's a cold
process, but it's rather slow.


On Wed, Jul 28, 2021, 1:28 PM Todd Zuercher <

>
> Is there any hope of repairing the table?  Are we going to have to replace
> the whole table?  Could the crack be welded, or is that a bad idea?  My
> main fear is that warpage issues will cause the linear guides to bind.
> (The table surface can always be re-milled flat.)  The crack isn't gaping
> or misaligned, and the table doesn't "look" warped now that It's cool.
>

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Re: [Emc-users] Metallurgical Advice?

[marcus . bowman]

On 2021-07-28 18:25, Todd Zuercher wrote:


Is there any hope of repairing the table?  Are we going to have to
replace the whole table?  Could the crack be welded, or is that a bad
idea?  My main fear is that warpage issues will cause the linear
guides to bind.  (The table surface can always be re-milled flat.)
The crack isn't gaping or misaligned, and the table doesn't "look"
warped now that It's cool.



Todd,

On several occasions in the past I have had to make alterations to large 
aluminium mould tools for vacuum forming.
When parts of the mould have been altered by welding, there can be 
distortion, although I suppose it depends on how the welding is done, 
and on whether the item is pre-heated and then cooled in a controlled 
way after welding (none of which was done by the company who did our 
welding).
I have had much more success when I machined a part (usually a plate or 
a block) which was then attached by bolts to the main mould casting.
If it was my table, I would bolt a thick aluminium plate under the 
crack, using aluminium bolts (specially made, in the case of my moulds) 
or stainless bolts (which work just fine, despite the moulds being 
repeatedly heated and cooled).


Regards,

Marcus


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Re: [Emc-users] Metallurgical Advice?

[Peter Blodow]

Todd, from my experience of the mechanical shop at my company (some time 
ago), where a lot of alu welding was done, a cast alu workpiece must be 
heated to at least 200 to 300 degree Celsius before attempting to weld 
it with a tungsten arc burner. At such a large piece I guess 4-6 men 
with strong torches ar needed to achieve that. You would need 300 to 400 
amperes for the arc and, as a guess, a 5 mm electrode with a rounded 
tip. The crack must be widened before by grinding it out generously. 
Besides, the welder - experienced specialist - will need long arms and a 
good heat protection suit, working so close above a mildly glowing plate 
that size, if I picture the position of the crack correctly from the 
description.


 And there is no guarantee that the crack will be healed permanently 
after cooling. Obviously there was a lot of tension already in the piece 
before, or else it would not have been cracked by the fire. My advice 
ist to forget it and try to get a replacement part. Alu has a good price 
momentarily at the junk dealers. Sorry!


Peter Blodow
Dipl.-Phys.


Am 28.07.2021 um 19:25 schrieb Todd Zuercher:

We had a bit of a disaster last night.  Because of poorly trained, inattentive 
machine operators on 3rd shift, we had a pretty bad fire on one of our CNC 
routers.  The improperly set the depth, then started the machine, turned and 
walked away, then evacuated the building when the fire alarm went off, and 
never even looked at or stopped the machine.  It ran on and burned for more 
than 20 min until the FD showed up.

It burned off all the dust-shroud brushes, the dust collector hose, and the 
vacuum hose to the table.
Not sure if the wiring for the air cylinder sensors for the dust-shroud doors 
will be ok. (They look a little melted)  Or if the air cylinders will still 
work. The lines to them will have to be replaced

The a 10kw HSK63f router spindle is wrecked (doesn't spin free), we'll send it 
out to see if it's rebuildable.

But the biggest problem is that the 5ft by 10ft 1.5inch thick cast aluminum 
table cracked!  It cracked about 2ft in from the front left corner and runs 
about half way across the table in the 5ft direction.  The table is supported 
from below by 10 linear guide blocks on two rails. The crack runs across 
between the 1st and 2nd set of blocks, about 4inches from the 2nd block.

Is there any hope of repairing the table?  Are we going to have to replace the whole 
table?  Could the crack be welded, or is that a bad idea?  My main fear is that warpage 
issues will cause the linear guides to bind.  (The table surface can always be re-milled 
flat.)  The crack isn't gaping or misaligned, and the table doesn't "look" 
warped now that It's cool.

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031


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Re: [Emc-users] Metallurgical Advice?

[Todd Zuercher]

Well, we could lose the 20ft long Bosch Rexroth linear rails and bearings.  
(Which I'm guessing aren't particularly cheap either.)

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street 
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031

-Original Message-
From: andy pugh  
Sent: Wednesday, July 28, 2021 1:38 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Metallurgical Advice?

[EXTERNAL EMAIL] Be sure links are safe.

On Wed, 28 Jul 2021 at 18:28, Todd Zuercher  wrote:

> Is there any hope of repairing the table?  Are we going to have to replace 
> the whole table?  Could the crack be welded, or is that a bad idea?

It's probably a bad idea, but I would think that it is worth at least a try. 
You don't have a lot to lose.

--
atp
"A motorcycle is a bicycle with a pandemonium attachment and is designed for 
the especial use of mechanical geniuses, daredevils and lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Metallurgical Advice?

[andy pugh]

On Wed, 28 Jul 2021 at 18:28, Todd Zuercher  wrote:

> Is there any hope of repairing the table?  Are we going to have to replace 
> the whole table?  Could the crack be welded, or is that a bad idea?

It's probably a bad idea, but I would think that it is worth at least
a try. You don't have a lot to lose.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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